Liber Amicorum Prof. Dr. Ir. R.A.A. Oldeman

25 Jaar een ”Boom der vrijheid” Liber Amicorum Prof Dr Ir R.A.A. Oldeman

Edited by Hans Vester, Paul Romeijn and Hans van der Wal

Treemail publishers Heelsum, The Netherlands Treebook 8 October 2004, ISBN 90-804443-9-1 Treemail Publishers, Heelsum, The Netherlands

Earlier in the series:

Treebook 1: Struggle of Life: or the natural history of stress and adaptation. Martial and Line Rossignol, Roelof A. A. Oldeman and Soraya Benzine-Tizroutine; 1998.

Treebook 2: Green Gold: on variations of truth in plantation forestry. Paul Romeijn; 1999.

Treebook 3: Chinantec shifting cultivation: InTERAcTIVE landuse. A case-study in the Chinantla, Mexico, on secondary vegetation, soils and crop performance under indigenous shifting cultivation. Hans van der Wal; 1999.

Treebook 4: An exploratory study to improve the predictive capacity of the Crop Growth Monitoring System as applied by the European Commission. Iwan Supit; 2000.

Treebook 5: Five thousand years of sustainability? A case study on Gedeo land use (Southern Ethiopia). Tadesse Kippie; 2002.

Treebook 6: Let them eat grass: Understanding pasture-finished beef cattle farms in the American Appalachians. Jane Shaw; 2002.

Treebook 7: Updated system description of the WOFOST crop growth simulation model as implemented in the Crop Growth Monitoring System applied by the European Commission. Supit, I.; Van der Goot, E.; Editors; January 2003.

© 2004, Copyright by Treemail. All rights reserved. No part of these materials may be reproduced, or stored in a retrieval system, or transmitted, in any form, or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner.

Treebooks are freebooks. They are published by Treemail according to the criteria of free, independent, original thinking and high quality warranted by the scientific performance of its authors. www.treemail.nl/books Thanks!

This collection of papers, essays, letters, poem and a song was the result of a spontaneous reaction to a letter we sent to a list of ex alumni, colleagues and friends of “our Prof” saying: Dear friends,

Prof. Roelof Oldeman will retire this year. During his 25 years of professorship (1977 in Montpellier; 1978-2002 in Wageningen), participation in workshops, symposia, courses and publications, he has influenced the thinking of many students and scholars in the field of forestry and ecology. His theoretical contributions are reflected in a great number of concepts and principles presented in a stimulating style that invites to think across disciplinary borders, integrating knowledge of varying areas in an explicit holistic picture.

We feel that it is appropriate and desirable to recognize work of this standing and to let Prof. Oldeman know that his contributions, pioneering role and integrity have been appreciated. We are sure that many people want to say “thank you, Prof. Oldeman, for what you have daringly done”. We propose to do this by means of original essays or graphic work reflecting his work in today’s undertakings of you, former students and colleagues in different parts of the world.

In the coming months your contributions will be integrated in a book in the form of a “liber amicorum”, which will be handed over to Prof. Oldeman at the occasion of his retirement.

As you are a special person to Prof. Oldeman, we invite you, ex- student, colleague or ex-colleague to participate and to write and send us an essay before the first of August (details are specified below) that somehow reflects Prof Oldeman´s contributions to your own work, and/or to contribute to the printing of this work through a gift of 100 euro. […]

We did as little editing as possible in order to maintain spontaneity and originality. There was no such thing as a peer review! A very preliminary version of the texts was presented with heart warming results on the day of Prof. Oldeman’s retirement. Since then some more contributions were received and included. We thank all contributors, and greatly appreciate Sofia Carballo for her excelent job in organizing the text and the figures and giving this liber amicorum its layout. The editors who gave permission to use copyrighted figures are acknowledged in the separate texts.

Chetumal, Campeche, Wageningen, September 26, 2003

Hans Vester Hans van der Wal Paul Romeijn 4 Preface Professor Roelof A.A. Oldeman: From Roots to Canopy

In the summer of 1985, I met Professor Oldeman for the first time. As a newly appointed professor of ecology at the University of Nijmegen, I intended to carry out research into the adaptive responses of plants growing under flooded conditions. In waterlogged soil, it is the roots of the plants that first experience flooding conditions, and I was interested in studying root systems of plants growing in flooded soils. I had read about Professor Oldeman and his team, who were able to study roots growing under natural conditions at the Agricultural University of Wageningen.

I clearly remember our first meeting. An impressive man dressed in a three-piece suit, Professor Oldeman was sitting behind a heavily laden desk, smoking a pleasantly aromatic pipe. I told him the purpose of my visit, and it was at that moment that he became my teacher. With great enthusiasm he invited me to the greenhouses of his institute at Wageningen, where he showed me his root boxes in which saplings of various tropical trees were growing. His stimulating explanation of experimentally perforated soil systems, and the opportunity to observe the growth of tiny roots by means of an intrascope, formed the starting point of our sustainable collaboration. In fact, I myself experienced only a mere glimmer of his teaching capacities. One meeting is all it takes for Professor Oldeman to impress his audience with his willingness to share his knowledge about all aspects of tropical forests. Professor Oldeman is a marvellous teacher, expertly guiding his students to their Master’s or Doctor’s degrees. Many of our meetings took place at his home, mostly in his beautiful garden. The hospitality of his wife Wil was heart-warming. Her fortifying cups of tea accompanied by pastries, cakes and tarts, transformed many discussions and exhausting debates into joyful gatherings.

Professor Oldeman studied tropical silviculture at Wageningen University, after which he went on to Montpellier, France to work on his doctoral thesis. In 1972, he passed his examinations with the highest honours. He then became Docteur des Sciences Naturelles, which entailed a research period of seven years. As early as 1977, he was appointed full professor of silviculture at Wageningen University. In 1986, his professorship was extended to silviculture and forest ecology. He specialised in research on tropical rain forest ecology, and has been a member of many advisory boards all over the world. He was the founder and chief of the Forest Botany Section of the Office de la Recherche Scientifique et Technique Outre-Mer in French Guyana, and served as Maître de Recherches Principal at that office. He was also appointed Professeur associé en Ecologie forestière tropicale at Montpellier University. He has travelled around the globe studying tropical forests, teaching, and giving seminars, and he has been invited to appear as the keynote speaker at numerous congresses and symposia. He has organised many workshops and is able to translate complicated scientific theories on tropical systems, for example the architecture of trees in rain forests, into fascinating stories that a lay audience can understand. He has also appeared in television programmes on ecology, natural habitats, nature conservation, and popular science. All in all, Professor Oldeman has become a very respected and distinguished guest at many meetings where questions about processes in (sub-)tropical areas are discussed.

PhD students from all over the world have been supervised by Professor Oldeman. Many of his students come from Indonesia, a country that has his special interest. His laboratory became a melting pot of pupils from a variety of ethnic backgrounds. He speaks six languages fluently and manages to make himself understood in many others. This, together with his wife’s open-hearted hospitality, makes the students feel at home when they study in his laboratory.

5 Professor Oldeman’s work on tropical forest canopy is famous all over the world. He has studied the architecture and inhabitants of this ecosystem, with special emphasis on the phyllosphere. His publications on this environment, in which he describes the occurring epiphytes and Arthropods, are among the most frequently cited papers in the literature on tropical systems. In 1989, Professor Oldeman was the initiator and one of the founders of the Tropical Rain Forest Canopy Foundation (Stichting Het Kronendak). He serves as the chairman of this foundation, which aims to support the study of the ecological processes occurring at the tops of trees in the tropical rain forest. The Foundation is also responsible for securing funds for continuing research into these ecosystems, and for canopy farming using sustainable methods. Professor Oldeman has succeeded in building a strong organisation. He chairs the foundation with the great enthusiasm and expert knowledge that are so typical of him. Without a doubt, Professor Oldeman is an excellent scholar who possesses an admirable personality that stimulates so many scientists all over the world. His work has proved to be very important for tropical silviculture, canopy studies, and ecology in general. The scientific community all over the world is forever in his debt.

Prof. Dr. C.W.P.M. Blom Rector Magnificus Radboud University Nijmegen The Netherlands

6 Roel-lof

Willem Beekman schrijver, bioloog, voormalig medewerker Vakgroep Ecologische Landbouw, 1990 – 2000. Hoveniersweg 69, 4001 HS Tiel

Niemand draagt zijn titel van professor met meer waardigheid dan Oldeman. Het eenvoudig uitspreken van zijn voornaam, zo makkelijk gedaan bij politici en schrijvers, kost mij meer dan normale moeite. Ik heb zelfs dagenlang moeten oefenen in het zeggen van die naam, zij het in de besloten intimiteit van mijn eigen werkkamer. Eenmaal daarbuiten leek Roelof niet meer te bestaan, alsof hij nooit een voornaam had. Ik betwijfel zelfs of zijn ouders hem wel een voornaam hebben gegeven en ik sluit niet uit, dat de naam Roelof pas later tijdens zijn leven is ontstaan, meer bij wijze van grap van medestudenten dan als een serieuze eigennaam. Oldeman is de beste omschrijving voor Oldeman.

Grote bewondering had ik, tijdens onze gezamenlijke periode bij de Vakgroep Ecologische Landbouw, voor zijn consequente wijze van aanspreken van collega’s, zonder spoor van twijfel of de geringste blijken van onzekerheid. In vergaderingen sprak hij zijn collega hoogleraar (in dit geval Eric Goewie) steevast aan met professor, in de wandelgangen was het tussen hen gewoon Eric en Roelof. Het onderscheid tussen de dragers van de professortitel en de anderen is bij Oldeman tot in zijn fysieke gestalte gestold. Hij kijkt eenvoudigweg anders naar de onderscheiden categorieën. Niettemin is hij voor een ieder even beleefd, vriendelijk en behulpzaam. Je bent in eerste instantie medemens en pas in tweede een titeldrager of functionaris. Die scherpte van onderscheid heb ik nooit bij anderen mogen ontdekken en ik meen dan ook dat Oldeman hierin op eenzame hoogte staat.

Eenzelfde hoogte die hem ook ten deel is gevallen in zijn academische werk. Het simpele feit dat hij het kronendak van tropische bossen opzocht symboliseert de innerlijke hoogte waarop hij zich bevindt. Des te opmerkelijker is dan ook zijn sterke geworteldheid. Hij staat als een huis en weet op die manier zowel de aarde als de hemel met elkaar te verenigen. Die kosmische omvattendheid van zijn instelling en werk maakt hem tot een witte raaf in de academische wereld, die in toenemende mate wordt bevolkt door specialisten en tunneldenkers die de veiligheid zoeken van het beperkte gelijk.

Oldeman heeft geen last van beperkingen. Zijn gelijk is dat van de pionier en ontdekkingsreiziger: groot door zijn daden. De brede penseelstreek is hem vertrouwder dan het minutieuze craquelé van het glazuur. Zijn theekopje kan een oceaan bevatten en dan is het ongepast om te verdwalen in details. Hierin zie ik ook zijn voorkeur voor citaten uit de wereldliteratuur, die hij onvermoeibaar verzamelt. Met citaten draag je bij aan de sfeervolle ondersteuning van een betoog, niet aan het bewijzen ervan. Die sfeer nu, dat nauwelijks merkbare fluïdum, is voor mij de betovering van Oldeman en reden waarom ik graag in zijn gezelschap vertoefde. Zijn gedachten dragen ver en hoe heerlijk is het om op zijn draaggolf mee te bewegen naar de weidse horizonten die hij weet op te roepen.

Waarde Oldeman, bedankt voor die inspiratie!

7 Professor Oldeman, a Master

Denise Bittencourt Amador Fazenda São Luiz, São Joaquim da Barra, SP, Brazil www.fazendasaoluiz.com

Much more than a teacher... he’s a Master. The one who teaches us to observe, to see the world, to appreciate and to love. He’s a poet and a scientist at the same time and that’s what makes a big difference. He has a modern mind with all the old culture.

Oldeman is a friend always ready to help and to open the pathways for whoever looks for him with a good intention.

His deep love for the plants and the forests guides his students to learn using the eyes of the heart. This is his best lesson and what makes him this wonderful and unique professional.

Prof. Oldeman is a teacher that really likes to teach and to share his feelings and observations about each situation. We become able to look at the ecosystems and all the links inside it clearly, understanding the mean- ings and the patterns. Mr. Oldeman leads us from the “micro to the macro” passing through all the scales we can imagine discovering the role and meaning of the existence of each individual into the hole big house. Our common house. From the canopy microscopic fungi to “Gaia”...

The first time I met Prof. Oldeman was a big gift for me. I had the opportunity to meet my bibliographic reference! Someone for whom I had already deep admiration and respect being one of the best forest researchers in the world. At that time, Oldeman was so pleasant, he surprised us for his simplicity. He showed us his Lab, gave us some of his articles, took us to know Wageningen and told us good stories. Besides that, he was very interested in our work in Brazil. At some point that day he told me something that changed my young scientific mind:

“Tell Prof. Virgilio Viana we cannot use the classic statistics to evaluate agroforestry or complex ecosystems. We’ve got to find other evaluation methods”.

At that time I was seriously questioning the efficiency of conventional statistics on complex systems. I finally found an accomplice, a master saying something that I really believed.

After that I had a precious opportunity to have Prof. Oldeman for 15 days with us at the farm where I live, leading a course called “Ecosystems ecological management and sustainable development”. He gave many ideas for the landscape, the forests and for our lives; shared his knowledge about tropical forests, forests dynamics, plants architecture, agroforestry, and much more. All the members of the group learned a lot. It was unforget- table for all of us.

Prof. Oldeman participated on my master science thesis “qualification”, giving many good ideas, counsels, references and constructive comments. It was an honor for me, and a precious collaboration to the work.

It’s so good to remember all these facts and feel that Prof. Oldeman is very important for me. He was a master that life put me to meet. And as we both are Virgo and have some similarities, we identify some attitude in one another and laugh about that. Another thing I could not leave out is to mention his deep and sacred love for his wife (who I haven’t had the pleasure to meet yet) that makes everyone appreciate his careness and dedication.

8 Beautiful!

After all this admiration and love for this man, it’s very good to have a dutch friend. We live in such different parts of the world and we can exchange our points of view and help to create a real link contributing to peace and love around the world. Professor Oldeman is always young in his dreams and in our friendship.

Thank you Professor Oldeman, for everything you’ve done for us, your pupils all around the world;

Thank you for everything you’ve done for the tropical forests of the Mother Earth;

Thank you for being this inspiration source for all human beings.

Receive your deserved congratulations for your brilliant career and I hope you enjoy your next step in your life full of health and peace.

Receive my warm regards and love,

Denise Amador, Brazil

9 Photosynthetic light acclimation in three tropical rain forest Syzygium species

Kun-Fang Cao & Xin Qi Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming Office: 88 Xuefu Road, Kunming 650223, China. [email protected]

Introduction Tropical rainforests are very rich in plant species. The maintenance or coexistence of the many plant species in these forests is a core question for tropical biological research. The regeneration niche hypothesis (Grubb, 1977), is one of the theories that attempt to answers this question. It suggests that different ecological plant groups require different microhabitats within a forest for successful regeneration (also cf. Whitmore, 1989; Oldeman & van Dijk, 1990). In fact, forests are very heterogeneous in both abiotic and biotic environments, largely because they are mosaics of small forest patches, eco-units (Oldeman, 1983 and 1990) in different development phases, resulting in a mosaic of different biotic and abiotic environments. Hence, plant species with different regeneration requirements can find their proper sites within forests for their successful regeneration leading to the co-existence of many species within the forest.

Ecological tree temperament (sensu Oldeman & van Dijk, 1990), which defines both the regeneration niche and its development niche, is strongly related to the tree´s physiology. For example, hard gamblers that are early successional species require high light for successful regeneration (Oldeman & van Dijk, 1990). They usually have a high assimilation capacity and high physiological plasticity. In contrast, hard strugglers that are late successional species can establish in shade and their juveniles can survive in shade for a long time. They usually have a low photosynthetic capacity and low physiological plasticity (Boardman 1977; Björkman 1981; Ramos & Grace 1990; Chazdon et al. 1996; Cao & Booth 2000). In spite of their low photosynthetic capacity, some strugglers can grow well in high light such as in canopy gaps (e.g. Cao 2001) but they usually fail to sufficiently increase photosynthesis when they grow in high light. Consequently, they experience excessive light energy that cannot be used for photosynthesis and which even may cause chronic photoinhibition of photosynthesis (Demming-Adams & Adams 1992; Long et al. 1994; Scholes et al. 1997). The excessive light energy can dissi- pate unharmfully, through the xanthophyll cycle mainly (Demming-Adams & Adams 1992; Long et al. 1994), a process, which can be detected undestructively through the chlorophyll fluorescence technique (Bilger & Björkman 1990). So far, little is known about the degree to which this thermal dissipation prevents irreversible photoinhibition.

In this paper, we examine the photosynthetic acclimation of three Syzygium species. Specially, we address three questions: (1). What are the effects of light on the photosynthesis of the three Syzygium species with different shade tolerance? (2). Do the shade species suffer severe irreversible photoinhibition when growing in high light? (3) To which degree the dissipation of energy in the xanthophyll cycle prevents photoinhibition?

Methods This study was conducted in the Xishuangbanna Tropical Botanical Garden (21° 56' N, 101° 15' E, 600 m altitude) of the Chinese Academy of Sciences, which is situated in the southern part of Yunnan Province, Southwest China. Here, the annual temperature is 21.7 °C. and the annual precipitation is approximately 1500 mm, 83% of which is concentrated in the period from May to October. The period from November to April has a deficit of rainfall. However, during the period from November to February, the fog, which occurs almost everyday from midnight to about 11 o’clock the next morning, significantly alleviates the water deficit. Various formations of tropical forests occur in the region, which are rich in biodiversity (Cao & Zhang 1997; Zhu 2000). Syzygium (Myrtaceae) is an important tree genus in these forests, and 25 species from this genus 10 occur in the region of Xishuangbanna Prefecture with an area of 19220 Km2. Three Syzygium species, introduced below, were chosen for the present study. Syzygium latilimbum Merr. et. Perry is a late successional canopy species, S. cumni (linn.) Skeels a middle successional species, and S. szemaoense Merr. et. Perry an early successional species.

In November 2001, healthy wilderings about 1 or 2 years old with entire root systems of the three species were collected from tropical rain forests near the Xishuangbanna Tropical Botanical Garden, and transplanted into pots (30 cm in internal diameter, 23 cm in depth), and nursed at first in a shaded plot with 14% daylight for two months. One plant per pot was planted; the upper 10-cm forest soil was used. They were then moved into a fully open site, and three shaded plots with 4.5%, 14% and 42% daylight respectively. The plants were watered every day and were regularly sprayed with pesticides to control insects and diseases. The seedlings grown under 4.5% daylight, of both S. Szemaoense and S. cumini died in April 2002, and of S. latilimbum did not have leaves mature enough for measurement. Thus, no measurements were done on the seedlings grown in 4.5% daylight.

In July 2002, we performed physiological measurements. Using a Li 6400 portable infrared gas analyser (LI- COR, Lincoln, NE, USA), photosynthetic light response curves were conducted on 4 to 5 seedlings of each species under each light regime. Starting from the highest light intensity, the following light dosages were sup- plied to leaves from a LED light source, 2000, 1500, 1000, 800, 500, 300, 250, 200, 150, 100, 50, 20, and 0 µmol m–2 s –1. In order to obtain full photosynthetic induction, leaves were first exposed to an artificial light for 30 min, with the light intensity varying from 800 to 1500 µmol m–2 s –1 depending on the light saturation point of a given species under a given light regime. This light source was provided by several lamps hanging above a glass water bath with flowing tap water in it. Then, the leaves were exposed to each of the light dosages given above for 200 s, and photosynthetic rates were determined. During the measurement, in the leaf chamber, the air CO2 concentration was maintained at 360 µmol mol–1, the air humidity between 70 and 75%, the leaf temperature at 25 0C, and the air flow passing speed at 0.5 l min–1. The photosynthetic curves were fit with the model described by Bassman and Zwier (1991), from which the following parameters were derived: maximum photosynthetic rate (Pmax), photosynthetic light saturation point (LSP), and light compensation point (LCP). The leaves were then exposed to dark for 5 min, at the end of which dark respiration rates (Rd) were measured. All these measurements were conducted on overcast or rainy days.

In the same month (July), but on clear days, chlorophyll fluorescence emissions in the diurnal course were detected from the seedlings of the three species, using a fluorometer (FMS 2.02, Hansatech, U.K.). The measurements were conducted from 8 h to 19 h (Beijing Standard Time), with a time interval of 2 h between each measurement. The clock time here follows the Beijing Standard Time and is therefore about 1 hr later than the actual solar time. The method for the fluorescence measurement followed Feng et al. (2002a). The maximum photochemical efficiency of photosystem 2 (PSII) was calculated as Fv/Fm = (Fm – Fo)/Fm. The non-photochemical quenching coefficient was calculated as: NPQ = (Fm /Fm' – 1) (Bilger & Björkman 1990), in which Fm were the earliest measurements. A decrease of Fv/Fm value indicates the occurrence of photoinhibition of photosynthesis. Fluorescence light responses were constructed, using the light dosages of 250, 500, 800,1000, 1200, and 1500 µmol m–2 s –1, which were provided by the same light source used for the photosynthetic induction. The leaves were stabilized in each of the light dosages for 20 min. Based on these data, NPQ light response curves were made. Leaf chlorophyll concentration of the seedlings was determined, according to the method of Arnon (1949). In order to determine leaf dry weight per unit area (LMA), some mature leaves were harvested, from which leaf samples were taken with a pincher, and dried in an oven at 80 0C for 48 h.

All the above measurements were repeated for 3 to 5 individuals of each species under each of three light regimes. These data were subject to an analysis of variance in order to examine the differences in leaf physiological and morphological traits.

11 Table 1. Gas exchange parameters for the seedlings of three Syzygium species under the three different light regimes. The entries are means ± standard errors (N = 3–5). Different uppercase letters within columns indicate significant intraspecific differences in the means among the irradiance regimes (P < 0.05, Anova). Different lowercase letters within columns indicate significant interspecific differences in the means under the same irradiance regimes.

Light Maximum net Light saturation Dark respiration Light regimes compensation Species photosynthesis rate point rate (daylight %) point (µmol m-2 s-1) (µmol m-2 s-1) (µmol m-2 s-1) (µmol m-2 s-1)

100% 3.36±0.19 A, a 797±6 A, a 14.6±0.4 A, a -2.14±0.13 A, a

Syzygium 42% 6.37±0.55 B, a 556±14 B, a 7.4±1.9 B ,a -2.04±0.11 A, a altilimbum

14% 4.37±0.16 C, a 404±43 C, a 5.8±0.3 B, a -1.79±0.12 A, a

100% 9.39±0.77 A, b 974±24 A, b 15.7±2.1 A, a -2.10±0.04 A, a

Syzigium cumini 42% 9.31±0.79 A, b 918±41 A, b 8.3±1.3 B, a -2.10±0.15 A, ab

14% 6.18±0.06 B, b 464±44 B, a 4.7±0.7 B, a -1.79±0.17 A, a

100% 18.55±0.33 A,c 997±21 A, b 17.5±1.2 A, a -2.50±0.15 A, b

Syzigium 42% 11.59±0.88 B, b 914±57 A, b 6.5±1.5 B, a -2.46±0.11 A, b szemaoense

14% 9.69±0.55 B, c 543±79 B, a 4.5±0.4 B, a -1.90±0.08 B, a

Figure 1. Representatives of photosynthetic light response curves for three Syzygium species under the three different light regimes.

12 Results Under the same irradiance levels, S. Szemaoense had markedly greater Pmax values than the other two congeneric species, with the lowest values for S. latilimbum (Fig.1, Table 1), and the Pmax for S. szemaoense significantly increased with irradiance. Also, for both S. latilimbum and S. cumini, Pmax values for the seedlings grown in 42% daylight were significantly higher than those in 14% daylight. However, for S. cumini, the Pmax values remained similar between the seedlings grown in 42% daylight and fully open site, while for S. latilimbum, when grown in the fully open site the Pmax value was significantly lower than that for 42% daylight. For all species, both LSP and LCP values tended to increase with irradiance, although some of the differences were not statistically significant (Table 1). In the fully open site and under 42% daylight, the LSP values for S. latilimbum were significantly smaller than the other two species under the same light levels. Among species, LCP values under the same light levels were quite similar. Only for S. szemaoense, mean Rd value was significantly greater in the seedlings grown in 42% daylight than those in 14% daylight.

The dawn Fv/Fm values slightly decreased with increase of irradiance intensity for all species (Fig. 2), suggesting increase of stress with the growth irradiance. In the diurnal course, Fv/Fm values decreased with increase of incident light intensity, with the lowest value on midday when the incident light intensity was the greatest (Fig. 2). The Fv/Fm slowly recovered in the afternoon with diminishing of incident light intensity. Diurnal reduction of Fv/Fm was stronger with increase of the growth irradiance level; the extent of the reduction was quite similar among species.

Comparing NPQ light response curves among species under the same irradiance regime, below about 1250 µmol m–2 s–1of photon flux density (PFD), the increase of NPQ with PFD was the strongest for S. latilimbum, and the weakest for S. szemaoense (Fig.3). NPQ rates were suppressed for S. latilimbum under 42% daylight and for S. cumini in both the fully open site and under 42% daylight. For all species, with increasing of light level,

Figure 2. Diurnal fluctuation of maximum photochemistry efficiency of photosystem II (Fv/Fm) for three Syzygium species under the three different light regimes.

LMA tended to increase (Fig. 4a), while ChlM tended to decrease (Fig. 4c).

13 Discussion Our results are consistent with previous studies that show that early successional species have high photosyn-

Figure 3. Light response curves of non-photochemical quenching (NPQ) for three Syzygium species under the three different light regimes.

Figure 4. Dry weight per unit leaf area (a) and chlorophyll contents on both leaf area (b) and mass (c) bases for Syzygium latilimbum (SL), S. cumini (SC) and S. szemaoense (SS) grown in the fully open site (open bars), 42% (hatched bars) and 14% daylight (solid bars), respectively. Data are means ± SE (N = 3–5). Different uppercase letters within the panels indicate significant intraspecific differences in the means among the irradiance regimes (P < 0.05, Anova). Different lowercase letters within the panels indicated significant interspecific differences in the means under the same irradiance regimes.

thetic capacity and greater physiological plasticity than the late successional species (Boardman 1977; Chazdon et al. 1996). The early successional species increased photosynthetic capcacity with growth light level (Table 1, Fig. 1). In contrast, in the fully open site, the Pmax of the late successional species S. latilimbum was remarkably suppressed. Nevertheless, although dynamic photoinhibition was detected for all species, no severe irreversible photoinhibition was found for any species under this circumstance (Fig. 2). The high thermal dissipation capac-

14 ity of the late successional species (Fig. 3) should explain why it did not suffer from irreversible photoinhibition while growing the high light despite of its low photosynthetic rate.

All species showed reduced LMA and increased chlorophyll concentration per unit leaf mass with the decrease of irradiance (Fig. 4 a). This is favourable for plants grown in low light to achieve positive carbon gain: by investing less mass in construction per unit of assimilation area but capturing light more efficiently due to higher ChlM. Moreover, although statistically not significant for two of the three species, all species tended to reduce dark respiration rate when growing in lower light. This is also a favourable acclimation for the plants grown in low light to achieve low maintenance costs.

Our physiological data are consistent with the regeneration niche hypothesis (Grubb 1977). In the small region of Xishuangbanna with a size of Morocco, 5000 plant species occur here, and 25 species are found here in the genus Syzygium alone. The three Syzygium species examined in this study varied largely in the capacities of light energy utilization and dissipation and in the physiological light acclimation. These physiological variations possibly led these species to partition different mircro-habitats within the forests for successful regeneration and growth, hence to their coexistence.

In summary, the three Syzygium species differed significantly in their photosynthetic capacities and photosynthetic light acclimation capacity. The early successional species was able to increase photosynthetic capacity with irradiance intensity, but increase of photosynthesis was not achieved in the open site for the middle successional species. In contrast, in the open site, the photosynthesis of the late successional species was strongly suppressed. Nevertheless, none of the three species suffered from irreversible photoinhibition when growing in high light. This is largely attributable to the increased photosynthesis in the early successional species and to the high energy dissipation capacity of the late successional species.

References Arnon, D. I. 1949. Copper enzymes in isolated chloroplast: polyphenol oxidase in Beta bulgaris. Plant physiol 24: 1–15. Bassman, J. and Zwier, J. C. 1991. Gas exchange characteristics of Populus trichocarpa, Populus deltoids and Populus trichocarpa * P. deltoids clone. Tree Physiology 8: 145–149. Bilger, W. and Björkman, O. 1990. Role of the xanthophyll cycle in photoprotection elucidated by measurements of light- induced absorbance changes, fluorescence and photosynthesis in Hedera canariensis. Photosyn Res 25: 173–185. Björkman, O. 1981. Responses to different quantum flux densities. In: Lang, O.L., Nobel, N.S. Osmand, C.B. and Ziegler, H. (eds.) Physiological plant ecology I, encyclopaedia of plant physiology, N.S. 12 A. Springer Verlag, Berlin. Pp. 57– 107. Boardman, N. K. 1977. Comparative photosynthesis of sun and shade plants. Annual Review of Plant Physiology 28:355– 377. Cao, Kun-fang, 2001. Morphology and growth of evergreen and deciduous broad-leaved saplings in a Chinese beech forest with dense bamboo undergrowth. Ecological Research 16 (3): 509–517. Cao, K.F. and Booth, E.W. 2001. Leaf anatomical structure and photosynthetic induction for seedlings of five dipterocarp species under contrasting light conditions in a Bornean heath forest. Journal of Tropical Ecology 17: 163–175. Cao, M. and Zhang, J. H. 1997. Tree species diversity of tropical forest vegetation in Xishuangbanna, SW China. Biodiversity and Conservation 6: 995–1006. Chazdon, R.L. and Kaufmann, S. 1993. Plasticity of leaf anatomy of two rain forest shrubs in relation to photosynthetic light acclimation. Functional Ecology 7: 385–394. Chazdon, R. L., Pearcy, R. W., Lee, D. W., and Fetcher, N. 1996. Photosynthetic responses of tropical forest plants to contrasting light environments. In: Mulkey, S. S., Chazdon, R. L. & Smith, A. P. (eds.) Tropical Forest Plant Ecophysi- ology. Chapmann and Hall, New York. Pp. 5–55. Demmig-Adams, B. and Adams, W. W. 1992. Photoprotection and other responses of plants to high light stress. Annu Rev Plant Physiol Plant Mol Biol 43: 599–626. Feng, Y. L., Cao, K.F., and Feng, Z. L., 2002a. Acclimation of lamina weight per area, photosynthetic characteristics and

15 dark respiration to growth light regimes in four tropical rainforest tree species. Acta Ecologica Sinica 22(7): 901–910. Feng, Y. L., Cao, K.-F., and Feng, Z. L., 2002b. Effect of growth light intensity on the photosynthetic apparatus in four tropical rainforest tree species seedlings. Chinese Journal of Plant Physiology and Molecular Biology 28(2): 153–160. Grubb, P. J. 1977. The maintenance of species-richness in plant communities: the importance of the regeneration niche. Biological Review 52: 107–145. Krause, G.H. 1988. Photoinhibition of photosynthesis: an evaluation of damaging and protective mechanisms. Physiologia Plantarum 74: 566–574. Long, S. P., Humphries, S. and Folkowski, P.G. 1994. Photoinhibition of photosynthesis in nature. Annu Rev Plant Physiol Plant Mol Biol 45: 633–662. Oldeman, R.A.A. 1983. Tropical rain forest, architecture, silvigenesis and diversity. In: Sutton, S.L., Whitmore, T.C. & Chadwick (eds.) Tropical rain forest ecology and management. Blackwell, Oxford. Pp.139-150. Oldeman, R.A.A. 1990. Forests: elements of silvology. Springer-Verlag, Berlin. Pp.624. Oldeman, R.A.A. and van Dijk, J. 1991. Diagnosis of the temperament of tropical rain forest trees. In: Gomez-Pompa, A. Whitmore, T.C. & Hadley, M. (eds.). Rain forest regeneration and management. MAB Series 6. Parthenon, Carnford, U.K. Pp.21-65. Ramos, J. and Grace, J. 1990. The effect of shade on the gas exchange of seedlings of four tropical trees from Mexico. Functional Ecology 4: 667–677. Scholes, J. D., Press, M. C. and Zipperlen, S. W. 1997. Differences in light energy utilization and dissipation between dipterocarp rain forest tree seedlings. Oecologia 109: 41–48. Whitmore, T. C. 1989. Canopy gaps and two major groups of forest trees. Ecology 70: 536–538. Zhu, H. 2000. Ecological and biogeographical studies on the tropical rain forest of south Yunnan, SW China, with special reference to its relation with rain forests of tropical Asia. Journal of Biogeography 24: 647–662.

16 Het ontwaken van de bosmoestuin

Marieke Cieremans, MSc Permaculturist, bewoner van Gaia. [email protected]

Aan Prof. dr. ir. R.A.A. Oldeman, Vol dankbaarheid schrijf ik hier voor U een impressie van de jaren dat ik heb mogen studeren onder Uw toegewijde en inspirerende begeleiding. Hoe de bosmoestuin ontwaakte

Een winterse dag op de barak, een voorstel op één a4-tje, het prille begin van een afstudeervak. Een zomerse reis naar Siberische berkenbossen – de kiem ontsproot,... wortelde,... groeide verder,... en werd gevoed door Pace-, space- & placemakers:Integratie van ruimte & tijd; stabiliteit en flexibiliteit in diversiteit; EkoLand&EkoBos: een ijzersterk concept voor natuurlijk, veelomvattend landgebruik; Diagnosis of Complex Ecosystems; een natuurlijke manier om de natuur aan onderzoek te onderwerpen; De complexe Orde van Chaos; fractals, en meer... Elements of Silvology; de basis van het bos transecten, schetsen, figuren en de schat aan andere ideeën, met of zonder naam.

en werd tot de bosmoestuin

een veelzijdig landgebruiksysteem, gebaseerd op natuurlijke processen en interacties; gekenmerkt door diversiteit, complexiteit, flexibiliteit en stabiliteit; opgebouwd uit een matrix van structurele en functionele elementen; hun ritmische opbouw en samenhang in de tijd weergegeven in cirkels in cirkels in cirkels ...

Onze samenwerking heeft mij een schat aan kennis en ervaring gegeven, mij gesterkt in mijn overtuigingen en geholpen deze een plaats te geven in de wereld. Uw brede belangstelling, onderzoekende aard, vernieuwende inzichten, betrokkenheid en positieve blik hebben in mij de zaden gezaaid voor vele nieuwe ontwikkelingen, die in de verdere levensloop ontluiken, bloeien en hun vruchten afwerpen, elk op hun tijd. Het opgroeien van de bosmoestuin is nauw verweven met mijn verdere activiteiten en de ontwikkeling van onderliggende en meeromvattende inzichten. In de loop der jaren heeft mijn blikveld zich verruimd via creatieve kruisbestuivingen met vele uiteenlopende inspiratiebronnen. De bosmoestuin is hierin een steeds terugkerend element, verrijkt met nieuwe facetten, en is zo geworden tot metafoor voor het leven.

Professor Oldeman, dank U wel voor alles! Ik wens U het allerbeste.

Met de meeste hoogachting, Marieke Cieremans Apeldoorn/Sint Petersburg, september 2002

17 Roelof A.A. Oldeman, el famoso profesor de los modelos arquitectónicos de los árboles

Antoine M. Cleef Universidad de Amsterdam Kruislaan 318 1098 SM Amsterdam Holanda [email protected]

Escribo mi contribución al Liber amicorum de Roelof Oldeman en la ocasión de su retiro académico o jubilación de la Universidad de Wageningen en castellano, porque nuestra conexión científica y amistad siempre giró alrededor de las selvas y bosques de América Tropical, más específicamente las de Colombia. Escribo desde esta perspectiva y experiencia. Así es también como la mayor parte de los colegas y estudiantes latinoamericanos conocen a Roelof.

Nuestro primer contacto operativo se estableció hace más de 20 años cuando recibió y hojeó mi Tesis de Doctorado (sobre los páramos colombianos) en su desayuno. Aparentemente a Roelof le gustaron los perfiles dibujados de los diferentes tipos de la vegetación alto-andina ecuatorial con los característi- cos frailejones (Espeletia spp., Asteraceae). Me escribió pos- teriormente agradeciéndome el envío con referencia especial a estos dibujos (Fig. 1). Poste- riormente adaptó alguno para su obra ‘Silvology’ (Oldeman, 1990).

Nos conocimos algo mejor durante reuniones del grupo de trabajo sobre ‘Bosques tropicales’ en el ático de Hinkeloord; Roelof presidió las sesiones con mucha imaginación y Figura 1. Reproducido de Cleef, A.M. 1981. The vegetation of the páramos of the entusiasmo. Hoy día se conoce Colombian Cordillera Oriental. Diss. Bot. 61. 321 Vaduz. como el grupo de bosques tropicales de la IUCN de Holan- da. Luego, y me parece que ya estamos en el año 1985, Roelof moldeaba la organización TROPENBOS (este nombre en holandés hace referencia al ‘bosque tropical’). Junto con el Dr. Wim Sombroek y Thijs Heering visitaron el laboratorio “Hugo de Vries” en Ámsterdam para sondear con el Prof. Dr. Tom van der Hammen y un servidor la posibilidad de establecer un subprograma de Tropenbos en la Amazonía colombiana. Hasta la fecha este Programa Tropenbos-Colombia

18 está operativo en Araracuara y en el Parque Natural de Amacayacu cerca de Leticia. Era una iniciativa muy importante para Colombia; el programa Tropenbos hoy día figura entre los más apreciados en el país. Desarrolló a continuación otra iniciativa importante: la Fundación ‘Het Kronendak’ o ‘Dosel del bosque’. Al mismo tiempo, desde las expediciones de ECOANDES en Colombia (1977-1983) yo estaba muy curioso y sensitivo para conocer más de la ecología y diversidad del epifitismo y de la dinámica en el dosel de los bosques (Cleef et al. 1984). Estaba también entusiasmado por mis colegas de aquel entonces, Prof. Dr. S. Rob Gradstein (Goettingen) y Dr. Harrie Sipman (Berlin) durante mi estancia (hasta 1984) en el Herbario de la Universidad de Utrecht. Desde Utrecht (Prof. Werger & Gradstein) y Amsterdam (Cleef) se sometió el proyecto ‘Biogeographical, vegetational and ecological investigations on epiphytic vegetation of Colombian montane forests’ a WOTRO- NWO para investigar las copas de los bosques (alto-) andinos y subandinos de la Cordillera Central en Santa Rosa de Cabal, cerca de Pereira en el Departamento de Risaralda. Eric Veneklaas y Jan H.D. Wolf obtuvieron su título de Ph.D a través de este proyecto. Roelof estaba invitado al jurado de Jan Wolf en 1993 en la Universidad de Ámsterdam, y me acuerdo de su oposición en la Aula Magna como si fuera el día de ayer. Desde entonces Roelof apareció con alguna frecuencia en Amsterdam.

Mientras tanto otro candidato al Ph.D se presentó en Amsterdam, el ingeniero forestal Hans F.M. Vester. Tenia una formación adecuada y el interés en arquitectura de los árboles y la dinámica de los bosques tropicales. El sitio más llamativo se presentó en los alrededores de Araracuara en la Amazonía colombiana. El Dr. Johannes Battjes había documentado ya en 1988, para su maestría una serie de sucesiones de rastrojos y bosques secundarios después de la chagra tradicional indígena. Estudiar este fenómeno en términos de arquitectura y dinámica de bosque era un sueño para Hans Vester, como igualmente para sus promotores, Roelof y yo.

Con la ayuda de la fundación ‘Het Kronendak’, y en especial del Mr. Chr. Thurkow, y gracias a la implementación del proyecto por WOTRO-NWO, Hans Vester se fue por fin a Araracuara en Colombia. Su Tésis de Ph.D. en 1997 (Vester, 1997) era la culminación de las esfuerzas combinadas. Además, este tesis fue laureado (con 'cum laude'), un evento raro en los actos de Doctorado de la Facultad de Ciencias de la Universidad de Amsterdam. Se trató de la aplicación de los conceptos de Roelof (Hallé , Oldeman & Tomlinson, 1978) en diferentes eco-unidades del bosque secundario amazónico.

Desde el inicio de la Fundación ‘Het Kronendak’ en 1989 fuí invitado como uno de sus asesores científicos. Durante esta etapa he tenido más frecuentemente contacto directo con Roelof y he podido apreciar mucho más sus conocimientos de los bosques tropicales. En especial muy atractivo y un ‘eye opener’ para mi fueron (1) sus modelos arquitectónicos de los árboles y luego (2) el concepto de eco-unidades. De sus modelos pensé obtener una nueva aproximación a la sucesión de los bosques, al lado de los existentes basados en la estructura (sensu Barkman) y en la fitosociología (p.ej. la escuela Zürich-Montpellier).

Los modelos y su aplicación al bosque secundario de Araracuara resultaron muy interesantes y al mismo tiempo más complicados que lo que había pensado al inicio de la empresa...

Roelof, todavía nos queda, la Tesis de Ph.D. de Catalina Londoño Vega de Medellín. Me doy cuenta que has hecho mucho en términos de conceptos y metodologías científicas y te felicito por ‘vida y obra’ como suelen hacer con una persona como tu en Colombia. Has guiado muchas personas al Doctorado, una proporción subs- tancial no-holandeses.

Me doy cuenta también que todo esto empezó en Cayenne, la Guyana francesa, donde por una coincidencia conocí al herbario “Roelof A. Oldeman”, fundado por ti. Toda esta ‘vida y obra’ no se habría desarrollado así, de no ser por el apoyo firme y permanente de tu esposa, Wil. A ella también corresponde una parte de todo esto. Quiero felicitarles con este 'milestone'. Naarden, 19 de agosto de 2.002 Antoine M. Cleef

19 Agradecimientos El derechohabiente del derecho de autor de la figura 1, el editorial: J. Cramer in der Gebr. Borntraeger Verlagsbuchhandlung (http://www.schweizerbart.de), dio permiso para su reproducción en este libro.

Referencias Cleef, A.M., Rangel, Ch. O., van der Hammen T. y Jaramillo, M. R. 1984. La vegetación de las selvas del transecto Buritaca. En: van der Hammen T. y Ruiz, P. M. (eds.) La Sierra Nevada de Santa Marta (Colombia), transecto Buritaca - La Cumbre.. Stud. Trop. Andean Ecosystems 2 (with extended summary in English). J. Cramer, Berlin - Stuttgart. Pp.267- 406. Hallé, F., Oldeman, R.A.A. and Tomlinson, P.B. 1978. Tropical trees and forests. An architectural analysis. Springer, Berlin. Oldeman, R.A.A. 1990. Forests: Elements of silvology. Springer, Berlin.

20 Agricultural scientists cannot see the wood for the trees? The quest for holistic science Toon van Eijk agronomist: P.O. Box 12548, Dar es Salaam, Tanzania

Sustainability and holism The development of sustainable farming systems demands a holistic approach. The multi-facets of sustainable rural development, expressed in multi-functional land use, demand that farming systems be sustainable from ecological, technical, economic, political and socio-cultural points of view. The concepts of sustainability and holism are closely related. Holism not only refers to an approach which pays attention to all possible aspects of farming systems, but also refers to the recognition that the whole is more than the sum of its parts (unpredictable emergent properties do exist). The operationalization of the concepts of sustainability and holism, however, remains problematic. How can farmers and other stakeholders in the multi-dimensional process of rural development gain a comprehensive view of farming systems?

Positivists and constructivists Under the constant pressure of various stakeholders the train of agricultural research rolls on without breaks (brakes) for reflection. While the development of sustainable farming systems demands systems thinking and bridging of the gap between the natural and social sciences, most agricultural researchers are fully occupied with solving practical problems. Difficulties in communication between hard (natural) and soft (social) scientists are grounded in their corresponding positivist and constructivist assumptions about the nature of human knowledge. While in the positivist paradigm scientific knowledge is considered to be an objective, universal and context-free commodity, the constructivist position in social sciences holds that all thinking is value-laden and in stead of objectivity the norm is intersubjectivity. For constructivists facts are not given phenomena, but facts are made. Positivists attempt to keep values and norms outside the rational discussion: a strict fact-value dualism is the aim. One assumes that the goals are ‘given’ and focuses on the best technical means to achieve them. In the constructivist paradigm, however, goals are the bone of contention and values and norms are the source of rational discussion.

Economy and ecology Monocultures of crops, animals and trees are the logical outcome of the dominant positivist-reductionist scientific paradigm in ‘hard’ science. The science-induced addiction of conventional farmers to chemical-based monocultures and the addiction of many, highly specialized, agricultural scientists to ‘high-tech’ approaches demand ‘detoxification’. To kick these habits, the dominant positivist paradigm needs to be reviewed. The fact- value dualism allowed technology development to become an apparently autonomous power. The latest example is the genetic modification of living material, which can be classified as the next ‘magic bullet’ approach. So-called ‘inevitable’ technological development, however, is a fabrication which can be undone. Monocultures of (transgenic) uniform crops are designed to favour economies of scale through lower production costs per hectare. Monocultures are thus grounded in economic thinking, whereas the ecologisation of farming systems must be based on ecological principles. Monocultures go against the evolutionary forces that have resulted in huge biological diversity, a diversity that is an essential part of sustainability. How can the two opposing tendencies of economy and ecology be reconciled?

21 Attitudinal change The operationalization of the integration of economy and ecology remains problematic. How do we strike a dynamic balance between economy and ecology? While ecology is characterized by an integrative tendency, today’s economy emphasizes a self-assertive tendency (i.e., get as much personal profit as possible with minimal attention for the larger eco-system and social environment). In order to ‘walk the talk’ of sustainable development we must think and act sustainably. Sustainable thinking and acting in the domains of economy and ecology demands new attitudes. Attitudinal change resulting in more sustainable behaviour, however, does not come easily. While many people might agree that the main underlying cause of the current unsustainable agricultural system is related to faulty attitudes, practical and effective methods to change attitudes remain scarce. Most training methodologies have little impact in this respect, probably because training focuses on thinking and acting without addressing the pure consciousness that underlies all thinking and acting.

Experiential spirituality Conventional science and most other human behaviour are grounded in the concept of ‘thinking-being’. This most dominant mode of ‘being’ expresses itself in a continuous flow of thoughts, in an incessant ‘inner talk’. Most people are not even aware of this continual ‘talking to ourselves’ because it is the predominant mode of being. In contemporary society ‘thinking-being’ is considered the only possible mode of being. In addition to ‘thinking-being’, however, an experience of ‘just being’, of ‘consciousness-as-such’ (transcendental or pure consciousness) is possible. The process in which one (preferably) systematically trains the receptivity to gain (preferably) regular access to this transcendental consciousness can be referred to as spirituality. Spirituality is here understood as an individual and, above all, experiential spirituality which is not based on dogmas, but on do-it-yourself techniques to break the continuous spell of the mode ‘thinking-being’1. The domain of experiential spirituality is open to investigation by scientific methods, i.e., open to experiential validation or refutation.

Wholeness Sustainability is an integrative, holistic property which encompasses ‘wholeness in human beings’ and ‘wholeness in society’. Economy and ecology (and many other aspects) must be integrated in the personal and collective spheres of life. The building blocks of any society, however, are individual human beings, who together construct socio-economic and cultural ‘structures’. To my mind it is an illusion to believe that complex inter- dependencies at high levels of integration (for example, between socio-economic structures and the ecological environment) can be grasped by intellectual reasoning (‘thinking-being’) alone. At the level of the individual person intellectual reasoning alone does not result in wholeness. This is exemplified in the rather weak performance of most educational programs which are supposed to assist in the formation of intellectually, emotion- ally and socially ‘healthy’ and environment-conscious citizens. One can try to exercise ‘both-and’ thinking, but in most cases this also does not result in true integration of opposing tendencies (in ‘the one thing as much as the other’). Perhaps the co-existence of the two opposing tendencies of economy and ecology (self-assertion and integration) can only be ‘lived’ at higher levels of awareness, as E.F. Schumacher maintained.

A new agricultural professionalism The development of sustainable farming systems demands a shift in attitudes of farmers, extensionists, researchers, environmentalists, civil servants, politicians, consumers and other stakeholders. Group synergy needs to emerge on social platforms where this multitude of actors of different walks of life are supposed to collaborate. The large number of variables and actors that are at play in agriculture make it difficult to grasp the complexities

1 The do-it-yourself technique that I practise (since 1972) is the transcendental meditation (TM) technique as teached by Maharishi Mahesh Yogi. This technique has been subjected to a large amount of research with results published in refereed scientific journals.

22 of farming systems at the intellectual level. Conventional research suffers from ‘the illusion of intellectual holism’. Pretty and Chambers (1994) advocate a new agricultural professionalism about which they remark: “Personal behavior and attitudes remain the great blind spot of agricultural research and extension. … Per- sonal change will often have to precede as well as accompany changes in the cultures of organizations”2. This applies also to Wageningen University and Research Center and its staff and students.

Collective agency In a sustainable agriculture farmers are not only entrepreneurs but also natural resource managers. This demands collective learning of various actors in order to reach group synergy or joint agency, i.e., the ability to act as a like-minded structures or group. Hitherto the ability of the multitude soft social systems of actors to create effective collective agency is insufficiently developed, resulting in today’s unsustainable farming systems. The question is then under which specific collective sets s of social hard consciousness ecosystems conditions collective agency emerges. The practices or b ehaviors development of sustainable farming systems entails (preferably) mutually beneficial interactions between many individual actors, their (socio-economic, cultural and political) individual structures and ecosystems. The interactions actors / agents between individual actors, their structures (soft social systems) and (hard) ecosystems are represented in Diagram 1. Diagram 1: the interactions between soft social systems and hard ecosystems Collective consciousness The actor/structure debate in social psychology and in the sociology of rural development does not really clarify, to my mind, how exactly the interaction between actors and structures comes about. In Diagram 1 I have placed the concept ‘collective consciousness’ at the interface between actors and structures. Social scientists (e.g., Sorokin and Durkheim) say that society is something outside, and something inside us. Society has an objective aspect (a concrete social structure) and a subjective aspect (a collective consciousness). The collective consciousness and the social structure are the inner and outer side of the same socio-cultural reality. The central ideas and values, that are internalized in the collective consciousness, form the basis of all sub-structures in a society. The socio- economical, political, cultural and religious sub-structures of a society are connected through this collective consciousness (in Diagram 1 the box representing ‘structures’ can be any one of these sub-structures). All individuals who together form these sub-structures are connected through this ‘field’ of collective consciousness. The collective consciousness is the integrating, inner structure of a society. The concept of collective consciousness could be the missing link in the long-standing actor-structure debate, since it clarifies the interaction between actors and structures and thus can integrate the socio-psychological and structural approaches.

Social capital Positively oriented collaboration and effective co-ordination between actors, i.e., collective agency, demand a coherent and ‘high quality’ collective consciousness . All noses need to point in the same direction. A ‘high

2 Pretty J. and R. Chambers (1994). Towards a learning paradigm: new professionalism and institutions for a sustainable agriculture. In: Scoones I. & J. Thompson (Eds). Beyond farmer first. Rural people’s knowledge, agricultural research and extension practice. Intermediate Technology Publications Ltd, London. pp. 182-202.

23 quality’ consciousness of individual actors results into a ‘high quality’ collective consciousness3, which in turn can generate more appropriate social systems or structures. A ‘high quality’ individual and collective consciousness result in more positive (e.g., more environment-friendly) behavior, which would have a positive impact on ecosystems (these interactions are represented by the right-pointing arrows in Diagram 1). The left-pointing arrows indicate, for example, that monitoring of changes in ecosystems by scientists can change behaviors and thus social systems and attitudes of individual actors. This, however, proves to be a slow process. Deliberate management of human interaction with ecosystems requires the generation of ‘social capital’, resulting in mutually beneficial co-operative behavior. High levels of social capital are grounded in a ‘high quality’ collective consciousness.

Holistic science The quest for holistic science at Wageningen (with Prof. Oldeman being one of its most open-minded and productive proponents) requires, in addition to specialists, scientists who can work in an inter-disciplinary mode. This demands a transformation of attitudes and a trans-disciplinary, overarching paradigm that encompasses natural sciences, social sciences and effective techniques for consciousness development. The last ones can actually help us to transcend the numerous trees and see the forest (the trees might refer here to the numerous disciplines within Wageningen University as well as to the many actors and structures in the real world). The state of our agriculture is a reflection of the state of our mind4.

3 An example of negatively oriented collaboration, caused by a coherent yet ‘low quality’ collective consciousness of a group, would be the behavior of football hooligans. 4 This paper is largely based on my Ph.D. thesis. For more details see: Van Eijk T. (1998). Farming Systems Research and Spirituality. An analysis of the foundations of professionalism in developing sustainable farming systems. Ph.D. thesis, Wageningen Agricultural University, The Netherlands.

24 What is sustainable farming? Eric A. Goewie Wageningen University Research Centre

DEDICATION

This article is dedicated to my friend and colleague

Prof. Dr. Ir. Roelof A.A. Oldeman

Being a member of the former Department of Ecological Agriculture of the former Agricultural University, he brought in Department’s sense of freedom in academic education and research. New concepts such as ‘eco units’, ‘architecture of living systems’, ‘canopy farming ’and ‘fuzzy logic’ became introduced in Department’s thinking and facilitated Department’s skills in the formation of elegant hypothesis and new theories relevant for advanced development of organic farming as subject of academic interest. I want to thank him for his deep interest, his encouragement and his support for organic thinking in agricultural sciences.

Abstract Is it possible to “measure” the degree of sustainability of a production farm or of any other sort of land use? In fact this is not, as sustainability presumes that we have knowledge about what future generations need. It is only possible to speak about sustainable development. Sustainable development means that the present generation must reduce their use of non-renewable resources to a large extent, thus leaving as much as possible for future generations. This article shows that the degree of sustainable development might be expressed as the tangent on the hyperbole described by the equation: the expenses for internal inputs at a farm are equal to the reverse of the expenses for external inputs at the same farm. Our description of sustainable development shows that high production levels cannot go together with sustainable development. Neither high levels of sustainable development can go together with a high level of profitability. The conclusion is that a farm is in a state of sustainable development when the loss of production because of chemical-free production methods is compensated by the reduction of costs for external inputs.

Introduction Sustainability is an issue that inspired policymakers, teachers and scientists. However, most of them got into problems when trying to make this notion applicable. Rigby et al (2001) identified even more than 386 definitions of sustainability. This is not surprising as the notion ‘sustainability’ became introduced as something that has to be referred to the needs of future generations (UN, 1992). The Dutch Scientific Counsel for Governmen- tal Policy, the WRR (1994) shows that sustainability is hard to quantify, as nobody knows what future generations actually need. At best, the WRR states that we might talk about ‘sustainable development’ only. In other words: present generations must leave some part of their available natural resources for the benefit of future generations. Goewie (2003) observes that sustainability is not a question of energy saving or efficient use of natural resources only, but that it is an attitude as well. Röling (2002) says that such an attitude is dependent on humankind’s willingness to leave certain amounts of natural resources untouched. Kremers (1993) examined forty interpretations of sustainability related with agricultural land use. He categorised

25 them by means of the Multifaceted Structured Entity Modelling (Rozenblit et al, 1986), an electronic tool for classification and weighing of soft data, like notions, descriptions, definitions and interpretations. He demonstrated that most descriptions for sustainability of agricultural production systems are related to potentialities of self-restoration of production factors used for farming. So ‘sustainability’ could be a function of the possibilities for self-restoration inside a farm (see box 1). Indeed, Smeding (2001) demonstrated that biodiversity inside farms increases the longer they are managed organically. Is there more evidence for it? The next chapter gives an answer.

Biodiversity inside a farm and the possibilities for self-restoration of the natural resources involved Sustainability is related with: The aim of farming —control of conditions for the • an ever lasting and achievable production of top levels of biomass (a limited number of management objective crops and animals)— becomes that of striving for minimal • cyclic processes disturbance of production conditions in soil, crops and • application of renewable natural resources animals (Porceddu et al., 1997). Natural differences in soil only fertility are reduced through the use of synthetic compounds • biodiversity as carrier of self organisation and various tillage methods. Natural differences in one crop in ecosystems become levelled by means of herbicides and with • ‘polluter pays’ principles homogeneity among varieties. We may assume therefore • energy balances that the biodiversity of mainstream (capital intensive) farms must be low. So the possibilities for self-restoration of farm- bound natural resources have no meaning for the farmers Box 1. Dominating items found among forty descriptions of involved. All production concerned is the result of efficient sustainability (Kremers, 1993) use of external inputs primarily. So the soil of such farms is considered as nothing more than a substrate necessary for bearing some kind of production. But is the inverse true as well? Is it reasonable to assume that increasing biodiversity contributes automatically to the development of more self-restoration of farm-bound living production factors such as soil fertility and prevention of diseases or pests? We will address this question by way of three lines of approach:

- the relation between biodiversity and the type of soil use; - the relation between biodiversity and the development of a farm as an agro ecosystem and - the relation between biodiversity and the possibilities for self-restoration inside agro ecosystems.

The relation between biodiversity and the type of soil use Grime (1979) demonstrated an optimum connection between species diversity and the standing crop. He found that the maximal standing crop is correlated with production limiting factors (stress) and/or with removal of above soil biomass (disturbance). Bakker et al. (1995) concluded that a low standing crop and species diversity could cohere with limitations in production such as very dry, dark, salt or nutriment poor substrate. So a high standing crop and low species diversity could cohere with nutrient rich substrates, where only some quickly growing species eliminate moderately growing species easily. Naveh et al. (in Bakker, 1989) found high species diversity in over grazed pastures. He explained that phenomenon by assuming that heavy grazing during long periods induces evolutionary changes along with the introduction of new species. The latter ones settle easier the more the vegetation is kept open. Huston (1979) demonstrates that the production of slowly growing standing crops combined with their removal at low frequencies induces high species diversity. Species diversity remains low, however, when fast growing standing crops are combined with high harvest frequencies inside a farm. Both situations correspond with an organic and a mainstream farm production system respectively (Mäder et al, 2002). Table 1 shows the difference between both types of farms.

26 Table 1. Overview of characteristics of two popular farming systems

Growth Number of Soil fertility of Year round Farm-bound Description rapidity of the commodities production soil coverage biodiversity standing crop per farm land

Low standing Slow and organic (slow High controlled High Low High farming growing). low growing harvst regime

High standing Fast and Mainstream crop (fast Low forced Low High Low farming growing), high growing harvest regime

The relation between biodiversity and the development of a farm as an agro ecosystem An ecosystem left to its own devices evolves gradually towards its next succession under simultaneous levelling of abiotic variations of the soil involved (Odum, 1971). Figure 1 shows that.

An ecosystem becomes exhausted when it is prevented from evolving to its next following succession phase and drops back to its preceding succession phase (Bakker, 1989; Tilman, 1988). In other words, an ecosystem can only be kept in one and the same succession phase when external inputs are introduced continuously. Another possibility is that we stimulate the ecosystem to produce higher amounts of the nutrients required. That is the situation in organic farms (see table 1). The manager of an organic farm must therefore enhance biodiversity in order to become able to produce all required inputs.

Our conclusion is that a mainstream, capital-intensive farm is comparable with a pioneer ecosystem in which natural differences in fertility of soil are levelled by means of external synthetic inputs. That makes rapid growth and removal of biomass possible, thus preventing the increase of farm-bound biodiversity. An organic farm is comparable with the succession phase, following the pioneer phase, as natural differences in soil fertility fluctuate depending on the extent of crop rotations involved. So, there must be a positive corre- lation, with the complexity of soil use.

The relation between biodiversity and the potentiality for self-restoration inside agro ecosystems Ecologists contrast system approaches concerning life phenomena with mechanistic approaches advocated by classical agro-ecologists. In system approaches it is more important to pay attention to the mutual relations among system elements rather than to the individual elements (fixed structures) themselves. Life processes determine structures of organisms and ecosystems. Machine like concepts start only from the structure of the system. Machines hold the law of cause and effect: when they break then there is a cause. Functioning of organisms are determined by cyclic running information streams (feed back loops). Disturbances may originate in more than one site and become reinforced by positive feed back or extinct by negative feed back mechanisms. The first play a part in learning and evolution processes, the latter in regulation of physiological processes (e.g. body temperature, blood pressure). Living beings and ecosystems are open systems. That means that they must exchange energy and matter with their surroundings constantly. By doing so they keep themselves far from their thermodynamic equilibrium. Once they are dead they follow the second law of thermodynamics and develop their structure from order to disorder. The stability of organisms and ecosystems is not invariable, although very dynamic (Verhoef et al., 1995).

27 They keep their structures despite permanent variation and interchange of elements. Many variables are mutually dependent and oscillate between an upper and lower limit, even when there is no disturbance. This condition (homeostasis) is very flexible. It has many alternatives for interplay with its surroundings (figure 2). So there is dependence on the environment, while at the same time, however, also a relative autonomy, that is to say maintenance Figure 1. Succession phases in the development of ecosystems according to Odum (1971) and De Zeeuw et al. (1998). From an ecological point of view, intensive agriculture (very of organisms’ structure. much dependent on external synthetical inputs) is comparable with an ecosystem in its pioneer Immune deficiencies phase. Organic farmers replace synthetical external inputs by ecological principles (e.g. animal manure, leguminoses, predation) on purpose. Such a system focusses on maintaining among animals and human (management) of food chains among organisms. From an ecological point of view, organic beings demonstrate that farms could therefore be considered as ecosystems in a phase directly following the pioneer phase. their systems autonomy is weak. Life phenomena such as immunity and homeostasis are part of self-regulation (Rossignol et al, 1998). A living system adapts itself to changes in its environment as long as the regulation is not beyond its normal fluctuations of homeostasis (e.g. enhanced pulsation or loss of - turgidity during dry weather). When a variable is pushed towards its limit, there is talk of stress. In such cases, the variable loses its elasticity and is no longer able to adapt. When situations of stress continue, adaptation Ecosystems occurs by complete and irreversible changes in the Biotic Process and function physiology of the system (e.g. development of integration levels integration levels resistance against chemicals). If more extreme adaptations are required, genotypical changes become Organism Energy-storage necessary. They provide ecosystems with more Species Nutriënt cycles Population Food chain possibilities for variation or room for flexibility. They Ecosystem Decomposition are irreversible, however, for those individuals that Biocoenose Succession are part of the ecosystem concerned.

Self-renewal by self-regulation is a very important Ecosystem approach aspect of living systems. Organic farmers know how to manage such processes. They especially use the Figure 2. Ecosystems may be investigated along two different following methods. points of view: either from the structuring elements involved or from the system conditioning processes (Anonymous, - Organic matter (e.g. manure, plant extractions) 1993) is applied instead of synthetic chemicals. - Special organisms are used for natural production

28 of required substances, such as nitrogen fixing bacteria by leguminous plants or phosphate mineralisation by VA-Mycorrhyza (Lee, 2002). - Farm bound food webs are reinforced (Lee, 2002; Smeding, 2001).

We may conclude again that a relation exists between biodiversity and possibilities for enhanced self-regulation of farm bound natural resources.

What implications do the above three conclusions have for our possibilities of making sustainability in farming measurable? This question will be answered in the next chapters.

Quantification of sustainable land use Stoyke et al (1994) tried to make sustainable development of production farms quantifiable. They state that sustainable development of production farms is strongly related with farmers’ skill in getting the amount of non- renewable natural resources necessary for production reduced, under simultaneous maintenance of farm’s profitability. Van Leeuwen (1993) introduces the term ‘restorability’ of natural resources. He explains that ‘restorability’ is the regeneration of affected populations and ecosystems to the situation before the situation of impairing. Resto- ration of impaired ecosystems costs money and must be considered as costs made for renewing natural resources. Goewie and Van der Ploeg (1996) postulated that there is a relation between the reduction of non-renewable resources in land use and the maintenance of profitability of that same land. That relation is tightened by an orthogonal basis. The relation concerned is a hyperbola representing all different rates of sustainable land use.

A relation between sustainability (S) and self-organisation of a living system (s) was assumed. So

a) S ≈ f (s)

In the preceding chapter it was determined that the number of possibilities for self-regulation inside a production farm is proportional to its level of biodiversity (species per area unit).

b) s ≈ f (b)

Substitution of a) by b) results in

c) S ≈ f (b)

Consider this equation for a production farm: one using and one not using synthetic chemicals. We may expect that biodiversity in the farm using synthetic chemicals will be lower than in the farm that does not apply synthetic chemicals (Stoyke and Waibel, 1999). Let us compare both situations. First we consider the situation for a farm that uses synthetic chemicals, and then we do the same for an organic farm, so one that does not apply synthetic chemicals at all.

When a farmer uses synthetic chemicals, we must expect that biodiversity on his farm (number of species per m2) will be low (Eijsackers et al., 1995). So a low biodiversity must be a function of the high expenses (E) that a farmer must incur for synthetic chemicals. So

≈ ≈ d) b f (1/Esynthetic chemicals) f (1/Eexternal inputs)

When a farmer does not use synthetic chemicals, we must expect that biodiversity on his farm will be high (Kenmore, 1991; Smeding, 2001; Lee, 2002; Van Schoubroeck, 1999). This implies that more species will

29 compete for the same natural resources like nutrients, water or space (Ittersum et al, 1997). According to figure 1 such competition will result in lower production per ha. A lower production, or in other words, a higher loss of harvest, also implies a lower income. Financial losses might be quantified by taking into account current market prices (De Haan et al, 1993; Waibel 1999). So a loss of harvest, expressed in kilograms per ha times the market price of the mainstream commodity involved, could indicate the reduction of income. This figure could be considered as the price that a farmer has to pay if he wishes to produce organically (without synthetic chemicals). In this case, the farmer has to rely on biological control systems, on possibilities for crop rotation (rational application of predators and antagonists) and on organic manure, available at his own farm. We call such farm- bound natural resources as “internal input”. Our way of reasoning permits us to conclude that the price for farmer’s confidence in his farm-bound natural resources is quantifiable, namely in the reduction of the actual production times the market price of the commodity involved. So

≈ ≈ e) b f (Efarm bound natural resources) f (Einternal inputs)

Substitution of equation e) in d) results in

≈ f) E internal inputs 1/E external inputs

This is a hyperbola, graphically presented by figure 3

How to measure sustainability in farming systems? Figure 3 provides us with an interesting opportunity for making a certain amount of sustainability measurable. Therefore we have to consider the tangent of the hyperbola. So

E external inputs g) α = E internal inputs

Both expenses (E) are quantifiable, so a must be knowable. When α > 45o, than the farming system involved must be considered as unsustainable (the farm consumes proportionally too much irreversible natural resources). When α < 45o then the farming system involved must be considered as sustainable (the farm leaves proportionally sufficient irreversible natural resources). But what happens if α = 45o? α o When = 45 , we expect that E external inputs = E internal inputs or in other words, a loss of income will be compensated by a similar reduction in costs. That happens if the tangent touches the hyperbola at its summit. At this point the hyperbola establishes a type of land use that we call “sustainable agriculture”. At this point the internal farm-bound natural resources are dynamic enough to buffer applied external inputs and to compensate income reduction due to lower production ambitions. The summit of the hyperbole thus sets a form of agricultural land use that must be also sustainable from a farm social-economical point of view.

This hypothesis also offers an interesting starting point for governmental policy making. For the situation where α = 45o, entrepreneurs could make their farm more sustainable by themselves without loss of profitability since costs are lowered without loss of produce. However, when α > 45o and the government wants to make agriculture more sustainable, then it will have to subsidise. In the case of α < 45o and the government will not subsidise, market prices should increase. When neither subsidies nor elevated market prices are possible and the government compels sustainability by laws and regulations, then the farmer pays the bill, which is not an acceptable option either.

Strengths and weaknesses of the concept ≈ Figure 4 shows the hyperbola E internal inputs 1/E external inputs at a randomly chosen site of the abscissa and ordinate. But what does it mean when the hyperbole appears at other sites between abscissa and ordinate? We

30 Figure 3. Graphical presentation of equation f). The curve sets all types of agricultural and forest land use that were realised in practice. The position of each type of land use, indicated at the hyperbola, is arbitrary. The summit must be of a special meaning. The figure makes two things clear. First, a high production goal cannot meet demands for sustainability and a low production goal cannot meet demands for profitability. Second, integrated and ecological land use are two types of land use with differing priorities. Integrated farming or forestry gives an accent on profitability with sustainability as a side product. Ecological agriculture and forestry do the opposite. They seek profitability after having set the principles for sustainability. Which one is the best is a matter of political and ethical decision-making

consider four situations, when the hyperbola appears: • close to the origin (of abscise and ordinate); • far from the origin; • moved away over the ordinate from the origin; • moved away over the abscissa from the origin.

If the hyperbola shows up close to the origin of abscissa and ordinate and if its summit has the same distance to both axes, we may conclude that the reduction of external inputs, in compensation for the loss of production, makes no sense. Here we encounter a situation of exhaustion. Farming in such a situation is undesirable. We find such forms of land use south of the Sahara in Africa (Sanchez et al., 1995). This happens when soils have no form of buffering of water and nutrients. Availability of water or nutrients decreases quickly to a minimum (figure 5A).

If the hyperbola shows up far from the origin of abscissa and ordinate and if its summit also has the same distance to both axes, we may conclude the following. A reduction of external inputs for the compensation of a loss of production only makes sense if market prices are elevated. Here we encounter a situation where agriculture functions according to a free market system. In such a market, the consumer compensates all costs involved with the production of his food, including the costs for cleaning the environment, protection of nature and maintaining a health care system (De Haan et al., 1993). Such a situation is comparable with the market for industrial goods. All external costs involved with industrial production are paid by industries themselves. Industries finally charge the consumer. Here the polluter pays principle has been fully realised (figure 5B). In case a government desires to regulate the market (EU policy on agriculture for example), the government has to subsidise.

If the hyperbola is moved over the ordinate, away from its origin, we encounter the present situation of mainstream agriculture. This kind of land use is dependent on synthetic external inputs, water, capital and in

31 the near future, on transgenic organisms. In the last fifteen years agricultural sciences, forced by the new insights from environmental and medical sciences (Vito et al., 1993), developed new types of agricultural land use (figure 5C). Farming has become more and more efficient (Haverkort et al, 1997). That is to say, farmers can produce the same with smaller amounts of external inputs. The resulting type of agricultural land use is known as “integrated agriculture”. The basic principle in present agricultural research assumes that the ratio output (O) versus input (I) should tend to one time- wise, or

h) O / I → 1 ∆T Figure 4. The summit of the hyperbola indicates where agricultural land use fully buffers applied external inputs in a farming system. We may expect Computer modelling facilitated by electronic information that such buffering helps maintain self-organisation in farm-bound natural resources. So, the type of land systems made this principle achievable. The resulting farming use involved must be of a sustainable nature. Thus systems became capital intensive and together more friendly sustainable farming is the theoretical optimum between the already existing “integrated agriculture” for the surroundings of the production sites involved. on the one hand and “organic agriculture” on the Profitability of such farms has to come from making the most other. A “sustainable farm” practically comes into existence when the growing efficiency of external of up scaling (Van der Ploeg, 1999). So integrated farming must inputs in integrated systems on the one hand and result in large farms that fully separate land use for agriculture the growing effectiveness of productive capacities of farm-bound natural resources on the other, meet and land use for nature (WRR, 1992). There are signs that each other. We consider sustainable agriculture this kind of land use will not be accepted by the society therefore as a mix of the best of both types of land use and being acceptable, from a societal point of view since the loss of income, due to the reduction of harvest, is compensated by an equal reduction of costs. If not, then the price of food should increase or the government must subsidise. Arrows indicate where policy making on organic or integrated farming should have to strive for.

(Anonymous, 1996). Consumers’ and environmental protection organisations fear permanent dependency on chemicals and multinationals. Consumers’ resistance against gene technology in open field systems or unfriendly kinds of animal husbandry might Costs for internal inputs Costs for internal inputs be another herald (De Jonge and Goewie, 2000).

Figure 5. Four positions of the hyperbola representing the sets of all If the hyperbola is moved over the abscissa, types of agricultural land use realised in practice. Situation A (left, away from its origin, we encounter the present above) represents a situation where reduction of external inputs is almost useless, as farming must happen in a resource poor (exhausted) situation of organic land use (figure 5D). This production situation. Situation B (right, above) represents a situation kind of land use depends on available farm- where reduction of external inputs is fully compensated by market prices. Situation C (left, below) represents the present situation of mainstream bound natural resources. In the last ten years, or integrated farming. Situation D (right, below) represents the situation much research has been done in this field. The of organic farming basic principle followed by this so called

32 “organic agriculture” says that the farmer is not allowed to introduce more nutrients (external inputs in general) to his land than what his crop or husbandry will remove by harvest or selling meat or milk. In other words, the farmer must produce under the strict condition of no more input (I) should be applied than what can be extracted by output (O), right from the beginning on, or

i) O - I = 0 (right from the beginning of the production in question)

Biology and ecology as sciences and facilitated by information technology made this principle applicable.

Conclusion Our description of sustainability in farming accommodates various realistic types of land use. Land use is in a state of sustainable development if the managers involved permanently strive for equilibrium between what they apply to and what they remove from their land. So, ecosystems will not be burdened in an irreversible way. Integrated management of land use systems strive for that equilibrium by trying to produce the same with decreasing amounts of external inputs involved. Organic management of land use systems substitute external inputs with organic inputs. Organic inputs are obtained from natural resources like biological nitrogen fixation, biological control of pests or maintaining a high level of permanent soil fertility. Such resources are found in farm- or forest-bound ecosystems. Management of such systems is therefore ecosystems oriented and pays attention to the self-organising properties of the ecosystems concerned.

Another conclusion refers to the kind of scientific research needed. Up to now, most agricultural research is organisms (e.g. crops, animals, pests) oriented (Goewie, 1997). So we learn more about less or, we spend more money on less needed knowledge. Sustainable development of agriculture needs systems oriented knowledge. This demands a less disciplinary or commodity oriented attitude of researchers and research institutes.

Acknowledgements This article began as a discussion with scientists of EMBRAPA Clima Temperado, the Brazilian research organisation for agriculture and nature in the state of Rio Grande do Sul and with the farmers of the same state. The author are grateful to Dr. Bonifacio Nakasu, general director of EMBRAPA Clima Temperado, for his kind hospitality and support. I thank Dr. Lee from the Horticultural research Centre of the University of Bogotá Jorge Tadeo Lozano in Colombia for reading the manuscript and for useful suggestions and improvements. Last but not least, I would like to thank Prof. Dr. Ir. Oldeman for his inspiration and discussion concerning the ideas laid down in this article.

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35 36 Dear Professor Oldeman,

With this I send you greetings and congratulations on your marvelous wonderful retirement. As the old adage goes any successful person is built on the shoulders of skillful and dedicated individuals who generously give off their life to cooperatively contribute to a common goal. This is also the case in your history, Professor Roelof Oldeman, who, by chairing Silviculture & Forest Ecology at Wageningen University over the years, effectively supported us till we’ve successfully reached this far in our life. We do recognize that and thank you for a “job well done” on behalf of future generations of students, researchers and professors who’ll benefit from your life’s work! Please be reminded that I’ve taken note of the contact address of your selected works and will get back to Mr.Taselaar as soon as I’ve the bearing power to do so. Till next time, once again congratulations; have my greetings and please do extend same to madam. Best wishes for a healthy and peaceful Christmas and Prosperous New Year in advance. Best regards,

Eddie [Glover] Researcher Department of Forest Ecology Viikki Tropical Resources Institute (VITRI) P. O. Box 28 (Koetilantie 3, Viikki) FI – 00014 University of Helsinki Helsinki Finland

37 Roelof, te souviens-tu…….. ? ou…la Guyane de jadis en quelques photos

Le “Centre ORSTOM de Cayenne” dans les années soixante, tel que nous l’avons connu, simple, dépouillé, familial. Au fond, l’ancien « han- gar des roches » de l’époque des géologues, où naîtra et se développera la botanique guyanaise “moderne” pendant des décennies…

…et le tout nouvel herbier que tu venais Ton bureau n’avait pas de fenêtres car tu le de créer ! C’est Wil qui découpa et colla voulais plus propice à la réflexion, sans regards les centaines de casiers en carton qui vers l’extérieur. contenaient les premières collections.

38 Seuls moyens d’accès aux forêts de l’intérieur : l’avion, les pirogues et… la marche à pieds !

A travers le hublot du vieux “Dragon”, pas un détail de la végétation, Prêt pour de nouvelles aventures sur les rivières Approuague et pas une cîme ne t’échappaient (à droite Joseph Kong dit “Ti-Jo” et, Arataye... Que de kilomètres parcourus sur les fleuves et les au fond, Jean-Marie Brugière et Jean Lescure dit “Le-Père-La- “criques” pour l’inventaire méthodique que tu avais entrepris ! Grenouille”). Jamais ta pipe ne te quittait, quoi qu’il arrivât.

Les cours d’eau de Guyane sont loin d’être de “longs fleuves tranquilles” et le passage des “sauts” est souvent spectaculaire. En haut, halage à la “cordelle” tandis que notre fidèle Burgot maintient la pirogue. En bas, “Tatou” guide le canot à la pagaie.

39 Après les épreuves sportives, il fallait...réparer les dégâts et les trous dans la coque. C’est alors que l’équipage sollicitait ta bonne volonté pour...faire contre-poids pendant les travaux!

Les «photos de famille» n’ont rien de conventionnel au fond des “grands bois”!

De gauche à droite :Ti-Dontaire, Roelof, Burgot, Tiburce, Lébène, Jean-Jacques, Chiquito, Georges et, assis au premier rang, Edgar, Didier et Angelo. Même les chiens posent pour la photo !

40 Est-ce toi qui est grand ou les Amérindiens qui sont petits ? (mission A Saül, au cœur de la Guyane, tu fus le premier à développer un sur la rivière Yaroupi en 1970) programme de recherches botaniques et à implanter une petite station permanente....dans le vieux presbytère, générausement prêté par l’évêque!

Mais, parfois, tu savais aussi céder aux tentations de la vie mondaine!

…chez notre Directeur de Centre, Jean-Marie Brugière, à l’occasion d’un barbecue amical, en compagnie de Denis Groéné et de Jean-Jacques de Granville…

41 …et au cocktail offert à l’hôtel Montabo par Guy Camus, alors Directeur Général de l’ORSTOM.

Roelof, merci d’avoir guidé mes premières recherches sous les tropiques américains et de m’avoir fait découvrir et aimer la GuyaneÉ. J’y suis encore, 34 ans plus tard!

Jean-Jacques

42 Architectures de plantes de l’Ile Robinson Crusoe, Archipel Juan Fernández, Chili

Francis Hallé Philippe Danton Christophe Perrier

Il y a plus de trente ans, Roelof A.A. Oldeman isolait et délimitait les concepts de base de l’architecture — séquence, modèle, réitération— en forêt humide de Guyane ; l’un de nous faisait de même en Côte d’Ivoire et au Congo (Hallé et Oldeman, 1970; Oldeman, 1974; Hallé et al., 1978). Dans ce type de forêts à très bas niveaux de contraintes climatiques, il est admis que les concepts architecturaux fonctionnent, permettant à la fois de reconnaître les plantes et de mieux les décrire. A l’occasion d’un séjour sur l’île Robinson Crusoe*, il nous a semblé intéressant de tester la validité de ces concepts dans un environnement climatiquement rude, profondément différent de celui où ils ont été définis —et sur une flore endémique d’une originalité exceptionnelle.

L’Archipel Juan Fernández A 33° de latitude Sud, l’archipel Juan Fernández se situe dans le Pacifique, au large du port chilien de Valparaíso. Il est constitué de trois îles et de plusieurs cailloux isolés (morros). (Figure 1).

Alejandro Selkirk, (4464 hectares), est à 800 km à l’Ouest de Valparaíso, d’où son nom espagnol de Masafuera. D’accès difficile, sans port, elle ne fournit qu’un habitat temporaire; elle contient le point Figure 1.- L’archipel Juan Fernández, à 700 km à l’Ouest de Valparaíso culminant de l’archipel, le Cerro los

Inocentes (1319 m). (Figure 2).

Santa Clara, la plus petite (223 hectares), n’est qu’un îlot sec et inhabité. Son nom ancien d’Ile des Chèvres évoque la disparition de la végétation arbustive qui la couvrait. (Figure 3).

Robinson Crusoe, ou Masatierra, est à 670 km du continent. Sa superficie est de 4711 hectares. Elle abrite le seul village permanent de l’archipel, San Juan Bautista (600 habitants); elle est desservie par bateau depuis Valparaiso et par avion depuis Santiago du Chili (Danton et al, 1999) (Figure 3).

Géologie, Topographie Figure 2.- L’île Alejandro Selkirk ou Masafuera. Il s’agit de trois îles océaniques résultant vraisemblablement de l’activité d’un " point chaud ". Les relevés bathymétriques révèlent des

43 montagnes sous-marines qui complètent l’archipel, formant une chaîne Est-Ouest de 400 km de longueur (Stuessy et al., 1984) (Figure 4).

Santa Clara et la partie Ouest de Robinson Crusoe sont sorties de l’eau les premières, il y a 5, 8 millions d’années, d’où une érosion très avancée. La partie Est de Robinson Crusoe est plus jeune - entre 4,2 et 3,8 millions d’années - et le relief y est marqué par de larges vallées propices à l’installation humaine. Alejandro Selkirk, la plus jeune, n’est sortie de l’eau qu’il y a Figure 3.- Les îles Robinson Crusoe, ou Masatierra, et Santa Clara. 2,4 millions d’années et l’activité volcanique s’y faisait encore sentir il y a un million d’années, ce qui explique son relief jeune marqué de profonds canyons. Du fait qu’elles sont récentes, ces trois îles ont une topographie très forte, voire vertigineuse. Des falaises verticales de plusieurs centaines de mètres de hauteur y sont fréquentes.

Les roches, essentiellement basaltiques (Stuessy et al., Figure 4.- Des montagnes sous-marines complètent 1984) portent des sols acides qui peuvent être très fertiles, l’archipel Juan Fernández. D’après Stuessy et al. (1984). mais qui sont également fragiles, peu épais, susceptibles de glisser vers la mer sur des pentes fortes ou d’être détruits et emportés par l’érosion éolienne, surtout s’ils sont déforestés.

Le Climat Le climat est tempéré chaud, l’archipel Juan Fernández étant situé à la même latitude, au Sud, que Madère dans l’hémisphère Nord. Les températures à San Juan Bautista sont en moyenne de 18°C, avec une amplitude de 6 à 25,5°C. L’hiver, de juin à septembre, est sensible mais doux ; le gel n’existe pas à Robinson Crusoe (Masatierra), mais il existe à Alejandro Selkirk (Masafuera) où les altitudes sont plus élevées et où la neige est parfois signalée sur les sommets (Skottsberg, 1952).

Les vents, principalement du secteur Sud, sont parfois forts, atteignant 50 nœuds (= 90 km/h). La pluviométrie est de 1041,5 mm à San Juan Bautista, avec une variabilité interannuelle importante, de 871 à 1459 mm. Toutefois, ces chiffres ne concernent que les basses altitudes, les seules où la pluviométrie ait été relevée ; il est certain qu’elle est beaucoup plus forte sur les hautes pentes si l’on en juge par la riche flore de fougères qui s’y déploie (Skotttsberg, 1952).

Les sommets sont très fréquemment dans les nuages, ce qui est un élément important de l’écologie des hautes pentes ; les orages seraient rares, voire absents, mais la grêle a été signalée.

Avec de telles conditions climatiques, on conçoit que la végétation d’origine ait été forestière, du niveau de la mer jusqu’aux sommets les plus élevés, mais l’état actuel de dégradation oblige à prendre en compte le peuplement humain, ainsi que les animaux et les végétaux qui l’ont accompagné.

Le Peuplement humain Les îles furent découvertes en novembre 1574 par le navigateur espagnol Juan Fernández qui recherchait une route maritime permettant de descendre vers le Sud, le long de la côte chilienne, tout en échappant au courant

44 de Humboldt. A Masatierra, Juan Fernández débarqua les premiers habitants, ainsi que quelques couples de chèvres et —vraisemblablement— de rats. C’est à cette époque que débute le déboisement des basses pentes, notamment pour la construction navale et l’exploitation du bois de Santal.

Après divers échecs de l’implantation humaine, une population stable s’installa en 1877, avec la création de conserveries par Alfred de Roth. L’activité industrielle contribua à l’augmentation de la population ainsi qu’à l’implantation d’animaux domestiques, moutons, vaches, chevaux, et de divers animaux sauvages, lapins de garenne et Coatis. Les liaisons de plus en plus fréquentes avec le continent permirent l’arrivée de nombreuses espèces végétales dont certaines devinrent des pestes.

La population actuelle de l’archipel est évaluée à 600 personnes; le tourisme, encore timide, tend à s’amplifier.

La Flore endémique Les jugements élogieux n’ont jamais manqué, dès les premières expéditions botaniques. “Les îles Juan Fernández sont fameuses pour leurs formes endémiques si nombreuses et si particulières”; cette phrase de Carl Skottsberg date de 1922 (dans Skottsberg, 1952). “Le taux d’endémisme est l’un des plus élevés de la planète” (Pascal, 2002; Danton, en prép.) puisqu’il est évalué à 62,5%. Il s’agit de “l’une des flores endémiques les plus intéressantes du monde” (Marticorena et al., 1998).

Tout ceci a justifié dès 1935 l’instauration du Parque Nacional Archipiélago Juan Fernández, qui couvre 92% de la surface des. îles et, en 1977, l’inscription de l’archipel parmi les Réserves Mondiales de la Biosphère par l’UNESCO.

On compte actuellement dans l’archipel 211 espèces indigènes de plantes vasculaires, dont 132 endémiques. Le nombre des genres endémiques s’élève à 11.

Thyrsopteris Kunze, 1 sp. dans les fougères Dicksoniaceae Megalachne Steudel, 2 sp. et Podophorus Philippi, 1 sp. disparue, dans les Poaceae Juania Drude, 1 sp. dans les Palmiers Cuminia Colla, 1 sp. avec deux variétés, dans les Lamiaceae Lactoris Philippi, 1 sp. dans les Lactoridaceae Selkirkia Hemsley, 1 sp. dans les Boraginaceae, et enfin, dans les Asteraceae : Centaurodendron Johow, 2 sp. Dendroseris D. Don, qui est, avec 11 sp. le plus grand genre de l’archipel. Robinsonia D.C., 8 sp. Yunquea Skottsberg, 1 sp.

En outre, l’île Robinson Crusoe compte une famille endémique, celle des Lactoridaceae Engler, qui se limite à une espèce unique, Lactoris fernandeziana Philippi, dont la position systématique fait l’objet de nombreuses hypothèses (Tobe et al., 1993).

Les menaces sur la Flore endémique Cette remarquable flore endémique est, hélas, en voie de disparition du fait de la pression qu’exercent sur elle depuis quatre siècles les populations humaines des îles accompagnées d’une série de pestes animales et végétales. Le danger de disparition est tout à fait réel : le Santal endémique, Santalum fernandezianum F. Phil. semble être éteint depuis 1910 par suite de sa surexploitation ; le genre Podophorus n’a jamais été retrouvé et il en est de même pour Robinsonia macrocephala Decne., Eryngium sarcophyllum Hook.& Arn. ou Chenopodium nesodendron Skottsb., recherchés activement, mais sans succès, depuis 1997. Robinsonia berteroi (D.C.) Sanders, S.&M., n’est plus représenté que par un arbre mâle, d’ailleurs en très mauvais état, et sur Masafuera, Dendroseris gigantea Johow est dans le même cas.

45 En ce qui concerne les pestes animales —rats, lapins, moutons, coatis, chèvres, vaches, chevaux— elles ont une activité d’autant plus destructrice que la faune des îles ne comportait à l’origine aucun mammifère terrestre. Les espèces végétales introduites sont toutes potentiellement dangereuses pour la flore locale; il convient cependant d’en distinguer deux groupes.

Les arbres exotiques plantés à partir de 1930 —Cyprès, Pins, Eucalyptus, Albizia, Acacias— dont l’éradication n’est pas souhaitable puisqu’ils constituent la ressource en bois de San Juan Bautista. Il est cependant nécessaire et relativement aisé de limiter l’extension de ces espèces en procédant à des abattages dès qu’elles s’implantent à une altitude supérieure à 150 mètres et en dehors des abords du village (Bahia Cumberland).

Les pestes végétales représentent un problème beaucoup plus grave, vis-à-vis de la flore endémique; elles sont plus dangereuses encore que les pestes animales car elles sont plus difficiles à éradiquer. Il s’agit surtout de trois espèces exotiques:

• Le “Maqui”, Aristotelia chilensis (Elaeocarpaceae), un petit arbre à croissance rapide introduit pour la fabrication des casiers à langoustes. • La “Zarzamora”, Rubus ulmifolius (Rosaceae), une ronce d’origine européenne d’une extrême vigueur introduite vers 1920; la flore d’origine ne comportant aucune liane, les arbres locaux se laissent rapidement surcimer et meurent. • La “Murtilla”, Ugni molinae (Myrtaceae), un arbrisseau importé de l’île de Chiloe, au Sud du Chili, qui tend à recouvrir les crêtes d’un manteau monospécifique au détriment des endémiques et notamment de l’espèce locale Ugni selkirkii.

Le trio Maqui-Zarzamora-Murtilla est rendu plus dangereux encore par la présence du Merle Turdus falklandii magellanicus, qui disperse les graines de ces trois plantes zoochores depuis le niveau de la mer jusqu’aux points culminants des îles.

Dans ces conditions, l’un des buts de l’approche architecturale va être d’interpréter l’évidente supériorité des pestes végétales sur les espèces endémiques. Les caractères architecturaux permettent-ils d’expliquer qu’une plante soit “peste” ou “victime”?

L’Approche architecturale Ce qui suit concerne essentiellement Robinson Crusoe ou Masatierra qui est d’ailleurs la plus riche des trois îles sur le plan floristique. Quelques espèces originaires de Masafuera et de Santa Clara ont été incluses dans l’étude.

Intentionnellement, il n’a été tenu compte ni des arbres exotiques utilisés pour le reboisement (voir plus haut), ni de la flore des jardins; ces derniers, groupés autour de San Juan Bautista, sont souvent très soignés, riches en fruitiers —Agrumes, Châtaigniers, Nispero, Goyaviers, Avocatiers, Papayers, Poiriers, Noyers, Oliviers, Figuiers, Vigne, Pêchers, Grenadiers, etc…— ainsi qu’en plantes ornementales —Troènes, Montbretias, Valérianes, Hortensias, Balsamines, Camelias, Scabieuses, Roses, Pelargoniums, Bougainvillées, etc…

Sur les 22 modèles architecturaux actuellement recensés, 12 ont été retrouvés parmi les plantes de Masatierra ; il est intéressant de constater que le concept de modèle architectural est valable et que les endémiques prennent place aisément —à quelques détails près— dans les modèles connus (Hallé et Oldeman, 1970; Hallé et al., 1978).

Le modèle de HOLTTUM est représenté par cinq Asteraceae:

46 Dendroseris pinnata (Bertero ex Decne.) Hook. et Arn. (Figure 5). Dendroseris berteroana (Decne.) Hook. et Arn. Dendroseris regia Skottsb., endémique de Masafuera. Centaurodendron palmiforme Skottsb. Yunquea tenzii Skottsb., connu uniquement du sommet du Cerro El Yunque.

Carl Skottsberg avait repéré cette forme de plante; parmi ce qu’il appelait les “Arbres en rosettes”, il distinguait le “type palmiforme” à inflorescence terminale, ce qui correspond à notre modèle de HOLTTUM. Cette architecture très particulière, ajoutée à la présence de feuilles composées pennées, nous semble justifier le maintien du genre Phoenicosoris Skottsb. dont le caractère majeur, sur le plan architectural, est la monocarpie.

Le modèle de CORNER a été trouvé chez deux fougères arborescentes:

Dicksonia berteroana Figure 5.- Dendroseris pinnata, une (Colla) Hook, Asteraceae monocarpique qui atteint 5 mètres de hauteur, avec une faible Dicksoniaceae. croissance en diamètre. A gauche, le Blechnum cycadifolium stade juvénile. (Colla) Sturm, Blechnaceae (Figure 6).

Ces deux espèces marquent profondément les paysages, la première en sous-bois, la seconde sur les pentes ensoleillées où, sous le nom de “Pluma indio”, elle est devenue symbolique de la végétation insulaire. Il caractérise aussi “la Chonta”, Juania australis (Mart.) Drude ex Hook. f., Arecaceae, et Plantago fernandezia Bertero ex Barnéoud, Plantaginaceae, qui atteint parfois une hauteur de 4 mètres sur les falaises boisées (Figure 6).

Le modèle de CHAMBERLAIN semble ne concerner que le genre Gunnera L. Sa présence a été vérifiée chez G. peltata Phil. et G. bracteata Steud ex Bennett, Gunneraceae (Figure 7).

Le modèle de TOMLINSON est représenté par Thyrsopteris elegans Kunze, une fougère arborescente rampante des Dicksoniaceae (Figure 8); par Peperomia berteroana Miq., Piperaceae des falaises (Figure 8); par deux Campanulaceae, Wahlenbergia fernandeziana A. DC. et W. Figure 6.- A gauche, Blechnum grahamiae Hemsl., également des falaises, et enfin par une Lobeliaceae cycadifolium, une fougère arborescente introduite depuis la côte du Chili et naturalisée, Lobelia tupa L. de 3 mètres de hauteur ; des groupes de feuilles fertiles (au centre) alternent avec des groupes de feuilles Le modèle de LEEUWENBERG est de très loin le mieux représenté assimilatrices. A droite, Plantago fernandezia, une Plantaginaceae dans la flore locale de Masatierra. Carl Skottsberg donne une excellente monocaule atteignant 4 mètres de description de cette forme qu’il nomme le “type Candélabre”. La liste hauteur. est longue, des plantes qui se conforment au modèle de Leeuwenberg:

47 Chenopodium sanctae-clarae Johow, Chenopodiaceae. Chenopodium crusoeanum Skottsb., Chenopodiaceae (Figure 9). Eryngium bupleuroides Hook. et Arn., Apiaceae, “Pomponero” (Figure 9). Eryngium fernandezianum Skottsb., Apiaceae. Eryngium inaccessum Skottsb., Apiaceae. Eryngium sarcophyllum Hook.& Arn., Apiaceae, endémique de Masafuera. Selkirkia berteroi (Colla) Hemsl., Boraginaceae. Ochagavia elegans Phil., Bromeliaceae, “Ajo dulce” (Figure 9), ainsi que chez bon nombre d’Asteraceae endémiques: Centaurodendron dracaenoides Johow. Dendroseris gigantea Johow. Dendroseris litoralis Skottsb., “el col de Juan Fernández”, une plante populaire, souvent plantée à San Juan Bautista (Figure 10). Dendroseris macrantha (Bertero & Decne.) Skottsb. Dendroseris macrophylla D. Don. Dendroseris marginata (Bertero ex Decne.) Hook. et Arn. Erigeron fernandezianus (Colla) Solbrig (Figure 10). Robinsonia evenia Phil. (Figure 10). Robinsonia gayana Decne. (Figure 10). Figure 7.- Gunnera peltata, Gunneraceae. Les Robinsonia gracilis Decne. (Figure 10). inflorescences sont terminales et, le long du tronc, des Robinsonia masafuerae Skottsb., endémique de articles longs alternent avec des articles courts. Les Masafuera. limbes foliaires atteignent 1,5 mètre de diamètre. Robinsonia thurifera Decne., “Incienso”.

Le modèle de SCARRONE nécessite une mention particulière; il n’est représenté sous sa forme typique que chez deux endémiques devenues extrêmement rares, dont la ramification en étages est clairement visible:

Dendroseris neriifolia (Decne.) Hook. & Arn. dont il n’existe plus que deux exemplaires dans la Quebrada El Lapiz, mais qui est cultivé dans certains jardins de San Juan Bautista (Figure 11) et Robinsonia berteroi (DC.) Sanders, Stuessy & Marticorena, dont on ne connaît plus qu’un exemplaire mâle, en mauvais état, dans une vallée forestière située sous le Mirador de Selkirk, en direction de l’Ouest. L’architecture de cette plante a pu être confirmée grâce à la photographie publiée par C. Skottsberg (1952) (Figure 12).

Le modèle de SCARRONE présente à Masatierra une intéressante variante, dans laquelle se trouve maintenue la ramification en étages antérieure à la floraison ; mais lorsque cette dernière apparaît distalement sur un axe, celui-ci se défolie et finit par mourir Figure 8.- A gauche, Thyrsopteris elegans, une fougère arborescente atteignant une hauteur de 4 mètres. Les folioles basales (en gris) après la dispersion des fruits. La nécrose sont seules fertiles. A droite, Peperomia berteroana, une Piperaceae progresse vers le bas, soit jusqu’aux ramifica- poussant sur les falaises; les tiges dépassent 1 mètre de longueur. tions inférieures, soit jusqu’au niveau d’un ou

48 plusieurs relais qui apparaissent postérieurement à la floraison. Plusieurs mètres d’axes peuvent être perdus par cet étrange mécanisme qui n’est pas sans analogie avec la monocarpie du modèle de HOLTTUM. Les axes morts ne sont pas soumis à élagage mais restent dressés au-dessus de la plante, offrant une forte prise au vent; leur disparition, par simple érosion du bois mort, peut nécessiter un ou deux ans. Cette variante du modèle de SCARRONE a été trouvée par Skottsberg chez Robinsonia macrocephala Decne. [syn.: Symphyochaeta macrocephala (Decne.) Skottsb.], dont il analyse et figure le mécanisme de croissance. Cette espèce endémique est Figure 9.- A gauche, Chenopodium crusoeanum, une actuellement disparue. Fort heureusement, cette Chenopodiaceae arbustive atteignant 3 mètres de haut; la architecture originale subsiste chez: ramification est abondante et d’aspect anarchique. Au centre, Eryngium bupleuroides, une Apiaceae dont la ramification est, au contraire, absolument schématique. Hauteur: 1,5 mètre. A droite, • Dendroseris micrantha (Bertero ex Decne.) la ramification de la Bromeliaceae Ochagavia elegans est également régulière et aisément prévisible; cette plante forme des coussins Hook.& Arn. observé sous le rocher du Camote sur les falaises. (Figure 13) et • Dendroseris pruinata (Johow) Skottsb. dont un bel exemplaire a été vu au Cerro Alto (Figure 14). Cette même variante du modèle de SCARRONE existe chez une endémique des Canaries, Aeonium holochrysum, Crassulaceae, et différentes autres espèces du genre Aeonium Webb. et Berth. Le modèle de KORIBA n’a été trouvé que chez Pernettya rigida (Bertero ex Colla) DC., la seule Ericaceae de l’archipel, localement appelée " Murtillón " (Figure 15). Le modèle de STONE apparaît chez une Grossulariaceae, Escallonia callcottiae Hook.& Arn. (Figure 16) ainsi que chez le “Boldo”, Peumus boldus Molina, Monimiaceae, une plante médicinale chilienne plantée dans les jardins de San Juan Bautista.

Le modèle de ATTIMS est celui de Coprosma oliveri Fosberg, Rubiaceae. Haloragis masatierrana Skottsb., Haloragidaceae (Figure 17), Rhaphithamnus venustus (Phil.) B.L. Rob., une Verbenaceae arborescente connue sous le nom de “Juan Bueno” et peut-être aussi de

Figure 10.- Le modèle de LEEUWENBERG chez les Asteraceae endémiques. A gauche, en bas, Erigeron fernandezianus, une espèce sub-herbacée atteignant 1 mètre de haut; il est fréquent que l’axe 1 porte deux étages d’axes 2. A gauche, en haut, Dendroseris litoralis, “el col de Juan Fernández”; ce petit arbre aux beaux capitules jaunes atteint 4 mètres et ses feuilles peuvent avoir près d’un mètre de longueur. Au milieu, un exemplaire femelle de Robinsonia gayana. Hauteur : 1,2 mètre. A droite, en bas, Robinsonia gracilis. Hauteur: 2 mètres. A droite, en haut, Robinsonia evenia, un arbuste atteignant une hauteur de 2,5 mètre, représenté ici dans sa position habituelle, épiphyte sur une fougère arborescente.

49 l’Urticaceae Boehmeria excelsa (Bertero ex Steud.) Wedd. qui semble pouvoir réaliser indifféremment ce modèle ou le suivant.

Le modèle de RAUH occupe la deuxième place en fréquence et contient quelques espèces importantes pour l’écologie insulaire: Aristotelia chilensis

Figure 11.- Dendroseris neriifolia, une Asteraceae Figure 12.- Robinsonia arbustive de 2 mètres de hauteur, à tronc monopodial; berteroi, une Asteraceae arbustive d’une hauteur totale de les étages de branches sont indiqués par des flèches. 5,5 mètres; les étages de branches sont indiqués par des flèches.

(Molina) Stuntz, Elaeocarpaceae, le “Maqui” (Fig. 18). Boehmeria excelsa (Bertero ex Steud.) Wedd., Urticaceae. Voir ci-dessus. Cuminia eriantha (Benth.) Benth., Lamiaceae Drimys confertifolia Phil., Winteraceae, le “Canelo” (Figure 18). Fagara mayu (Bertero ex Colla) Engl., Rutaceae, le “Najanrillo” (Fig. 18).

Figure 13.- Dendroseris pruinata, une Asteraceae Figure 14.- Dendroseris arbustive chez laquelle la floraison entraîne des micrantha est un autre exemple d’Asteraceae chez laquelle la nécroses d’axes (en noir). Hauteur : 2 mètres. A droite, floraison entraîne des nécroses d’axes (en noir). Hauteur: 1,5 la forme de jeunesse. mètres.

Ugni molinae Turcz., Myrtaceae, la “Murtilla”. Ugni selkirkii (Hook.& Arn.) O. Berg., “Murtillón”.

Le modèle de CHAMPAGNAT est celui du “Palqui”, Cestrum parqui L’Hérit., une Solan- aceae chilienne, (Figure 19), de la “Zarzamora”, Rubus ulmifolius Schott, Rosaceae (Figure 23) et de Berberis corymbosa Hook. et Arn.

Enfin, le modèle de TROLL est représenté

Figure 15.- Pernettya rigida est la seule Ericaceae des îles Juan Figure 16.- Escallonia Fernández ; c’est aussi le premier exemple du modèle de calcottiae est une Grossulariaceae buissonnante de 2 mètres. KORIBA dans cette famille. Un arbuste de 1 à 2 mètres de Les très vieux exemplaires deviennent des arbres. hauteur.

50 par la “Luma”, Myrceugenia fernandeziana (Hook. et Arn.) Johow, Myrtaceae , qui est l’arbre le plus abondant dans les forêts de Masatierra (Figure 20). La plagiotropie généralisée du modèle de TROLL est bien visible sur les jeunes “Lumas” en sous-bois; l’adulte a des axes dressés, une sexualité latérale et se conforme au modèle de ATTIMS.

Le modèle de TROLL a également été trouvé chez la seule Flacourtiaceae de l’île, Azara serrata Ruíz & Pavón, chez la Papilionaceae Sophora fernandeziana (Phil.) Skottsb. et Lactoris fernandeziana Phil., endémique de Masatierra et membre unique de la famille des Lactoridaceae (Figure 21).

Avec 12 modèles recensés pour 4711 hectares, la flore de Masatierra est Figure 17.- Haloragis masatierrana relativement riche en architectures, ce qui n’est pas surprenant, compte tenu est une Haloragidaceae herbacée de la latitude (33°). La diversité architecturale diminue à mesure que l’on ou sous-ligneuse de 1 mètre de hauteur. s’éloigne de l’Equateur (Hallé et al., 1978) et ce chiffre de 12 modèles paraît conforme au caractère “tempéré chaud” du climat de l’île.

Il reste à déterminer si ces données architecturales permettent d’interpréter, au moins dans une certaine mesure, la supériorité du trio Maqui-Zarzamora- Murtilla sur les endémiques et, inversement, l’évidente vulnérabilité de ces dernières.

Figure 18.- Le modèle de RAUH. A gauche, le Maqui, Aristotelia chilensis, une Elaeocarpaceae arborescente devenue l’une des principales pestes végétales de l’île. Au centre, Drimys confertifolia, Winteraceae; cet arbre atteignant 15 mètres est l’une des composantes principales des forêts primaires. A droite, le Naranjillo, Fagara mayu, Rutaceae, atteint 20 mètres de hauteur: c’est le plus grand arbre de la forêt primaire.

L’Architecture des pestes végétales Figure 19.- Cestrum parqui est une La liste ci-dessus concerne exclusivement les modèles et elle ne Solanaceae buissonnante atteignant mentionne pas la réitération de ces modèles (Hallé et al., 1978), autre 2 mètres de hauteur. composante de l’architecture végétale. La forme de croissance observée sur le terrain est un ensemble formé par ces deux composantes, le modèle et sa réitération.

Nous proposons l’idée qu’il existe une balance entre ces deux composantes: lorsque l’une augmente, l’autre diminue, d’où résulte un continuum entre deux situations extrêmes; quelques exemples sont ici nécessaires.

51 L’un des extrêmes est constitué par des plantes incapables de réitérer et dont la forme reste exactement, pendant toute leur vie, celle de leur modèle architectural: Cocos, Elaeis, Juania et beaucoup d’autres palmiers sont dans ce cas.

Une situation presque identique s’observe chez des plantes dont la réitération se limite à la régénération des axes amputés, ou des axes dont l’orientation initiale a été accidentellement modifiée: Cyathea, Dicksonia, Encephalartos, Cycas, Araucaria, Abies, quelques Angiospermes comme Pandanus, Garcinia, Platonia, Allanblackia, Schumanniophyton. Cette situation est rare; elle ne concerne que des plantes anciennes, des arbres tropicaux pour la plupart, dépourvus d’aptitudes à la compétition entre espèces.

L’essentiel du continuum est constitué par des plantes chez lesquelles les deux composantes s’expriment, aisément visibles l’une et l’autre. En partant d’Agathis, Sequoia ou

Figure 20.- La Luma, Myrceugenia fernandeziana, une Myrtaceae atteignant une hauteur de 15 mètres, est l’arbre le plus commun des forêts primaires. Ici, en sous-bois, la forme juvénile est plagiotrope, avec des étages foliaires disposés horizontalement. A la lumière, chez la Luma adulte, les axes sont verticaux.

Pinus, chez lesquelles la “composante modèle” est encore favorisée, on arrive à Quercus, Shorea, Eucalyptus, Vochysia, Aesculus, Terminalia ou Tectona, dont les deux composantes, modèle et réitération, s’expriment de façon équilibrée, sans hégémonie de l’une sur l’autre. Il ne semble pas que cette situation d’équilibre soit particulièrement propice à l’émergence de “pestes végétales”; bien entendu, l’architecture n’étant qu’un caractère parmi d’autres, cette émergence peut provenir des performances de la sexualité: Buddleja davidii, Ailanthus altissima ou Miconia calvescens pourraient être dans ce cas.

Enfin, à l’autre extrême, on trouve des plantes chez lesquelles le modèle se fait beaucoup plus discret, l’essentiel de la forme de croissance étant dû au Figure 21.- Lactoris fernandezia, Lactoridaceae, est un mécanisme de la réitération (Hallé et al.,1978) au sens arbrisseau charnu et fragile, aux nœuds renflés, ne dépassant par 1,5 mètre. Quelle que soit la hauteur de la large, y compris l’émission de rejets basaux ou de plante, sa partie distale se courbe à l’horizontale, formant drageons, et la possibilité de marcotter spontanément. un plateau assimilateur; ce dernier est vu par dessus en haut à droite. En bas, les tiges âgées s’affaissent; la Les trois principales pestes des îles Juan Fernández sont réitération complète le buissonnement basal. dans ce cas, le Maqui, Aristotelia chilensis, la Zarzamora, Rubus ulmifolius et la Murtilla, Ugni molinae. Ces plantes

52 se comparent, sur le plan architectural, à des pantropicales comme Ximenia americana, Sambucus spp, Lantana camara ou Chromolaena odorata. Il semble que les pestes se recrutent préférentiellement chez des plantes dont la réitération montre une tendance à l’hégémonie. Chez le Maqui et la Murtilla, le modèle de RAUH est réduit à sa plus simple expression, avec un nombre d’étages de branches qui se limite généralement à 2, voire un seul; sur certains rejets basaux de Maqui, on n’observe aucune branche latérale et l’axe s’affaisse sans s’être ramifié: le modèle disparaît, submergé par la puissance de la réitération. En ce qui concerne la Zarzamora, le modèle de Figure 22.- Affaissement, buissonnement basal et réitération chez le Maqui. Le modèle architectural, à gauche, s’estompe et finit par disparaître. Le CHAMPAGNAT est, en lui-même, très dessin est simplifié ; au centre, les axes sont si nombreux qu’aucune lumière peu contraignant puisqu’il n’est fondé que ne traverse. Hauteur: 5 mètres. sur l’affaissement des axes successifs.

L’affaissement, dû à la gravité et à un bois peu abondant ou particulièrement souple, est un autre caractère de ces pestes, bien visible chez le Maqui ou la Zarzamora. Leurs axes affaissés meurent ou s’empilent les uns sur les autres en une couche épaisse de plusieurs mètres, dense, sombre et hostile (= roncier) qu’aucune plantule n’est capable de traverser: seules peuvent atteindre la lumière les réitérations basales émises par la Zarzamora ou le Maqui. Ce qui précède permet de comprendre la forme de croissance du Maqui (Figure 22).

La multiplication végétative est un facteur supplémentaire de l’agressivité des pestes. Le drageonnement et l’émission de rejets souterrains permettent à la Zarzamora de s’implanter de proche en proche et de gagner en surface au détriment de la flore locale qu’elle recouvre (Figure 23).

La multiplication végétative de la Murtilla se fait par l’émission souterraine, à des profondeurs variables, d’un réseau de stolons en arceaux (Figure 24), ne portant que des feuilles en écailles. Ces stolons sont ensuite capables de se dédifférencier, soit apicalement, soit latéralement, ce qui a pour résultat d’augmenter le volume du clone de Murtilla (Figure 25).

A ce syndrome de caractères architecturaux qui Figure 23.- Affaissement, buissonnement basal, confèrent l’agressivité végétative, vient s’ajouter réitération et multiplication végétative par drageons l’efficacité de la dispersion des graines, favorisée par chez la Zarzamora. Cette liane forme des ronciers de 4 mètres de hauteur et elle surcime des arbres de 10 l’avifaune locale (voir ci-dessus). Tout cela explique que mètres. le trio Maqui-Zarzamora-Murtilla constitue une véritable menace pour les espèces endémiques.

53 Ces dernières, par exemple les Asteraceae qui sont le symbole de l’endémisme insulaire — Centaurodendron, Dendroseris, Robinsonia, Yunquea— ont un modèle architectural contraignant qui les prive de plasticité écologique; dépourvues à la fois de réitération, de possibilités d’affaissement et de multiplication végétative, elles ont, en outre, adopté des mécanismes de pertes d’axes ou de monocarpie, qui étaient adaptés au contexte paisible d’une île intacte, mais qui prennent un caractère “suicidaire” face aux pestes. On comprend la vulnérabilité de ces précieuses endémiques, dans la compétition avec le trio Maqui- Zarzamora-Murtilla. La dispersion des graines par le vent, si elle a permis à leurs ancêtres de s’implanter dans les îles, est un mécanisme trop aléatoire pour leur permettre de résister à l’avancée implacable des espèces zoochores.

Figure 24.- Buissonnement basal et multiplication végétative Une solution, le Jardin botanique par stolons souterrains chez la Murtilla. Les stolons sont feuillés Dans le contexte actuel, la lutte contre les pestes lorsqu’ils sont jeunes, ce qui permet de les distinguer aisément des racines. Par la suite, la distinction reste aisée sur le plan végétales des Juan Fernández est sans espoir. anatomique : la racine a une section circulaire et une moëlle L’arrachage manuel, pour efficace qu’il soit, réduite, le stolon a une section quadrangulaire et une moëlle abondante. consomme trop d’énergie pour pouvoir être étendu à l’échelle des îles: la population réduite et la topographie souvent vertigineuse rendent le problème inextricable.

C’est pourquoi, dans l’immédiat, il semble que la seule solution réaliste soit la création d’un Jardin Botanique. Situé à proximité du village de San Juan Bautista, ce Jardin aurait pour vocation la sauvegarde des 132 espèces endémiques de l’archipel.

Figure 25.- L’accroissement d’un clone de Murtill Santa Clara, la plus petite (223 hectares), n’est qu’un îlot sec et inhabité. Son nom ancien d’Ile des Chèvres évoque la disparition de la végétation arbustive qui la couvrait (Figure 3)

54 Au-delà de sa fonction biologique, au-delà de son attrait touristique, ce Jardin permettrait à la population îlienne de manifester son attachement à un patrimoine naturel dont elle est fière et qui est partie intégrante de son identité culturelle.

San Juan Bautista, février 2003 Francis Hallé Philippe Danton Christophe Perrier

Remerciements Nous exprimons nos chaleureux remerciements à la Fondation Yves Rocher qui a assuré le financement de nos voyages, dans le cadre d’une enquête botanique consacrée à l’archipel depuis 1997.

Nos remerciements vont également à la CONAF, dont les guides, les gardes et les marins ont assuré l’encadrement des sorties sur le terrain, ainsi qu’à Juan Vera Álvarez, directeur de la Météorologie pour l’ile Robinson Crusoe, qui nous a aimablement communiqué les données sur le climat pour la période 1961-2001.

Bibliographie Danton, P. (en préparation). Plantas silvestres de la Isla Robinson Crusoe; Guía de reconocimiento. Danton, P., Breteau, E. et Baffray, M. 1999. Les îles de Robinson, Trésor vivant des mers du Sud entre légende etréalité. Yves Rocher / Nathan, Paris. Hallé, F. et Oldeman, R.A.A. 1970. Essai sur l’architecture et la dynamique de croissance des arbrestropicaux. Masson, Paris. Hallé, F., Oldeman, R.A.A. & Tomlinson, P.B. 1978. Tropical trees and forests, an architectural analysis. Springer Verlag, Berlin-Heidelberg-New York. Marticorena, C., Stuessy, T.F. and Baeza, C.M. 1998. Catalogue of the vascular flora of the Robinson Crusoe or Juan Fernández Islands, Chile. Gayana Bot. 55(2): 187-211. Oldeman, R.A.A. 1974. Architecture de la forêt guyanaise. ORSTOM, Paris. Pascal, O. 2002 Plantes et forêts de Mayotte. MNHN-Paris et Espaces Naturels 53, 108 pages. Skottsberg, C. 1952. The natural history of Juan Fernández and Easter Island. Almqvist & Wiksells, Uppsala. Stuessy, T.F., Foland, K.A., Sutter, R.W., Sanders, R.W. and Silva, M.O. 1984. Botanical and Geological significance of Potassium-Argon. Dates from the Juan Fernández Islands. Science, 225: 49-51. Tobe, H., stuessy, T.F. and Baea, C.M. 1993. Embryology and Karyomorphology of Lactordaceae. Am. J. Bot. 80(8): 933- 946.

55 Un hommage des Hladiks à Roelof A. A. Oldeman

Annette et Marcel Hladik Muséum National d'Histoire Naturelle Éco-Anthropologie et Ethnobiologie (UMR CNRS-Univ.Paris7-MNHN) 4, avenue du Petit Château 91800 Brunoy (France)

Ce fut d’abord la découverte des trois ensembles forestiers: ensemble du passé, ensemble du présent, ensemble du futur. C’était en 1975, nous allions, Marcel et moi, présenter à Washington —un colloque sur les animaux folivores—, notre travail réalisé à la station de Makokou au Gabon et nous venions de lire ton article «Ecotopes des arbres et gradients écologiques verticaux en forêt guyanaise» paru dans la revue de F. Bourlière (La terre et la Vie, 28 :487-520, 1974). Ta vision de la dynamique forestière correspondait exactement à ce que nous pouvions observer, spécialement pour accompagner les données que nous présentions sur la phénologie des productions de feuillage des diverses espèces d’arbres et de lianes de la forêt gabonaise. Nous avions traduit en anglais ensemble par class. Or, tu étais toi-même en train de traduire ce terme pour le HOT book (Hallé, Tomlinson & Oldeman) qui allait paraître en 1976 et bien sûr c’était beaucoup mieux de parler: about the three sets: set of the past, set of the present and set of the future... D’ailleurs tu avais reviewé une bonne partie de l’article. Voila ce fut un premier contact épistolaire, tu étais alors en poste ORSTOM au Pérou.

La vraie rencontre eu lieu à Paris, au Muséum, puis lors du colloque de Strasbourg avec une sortie de terrain sur une île rhénane. Ensuite il y eut beaucoup de tropicalité intense avec même une escapade dans le Gâtinais, près de Paris, illustrée ci-contre pour un programme de recherche sur les îlots boisés en zone de grande culture, sur initiative du Muséum National d’Histoire Naturelle et financement du CNRS. Mais que t’importe ces détails, Roelof, toi qui a réussi ton œuvre avec ou en marge des institutions! Pendant 3 mois, tu étais un professeur invité au Muséum et nous avions la grande chance de te voir disponible.

Ce qui compte c’est de parler —et quel talent tu as—, éduquer, analyser, créer et œuvrer pour les forêts. Conceptualiser est ton fort et beaucoup de formules célèbres que tu as crées restent, comme la D and D method (Diagnosis and Design, dans le cas des programmes en Agroforesterie) ou comme le simple mot ECOTROP qui désignait notre équipe de recherche en écologie tropicale...Il y eut aussi notre colloque Unesco, à Paris en 1991 «Tropical Forests, People and Food», publié en 1993, où tu disais: Shall we eat the tropical forest or shall we eat from the tropical forest?

N’oublions pas encore la grande mission en Indonésie pour des VIP, very important people! où la responsabilité des scientifiques était engagée auprès des décideurs. C’était une réponse à Rio et il fallait bien cela pour enfin découvrir le vrai goût du durian... et que vivent les agroforêts partout dans le monde!

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57 Professor Oldeman, a Friend

Rodrigo Junqueira B. de Campos Fazenda São Luiz, São Joaquim da Barra, SP, Brazil

Old man? No! All the man…

Young man, scientist man, friend man, curious man and teacher man. Oldeman.

Cheese man; he likes all the cheese, specially old cheese. The old São Luiz Farm cheese full of funghi. The funghi cheese.

He likes the funghi leaves and the bacteria leaves too.

He likes all forms of life.

He lives!

He loves his wife. He lives very intensively using all of his body. He loves what he does.

He lives in our mind since that time he spent at our house in 1998, teaching, acting, talking and laughing.

Thank you, Professor Oldeman, for this opportunity to know you and for everything you teach. It was important to learn from you more about the forest and forestry because we love forest and we’re planting forests!

Thanks Gaia, for this meeting;

Thanks God!

Regards and my best wishes, Rodrigo Junqueira

Photo 1. Prof. Oldeman, Denise and Rodrigo at São Luiz Farm, Brazil. Happyness and joy.

58 Photo 2. Plants Architecture Class at São Luiz Farm, São Paulo, Brazil, 1998.

Photo 3. A happy moment at São Luiz Farm: eating a delicious food made by Minda.

59 Observerende bosbenadering

Ir. C.J.F. Konings Churchillweg 1 6707 JA Wageningen [email protected]

Het bos observeren is een mooie bezigheid en erg leerzaam. Het is verbazingwekkend hoeveel je van bossen en zijn bomen kunt begrijpen door enkel observeren, met wat kennis opgedaan in de collegebanken of uit de literatuur kun je vervolgens veel herkennen en dichter bij het functioneren komen.

Hiervoor moet je dus wel in het bos zijn. Door goed te kijken kom je veel te weten over hoe het bos functioneert, zich ontwikkelt, hoe de verschillende boomsoorten zich gedragen, hoe het bos reageert op bepaalde ingrepen, allemaal essentiële informatie voor een duurzaam beheer. Deze observaties kunnen dan wel weer bevestigd worden door middel van onderzoek, echter daarvoor is in het beheer zelf gewoonlijk geen tijd. Bovendien zijn bossen en hun omgeving zo veranderlijk en per plaats zo verschillend, dat statistisch onderbouwd onderzoek veelal een specifieke of historische situatie weergeeft.

Daarmee wil ik niet zeggen dat onderzoek geen rol speelt in het bosbeheer. Het is goed dat bepaalde aannamen voor het beheer onderbouwd worden en dat factoren die de bosontwikkelingen bepalen, benoemd en gekwantificeerd worden. Het beheer kan hierop echter niet wachten. Als het beheer verantwoord moet worden naar derden, zoals voor een duurzaamheidscertificaat, zijn inventarisaties heel functioneel. Dit is echter een activiteit die “achter het beheer aan” komt.

De beslissingen voor het beheer die in het bos gemaakt worden, gebaseerd op waarnemen, maken het beheer verantwoord. In het bos zelf wordt aan duurzaamheid vorm en inhoud gegeven. De door Professor Roelof Oldeman gepresenteerde concepten en theorieën zijn hierbij voor mij van veel waarde.

60 BBA & E

Jaap Kuper Het Loo

Waarde Roelof,

In 1984 spraken wij voor het eerst over een dissertatie die voort zou kunnen vloeien uit de benadering van het bosbeheer zoals ik die voorstond voor Het Loo. De gedachte was om niet langer voort te borduren op de ordening in het bos zoals die in de vlaktegewijze aanpak tot stand kwam, maar om te streven naar het optimaal inspelen op de ogenschijnlijke chaos die zich vanuit spontane processen in het bos voordeed.

Dat idee van chaos, dat prikkelde je. Daarin zag je niet alleen een uitdaging, maar ook de logische weg naar ordening. In die chaos herkende je bosbeelden van de tropen. Daarin had je de weg van processen en structuren al eens eerder aangegeven. Een parallel naar de situatie in de gematigde streken zag je dan ook helemaal zitten. We hebben intensief gedebatteerd over de aanpak en opzet met betrekking tot de dissertatie. Het waren spannende bijeenkomsten die het uiterste vroegen aan concentratie en voorbereiding. Het resultaat was er uiteindelijk naar.

Nu kijk ik op enige afstand naar je betekenis voor de bosbouw in Nederland, anderen nemen je invloed op bosbeheer elders wel voor hun rekening.

Met je komst in Wageningen gaf je een enorme impuls aan het denken over bosbeheer. Die impuls kwam als een schok. Eerdere hoogleraren hadden vooral binding met het beheer. Jij bracht er direct een abstractie van denken en een waardevrije benadering in die onbekend was. Dat was tegelijk je kracht maar hield ook een kwetsbaarheid in. Het was niet gebruikelijk om op die manier met ons vak om te gaan. Er werd daardoor nogal heftig op je benadering gereageerd. Nou ben je zelf natuurlijk ook niet van alle eigenwijsheid ontbloot, dus was er alle mogelijkheid voor het niet optimaal tot zijn recht laten komen van een goed academisch debat. We weten er met z’n allen alles van.

De omslag in de benadering van het vakgebied ging niet geruisloos, zoals ik hierboven al aangaf. Het is niet nodig om daarop in te gaan. Omdat elk nadeel z’n voordeel kent was ook in jouw positie bij de WUR een dergelijk effect waarneembaar. Doordat de beslommeringen van een normale vakgroep van je wegvielen kon je alle tijd aan je vak en studenten besteden. In de praktijk waren dat niet meer zo zeer de gewone bosbouwstudenten (wat natuurlijk jammer was) maar vooral negenendertig promovendi die je in de vijfentwintig jaar hoogleraarschap hebt begeleid. Je hebt vooral zeer veel energie aan hen besteed. Je hebt jouw manier van denken, je abstraherend en ordenend vermogen met hen gedeeld. Je hebt ze overladen met ideeën. Je hebt ze vertwijfeld doen vertrekken na elk onderhoud dat je met ze had. Daarmee dwong je hen om hetzij constructief inhoud te geven aan je nieuwe idee, of om dat idee beargumenteerd ter zijde te leggen. Hoewel beide zaken niet eenvoudig zijn bracht je daarmee wel de nodige gedachtenvorming op gang. En niet alleen dat. Je toonde je studenten tevens de noodzaak om creatief te blijven.

Terug naar je betekenis voor het bosbouwvak in Nederland. Tot aan jouw komst op Hinkeloord werd het bos in Nederland nog te veel gezien als een landbouwproduct dat er nogal lang over deed om tot een oogstbaar gewas te ontwikkelen. Met jouw inzichten en ideeën over kroonontwikkeling werd er voor het eerst naar de dynamiek binnen het bos gekeken. Vanaf dat moment werd het bos meer dan een verzameling bomen. Spoedig volgden de components, de cohorten, de eco-units en silvatic mosaics. Daarmee werd de basis gelegd voor het op een andere manier, en meer academisch, denken over het vakgebied. Dat heb je doorgegeven aan veel

61 studenten, en aan je promovendi. Die doen er nu hun voordeel mee. Daarbij denken ze vast nog wel eens terug aan die bijzondere, briljante, analytische en eigenwijze hoogleraar van ze…, waarbij ze zeker hopen dat het hem goed zal gaan tijdens zijn emeritaat.

Jaap Kuper, Het Loo, 19 augustus 2002.

62 Functioning of palm trees in the Amazonian forest

Pieter JC Kuiper1,2 and Cécile MH Lapré13 1Department of Biological Sciences, P. Universidad Catholica del Ecuador, Quito, Ecuador, 2Department of Plant Physiology, University of Groningen, The Netherlands and 3Freelance Consultancy, Haren, The Netherlands

Many trees in the forest have a symbiotic relation with ectomycorrhizal fungi. Both, tree roots and ectomycorrhizal fungi, require oxygen and therefore many forest ecosystems do not tolerate flooding, which causes the death of the trees.

It is surprising that in wet and oxygen-poor conditions as in temperate wet alder forests (Alnus glutinosa in Europe, A. sinuata in the Western America,s) ectomycorrhizal fungi are abundant (Baar et al. 2000). Under temporary flooding conditions roots of Alnus glutinosa grow closer to the surface and exhibit abundant mycor- rhizal fungi. Atmospheric oxygen is transported through lenticels thermo-osmotically to the water-logged roots and fungi (Schröder 1989). However, black alder forests are unable to adapt to a more permanent rise of the water table in which situation the trees die. This was observed in the “Vragenderveen”, The Netherlands, when the water table of a desiccated Sphagnum bog was raised.

The situation in the Amazonian tropical rainforest is very different. It covers a huge floodplain area, with a decrease in water level of 1 to 2 cm per km river (Henderson 1995). During the wet season the ecosystem is exposed to a sudden rise in the water level, up to 10 m, following extensive rain, leading to frequent and prolonged flooding of the forest, from 4 up to 9 months. Parts of the forest are permanently flooded.

During a visit in November-December 2001 to yasuni national park, Ecuador, we focussed our attention on the numerous palms in the Amazonian forest. From the time of Von Humboldt (1850) and Wallace (1853) botanists have been amazed by the high frequency of palm trees in the Amazonian rainforest. Palm trees are abundant, particularly on the frequently and permanently inundated habitats, sometimes in pure stands. A possible role of the abundant palms in functioning of the temporary and permanently flooded Amazonian forests seems appropriate for further investigation.

Submerged adventitious roots of the palm Mauritia flexuosa were extensively associated with ectomycorrhizal fungi, as observed microscopically. The studied trees were standing in long-time stagnant water in pools, close by the “50 ha Forest Dynamics Plot” in the vicinity of the “Yasuni Research Station”, Yasuni National Park, Ecuador. One meter around the trees the water was coloured brown and furtheron grayish. The brown color indicates oxygen loss from the roots, and oxidation of the water around the stilt roots. Air transport from the leaves to the submerged roots seems appropriate for such a palm species. Considering its architecture the following is probably happening: on a sunny tropical day the air in the large leaves is heated above the temperature of the water around the roots; air transport through the spongy tree stem is likely being facilitated by the numerous intercellular spaces between the vascular bundles of this monocotyledon.

In order to proof this we have calculated air transport by: (i) isothermal diffusion, (ii) pressurized air flow, due to heat expansion of the air in leaves and stem during the day, and (iii) pressurized air flow by thermo-osmosis. At Yasuni NP the average daily minimum and maximum temperatures were 21.5 and 34.7 oC respectively (Nabe- Nielsen 2001). For the compound palmate leaves of Mauritia, exposed to the sun, the leaf temperature was

63 assumed to be 3 oC higher than the air temperature (Taylor & Sexton 1972). The following parameter values of this palm tree were used for the calculations: stem height 20 m, stem diameter 0.3 m, porosity of the stem 50 %, the number of leaves 14, the leaf area (175 leaf segments, 1.75 m long, 0.0475 m wide) 14.5 m2, leaf thickness 0.002 m and the internal air-space as 80 % (for details see Henderson 1995, Tomlinson 1990).

3 -1 Isothermal diffusion of O2 from the leaves into the root cell water was calculated as 0.00012 m .day , by far insufficient for the O2 demand of the roots and mycorrhizae.

The calculated daily pressure increase of the air in the leaves was 0,055 MPa for sunlight-exposed leaves. During the night the leaf temperature drops and air pressure is reduced to 0.1 MPa. The volume of air, which may be transported through the stem by pressure difference between air in the leaf and roots, depends on the number of leaves and the air volume within the leaf and the total air volume in the stem. We estimated that the temperature rise in a single day results in transport of up to 0.054 m3 air through the stem to the roots and ectomycorrhizal fungi, again a quite limited amount of air for respiration of roots and mycorrhizae.

Thermo-osmosis seems to be a more likely process for the aeration of the roots. According to the kinetic theory of gases (Jeans 1962) thermal diffusion of air molecules through pores of the size of stomatal openings results in a continuous pressure increase of 0.027 Mpa inside the leaf for a temperature difference of 16.2 oC between the sunlight exposed leaves and the roots (minimum daily temperature) during the day for our conditions, in agreement with actual measurements of a pressure difference (increase) between the leaf midrib of the yellow water lily, Nuphar luteum and the atmosphere (Dacey 1981). In this species thermo-osmosis resulted in a pressurized air flow rate of 60 ml.min-1 through the petiole. If we assume a leaf area (with stomata) of 700 cm2 for a yellow water lily leaf, we calculated for our palm tree an air flow rate of 0.174 m3.min-1 through the stem, assuming an equal number of stomata per unit leaf area for both species as the driving force. Undoubtedly, the structure of the palm tree stem will reduce the downward air flow considerably, since transport through a tree stem is much longer than that through a water lily petiole. Moreover, the latter has a higher porosity. However, the outcome is still that thermo-osmosis driven air flow is the most likely candidate for O2 supply to roots and mycorrhiza in palm trees.

Trees other than palms may also survive under the stressed conditions of flooding. We observed that big trees in flooded areas with stagnant water often were accompanied with one or more palm trees in close vicinity and part of the air supply to the palm roots could also benefit roots from other trees, in close vicinity of the palm tree.

Actual measurements of air flow through the palm stem and O2 levels of the water surrounding the trees are needed to test this last hypothesis. Air supply to the water of flooded forest may also explain why organic accumulation in the form of peat is so limited in many areas of the flooded Amazonian forest, air supply assures full aerobic conversion of the dead plant material.

Acknowledgements: We thank Prof. Oldeman for his inspiring guidance in understanding the functioning of forest ecosystems, in Ecuador he is still remembered for his enthousiasm and skills, so many decades after his stay in the country. We want to thank in Ecuador: Drs T de Vries, R. Valencia, L. Arcos, F. Koester and M Sc. J. Jaramillo for assistance and providing facilities at PUCE and Yasuni Research Station. In The Netherlands we want to thank for assistance: Drs K. Rappoldt, I. Weissenhorn and J. Baar.

References Baar, J., van Groenendaal, J.M. and Roelofs, J.G.M. 2000. Are ectomycorrhizal fungi associated with Alnus of importance for forest development in wet environments? Plant Biol. 2:505-511. Dacey, J.W.H. 1981. Pressurized ventilation in the yellow water lily. Ecology 62:1137-1147. Henderson, A. 1995. The palms of the Amazon. Oxford Univ. Press, Oxford, 362 pp. Humboldt, A. von. 1850. Aspects of nature. Translated by Mrs. Sabine. Lea & Blanchard, Philadelphia.

64 Jeans, J. 1962. An introduction to the kinetic theory of gases. Cambridge Univ. Press, 311 pp. Naber-Nielsen, 2001. Diversity and distribution of lianas in a neotropical rain forest, Yasuni National Park, Ecuador. J. Trop. Ecology 17:1-17. Schröder, P. 1989. Aeration of the root system in Alnus glutinosa. Annales des Sciences Forestieres 46:310-314. Taylor, S.E. & Sexton, O.J.. 1972. Some implications of leaf tearing in Musaceae. Ecology 53:143-149. Tomlinson, P.B. 1990. The Structural Biology of Palms. Clarendon Press, Oxford, 477 pp. Wallace, A. 1853. Palm Trees of the Amazon and Their Uses. Van Hoorst, London.

65 Exsiccatae Oldemani

L.J.G. van der Maesen & X.M. van der Burgt Biosystematics Group, Nationaal Herbarium Nederland-Wageningen University branch (Herbarium Vadense), Wageningen University, Generaal Foulkesweg 37, 6703 BL Wageningen, the Netherlands

Contributions to taxonomic botany During his many travels, particularly in the earlier phases of his career in forestry, Prof. dr.ir. R.A.A. Oldeman collected many plants for the herbarium. The African specimens are conserved in the Wageningen Herbarium (Herbarium Vadense, WAG*). Now the databases are continuously growing, a first overview of his contribution to taxonomical research of the Flora of Africa can be provided. The BRAHMS database (Botanical Research and Herbarium Management System, Filer 2001) is in full operation at Wageningen. Although not all specimens have been entered, the registered ones have been retrieved to present some details of interest.

In total 1010 collection numbers are entered in the field books, which are also stored in WAG. Of those, 396 samples have been entered into the database. As with many collectors not employed directly by the Herbarium Vadense or the then Department of Plant Systematics, details on Oldeman’s collections were not mentioned in the publication issued at the occasion of the centenary jubilee of the Herbarium Vadense (1896-1996) by Breteler & Sosef (1996). Mention is made, though, of his students whom he always inspired to make voucher collections where appropriate, and to store these in a reputable herbarium.

Countries where collections have been made The Herbarium Vadense has focused attention on groups of the African Flora since about 1955. Relative recent collections have been made in particular countries by various collaborators, and from some countries we conserve comprehensive collections. This is even more important where due to political unrest collections were damaged or destroyed (e.g. Congo Brazzaville, Liberia), or ravaging insects and moulds have reduced the value of collections. Tropical countries are not the most conducive for conservation of herbarium, so costly efforts are often required to maintain botanical (and zoological) collections. On-going activities concern collaboration with the National Herbaria of Gabon in Libreville (since 1984), Benin in Abomey-Calavi (since 1996), and the Centre Floristique in Abidjan (since 1956)

Overseas Oldeman collected in the following countries:

Senegal: nr. 1 (Dakar, 9 April 1963); exsiccatum in WAG: Casuarina equisetifolia L.

Ivory Coast: nrs. 2-732 (25 April 1963-7 Dec. 1963) exsiccatae in WAG.

Ghana: nrs. 733-842 (18-24 Dec. 1963) exsiccatae in WAG.

Ivory Coast: nrs. 843-1010 (5 Jan.-11 March 1964) exsiccatae in WAG.

French Guyana: exsiccatae in CAY (Cayenne) and P (Paris) (base de données AUBLET2 de l’Herbier de Guyane), duplicates in U.

Ecuador: 300-500 exsiccatae in QCA, Universidad Católica Pontífica de Quito.

Duplicates of Oldeman’s African samples were sent to e.g. K, BR, FHI, MO, LD, P, B and Z, some to S, FI,

66 GENT and IFAN in decreasing numbers as far as had been available, in exchange to samples from other African countries. Taxonomists have used the samples in several botanical revisions and contributions to Flora’s. Geerling (1982, 1987) employed many samples collected by Oldeman for his Field guide to the woody plants of the Sahel and Sudano-Guinean zone. The ECOSYN project (1996-2003) used the samples as well (Holmgren et al., 2004; Jongkind, 2004; Hawthorne & Jongkind, 2003). In total Oldeman collected at least 8000 accessions, in various series (A: ± 2700, B: ± 4345, T: 1061) and 280 numbers in collaboration with C.H. Sastre.

Taxa collected As far as can be gleaned from the 396 data in BRAHMS, from the following major taxa Oldeman collected many specimens in Africa: Euphorbiaceae, Leguminosae-Papilionoideae and Rubiaceae. The 396 collection numbers belong to 308 different species and 73 plant families. So far, three of his accessions from Ivory Coast served as nomenclatural types for newly described species, and two from French Guyana:

920 Sericanthe chevalieri (K.Krause) Robbrecht var. velu-tina Robbrecht (Rubiaceae); Tiobiel E of Tehini, Bouna Nat. Park, 29 Jan. 1964, described in 1978, holotype in BR, isotypes in CD, FHI, K, MO, P, WAG and Z.

x 962 Dichapetalum dictyo-spermum i

Breteler (Dichapetala-ceae); Abidjan, Forêt de Banco, 11 Febr. 1964, described in 1970, holotype in WAG, isotypes in B, BR, FHI, G, GENT, IFAN, IRSC, K, LD, 5 55 5555 5 5 MO, NH, P, SRGH, TCD, USL, 5 WRSL and Z.

55 5 985 Agelaea paradoxa Gilg var. svory2gost qhn microcarpa Jongkind (Con- naraceae); Morokro, N of Ndouci, 555 5 55 5 Tiassalé sous-préfecture, 17 Febr. 55 5 55 5 555 5 5 1964, described in 1989, holotype 555555555 555555555 in WAG, isotypes in B, BR, FHI, 5 55 5555 K, MO and P. SH H SH IHH ISH PHH PSH uilometers 2242 Enterolobium oldemanii Barneby & J. W. Grimes (Leguminosae-Mimosoideae); Ile Map: Dots indicating 396 of Prof. Oldeman’s accessions from Ivory Coast and Ghana, a good random sample representing all 1010 exsiccatae. de Cayenne, August 1966, described in 1996, isotype in U.

4132 Pourouma saulensis C.C. Berg & F. Kooy (Cecropiaceae, ex Moraceae); Saül, tracé de la Montagne Belvédère, 21 Oct. 1971, described in 1982, holotype in U.

Eponymy The IPNI (International Plant Name Index) database provides eight names of plant species that have been named after Prof. Oldeman up to now. Usually these names are based on typematerial he collected. Oldeman’s contibutions to botanical science were mentioned in some cases, in particular where he stimulated the

67 development of the Herbarium in Cayenne (CAY) under the auspices of ORSTOM. In alphabetical order by family: -Acanthaceae Justicia oldemanii D.C. Wasshausen — Brittonia 54(4): 287 (-292; figs. 1-2) (2002 publ. 2003). -Asclepiadaceae Matelea oldemanii G.N. Morillo — Ernstia n.s., 1: 115 (-116; fig. 4c) (1991).Leguminosae-- Mimosoideae Enterolobium oldemanii R.C. Barneby & J.W.Grimes — Silk Tree, Guanacaste, Monkey’s Earring. Mem. New York Bot. Gard., 74(1): 249 (1996). -Melastomataceae Blakea oldemanii J.J.Wurdack — in Phytologia, 43(4): 352 (1979). -Melastomataceae Miconia oldemanii J.J.Wurdack — in Phytologia, 45(4): 326 (1980). -Orchidaceae Epidendrum oldemanii E.A. Christenson — Brittonia 46: 54 (-56) (1994). -Palmae Geonoma oldemanii J.-J. de Granville — in Adansonia, 14(4): 553 (1974 publ. 1975). -Rubiaceae Rudgea oldemanii J.A. Steyermark — Brittonia 33(3): 397 (1981). References have been abbreviated as is common in plant taxonomy; the author names are not abbreviated.

Acknowledgements Dr. J.J. Wieringa skilfully manipulated Brahms into making the accompanying map.

References Breteler, F.J. & M.S.M. Sosef, 1996. Herbarium Vadense 1896-1996. Wageningen Agricultural University Papers 96-2. 136 pp. Filer, D.L., 2001. BRAHMS Reference Manual. Department of Plant Sciences, University of Oxford. 284 pp. Geerling, C. 1982. Guide de terrain des Ligneux Sahéliens et Soudano-Guinnéens. Meded. Landb.Hogesch. 82-3 (1982), 2nd ed. Agric. Univ. Wageningen Papers 87-4 (1987). 340 pp. Hawthorne, W. & C.C.H. Jongkind, 2004/5, in prep. A Guide to the Woody Plants in the Forests of Western Africa. Holmgren, M., Poorter, L., Siepl, A., Bongeres, F., Buitelaar, M., Chatelain, C., Gautier, L., Hawthorne, W.D., Helmink, A.T.F., Jongkind, C.C.H., Os-Breijer, H.J., Wieringa, J.J. and van Zoest, A.R. 2004. Ecological profiles of rare and endemic species. In: Poorter, L., Bongers, F., Kouamé, F. N’. and Hawthorne, W.D. (Eds): Biodiversity of West African Forests. An ecological Atlas of Woody PLant Species. CABI Publishing Pp. 101-389 Jongkind, C.C.H. 2004. Checklist of Upper Guinea forest specis. In: Poorter, L., Bongers, F., Kouamé, F. N’. and Hawthorne, W.D. (Eds): Biodiversity of West African Forests. An ecological Atlas of Woody PLant Species. CABI Publishing Pp. 447-477.

Websites http://www.brahms.co.uk http://www.cayenne.ird.fr/aublet2 http://www.benp.wageningen-ur.nl/ecosyn http://www.agro.wageningen-ur.nl/biosysnhn/nhnwag_content.html

* For herbarium acronyms see Index Herbariorum: http://www.nybg.org/bsci/ih/

68 Cette grandeur qui appelle celle de l’autre

Jeanne Millet Chercheure en architecture des végétaux et écologie Institut de recherche en biologie végétale 4101, rue Sherbrooke est Montréal, Québec H1X 2B2 Canada

Très cher Professeur Oldeman, Je suis très touchée d’avoir été invitée à me joindre à ceux qui vous sont chers pour vous adresser ici quelques pensées. Vous m’avez fait d’immenses cadeaux devant lesquels les mots sont si petits. Je tiens néanmoins à tenter d’en témoigner, ne serait-ce que pour vous dire merci.

Merci d’abord pour avoir pensé, élaboré et divulgué votre nouvelle approche de l’architecture des arbres. Par vos écrits chargés d’illustrations magnifiques, mon regard s’est ouvert sur la diversité des formes. Cette nouvelle conception du végétal m’a permis de percevoir, au-delà du fouilli apparent des branches d’une cime, les règles simples de leur organisation. Vous et votre collègue et ami Francis Hallé m’avez non seulement mis en main de nouvelles données qui ont su exalter ma soif d’apprendre et de comprendre, mais vous m’avez également offert la possibilité de participer à la découverte de la nouveauté. Étant étudiante, dans mon désir de m’orienter en recherche, j’avais l’exigence d’être entière. C’est mon coup de foudre pour l’architecture des arbres qui m’a donné la force et le courage de m’affirmer dans une différence qui me démarquait de mes collègues. Il fallait un brin de follie pour braver les exigences de productivité d’une société qui nous invite plus à la course qu’à l’arrêt. Il fallait un brin de follie pour s’installer pendant des heures devant un arbre afin de le dessiner. Que peut-on éprouver devant celui qui dessine une forêt? Je vous le dis, beaucoup de respect. À ma grande surprise et à mon grand bonheur, j’ai compris que c’est lorsqu’on sait s’arrêter vraiment qu’on en vient finalement à faire des pas de géant. On mettra du temps à faire honneur à tous les pas de géant que vous avez accomplis. Ils sont de diverses natures, en sylvologie biensûr (chaque mot marquant le pas) mais aussi dans votre perception de l’être humain et de son lien avec ce qui l’entoure.

Votre éveil face à l’importance de «l’attitude» du chercheur m’a entre autres inspirée. J’en ai reçu échos dans une phrase qui a fait son chemin jusqu’à moi avant même que je vous rencontre. Pour cette deuxième raison, je vous remerciais déjà du fond du coeur. J’étais en stage en Guyane française (Piste de Saint-Élie) en 1990 lorsqu’on m’a rapporté ces quelques mots comme venant de vous: «La recherche est un état, un état de disponibilité face à ce qu’on ne connaît pas encore. Pour se mettre en état de disponibilité, plusieurs outils s’offrent à nous. Le dessin en est un.» Par ces mots, qui se sont fort probablement transformés un peu en voyageant, vous m’avez ouvert une porte. Jusque-là, j’étais encore en réaction contre l’attitude des chercheurs de chez moi qui m’avaient formée et qui insistaient surtout sur la productivité et la compétition. J’avais risqué leur rejet en optant pour une attitude qui était la mienne et que je venais, dans un élan du coeur, tester en Guyane. Cette attitude impliquait avant tout de savoir m’arrêter afin d’identifier exactement ce qui me convient dans ma démarche. Mon expérience en forêt tropicale me surprenait déjà positivement lorsque vos mots sont venus me confirmer toute l’importance de croire en soi. En le nommant, vous m’avez encouragée à le développer, cet état de disponibilité que j’apprenais à cultiver. Lorsqu’on comprend la nature du défi qu’on se lance, on devient plus fort face à lui. Ce jour-là, sans le savoir, vous m’avez donné un petit coup de pouce qui m’a fait grandir. Ma première rencontre avec vous fût mon troisième grand cadeau. Au Colloque sur l’Arbre à Montpellier en septembre 1990, j’ai assisté à votre conférence. J’étais très heureuse de vous savoir présent au Colloque. J’avais craint que quelques problèmes de santé ne me donnent jamais la joie de vous voir. Dès votre entrée sur scène,

69 j’ai compris qu’il allait se produire quelque chose de particulier. D’abord, votre passion pour votre travail (et j’oserais dire pour la vie en général) illuminait votre regard et clouait déjà sur place l’assistance. Vous avez ensuite déployé devant nous, avec art, votre talent à susciter l’éveil de la conscience et à stimuler la curiosité. Vous vous êtes adressé à l’intelligence des gens, faisant ainsi appel à la force vive de vos interlocuteurs. J’ai compris qu’une conférence n’était pas qu’une occasion de rendre compte des résultats de ses recherches, mais bien aussi de faire participer l’autre au processus de questionnement et de conceptualisation et d’ouvrir des portes sur de nouvelles interrogations en stimulant l’envie de tous à s’y pencher. Quelle belle mobilisation des énergies autour de votre sujet exposé! Ce jour-là, vous auriez donné envie à n’importe qui de faire de la recherche. Nous étions déjà vendus à la cause. Ce fût pure joie.

Le plus gros cadeau que vous m’avez fait était pour moi inespéré. Vous avez participé en tant que membre externe au jury de ma thèse de doctorat en 1997, au Canada. Vous étiez la seule personne à pouvoir me donner autant de gargouillis au ventre. Je n’étais pas sans appréhension à l’idée d’être jugée par vous, mais en même temps je l’appréciais infiniment. Je souhaitais que ma soutenance de thèse soit pour moi l’occasion d’être vraiment mise à l’épreuve. Je souhaitais pouvoir donner la performance dont j’étais capable. Pour cela, il fallait pousser les limites à l’extrême. Vous m’avez offert cette occasion. À mon grand plaisir, vous ne m’avez pas épargnée. Cela m’a demandé de travailler fort et de me surpasser. Je me rappellerai toujours de chaque instant de ce moment qui fût très grand dans ma vie, ainsi que de la fête qui a suivi. Ce sont de ces évènements qui vous projettent vers d’autres réalisations dans un enthousiasme et un besoin renouvelé de se surpasser.

Enfin, je ne saurais passer sous silence combien j’apprécie l’humain en vous. Cette qualité que vous avez d’explorer de larges horizons sans perdre contact avec la vulnérabilité de la vie vous donne cette grandeur qui appelle celle de l’autre. Dans un enseignement, vous savez toucher les gens dans ce qu’ils sont et vous leur montrez qu’il n’est pas besoin d’artifice pour comprendre la vie, au contraire. L’explosion de votre force dans un contact avec l’essentiel laisse sa trace en chacun et lui rappelle qu’il a au fond de lui-même une source intarissable d’énergie. Merci d’avoir su croire en vous-même, d’avoir offert si généreusement le fruit de vos efforts et de votre travail et de savoir si bien écouter l’autre, l’encourageant ainsi à faire de même. J’espère avoir longtemps l’occasion de partager avec vous des réflexions. C’est toujours avec un immense plaisir que je me laisse surprendre par la verbalisation de votre pensée et qui m’invite à pousser toujours plus loin mes questionnements dans une conscience grandissante de ce qui relie les différents niveaux d’organisation de la vie. C’est un privilège de vous connaître et je l’apprécie. Je vous souhaite de profiter pleinement de l’occasion qui vous est offerte et qui vient avec ce qu’on appelle la retraite, c’est-à-dire la plus totale liberté de vous épanouir à la façon qui sera la vôtre. Passez de bons moments dans tout ce qui vous tient à coeur. Je vous souhaite la meilleure des santés.

Au très grand plaisir d’une prochaine,

Bien amicalement, Jeanne Millet (Canada)

70 Congratulations Professor Dr. Ir. Roelof A.A. Oldeman

Vidar J. Nordin, B.A., B.Sc.F., Ph.D., R.P.F. Professor and Dean Emeritus University of Toronto President, V.J. Nordin Associates Inc Ottawa, Canada

I will leave the essays and detailed accounts of your outstanding career to your close colleagues, former students and friends who have been closely associated with you and your studies in Montpellier and Wageningen over the past 25 years.

I first met you in Wageningen some 15 years ago and even before my visit your distinguished role as a teacher and scientist was well known and established. Julie and I will never forget the warm hospitality of Roelof and Wilhelmina with your friends and students.

While we have not met again since that time we have kept in touch and when we needed challenging book reviews for The Forestry Chronicle, you were there with your penetrating, thoughtful analysis.

I congratulate you for your many exceptional contributions to forest science and to the field of education in the global forestry resources sector and I am confident in your “retirement” we will hear from you often.

Best wishes now and in the future.

Your Canadian friend and colleague, Vidar.

71 Remembering Professor Oldeman

Frans van Ogtrop De Savornin Lohmanstraat 53 6702 BN Wageningen tel: 0317-412842 [email protected]

As a student it took me some time to establish the direction in which I intended to develop myself and my study —and I don’t mean specifically my study profile. During these initial years I remember Prof. Oldeman as a lecturer at some distance. Utterly capable, but I didn't know exactly of what.

We had started our forestry career Wageningen at the same time: 1978 —I as KA-student Forestry, he as professor. The start was not easy: at that time almost all forestry education material came in as stencils: one by one or package by package. The ones of our Prof. were of the small size, but illustrated. The education material was being built up from scratch: after many years of letting the Forestry Department muddle on by itself, the triad of professors had changed.

After I had established my direction, I found myself following a path that might lead somewhere. Professor Oldeman was pre-eminently the person who could follow as well as stimulate me in this direction. I have had many small conversations with Prof. Oldeman, starting already rather early in my study and extending for years, as I was not eager to put an end to my strife for my first title. To me, Professor Oldeman is my mentor —and up to now I could find me no other. Not the man to restrict himself to changing the dots and commas in my text: that is for free.

Of utter importance, I think, was the way in which I got his consent to answer on a request from the Forest State Corporation Java for two students to orient ourselves and the Wageningen forest student population to the Indonesian way of working with the forest and the people in the forest: i.e. on Java. Not in a policy vacuum, but in accordance with a line of formerly elaborated concepts, which already had been reported and which had been presented at the World Forest Congress in Jakarta in 1978. A line, which, as far as to my experience, has barely, if ever, been recognized by any of the persons and organizations that have cooperated with the Forest State Corporation Java.

Before we departed, on instigation of prof. Oldeman we had many talks with the Indonesian links he could offer us in Wageningen. In the same line I might mention the way the report on our experiences came into being. Positive, in full trust. The rest is history.

I must admit, I always referred and refer to him as Professor Oldeman. I suppose that Roelof himself decided to keep somewhat more distance to his students than he had done before in his first few classes. That is, I think he did. And of course, in this he is a master, probably to dismay of many.

To be short, to me “the Prof.” is a very good listener. During my study he has helped me with concepts and views, i.e. towards a better understanding of the greater world of forestry. Something that I hardly recognize in the present state of affairs in Wageningen, in the Netherlands and even in the global scale. Just as ‘Wageningen’ is a total blank in public discussions on agriculture, ‘forestry’ has become a blank in the public discussion on global forest deprivation.

72 To a large extent, in the last decennium the Prof. has been deprived of his opportunity to speak on behalf of consistent forest policy lines towards the future. May he reconquer full permission to speak as a quality of his retirement. And may we have a more open ear to his sayings, as he had for me in the decade that our paths did match.

73 Professor R.A.A Oldeman: On Park Design

Dr. Michael Oneka AYA Press Rotterdamsedijk 28c 3112 BC Schiedam The Netherlands Tel.: +31 618470651 [email protected]

Introduction The present text was written with the retirement of Professor Oldeman in mind. I first heard of Professor Oldeman from my former Brazilian classmate, Ney Pinto. From his name my first impression was that he must be a very old man, at the verge of retiring. I was just getting used to the idea of people retiring, having had to face the retirement of Professor Is Zonneveld in Enschede. In between was a most painful experience, the loss of Professor Dirk Thalen. As I write, I feel as if am one of the proverbial five blind people trying to describe an elephant. In the same manner, having encountered Professor Oldeman, it is difficult not to have own description of him. I have had the privilege and pleasure of working under his guidance on the design of national parks. The work shows that many national parks and protected areas are failing because of deficiencies in the institutions and approaches.

First Meetings From our first meeting I actually remember more clearly talking with Mrs Oldeman than with the professor. This was in Amsterdam after a party at the retirement of Professor van der Herman. I had a lift with friends to the occasion. Since the person in whose car we went wanted to leave early, we left the reception to travel back to Wageningen. As we prepared to leave, there came another friend also by car and returning to Wageningen much later. I therefore could stay longer at the reception. As we walked back towards the reception we bumped into Professor and Mrs Oldeman. I do not remember who greeted first, but it was spontaneous and cordial. We shook hands with brief introductions. On hearing the name Oldeman, I reacted with great surprise. “Forestry Professor Oldeman from Wageningen?” “Yes,” they answered. We shook hands again. His wife told me to note his contact details and call his office to make an appointment if I wanted to talk with him. A couple of days later I called his office and made an appointment for our first meeting. This was to mark the beginning of our long- lasting relationship.

Prior to coming to Holland I worked as a researcher for the Uganda National Parks. Most of my research was on fire and vegetation dynamics in the Murchison Falls Park. This park, created in 1952, is located on the banks of the Nile River as it crosses into the western Rift Valley. This was a tsetse fly infested area evacuated towards the end of the 19th century because of a sleeping sickness epidemic. Wildlife population built up in the following decades making it one of the important hunting safari destinations in East Africa. Soon after World War II, the British protectorate authority began taking steps to protect the wildlife and to develop the area as a tourist attraction. Around the protected areas the British made local people cultivate cash crops such as cotton to pay taxes. Then came the conflicts —wild animals destroying crops in the villages. The book of Willock, The enormous zoo, describes what happened. In brief, because wild animals were killed outside, they became confined to the protected areas. Local people were banned from hunting inside the protected areas. There, the sustained high concentrations of animals devastated the vegetation and landscapes. In their book, Elephants and their habitats: the ecology of elephants in North Bunyoro, Uganda, Laws, Parker and Jonestone described how these problems were addressed. In brief, first, they examine who was to blame: fire or elephants. Second, they examine

74 some of the options —to intervene or let nature take its cause. Both fire and the elephant were blamed and there was intervention.

At the time of intervention, there were about 14000 elephants in the Murchison Falls Park area. Some of these were killed in an experimental culling programme. In the 1970s the national political situation rapidly deteriorated under Idi Amin regime. The rule of Law and order also collapsed. Uncontrolled hunting exploded in the protected areas and reduced the elephant population to less than 2000 by 1980. Into the 1980s there were still no signs of real recovery of the forest and woodland vegetation in the park. Was there now so much grass that the resulting fire was preventing forest development? This was the question Professor Oldeman and I got entangled in! Results of the work are in my doctorate thesis, On park design: looking beyond the wars. The book shows how parks are submerged in all kinds of wars, that the wars are real parts of the park system dynamics. The design of such parks can only succeed if these realities are recognised, understood and addressed in the design.

I sent to Professor Oldeman a very early draft of my report on the fire vegetation studies. The main purpose was to discuss with him what we could do with the data. Since the death of Professor Thalen I had failed to find a clear framework within which to finish work on the data. When we met, Professor Oldeman had commented extensively on the draft. He had also opened a file for me as a potential promovendus. I do not remember giving him even my curriculum vitae. The comments demonstrated he had actually seriously studied what I gave him. He was constructive and genuinely interested. This was quite refreshing and inspiring. The first discussions were more collegial than I was used to. We could, directly, focus on the scientific contents of the work in depth without any interference.

Finding the way Professor Oldeman arranged my admission to the doctorate programme but I remained in the then Department of Nature Conservation under Professor Stortenbeker. Many things happened before that stage. During the brief period I was with Professor Thalen he convinced me that modelling was probably the way forward with my work. We never had opportunity to elaborate his ideas. After him, I tried to get something out of my data using contacts I got in the Wageningen University computer centre. Here, Mr van t’Hoff tried his best to help me with some modelling using my data. On his advice I took up contact with the group of Professor Rabbinge and worked briefly with Dr. Van der Werf. I was exposed to working at the microbiological scale. What I remember was that, in a way, this was like we came from different planets and spoke different languages. Afterwards, I believe about the time I met Professor Oldeman, I followed a course offered by Ir. Ingrid Duchhart on Landscape planning for the tropics. I immediately felt at home and could see many opportunities. When my admission was being formalised I therefore opted to build a research programme that would bring together the modelling, landscape architecture, landscape planning and geographic information into a decision support system for management of protected areas. Professor Oldeman helped to put together a team of four professors and other supervisors. It took us almost two years trying to build this programme without clear funding possibilities and with a lot of problems making and maintaining functional committee. In the end it really did not work. Professor Herbert Prins took over from Stortenbeker and tried to focus the work on the ecological dynamics. Eventually it was not possible to continue the work in Department of Nature Conservation. Professor Oldeman who had moved to the Department of Ecological Agriculture, invited me to join them. There were no funds per se to do the work, but I could share with them whatever they had. I often used his office, computer and personal facilities. We effectively moved all around the university to arrive at the work together. It was actually as if my doctorate research just started. Working in the new Department meant that my work had to pay more attention to design aspects. This was no problem because I could draw on many of the exposures I had in the preceding years. My research would have been impossible without the institutional space and clear framework provided by Professor Oldeman and the group of Professor Eric Goewie.

75 Park system design Working with professor Oldeman was a learning process in itself. You start with the big picture, and then go systematically into the details, with a lot of reading and writing in between. He created time for your work, studied the drafts and seriously prepared for the next meeting. In the meetings he liked to discuss freely. If in a discussion new ideas emerged, he would directly point to possible references. In the later phase of our work on my thesis his attention to details meant we did not need external editing in English, French or Dutch. A couple of his ideas keep coming back to my mind. These are detailed in the book Forest: elements of silvology. I will elaborate on a few of the ideas.

Zero events Professor Oldeman provided us a way to look at forest succession. Imagine an event that eliminates a forest system, e.g., a storm, fire or flooding. Such an event effectively sets the forest system back to where it where it started. Such an event can be viewed as a zero event. A zero event triggers many landscape processes. Many life forms dependent on the destroyed big trees may be killed. Other life forms previously suppressed by such big trees suddenly have a chance to flourish. The forest system starts recovering. The results might be completely different from what previously existed. Professor Oldeman has shown us some of the patterns that may be observed. The disasters, therefore, create opportunities to start anew.

In our Murchison Falls Park we identified some interesting points. We found that the lack of visible recovery of forests and woodlands was caused in part by many interacting factors. We studied woodlands previously dominated by Terminalia trees. The vegetation appeared more like wooded savannah than forests. The original idea was that trees limited grass growth in the woodlands. With the trees dead, grass growth increased. Because there was more fuel, the fires were more severe and burnt back small trees. The park is dry during December- March and June-August months. Most fire was in the December-March dry season. At the time of fire the fuel load in the grassland and the remaining woodlands were similar. Early in the year there was more grass growth in the shaded sites and later more in the grassland sites. Early in the year the limiting factor was access to moisture so the shaded areas had more grass growth. Later in the year the limiting factor appeared to be light so the grassland had more grass growth. These differences did not exist any more when most of the fire took place. Accidentally, we identified many factors which significance was not directly apparent. These factors included the details on fire behaviour, weather patterns, activities of termites and large herbivores. These factors worked together in manners that would be difficult to detect using widely applied ecological approaches. This convinced us of the need for new approaches to deal with comparable challenges. The deficiencies in our technical approaches may explain why many programmes for protected areas are ineffective.

The idea of linking disasters and opportunities to start afresh was an important inspiration to On park design: looking beyond the wars. It is not that disasters are desirable but that in many cases we cannot prevent them. We should, at least, try to transform the ravages of war into opportunities to start afresh. We found that many protected areas are trapped in institutional settings that make it impossible for them to develop normally. Many have persistent lack of insight into their dynamics. Often, this is largely the result of the too narrow-focused research and non-holistic development programmes. Imagine the five blind people describing an elephant. Now, instead of the elephant, think of the park being described and controlled by a team of biologist/ quasi ecologists. No wonder we have had millions of dollars spent on protected areas and yet species get extinct in the same areas. Some of the worst conservation problems are in regions than receive the most support. A situation comparable to driving up slope using the wrong gears and probably heading the wrong direction. Luckily, you might get to the destination because the car failed to climb the hill and instead revered to your destination. However, in the process, you generate a lot of noise, pollution and time wastage without real progress. A zero event would nullify an existing stagnation and enable a fresh start. Better insights into these phenomena should help develop effective institutions to manage natural resources.

Trees of the past and trees of the future

76 This is another fascinating concept developed extensively in the work of Professor Oldeman. The idea is that when you look at a forest structure there are species that dominated in the past, others that dominate now and still others set to dominate the forest structure in the future. The categories are based on the life cycles of the species, their growth patterns and plant behaviour. For example, mature Acacia trees scattered in a savannah are effectively trees of the past. Once such trees are dead, they are unlikely to be replaced by the same species. In our Terminalia woodland case, the species belonged to a forest succession stage. With further development of the woody vegetation the species is unlikely to feature as prominently. For the existing woodlands, it was therefore in effect a tree of the past. Subject to site conditions, other species, which may look insignificant in the existing structure, actually constitute part of the trees of the future for the vegetation. These concepts have a lot of potential in the assessment of forest systems and can contribute significantly to better landscape planning and management. It is also comparable to viewing the present as the mirror of the past and at the same time as an image of the future. How can one design a system when one neither understands how it is nor can visualise its future? What type of aforestation programme can you expect from such a designer?

What is a park system? When we started working together it soon became clear that we did not view park system the same way. The first discussions focused very much on the relationship between such factors as animals and vegetation, and vegetation and soils. As we got deeper into the work, it became clear that if we really wanted a functional design, our definition of the park system needed to be more comprehensive. It was at this stage, I feel, we really got face to face with the real park design issues. We realised that people hunting illegally in the park, soil erosion and the use of pesticides outside the park, etc., were as much parts of the system dynamics as were fire, herbivores, lions, etc. A park system was certainly more than the sum of its individual pieces. The system structure definitely also included various social and economic factors on the park. With this in mind, we could explain why many protected areas worldwide were in deep trouble. Most of the troubles were caused by defects in how the park system was perceived. In many cases, attention was given almost exclusively to the larger animals. Consequently, the design of the park systems and related management programmes could only achieve real effects by sheer luck.

With the park systems so complex and dynamic, we felt, the most practical way to design them was to focus on the processes. Start by developing a general all-inclusive framework. Provide on the basis of that a working arrangement and then initiate a process to obtain and to work with the details. This perception recognise clear roles for pure and applied research as well as broad-based consultations. The more inclusive the consultations are the safer it will be. We also realised that given the prevailing circumstances, the more insight is not necessarily the easier. A lot would depend on how such insight was developed. There may have been cases of censored learning, concealed evidence or other undocumented facts.

Professional development Many people have shaped my professional development. The undergraduate training in Uganda provided a rare background in geography of natural resources. This prepared me for the work in the Uganda National Parks. The park system was more than the animals and plants. The ITC group of Professor Zonneveld equipped me with landscape ecological skills to develop ecological monitoring programmes in a research driven management- planning process. The mapping skills are crucial to my attention to working at the appropriate scale in dealing with natural resource management issues. From a different angle, the groups of Dr. Chris Geerling, Dr. Steven de Bie and Ir. Ingrid Duchhart helped me to start viewing the same problem but more from a perspective of research driven by planning objectives. These were people heavily involved in Africa with many of the problems that bugged me all the time. They treated issue of poverty, hunting, soil erosion and other forms of landscape degradation as equally important aspects of nature conservation. Much as I was concerned about what happened in the park, I could not avoid the fact that we had to live at home with many of the realities of the changes in the landscape. Even when no longer able to work in the park, life in the villages will remain an inevitable reality. Working with Professor Oldeman, some how, made all these aspects come together in a fairly integrated manner. Design of parks in the then Department of Ecological Agriculture increasingly made the most sense. It

77 was kind of as if it was all by design.

From the above background I can understand rather well the problems of many park systems. Holistic scientific approaches remain elusive, especially for parks. Most of the training and research institutions remain rather narrow-focused. On the ground, the situations get more urgent especially in many countries crippled by civil unrest and mismanagement of natural resources. What we seriously lack is true professionalism in all fields. Rather than younger professionals we need more newer ideas and better approaches. I view Professor Oldeman more as a professional of the future, rather than one of the pasts. In many ways he is far ahead of our times and therefore may seem too abstract. I foresee that his work, especially on tree architecture and silvogenesis, will become more widely applied in the years to come than what many younger professionals will ever achieve.

Reference Oldeman, R.A.A. 1990. Forests: elements of silvology. Springer-Verlag, Berlin. Oneka, M. 1996. On park design: looking beyond the wars. Ph.D. thesis, Wageningen Agriculture University, Wageningen. Laws, R.M., Parker, I.S.C. and Jonestone, R.C.B. 1975. Elephants and their habitats: the ecology of elephants in North Bunyoro, Uganda. Clarendon Press, Oxford. Willock, C. 1964. The enormous zoo. A profile of the Uganda national parks. Collins, London.

78 On Diversity, Oldeman, and the acceptance of the odd

Dr. Ir. Gaston G.A. Remmers Bureau BUITENKANS: ondersteuning bij innovaties op het platteland Trouringhstraat 34-bel 1055 HC Amsterdam email: [email protected]

Prof. Oldeman is one of the most peculiar persons I have met in my life. I was one of his students on agroforestry, and later he was co-director of my PhD thesis. “Tenderness” is maybe the word that comes close to what I feel when thinking of him. This may seem quite a strange qualification for a scientist of such magnitude, known for his intellectual capacity and the somewhat old-fashioned social relations he used to establish with his students. Yet, I came to recognize tenderness not only in the warmth he carries within and expresses when one shows to respect his borders, but also in the way he treats his research objects. It is as if he caresses unknown issues with care, compassion and belief that something valuable may come out of it. These issues go beyond disciplinary borders, not as an exception to a rule but more as a standard procedure. When writing this, I realize that I recognize these qualities, because they resonate with my personal inner drives. In this sense, I experienced Prof. Oldeman as a father in the true sense of the word: a man who backs you up, gives you confidence, and believes in what you do. When you resonate with him, he blesses you.

To give an idea of his capacity to hang on to the most diverse of subjects, I will highlight some of the issues I was able to elaborate under his guidance. Shortly after graduating as an agroforester, I became more and more oriented towards rural sociology. I worked in Southern Spain as a researcher in rural development and sustainable land-use, trying to find the borderline where ecology met sociology, and where the natural world transformed the social world and vice versa. I worked in a so-called remote area, where —for European standards— farmers practiced completely outdated agricultural methods. I came to formulate a theory on “cultivation stops”, not in the sense of a place or time where cultivation stops, but as an analogy to “bus stops”, where genetic material hops on and off a carrier —the farmer. The concept (translated in Dutch as “teelthalten”, in Spanish as “paradas de cultivo”) provides a perspective on the network involved in the spread and gradual adaptation of genetic material (of cereals and horticultural species). It positions the farmer as the intentioned and capable grower, in observation of and interaction with his environment (Remmers, 1998:80-85).

In the same piece of work, I elaborated a metaphor to elucidate the composing skills involved in farming. “Agriculture is jazz”, I positioned: harmony, rhythm, technical skills, love for the art and “sense for the form” are the elements that unite the two. From this image, I went on to study design processes, and tried to come to grips with change and continuity in development processes. I was particularly puzzled by the unintended outcomes of intentioned action. This is an issue that a famous British sociologist has written about (Giddens, 1984); yet, what kept me fascinated was what I recognized as the vitality of the unintentionedness of both the action and the outcome. It seemed to me that precisely the unpredictability of Life was a guarantee for the reproduction of Life. And that the dominant agricultural modernization approaches that prevail the worlds’ development projects, are way too much versed towards control and exclusion of errors to be effective. Likewise, Oldeman has repeat- edly stated that mathematical images of the growth of forests are helpful in mapping and portraying Life, but not in explaining it conceptually (Oldeman, 1990: 350-372, 1992). The reason is that in “real” Life, deviations are integral part of the deal, where in computers they are not. Hence Oldeman’s interest in fuzzy limits and shifting dynamics as opposed to crisp limits and unerring processes. Hence also his emphasis on The Struggle of Life (the title of one of his latest books), instead of for Life: it is Life itself that imperfectly proceeds towards seemingly coherent performances, as opposed to the image of an individual species that works its way up using elbows and

79 other evolutionary advantages. The Struggle of Life is a grand effort of him and his co-writers (Rossignol et al., 1998), to substantiate, from the enormous range of cellular dynamics to forest architecture and climatic and oceanic behaviour, a theory of “the natural history of stress and adaptation”. It is no less than a search for the essence of Life.

Thus, it was not strange to find Oldeman as an ally in my endeavours to construct a theory of the generation of diversity (Remmers, 1998, 1999), in which I intended to bring together both the physical world with the social world into a conceptual framework that specifically addressed the interaction between a plan (be it a human project, or cellular DNA), a context (social, natural, known, unknown), and the resulting performance. I would argue that performances (in general: anything we do, anything that occurs; more concrete: e.g. agricultural experimentation, a play on stage) are always hybrids, i.e. they are never solely social nor solely biophysical. Nor are they static: biodiversity, thus, is not a thing that can be conserved, but something that is to be reproduced. Oldeman wholeheartedly subscribes this point of view (see e.g. Rossignol et al, 1998:201).

While writing this, I realize that sometimes the usefulness of this type of theoretical work on diversity may not be apparent. Its main contribution, I believe, is that it generates a kind of wonder and humility before the complexity of Life, a reflexive state in which surrender prevails over domination and resistance. It yields, so to say, a subtler and softer state of body and mind, that enables us to accept things as they are, and not as how we want them to be. It invites us to have an eye for the value of odd facts, deviant behaviour, and “illogical” coherence. In my view, this is precisely one of the key-virtues of Prof. Oldeman.

I would like to finish this modest contribution remembering a visit Oldeman paid to Córdoba (Spain) in 1994. I invited him to deliver a series of lectures on Forest Diagnosis and Design at the Faculty of Agronomy. He came with his wife Wil Helder, and stayed for a week. I will always recall them walking through the old city, strolling along the Mezquita, taken by the hands. Their togetherness, as different as the two of them may seem to be, was so natural, and I was touched by the warmth that emanated from this couple. Again: I saw tenderness. My tribute to Prof. Roelof Oldeman is also a tribute to his wife Wil.

References Giddens, A., 1984. The constitution of society: outline of the theory of structuration. Polity Press. Cambridge. Pp.402. Oldeman, R.A.A., 1990. Forests: elements of silvology. Springer-Verlag. Berlin etc. Pp.624 Oldeman, R.A.A., 1992. Architectural models, fractals and agroforestry design Agriculture, ecosystems and environment 41: 179-188. Remmers, G.G.A., 1998. Con Cojones y Maestría: un estudio sociológico-agronómico acerca del desarrollo rural endógeno y procesos de localización en la Sierra de la Contraviesa (España). (With balls and mastery: a sociological-agronomic study of endogenous rural development and localization processes in the Contraviesa mountains (Spain)). Wageningen Studies on Heterogeneity and Relocalization 2. Circle for Rural European Studies, Wageningen Agricultural Univer- sity. Thela Publishers, Amsterdam. Pp. 398. Remmers, G.G.A., 1999. Towards a theoretical understanding of the generation of diversity in the countryside. In: Kasimis B. and Papadopoulos A. (eds). Local responses to global integration: exploring the socio-economic aspects of rural restructuring'. Ashgate Publishing Ltd., London. Pp.41-61. Rossignol, M, L., Oldeman R..A.A. and Benzine-Tizroutine, S. 1998. Struggle of Life, or the natural history of stress and adaptation. Treemail. Wageningen. Pp.237.

80 Roelof Oldeman, the grand old man of the forest

Dr. Paul Romeijn Director Treemail Prins Bernhardlaan 37 6866 BW Heelsum The Netherlands www.treemail.nl

First encounter Hinkeloord, this is the place where it all began. When I walked up to the mansion for the first time, in 1980, the thought struck me that in such a building it might be possible to develop a personal relationship with staff members. I was hooked. Not knowing what I was in for, I registered myself as a student of tropical forestry.

Meeting Prof. Oldeman is a memorable experience. I remember well his entries in the lecture hall. A towering figure appears, clad in a green cape, his posture a striking blend of Sandeman and Zorro. So I had met with Prof. Oldeman: a lucid, multilingual, well-spoken gentleman, who travels all continents and boasts a wide range of interests that includes his students. These were the beginnings of our very dear friendship that now spans two decades (…well, almost). The image shows Hinkeloord.

In the mid-eighties the department was vibrant and thrived. Here I recall the frequent media attention, the international staff/student IUFRO meetings, the birth of the Canopy Foundation (Stichting Het Kronendak in Dutch), the BOS foundation, and Tropenbos, celebration of the centennial of forestry education in Wageningen and, under Prof. Oldeman’s guidance, my apprenticeship at CATIE in Costa Rica and laying foundations for a national park that was established on the highest summit of the Kingdom of The Netherlands on ‘The Mountain’ of Saba, the smallest island of the Dutch Antilles (Romeijn, 1987 and 1989; and WWF, 1997).

Enter Science Prof. Oldeman’s scientific excellence hardly needs an introduction; for beginners his book ‘Elements of sylvology’ (Oldeman, 1990) is a good point of departure. In my dissertation I referred to the fact that from his lessons “I have learnt most and understood least” (Romeijn, 1999a). Early on in his career, Prof. Oldeman started out in French Guyana with little more than pencil and paper, and the forest of course. There he developed the fundamentals of tree architecture and forest structure dynamics, together with Prof. Francis Hallé. The concepts were initially ridiculed, in The Netherlands rather than in France, for having no practical use.

Tree architecture and forest structure dynamics are such elegant and simple concepts that they are difficult to grasp, much like Einstein’s E = mc2. A number of very bright-minded young persons did follow-up the concepts and they proved to understand them as, e.g., Vester (1997) and Van der Wal (1999) did in their cum laude dissertations. Meanwhile, proof that these concepts correspond to realities in world of physics would come from a completely different angle: from space. In the early days of space exploration, someone dreamt up the clever idea to point the satellite instruments upside down, i.e. towards earth, which marked the beginning of what we now term remote sensing or earth observation. Spaceborne images suffer from deformations, made by the convex shape of the earth, rugged terrain, mountains, different instruments (e.g., radar, infra-red, optical) or camera positions or resolutions (when working with multi-temporal images), to name but a few. At Privateers NV, the problem of how to fit the pixels from different

81 satellite images precisely on top of each other has been largely solved, witness the highly accurate contour maps of Southern Ethiopia that were made to help research the Gedeo land-use system (Kippie et al. 2001). This allows for proper pre-post analysis of major catastrophes, including earthquakes and hurricanes, given the proper processing software that is. Now that this has been combined with speed, the satellite image processing operations can follow events in near real-time (as reported in, e.g., Nezry et al. 2001, and BBC, 2001, for the case of an earthquake in El Salvador).

Dr. Francis Yakam of Privateers NV shows this to good effect in the case of the damage caused by Hurricane Mitch. To the left we see him during ground truth inspection of a damaged bridge in Honduras, to the right is the corresponding image. In Tegucicalpa, individual houses that were damaged were correctly identified (Yakam et al. 2000).

Once this level of precision of image processing was attained, Privateers NV worked to develop applications that were of practical use to forest monitoring. This is actually quite difficult and at Privateers NV we habitually refer to remote sensing as being ‘very remote with little sense’. Finally, it took us seven years of research to crack the nut of how timber volumes can be derived from satellite images with good results. The matter boiled down to one central question of physics: How does a radar signal behave within the forest canopy? The answer to this question was located within the cornerstone concepts of tree architecture and forest structure dynamics developed by Prof. Oldeman, precisely (Nezry et al. 2000a).

At this point I would do great injustice to Prof. Oldeman if I give the reader the impression that his scientific contributions are limited to the subjects described above. Over the years, numerous fruitful discussions have led us to many ‘places’. Fractal geometry is one such ‘place’. Fuzzy logic is another. This teaches us that history can only repeat itself in similar, and never in identical ways. Fuzzy logic was quite elegantly practiced by Jane Shaw in her work on complex land use systems in the American Appala- chians (Shaw, 2002). Hutan Lestari is yet another one of these places. This Indonesian initiative was housed at Wageningen University. It has led to numerous dissertations by Indonesian students (e.g., Indrabudi, 2002) and, indirectly, to a Privateers NV forest monitoring mission to Sumatra in the context of a project for the Japanese Space Agency, NASDA (Nezry, 2002). The image shows Supit (to the right) and Romeijn inspecting a forest disturbance in central Sumatra, Indonesia.

Other special places are those of the rhizosphere and its aboveground counterpart, the phyllosphere. Both these environments, of the roots and the leaves, were largely terra incog- nita. For improvement of our understanding of these environments, Prof. Oldeman has made great contributions. Here I take only the phyllospshere as an example because this is the sphere that I am most involved in. Prof. Oldeman is co-founder and the current Chairman of the Canopy Foundation. Over the last decade, the Canopy Foundation supported over 60 scientific publications in its field (ref: http://www.treemail.nl/kronendak and do view, e.g., Visscher, 2002). The Foundation instigated the new chair of Canopy sciences at the Univer- sity of Amsterdam, currently held by Prof. Jan Wolf (Wolf, 2001). To help rationalize use of the phyllosphere, Prof. Oldeman developed his copyrighted concept ‘canopy farming’. Canopy farming© leaves the forest essentially intact: “cultivation of canopy products takes place within their natural habitat itself, i.e. the canopy” (Van

82 Weezendonk and Oldeman, 1997). It seeks to maximize added value, with minimum mass. In its purest form this relates to information (Romeijn, 1997). Canopy farming© thus starts there where extractionist concepts stop. The image shows the canopy raft over tropical high forest in French Guyana. This raft was designed in the late eighties by Prof. Francis Hallé, together with a pilot and an architect (photo: Oldeman©).

The Gedeo Country, in the Southern Highlands of Ethiopia, is another one of these special places, too. Tadesse Kippie, a native Gedeo born of illiterate parents, described the ancient Gedeo land-use practice in a dissertation that was supervised by Prof. Oldeman. The system feeds over 450 people/km2 in a rugged mountainous tropical region. This is achieved without terracing, tilling or agrochemical inputs, while soil fertility and a strong performance in security of production are retained; a matter of life or death to local farmers. Tadesse Kippie found that food —and production— security are largely safeguarded by maintaining a complex, multi-rotational system with high biodiversity. The staple crop Ensete plays a key- role as a pacemaker species; Kippie described its cultivation in different climate zones and its processing. Understanding this unique land use system is likely to be of high relevance to establish or maintain biodiversity and food security in all mountainous tropical areas of the world. Dr. Kippie’s dissertation is a unique document as it is a true inside job, and because it touches upon a number of very fundamental issues in both forestry and agriculture (Kippie Kanshie, 2002, and Nezry et al. 2000b; also see Diamond, 1997, and Monbiot, 1989). The image shows Dr. Kippie at the 8th International Symposium on Remote Sensing of the International Society for Optical Engineering, SPIE, in Toulouse, France.

Exit Science —enter politics One should bear in mind that science provides no guarantee for fair play. The late and much respected Professor of Philosophy at Berkeley, Paul Feierabend was well aware of this and wrote: “Financial arrangements can make or break a research programme and an entire profession. There are many ways to silence people apart from forbidding them to speak —and all of them are being used today. The process of knowledge production and knowledge distribution was never the free, ‘objective’, and purely intellectual exchange rationalists make it out to be” (Feierabend, 1993, pp 126-127). The great Prigogine sensed this at the time, too. “Tradition tells that as a result of a hostile religious and social reaction, philosophers were accused of atheism and were either exiled or put to death” (Prigogine and Stengers, 1984). Since we know Prof. Oldeman has not yet been put to death, the attentive reader is able to figure out what fate was bestowed upon him by staff members, managers and politicians who were comforted by the blessings and support they received from civil servants. Prof. Oldeman, however, did not stand alone in his fate as I was able to figure out only later.

There is a larger picture that has to do with the role of science within the society at large. Towards the end of the nineties, I described it as follows: “Once upon a time, in the dark Middle Ages, the Church held the Keys to The Truth. The Church had forgotten its mission and vision. It sold Variations of Truth as letters of indulgence. […] Today, in the twilight of the Age of Enlightenment, Science holds the Keys to The Truth. Science is in the process of forgetting its mission and vision. It sells Variations of Truth as research results and provides its commissioners with highly desirable absolution; be it in an environmental, financial, legalistic or even ethical sense. Once again The Truth has become a commodity; it can be sold rather than searched. In retaliation, scientists now circumvent the prevailing peer review system by publishing their research results directly over the Internet” (Romeijn, 1999b). Indeed, today, Wageningen University sells its name to promote, e.g., detergents in TV commercials.

83 And back to the forest The aforementioned elements of sylvology do not tell the whole story. There are many ways to look at forests, and there can be no doubt that Prof. Oldeman has come to grips with several of them. This is no mean feat, as these ways are related to human perception and because human perceptions differ greatly from one culture to the next. Prof. Oldeman is well aware that forests exist within several, complex, contexts. Perhaps this is best illustrated by the interdisciplinary treatise ‘Struggle of life: or the natural history of stress and adaptation’ (Rossignol et al. 1998). This book has remained little known and, as yet, little understood, possibly because of the wide subject range that it encompasses. The ‘Struggle of life’ simply teems with far-reaching, novel ideas; and it offers in-depth views of complex systems, from sub cellular-, to climatic- and solar- system level. The work reminds one of the old Chinese proverb: “When a mouse looks at the tree, it sees the sky” (Quing Zhu, 1299). Following its appearance in 1998, the findings reported in ‘Struggle of life’ have been substantiated by new research on many occasions. Definitively not easy but there it is and, moreover, …it is there.

One of the great privileges of befriending Prof. Oldeman for two decades perhaps lies with being there while his unrestricted view of forest was developed. An unrestricted view, as the term is used here, includes freedom from tutelage (see, e.g., Hecht and Cockburn, 1990, pp 219-221) and from mono-disciplinary views (see, e.g., Diamond, 1997). Almost en passant and certainly without intent, Prof. Oldeman introduced me to a wealth of knowledge on the nature and physics of information transport. This technology has direct practical implications for enhancement of audio equipment and the unobtrusive enhancement of the acoustics in large buildings; the latter being a rather shocking experience. Currently this leads to research of applications in the fields of biological —and biomedical— processes (Romeijn, unpublished).

Prof. Oldeman and his endearing wife, Mrs. W. Helder, have thus generously offered a continuous source of information and inspiration to all who would hear, and even to all those who would not. Modesty is the sign of a great man, and Prof. Oldeman has it in spades. This modesty shows in Prof. Oldeman’s conviction that he received his most moving compliment ever from a Wauwrani tribesman. The Indian placed his hand on the Professor’s heart and simply said “wauwrani”, meaning ‘human being’. At the time, more than 20 years ago, there were only 500 Wauwrani left. This, together with the above, makes our dear Professor out to truly be Roelof Oldeman, the grand old man of the forest.

One final element remains to be mentioned, that of his fine sense of humour. Over the years we have shared many good laughs, of which I introduced a single, tiny one in this document. I now leave it to the reader to find it … Prof. Oldeman has long spotted it from a mile away.

And to our grand old man of the forest I exclaim: “Onward!”

Sources BBC 2001. Aid from space. BBC News, London UK. Article by Ivan Noble, February 16, 2001. Diamond, J.1997. Guns, germs and steel: a short history of everybody for the last 13,000 years. Vintage, Random house, London (first published by Chatto & Windus, 1997), 480pp. Feierabend, P. 1993. Against method. Third edition. Verso, London and New York. 279pp. Hecht, S., Cockburn, A. 1990. The fate of the forest: developers, destroyers and defenders of the Amazon. Penguin (published with revisions), London (first published by Verso, London and New York, 1989), 349pp. Indrabudi, H. 2002. Forestland: its dynamics, disorganised uses and planning in South Kalimantan, Indonesia. Wageningen University, in print. Kippie, T., Romeijn, P., Nezry, E., and Yakam-Simen, F., September 2001. Radargrammetry helps fight hunger in Ethiopia. Invited paper at the 8th International Symposium on Remote Sensing of the International Society for Optical Engi-

84 neering, SPIE, 17-21 September 2001, Toulouse, France, 9pp. Download this document in '.pdf' format (Note: size is 475 kb). Kippie Kanshie, T. May 2002. Five thousand years of sustainability? A case study on Gedeo land use (Southern Ethiopia). Treebook 5. Treemail Publishers, Heelsum, The Netherlands. ISBN 90-804443-6-7, ca 295pp, with 20 pages of color illustrations. Download this document in '.pdf' format (Note: size is 7.3 Mb). Monbiot, G. 1989. Poisoned arrows: an investigation in the last place in the tropics. Abacus, Sphere Books Ltd, 248pp. Nezry, E., Yakam-Simen, F., Romeijn, P., Supit, I. and Demargne, L.; 2000a. Advanced remote sensing techniques for forestry applications: a case study in Sarawak Malaysia). Multi-Conference on Systemics, Cybernetics and Informatics (SCI2000), Orlando (Fla.), 23-26 July 2000, 6pp. Download this document in '.pdf' format (Note: size is 2.7 Mb). Nezry, E., Yakam-Simen, F., Kippie K., T. and Romeijn, P.; 2000b. Gedeo Zone mapping project, phase 2, final report. Web version, 12pp + annexes. Download this document in '.pdf' format (Note: size is 1.2 Mb). Nezry, E., Romeijn, P., Sarti, F., Inglada, J. and Supit, I.; 2001. Breaking new grounds for remote sensing in support of disaster relief efforts: detecting and pinpointing earthquake damages in near real-time (El Salvador, January 2001). 8th International Symposium on Remote Sensing of the International Society for Optical Engineering, SPIE, 17-21 Sep- tember 2001, Toulouse, France, 9pp. Download this document in '.pdf' format (Note: size is 650 kb). Direct access to Privateers NV images of the damages (January 13, 2001). Nezry, E. May 2002. JERS-1 2nd Research Investigation Program /Interim Report PROJECT J-2RI-008: Assessment of JERS-1 data to implement a fire prevention project in Indonesia. Privateers NV, 29pp. Oldeman, R.A.A. 1990. Forests: Elements of sylvology. Springer Verlag, 624pp. Prigogine, I. and Stengers, I. 1984 (2nd ed. 3rd impr. 1988). Order out of Chaos: Man’s new Dialogue with Nature. London, Fontana Paperbacks (Collins Publishing Group), Flamingo Books, 349pp. Quing Zhu, L. 1299. Oblique strategies: hidden dragons, mice and their ways. Unpublished manuscript, 327pp. Translation M. Hashimoto. Romeijn, P. 1987. Saba (N.A.), bos en nationale parken. Landbouwuniversiteit Wageningen, 47pp. Romeijn, P. 1989. The forests of Saba. BOS Newsletter no. 19, vol 8(2), 1989: pp44-51. ISSN 0923-7488. Romeijn, P. 1997. Information, knowledge and know-how. Lecture notes for the Department of Ecologial Production at Wageningen University. Unpublished,12pp. Romeijn, P. January 1999a. Green Gold: on variations of truth in plantation forestry. Treebook 2, ISBN 90-804443-3-2 (soft cover), ISBN 90-804443-2-4 (hard cover), Treemail publishers, Heelsum, ca 220pp + CD-ROM. Download this document in '.pdf' format (Note: size is 614 kb). Romeijn, P. June 11, 1999b. Martin Luther, Science and the Internet. FID Review, Vol. 1, Nr. 1, 1999, p 9-12. Download this document in '.pdf' format (Note: size is 326 kb). Rossignol, M., Rossignol, L., Oldeman, R.A.A. and Benzine-Tizroutine, S. 1998. Struggle of life: or the natural history of stress and adaptation. Treebook 1, ISBN 90-804443-1-6, Treemail Publishers, Heelsum, ca 240pp. Shaw, J. June 2002. Let them eat grass: Understanding pasture-finished beef cattle farms in the American Appalachians. Treebook 6, ISBN 90-804443-7-5, Treemail Publishers, Heelsum, ca 82pp with color illustrations. Download this document in '.pdf' format (Note: size is 1.2 Mb). Vester, H. 1997. The trees and the forest: the role of tree architecture in canopy development; a case study in secondary forests (Araracuara, Colombia). University of Amsterdam, 1997, ca 182pp. Visscher, A. August 2002. Medicinal plants of the canopy: a selection from the Amazon rainforest of Peru. On-line publication (in Spanish and English), Treemail Publishers, Heelsum. Access this document. Download this document in '.zip' format (Note: size is 2.7 Mb). Wal, H. van der November 1999. Chinantec shifting cultivation: InTERAcTIVE landuse. A case-study in the Chinantla, Mexico, on secondary vegetation, soils and crop performance under indigenous shifting cultivation. Treebook 3, ISBN

85 90-804443-4-0, Treemail Publishers, Heelsum, ca 162pp. Weezendonk, L.H.Th. van and Oldeman, R.A.A. 1998. Kronendak notes on canopy farming © in combination with conventional forestry. Stichting Het Kronendak. Access this document. Wolf, J.H.D. 2001. Juwelen in de kroon. Inaugurele rede, uitgesproken bij de aanvaarding van het ambt van bijzonder hoogleraar op de Mej. dr. Jakoba Ruinen-leerstoel Fyllosfeerwetenschappen vanwege de Stichting Het Kronendak aan de Universiteit van Amsterdam. ISBN 90 5629 216 1, Vossiuspers UvA, vrijdag 26 oktober 2001, 23pp. Download this document in '.pdf' format (Note: size is 105 kb, in Dutch). WWF 1997. Saba is niet zomaar een eiland. Auteur: Jeanette van Ditzhuizen. Panda, jubileumnummer, kwartaalblad van het Wereld Natuur Fonds, Nr. 4, herfst 1997, pp34-37. Yakam-Simen, F., Nezry, E., Romeijn, P., Supit, I. and Bally, P.; 2000. Evaluation of hurricane "Mitch" damages in Central America. Invited paper at Multi-Conference on Systemics, Cybernetics and Informatics (SCI2000), Orlando (Fla.), 23-26 July 2000, 6pp. Download this document in '.pdf' format (Note: size is 2.9 Mb).

Note to the photographs: Photo’s 1-4 and 6; courtesy and © Privateers NV. Photo 5; © Prof. Oldeman, with permission. Other publications by this author: Access Dr. Romeijn’s list of publications.

86 Livingstone achterna

Renaat S.A.R. Van Rompaey Université Libre de Bruxelles ULB Wim Sonneveldstraat 24 NL-6708 NB Wageningen [email protected]

Livingstone achterna Zoals vele grote onderzoekers en ontdekkingsreizigers had ook Prof. Oldeman een Afrikaperiode. Begin jaren 60 zette hij er zelfs zijn eerste schreden in het tropisch regenwoud, ecosysteem dat hij later zo intensief zou onderzoeken (Oldeman 1974, 1990). Op basis van in Ivoorkust verzamelde gegevens schreef hij tevens zijn eerste wetenschappelijke publicatie: Oldeman (1964), een taxonomische revisie van het boomgeslacht Didelotia, Caesalpiniaceae. Achteraf bleken deze soorten prima indicatoren voor biodiversiteitshotspots binnen het West- Afrikaans regenbosblok (Van Rompaey 1993, 1996, 2000, 2002).

Directeur du Centre Néerlandais Als student-beheerder trok hij, pas getrouwd, in 1963 naar het Centre Néerlandais, een Wageningse annex op het grote ORSTOM (deze Franse onderzoeksorganisatie in de tropen heet nu IRD, Institut de Recherche pour le Développement) onderzoeksterrein te Adiopodoumé, 17 km ten westen van de Ivoriaanse hoofd- en grootstad Abidjan. Onder andere verzamelde hij er meer dan 1000 herbarium collecties tussen 25 april 1963 en 11 maart 1964 (zie Figuur 1 voor verzamellocaties).

Vierentwintig jaar later is mezelf hetzelfde overkomen, zij het zonder directeurschap, in de periode 1988- 1991. Mijn AIO-schap was overigens een duidelijke follow-up van Oldemans eerste verblijf in Ivoorkust. Samen met mijn voorganger Fred Vooren, had hij mijn AIO-project opgenomen in het interdisciplinaire programma (Oldeman 1984) dat de toenmalige Landbouwuniversiteit in 1984 gestart had in Ivoorkust, voor de duurzame ontwikkeling van de Taï-regio, het gebied ten westen van het 500.000 ha grote Taï Nationaal Park, het laatste grote regenwoudrestant in Ivoorkust. Vóór mij hadden Fred Vooren (1999) als bosbouwer en Anneke de Rouw (1990, 1991) als vegetatiekundige er sinds 1978 promotieonderzoek verricht samen met Franse ORSTOM- onderzoekers, zoals Guillaumet (1967), Huttel (1977) en de Namur (& Guillaumet 1978).

De Werkgroep Ivoorkust-tijd Tijdens mijn veldwerkperiode, 1988-1991, werd de begeleiding vanuit Wageningen verzorgd door Reitze de Graaf van de vakgroep Bosbouw (Parren & de Graaf 1995), die ik kende van mijn afstudeerwerk in Suriname. Diverse Wageningse vakgroepen (tropische landbouw, gezondheidsleer, vegetatiekunde, bodemkunde) hadden in 1986 een Werkgroep Ivoorkust opgericht, waarvan Oldeman de eerste voorzitter was. Dit initiatief lag ook aan de basis van de Tropenbossite Ivoorkust, gezien Oldeman in die tijd ook president van Tropenbos was.

Het Séminaire d’Abidjan, 1991 In februari 1991 kwam Oldeman echter zelf naar Ivoorkust voor het ‘Séminaire sur l’Aménagement Intégré des Forêts Denses Humides et des Zones Agricoles Périphériques’ (Vooren et al. 1992), dat tevens het einde inluidde van zovele jaren actieve Wageningse aanwezigheid in Ivoorkust. Tropenbos en GTZ zouden de fakkel overnemen in Taï voor respectievelijk onderzoek en beheer van het Nationaal Park, met het promotieonderzoek van Léonie Bonnéhin (1999) als vlaggeschipproject. Opnieuw was Oldeman promotor.

Naast de fameuze slotspeech op het Séminaire herinner ik me vooral de excursie naar Zagné en Taï achteraf,

87 de tocht door mijn proefperk bij Zagné (Van Rompaey 1993) samen met Prof. Ellenberg van GTZ en Erik Lammerts van Buren van Tropenbos. Oldeman stond verbaasd naar de reuzesambas (Triplochiton scleroxylon) te kijken en vergeleek het bosbeeld met de vuurclimax die hij in Queensland, Australië, had bestudeerd (Oldeman & Van der Meer 1989). Terwijl we naar de reuzebomen aan het kijken waren, werden we vanonder aangevallen door een kolonne roofmieren (‘mangnan’), hetgeen menig komisch plaatje heeft opgeleverd.

Terug naar Abidjan had ik een vliegtuigje geregeld via de directeur van de zagerij in Zagné. Vanaf de air strip aldaar vlogen we in zuidoostelijke richting diagonaal over het Nationaal Park, met eerst de aangevreten bosrand waarvan de groentinten aanzienlijk minder contrast hadden dan de scherpe infraroodsatellietbeelden die ik gewend was. Naarmate we hoger stegen, werd het typisch rollende reliëf in de Taï regio, dat de soortensamenstelling zo duidelijk bepaalt (Van Rompaey 1993), onzichtbaar voor het blote oog. Boven de groene bomenzee rezen enkel de inselbergen, o.a. Mont Niénokoué, en de langgerekte heuvelruggen in het zuiden van het Park uit. Aangekomen boven San Pédro vloog de piloot pal boven de kustlijn en bij de aanblik van de monotone kokosbomenplantages werd Oldeman door slaap overmand, vermoeid na een zware congresweek. Later is Oldeman nog een laatste keer Figuur 1: Ivoorkust, West-Afrika, zoals gezien door de SPOT-Vegetation in Ivoorkust geweest ter begeleiding satelliet in februari 2000 (beeldbewerking door Ph. Mayaux, JRC, Ispra). Rood staat voor infrarood en dus voor vegetatie. De groengrauwe zone boven van Léonie Bonnéhin (Bonnéhin is de savannazone, dor in de droge tijd; steden zijn grijswit. De 1999). donkerroodbruine vlekken zijn de resterende bosgebieden. In roze omlijnd de nationale parken, in zwart omlijnd de staatsbossen. In groen enkele belangrijke steden, in lichtblauw de plaatsen waar Oldeman in 1963-1964 Een nieuwe wind door de relatie herbarium specimens verzameld heeft. Wageningen-Ivoorkust In 2000 hield ook het Tropenbos Ivoorkust Programma op te bestaan, het Centre Néerlandais was al jaren voordien overgedragen aan het IIRSDA en de Ivoriaanse autoriteiten. Enkel het Centre Suisse, het zustercentrum, heeft vorig jaar fier haar 50-jarig bestaan gevierd, en haar activiteiten nemen nog steeds uitbreiding, ook op botanisch vlak. Ivoriaanse studenten en onderzoekers zijn er nu even talrijk als Europese en ook wij, Wageningers, zijn er welkom (http://www.csrs.ch).

Léonie Bonnéhin is aan het hoofd komen te staan van de West-Afrika afdeling van Conservation International, de nieuwe en actieve Amerikaanse NGO die tal van natuurbehoudinitiatieven neemt in de regio (http:// www.conservation.org). Jonge botanici zoals Danho Neuba, Université Libre de Bruxelles, Constant-Yves Adou, Museum d'Histoire Naturelle Paris, en Steve Déngueadhé, Université d'Amiens et Bangui, verrichten promotieonderzoek bij genoemde zusteruniversiteiten van Wageningen. In regionale EU-gefinancierde projecten zoals ECOSYN, werkten Wageningse en Ivoriaanse onderzoekers samen aan toegepaste producten ten behoeve van natuurbehoud en natuurbeheer in de tropische bossen van West Afrika. In navolging van het pionierswerk van Prof. Oldeman, blijft de studie naar natuur en beheer van Afrikas regenwouden een boeiende passie én een dringende noodzaak. Ik ben ervan overtuigd dat de Oldemanschool hieraan in de toekomst nog een actieve bijdrage zal leveren.

88 Referenties Bonnéhin, L. 1999. Domestication paysanne d'espèces fruitières de la forêt de Taï: Coula edulis Baill. et Tieghemella heckelii Pierre. PhD thesis, Wageningen University. Pp.138. de Namur, Ch. et Guillaumet, J.L. 1978. Grands traits de la reconstitution dans le Sud-Ouest ivoirien. Cahiers ORSTOM, sér. Biologie 13 (3):197-201. Guillaumet, J.L. 1967. Recherches sur la végétation et la flore de la région du Bas-Cavally (Côte d'Ivoire). Mémoires ORSTOM no. 20, ORSTOM, Paris. Pp. 247. Huttel, Ch. 1977. Etude de quelques caractéristiques structurales de la végétation du bassin versant de l'Audrénisrou. Rapport ORSTOM, Adiopodoumé. Pp.33. Oldeman, R.A.A. 1964. Revision of Didelotia Baill. (Caesalpiniaceae). Primitiaea Africanae IV, Blumea 12:209-239. Oldeman, R.A.A. 1974. L'architecture de la forêt guyanaise. Mémoires ORSTOM 73, ORSTOM, Paris. Pp.204. Oldeman, R.A.A. 1984. Analyse en ontwerp van landgebruikssystemen in de Taï-regio (Ivoorkust). Project proposal, Working group Côte d'Ivoire, Wageningen Agric. Univ. Oldeman, R.A.A.1986. The programme 'Tropenbos' for tropical forest research stimulation. Vakblad voor Biologen 66(1986):14-17. Oldeman, R.A.A. 1990. Forests, elements of silvology. Springer Verlag, Heidelberg. Pp.24. Oldeman, R.A.A. & van der Meer, P.J. 1989. Diagnosis of Northern Queensland rain forests: the impact of selection silviculture. An independent study, contracted by the Department of Forestry, Queensland, Australia. Wageningen, Agricultural University, Department of Silviculture and Forest Ecology. Pp.70. Parren, M.P.E. and de Graaf, N.R. 1995. The quest for natural forest management in Ghana, Côte d'Ivoire and Liberia. Tropenbos Series 13, The Tropenbos Foundation, Wageningen. Pp.199. Van Rompaey, R.S.A.R. 1993. Forest gradients in West Africa. A spatial gradient analysis. Doctoral thesis, Department of Forestry, Agricultural University Wageningen. Pp.142. Van Rompaey, R.S.A.R. 1996. Rain forest refugia in Liberia. In: van der Maesen, L.J.G. et al. (eds.). The biodiversity of African plants. Kluwer Academic Publishers Pp.624-628. Van Rompaey, R.S.A.R. 2000. Mégatransect LIBCI: modélisation en continu dans le temps et dans l'espace du gradient floristique arborescent de 400 km de long dans les forêts de plaine du SE Libéria et SW Côte d'Ivoire. Dans: Servant, M. & Servant-Vildary, S (éds). Dynamique à long terme des écosystèmes forestiers intertropicaux. Publications issus du SympRoelof Oldeman, the grand old man of the forest Van Rompaey, R.S.A.R. 2002. New perspectives on tropical rain forest vegetation ecology in West Africa: typology, gradients and disturbance regime. IDS Bulletin 33(1):31-38. Vooren, A.P. 1999. Introduction de la bionomie dans la gestion des forêts tropicales denses humides. Thèse de doctorat, Wageningen. Pp.220. Vooren, A.P., Schork, W., Blokhuis, W.A. et Spijkerman, A.J.C. 1992. Compte Rendu: Séminaire sur l'aménagement intégré des forêts denses humides et des zones agricoles périphériques, UAW-GTZ, 25-28 février 1991, Abidjan.. Tropenbos Series 1, La Foundation Tropenbos, Wageningen. Pp. 307.

89 A New Species of Lecythidaceae, Lecythis oldemani sp. nov., from Amazonia

Marc G.M. van Roosmalen Departamento de Botânica, INPA Caixa Postal 478, 69.011-970, Manaus-Amazonas, Brazil

Fig. 1. Lecythis oldemani (Van Roosmalen L230). A. 4-Seeded fruit. B. 4-Seeded fruit seen from above. C. Seed. D. Fruit opened up by agouti showing 4 seeds without aril (x 0.5). E. Fresh leaf (x 0.5). F. Dry leaf (x 0.5).

Lecythis oldemani Van Roosmalen, sp. nov. Type. Brazil. Amazonas: Nova Olinda, left bank of Rio Aripuanã, at edge of farmed terra preta do Índio, 25 Nov 1997 (fr), Van Roosmalen L230 (holotype, INPA); Van Roosmalen L357 (leaves of holotype tree L230 collected Nov 2002). Figs. 1-5.

Foliis magnis chartaceis, elliptico-oblongis, majoribus (28-32 x 7.7-8.7 cm), marginibus foliorum revolutis et serrulatis vel crenulatis, apice foliorum acuminatus (1.5-2 cm longi), venis lateralibus foliorum numerosis (24- 30), petiolo 0.8-1 cm longo. Ovariis (1-)3-4-locularibus. Fructus sessilis, lignosus, pedicello brevi, 0-0.1 mm

90 longi; fructibus magnis, globosus angulatus, 7 x 11 cm (operculo incluso), seminibus angulosis, albis, anarillatus. Trees, to 35 m tall, without buttresses. Bark grayish-brown, with shallow vertical fissures, slash reddish-brown. Leaves chartaceous; leaf blades widest at the middle, narrowly elliptic or oblong, 28-31 x 7.7-8.7 cm, glabrous, with 24-30 pairs of lateral veins, margins revolute, serrulate or crenulate; apex acuminate over 1.5-2 cm; base acute, narrowly decurrent onto petiole; petiole 10-13 mm long, glabrous. Flowers not seen. Fruits sessile, woody, indehiscent, depressed globose, always wider than long, irregularly 3-4-lobed, 6-7.5 x 8.5-11.5 cm, the base truncate or the pedicel attachment prolonged into a woody knob 1.3 x 1.3 cm, the pericarp 7-8 mm thick, rough to warty, the calycine ring inserted at apex (distal end), Fig. 2. a. Base of medium-sized tree Van Roosmalen prominent, 5.5-8.5 cm diam., with 5 persistent woody, L360. irregularly thickened, downwardly oriented sepals situated at apex of fruit, opercular ring 3.7-5(-7) cm diam., supracalycine zone 0 cm, distance between line of opercular dehiscence and calycine ring (0.8-)1-2 cm; operculum umbonate (the umbo ca. 5 x 8 mm) or concave, circular, (3-)3.8 cm diam., sometimes elliptic, to 5 x 6.5 cm, the diameter always exceeding that of the opercular ring, not releasing when dry. Seeds (2-) 3-4, dry, plano-convex with 1-2 flat sides, 4 x 3.3 cm to 5 x 5.4 cm, reddish-brown, the major white veins connected at base by a reticulum of secondairy veins, sometimes markedly raised above the surface of the testa; aril lacking.

Notes: seeds very large; the pyxidia are indehiscent and fall to the ground with the seeds intact; the seeds can only escape after the pericarp has rotten away or scatter-hoarding rodents such as agoutis (Dasyprocta spp.) and acouchis Fig. 3. a. Bark of tree Van Roosmalen L360 (Myoprocta spp.) have gnawed an opening alongside and wider partly removed. than the opercular ring; I have seen these scatter-hoarders carrying seeds of this species in their mouth, sometimes over considerable distances from the parent plant, and cache them at a depth of twice the longest diameter of the seed.

Distribution. A medium-sized to large tree of non-flooded terra firme rain forest known only from Central Amazonia along the banks of the lower Rio Aripuanã, State of Amazonas, Brazil. Mature fruits have been collected from Nov to Jan.

Specimens examined. BRAZIL. Amazonas: Left bank of Rio Aripuanã, Van Roosmalen L360, Lago Capimtuba, Novo Oriente, 05º 43’ 4’’ S, 60º 17’ 1’’ W, Capimtuba transect, km 2.15, Dec 17, 1999 (fr), mature fruits picked up from ground

Local names. Brazil: castanha rana, jarana-da-folha-grande.

91 Fig. 4. a. Pyxidium of Lecythis oldemani opened up by an agouti.

I am pleased to dedicate this species to Prof. Dr. Ir. R.A.A. Oldeman with whom I have collaborated since 1980. Among many other issues, he particularly inspired me early on to focus fieldwork on the role vertebrates play as dispersers and predators of seeds and seedlings and their impact on the composition and structure of Neotropical rain forest.

92 “Good” and “bad” weeds in shifting cultivation

Anneke de Rouw Agronomist at IRD (ex – ORSTOM) National Agriculture and Forestry Research Institute B.P. 06 Vientiane Laos P.D.R. [email protected]

Introduction Shifting cultivation was the first cropping system used by early agricultural occupants of many forested areas all over the world. It is still widespread in tropical regions. The importance of shifting cultivation lies less on the productivity of the system than in the total area it covers. The system is used both by seekers of quick profits, unmindful of destruction, waste or problems it creates for the future and by careful occupants who think of the long-term good of the land (Ramakrishnan & Toky, 1981).

When local populations have adequate land area for cultivation cycles of shifting cultivation are usually ecologically sound. However, the system becomes destructive when local populations get too crowded, or when commercial motives begin to influence the practice. Intensification leads to shortened fallow periods and prolonged cultivation. This in turn causes problems of weed infestation, low yields and forest destruction. Our discussion is limited to low-input agriculture in the humid tropical areas. A distinction is made between “good” and “bad” weeds. Both categories of plants appear spontaneously in fields. “Good” weeds are less aggressive, woody plants. They are vital because they form the fallow. “Bad” weeds are short-lived arable herbs. Their invasion not only competes directly with the crop but slows down the development of a forest fallow. The rainfed rice system has been chosen because, more than in any other staple crop, successful cultivation depends on the careful management of both arable weeds and fallow trees.

Burning and tillage Agricultural use of a forest soil requires the removal of the forest and substitution by crop plants. In most cases, burning is the only means of clearing vegetation, but it also can help to improve certain soil properties. Burning liberates large quantities of mineral nutrients just before cropping and produces a rise in pH which stimulates further release of cations (Nye & Greenland, 1960). Burning also kills weed seeds, or prevents them from germinating. In Côte d’Ivoire, the stock of viable seeds in the soil dropped from about 2,000 m2before burning to 1,000 m2 after one overall burn (De Rouw & Van Oers, 1988). Equally important weed seed reductions after burning have been recorded from Central America and India.

Soils that have been under closed forest are normally loose and permeable. Planting can be done without tillage or cultivation. Shifting cultivators disturb the soil as little as possible because tillage triggers the germination of weed seeds. In Côte d’Ivoire only 10 % of the viable seed stock present in the topsoil actually germinates because the farmers refrain from disturbing the soil other than making planting holes or pulling out weeds (De Rouw & Van Oers, 1988). Besides, handpulling always results in selective weeding because farmers tend to remove the fast growing larger “bad” herbs while leaving the tiny seedlings of “good” forest species undisturbed. On the other hand, in weed-infested fields, handpulling becomes an ineffective form of clearing the ground. The topsoil has to be cultivated with some kind of implement. Consequently, tillage provides favourable conditions for the germination of many weed seeds, while simultaneously removing “good” and “bad” weed seedlings indiscriminately from the field.

After felling, many stumps and roots produce coppice shoots. Certain forest species may re-sprout after an

93 initial burn, but successive fires eliminate most. Shifting cultivators, who still practice long fallow periods, usually apply one quick overall burn. The intensity of the burning kills a sufficient number of weed seeds, but at the same time permits the survival of many re-sprouting forest stumps. The unburned or slightly burned patches in a field serve a vital function in forest regrowth because here, re-sprouting stumps and rootsuckers abound. With shortening of fallow periods, the amount of slashed material is also reduced and the fire less intense. To compensate for the fact that less weed seeds have been killed after the first burn, farmers pile up the unburned materials and burn a second and a third time. This practice may reduce weeds but has a negative effect on the re-sprouting ability of stumps, thus reducing the ability of the woody vegetation to regenerate. In many regions the elimination of re-sprouting plants by recurrent fires leads to the establishment of thickets and grassland which replace the forest fallows (De Rouw, 1991).

Fallowing Forest fallows performs many functions. Nutrients are stocked in the forest vegetation and through litter fall become incorporated in the topsoil. Thus, the leaching of nutrients is prevented or slowed. Many trees and lianas are deeply rooted which enable them to bring up extra nutrients from the subsoil. Increase in above ground biomass also implies increase in soil organic matter. Soil structure is improved both by the formation of stable aggregates and by the rich soil fauna that work the soil continuously. However, if one asks the farmers, they will respond that the chief function of the fallow concerns weeds.

The fallow period functions as a weed break when overhead shade is formed suppressing the arable weeds present, preventing the invasion of new ones and interrupting the re-seeding of the field (Alexandre, 1989). Shifting cultivators use shade as a tool against the general build up of infestation because weeds are highly heliophylic. The fallow vegetation creates shade at the appropriate moment and maintains it as long as necessary. Still, overhead shade can only be employed at the end of the cropping cycle because almost all food crops are strongly light demanding. Though post-cropping shade can be produced by a planted cover crop that develops after the main crop, or by the growth of planted fallow trees in agroforestry systems, most often however, it is the re-growth of the natural vegetation that checks the weeds (De Rouw, 1991). The shading out of arable weeds is cheap and effective. However it does demand relatively large areas of land.

Seedlings In forest soil, dormant seeds of many plants accumulate over time. After clearing this seed bank is responsible for weed infestation by “bad” weeds but also provides a seedling stock of valuable fallow trees (“good weeds”).

Most seeds germinate in the first months following clearing. The stock of forest seedlings is vital for the quality of the fallow but are easily weeded out. Only fallow trees that germinate during the cultivation period will produce overhead shade rapidly enough to drive out the weeds. Without tree seedlings, arable weeds will continue to occupy the site and produce endless crops of seeds. This pollution of weed seeds in the soil, together with the very slow rate at which forest plants invade an infested plot, will determine the re-use of the land for rice cropping. Figure 1 shows the relation between the duration of the fallow period and the density of spontaneous plants germinating in rice fields. It also indicates the proportion of “bad” arable weeds to “good” forest plants. The clearing of a regrowth only 6 months after the last harvest results in an average of 150 plants m2during the cropping season, almost all of them arable weeds. Few forest plants appear because the first felling and burning had permitted the seed stock to germinate and the stock had not yet been replenished. The stock of arable weeds however, had been filled up with seeds produced in the period between clearings. Rice cropping requires a second clearing prior to planting and as much as three weedings during the season. Farmers spend over a 100 days per ha on weeding, using a hoe most of the time.

Weed infestation by arable weeds is even worse after felling and burning a 1-year old fallow. It is mainly composed of second and third generation of the weed species that were able to exploit the new clearing.

94 1000 Arable weeds Secondary forest plants

100 Primary forest plants

1 0.1 1 10 100 Plants / m? in rice crop

0.1

0.01 Length of previous fallow (years)

Fig 1. Densities of non-crop plants in unweeded rice fields, 5 months after slashing and burning in relation to the length of the previous fallow period: 6 months, 1 year, 6 years, 20 years, 30 years and primary forest (100 years). A distinction is made between densities of arable weeds (“bad” weeds) and secondary and primary forest plants (“good” weeds). Field data are from on-farm experiments in the Taï region, Côte d’Ivoire, 1982-1989.

After slashing and burning a 6-year old forest, non-crop densities in rice fields were about 160 seedlings m2, 70 % belonging to “bad” weed species. Apparently the stock of weed seeds deposited in the forest soil 6 years before had been reduced considerably. Weeding operations should start immediately after sowing. All plants are small and they are removed indiscriminately. Two rounds of weeding are necessary, amounting for 30-50 days per hectare lost on weeding. Few tree seedlings survive the cultivation period. A longer period is necessary before the next fallow begins to provide overhead shade.

After clearing a 20-year old fallow, an average of 65 plants m2 germinate in the field. Arable weed densities are reduced to 20 plants m2. One weeding controls weeds, starting three months after burning. This requires around 18 days work for one hectare. Large aggressive weeds are pulled out, while many slow-growing forest seedlings escape. Though this is often called poor weeding, it simultaneously preserves a wide variety of trees species among the seedling stand. The latter, released from rice competition, will rapidly produce an overhead canopy.

In a field prepared in 30-year old secondary forest, forest plant largely outnumber the arable weeds, the latter are reduced to about 10 plants m2. Short-lived pioneer trees do not dominate the seedling population of forest plants but many tree species with longer life spans appear. Apparently, long-cycle secondary forest trees with a longer juvenile stage have had the opportunity to produce seeds. Secondary forest trees produce copious quantities of small, long-lived seeds continuously , whereas primary forest species produce fewer seeds, which are larger and generally short-lived (Whitmore, 1983). Thus, the soil under primary forest contains few seeds and fields in primary forest have the lowest densities in weed and forest plants. No weeding is carried out.

95 Re-sprouting plants in fields In many parts of Africa and Asia, farmers no longer allow the forest vegetation to re-establish. In Africa short fallow periods and subsequent uncontrollable weed infestation has resulted in a drastic reduction of rainfed rice cultivation. Former rice areas now rely on cassava, bananas, and maize for staple foods (De Rouw, 1991). In Asia on the other hand, rainfed rice cultivation continues despite very short fallow periods of 3-6 years and 200-350 days needed for weeding (Sankaran & De Datta, 1985). Short rotations, recurrent burning and clean weeding with a hoe has eliminated most of the forest seedling stock. The group of re-sprouting plants however, proves to be less vulnerable. Re-sprouting plants are essentially woody, including the sub-woody shrub Chromolaena odorata. The dominant position of re-sprouting plants (“good” weeds) leads to the suppression of the undergrowth of herbs and grasses (“bad” weeds) during the first two years of the fallow period. Though vigorous shoots can form shade rapidly, the cover remains patchy because the distribution of re-sprouting plants over a field is far from uniform. Efficient and relatively rapid establishment of cover depends on there being ample coppice stumps and suckers left at the end of the period of cultivation. The abilities of sprouting plants to exclude and suppress weeds have been used in many shifting cultivation systems suffering from land shortage (Kunstadter et al., 1978).

Figure 2 shows the weed biomass removed during weeding operations in rainfed rice fields in Northern Laos, split into (sub) woody plants, all of them re-sprouting, and arable weeds, mostly seedlings. Figure 2 illustrates that despite very short fallow periods, the woody component among non-crop plants persists in rice fields. The system is not sustainable because at each cultivation cycle, stumps, including Chromolaena stumps get lost and are not replaced. Subsequently, the open spaces between stumps are filled by new generations of weeds. In fields with high woody biomass compared to the herbaceous biomass, rice cropping may continue for another cycle. On the other hand, in those fields with relative low “good” woody weed biomass compared to the large quantity of “bad” weeds, rice cultivation 350 is no longer possible using only hand tools because of uncontrollable 300 weeds.

250

200 Conclusion In the traditional system farmers move from one field to another 150 annually. As a rule, they employ incomplete clearing and weeding 100 operations. Many forest plants therefore survive the cultivation period.

50 The sustainability of shifting cultivation depends on extremely rapid development of overhead shade after the harvest. Rapid shade in its 0 0 50 100 150 200 250 300 350 turn, develops only under three necessary conditions: (1) tree seedlings have to be present on the site at the end of the cultivation period; (2) Dry weight of arable weeds (gr/m?) re-sprouting forest plants have to survive the cultivation period; (3) forest plants should dominate arable weeds at the end of the cultivation period. Long fallow periods and residual or selective weeding fulfils these conditions. Fig 2. Weed biomass removed during a weeding operation in rainfed rice fields. Indicated is the relative In many humid regions in the world, shifting cultivation with forest importance of woody species, all re- sprouting plants (“good” weeds) and fallows can no longer provide enough food for the increasing cultivation. the weight of arable weeds mostly If repeated cutting and burning destroys the seed bank of forest plants germinating from seed (“bad” weeds). The farmers employ very while no effort is made to preserve re-sprouting forest plants, a closed or short fallow periods of 2-6 years. open grassy thicket replaces the forest fallow. Degradation of the land Field data are from on-farm experiments in the Luang Prabang forces the farmers to modify the system. Destruction of the seed bank of region, Laos, 2001-2002. forest plants makes rice cropping uneconomic in wet Africa. Elimination of both the seed bank and woody re-sprouting plants has led to the demise of rainfed rice cultivation in South-East Asia.

96 Selected references Alexandre, D.Y. 1989. Dynamique de la régénération naturelle en forêt dense de Côte d'Ivoire. Coll. Etudes et Thèses, ORSTOM, Paris. Pp.102. Kunstadter, P., Chapman, E.C. and Sabhasri, S. 1978. Farmers in the forest. East-West Center, Honolulu, Hawaii. Nye, P.H. and Greenland D.J. 1960. The soil under shifting cultivation. Technical communications of the Commonwealth Bureau of Soil Science 51: 140. Ramakrishnan, P.S. and Toky, O.P. 1981. Soil nutrient status of hill agro-ecosystems and recovery pattern after slash and burn agriculture (jhum) in north eastern India. Plant Soil 60: 41-64. Rouw de, A. and van Oers, C. 1988. Seeds in a rain forest soil and their relation to shifting cultivation in Ivory Coast. Weed Research 28: 373-381. Rouw de, A. 1991. Rice, weeds and shifting cultivation in a tropical rain forest. A study of vegetation dynamics. Doctoral Thesis, Agricultural University Wageningen, The Netherlands. Pp.292. Sankaran, S. and de Datta, S.K. 1985. Weeds and weed management in upland rice. Advances in Agronomy 38: 283-337. Whitmore, T.C. 1983. Secondary succession from seed in tropical rain forest. For. Abst., 44: 767-779.

97 Succession, architecture et forêts alluviales Annik Schnitzler Equipe de Phytoecologie (EBSE), Université de Metz, Rue du Général Delestraint F. 57070 Metz France

Introduction La singularité écologique des grandes vallées fluviales a fait l’objet d’une immense littérature durant la deuxième partie du 20ième siècle. Dès les premiers travaux (Wendelberger-Zelinka, 1952 ; Carbiener, 1970), l’aspect insolite des paysages forestiers, leur richesse biologique ou leur foisonnement végétal y ont été mis en exergue. Les premières interprétations ne mettaient guère l’accent sur les relations liant le fleuve et les forêts, sauf pour en souligner les actions qui semblaient négatives pour l’écosystème, comme les chablis à vaste échelle, l’asphyxie temporaire, la forte mortalité des semis après inondations, ou les modifications profondes des sols et des géoformes. Les impacts réels du fleuve sur la sylvigénèse sont apparus au fil des recherches en même temps que les chercheurs intégraient les impacts climatiques dans le fonctionnement des forêts (White 1979 ; Shugart, 1984 ; Oldeman, 1990 ; Peterken, 1996 ; Otto, 1998; Schnitzler, 2002). Trois conditions sont en fait à respecter pour assurer la pleine fonctionnalité aux écosystèmes alluviaux forestiers: la fonctionnalité hydrologique, qui assure une continuité biologique d’amont-aval et des connections latérales via les inondations, l’arrêt des interventons humaines (défrichements, gestion forestière) et la reconquête des milieux forestier autant que faire ce peut, sur le payages secondarisés.

1. Distribution spatio-temporelle des populations végétales ligneuses et niveaux de biodiversité Dans les grandes vallées fluviales des zones tempérées d’Europe et d’Amérique du nord, les genres se répartissent selon des gradients écologiques similaires (hydrologie, sols, distance par rapport au lit majeur)(Schnitzler, 1997). En cas d’inondations fréquentes et d’énergie cinétique élevée (cas des parties les plus en amont des fleuves), les substrats sont poreux et régulièrement dénudés. Les ligneux colonisateurs sont le genre Salix, Populus, ou Alnus. Leur bois tendre explique leur fragilité aux traumatismes et aux attaques de pathogènes, qu’ils compensent par des réitérations vigoureuses. Ces forêts pionnières ne vivent que le temps d’une nouvelle inondation qui les détruira totalement ou en partie. Les niveaux de tolérance aux conditions asphyxiantes temporaires sont également élevés parmi les Salicacées et les Betulacées. Saules, peupliers et aulnes supportent les niveaux d’inondation les plus élevés des espèces ligneuses alluviales, ce qui explique leur dominance absolue dans les chenaux les plus longuement inondés (Dister, 1983 ; Ernst, 1990 ; Van Splunden, 1997 ; Siebel et Blom, 1998). Dans ces chenaux, les forêts pionnières sont permanentes, les Salicacées vivant plus d’un siècle et se reproduisant par voie végétative. Les forêts dites à bois dur, constituées d’espèces variées (frêne, chêne, orme, tilleul, érable en ce qui concerne les strates élevées), se développent dans les endroits protégés des inondations les plus fréquentes. Ces espèces sont des successeurs précoces, aptes à croire sous l’écran léger des Salicacées et Bétulacées et à se maintenir ensuite sous leurs parents. Les trajectoires et les durées des successions sont infiniment variées en milieu alluvial, en étroite relation avec la dynamique fluviale. Les relations étroites qui lient les caractéristiques successionnelles, le développement spatio-temporel des écotones, et la connectivité (trois facteurs essentiels de la biodiversité), expliquent que les niveaux maximum de biodiversité s’observent dans les secteurs alluviaux dans lesquels les trajectoires de succession sont les plus variées et les niveaux de ressources élevés, mais transitoires (Ward et al., 1999).

La complexité du fonctionnement alluvial ne saurait s’analyser avec une seule méthode. La phytosociologie, l’analyse des structures spatiales, celles concernant les dynamiques de populations en fonction des caractéristiques engendrées par le système pulsé du fleuve ont fait l’objet d’innombrables travaux ces dernières décennies. Parmi les nombreux concepts étudiés, ceux concernant les successions ont sans doute été le plus largement abordés (Fig. 1). C’est dans ce domaine que les apports des concepts architecturaux m’ont été les plus utiles, en

98 complément des travaux que j’avais écrit sur le sujet (Schnitzler, 1988; 1995).

2. Contribution de l’approche architecturale à l’étude des successions Pour Oldeman (1990), le concept de succession diffère en fonction du niveau hiérarchique impliqué. A l’échelle de l’éco-unité, la succession correspond au remplacement d’arbres par d’autres arbres, aux stratégies souvent différentes. Au niveau hiérarchique supérieur, l’éco-mosaique, la succession correspond au remplacement d’éco- unités par d’autres éco-unités. En milieu alluvial, les processus de succession des espèces et des éco-unités diffèrent en fonction des secteurs hydrogéomorphologiques. Si on considère que chaque secteur correspond à une mosaique spatio-temporelle donnée, en étroite dépendance avec le régime local des inondations et les interactions biologiques et physiques qui leur sont liées, la succession forestière s’analyse très Maximum successional trajectories. confortablement à cette échelle.

complex Softwood and hardwood forests. Maximum species diversity Globalement, plus le régime hydrologique est dynamique et Increasing hydromorphy complexe, plus la plaine est étendue et riches en gradients écologiques, plus variées seront les

increasing disturbance types d’éco-unités et les severity trajectoires successionnelles (fig.1)

Hydrological pattern Long-term successional trajectories L’approche architecturale n’a Softwood and hardwood forests semble-t-il été utilisée que le long Short-term successional Medium species diversity du Rhin supérieur, dans les trajectories. reliquats de forêts alluviales Softwood forest only Poor species diversity rhénanes subsistant du côté simple alsacien (forêts de Marckolsheim Braided Anastomosed Meandering et de Rhinau). Les premiers profils ont été effectués par Walter (1979), Beekmann (1984), van Fig. 1. Idealized spatial and temporal mosaic pattern along three reaches (braided, Winckel (1984) et Vandeursen et anastomosed and meandering) sequentially arrayed along river corridor. The classical vegetation science point of view. Wisse (1985). Un des sites privilégiés de recherches est l’île de Rhinau, actuellement réserve naturelle. Ce site présente une haute valeur patrimoniale, en raison de la spontanéité de développement de la plupart de ses peuplements forestiers (même s’ils ont été initiés par les travaux hydrauliques de rectification en 1850, puis de canalisation en 1964) et du maintien d’inondations régulières par le Rhin. Cette ile comprend en particulier une mosaique forestière d’une douzaine d’hectares, âgée d’environ 170 ans, très riche en ligneux et d’une architecture naturelle somptueuse. Le premier naturaliste scientifique qui l’ait décrite est Roland Carbiener, professeur émérite à la Faculté de Pharmacie de Strasbourg. (Carbiener, 1970). Remplissant totalement son rôle de scientifique, il a été en même temps son principal défenseur contre les appétits des gestionnaires forestiers, alors adeptes de la futaie régulière assorties de plantations d’exotiques et de peupliers de culture. En 1989, Koop (1989) et son équipe reprennent les travaux de Vandeursen et Wisse et mettent en place une placette permanente d’un hectare au cœur de la réserve de l’île de Rhinau, dans une mosaique forestière à bois dur. Cette placette est revisitée en 2001 par la même équipe. Trois autres profils sont effectués dans trois forêts rhénanes proches, incluant celle de Rhinau, qui représentent un même niveau de maturité fonctionnelle, mais différent par leur niveau d’inondabilité. Pour ma part, j’ai effectué un profil supplémentaire dans une autre partie de la forêt de Rhinau (Schnitzler, 2001) encore peu étudiée, et qui a été comparé aux résultats collectés sur un profil effectué dans une forêt du Danube (réserve naturelle de Létea, delta)(Schnitzler, 2002). La forêt à bois dur de Rhinau est classée dans le Querco-Ulmetum minoris, avec deux sous-associations.

99 Autour de cette mosaique se trouvent plusieurs sous-associations du Fraxino-Populetum albae, Au regard des conclusions d’études sur les successions alluviales (Carbiener, 1970 ; Schnitzler, 1988 ; 1995), cette forêt est considérée comme un stade dit terminal de la succession, qui débute par une forêt à bois tendre pionnière (constituée de saule, peuplier noir), se poursuivant par l’introgression de nomades tels que le peuplier blanc, orme, frêne, chêne et de nombreux petits arbres et buissons. Les bois tendres subsistent toutefois, mais à l’état de reliques. Cette approche, issue de recherches phytosociologiques et écologiques, n’intègre que deux niveaux hiérarchiques: l’arbre et la mosaique forestière. L’approche architecturale va plus loin dans l’interprétation, en intégrant 3 niveaux hiérarchiques: l’arbre, l’éco-unité et la mosaique forestière. Ces trois niveaux interprétent sur la visualisation de l’écosystème autant que par la collecte de données (fig. 2).

Les profils architecturaux visualisent, mieux qu’une photographie ou qu’un tableau de chiffres, la complexité architecturale du Querco-Ulmetum. Les grandes dimensions des arbres de la canopée, la profondeur de leurs couronnes, l’abondance des petits arbres et des buissons y sont mis en exergue, de même que la variabilité dans les formes architecturales, quels que soient les modèles architecturaux présents (Rauh pour l’essentiel, mais également Troll, Champagnat, Scarrone, Fagerlind). On note le côtoiement de deux formes architecturales différentes pour le fusain, le cornouiller sanguin et le merisier à grappe : la forme à tronc unique droit et celle à tronc Maximum eco-unit diversity in size, fortement penché, dont la partie

complex lifespan and nature tournée vers la canopée est riche en Softwood and hardwood eco-units réitérations adaptatives. Ces deux

In h cre formes ne semblent pas liées ni à la y dro a g e s lumière ni à des traumatismes. in c m in n a o g as rp Deuxième curiosité architecturale, rb re hy c tu rity in e is v le gigantisme des buissons et des d se petits arbres (pommier sauvage et

Hydrological pattern Long-term** eco-unit development noisetier de 22m ; fusain de 9m, Softwood and hardwood eco-units Medium eco-unit/species diversity prunellier, cornouiller sanguin et Short-term* eco-unit development aubépine de 13 m, sureau de 11 m). Softwood eco-units only Autre particularisme enfin, Poor eco-unit and species diversity *Innovation and aggrading phases only **All development phases present concernant l’ensemble des ligneux

simple : l’abondance des réitérats. Les Braided Anastomosed Meandering espèces alluviales sont particulièrement aptes à la réitération traumatique et adaptative. Cette faculté augmente Fig. 2. Idealized spatial and temporal mosaic patterns along three reaches (braided, la survie des individus en période anastomosed and meandering) sequentially arrayed along river corridor. The hierarchical, architectural point of view. d’inondation (bien des branches cassées reprennent vie après avoir été brisées) les rend aptes à une fermeture rapide des chablis par le haut, par vigoureuse expansion des houppiers, qui conduit bien souvent à la perte des éco-unités les plus petites (processus proche du comportement ripicole, décrit par Oldeman). Cette vigueur réitérative concerne également le potentiel d’expansion végétative, notamment par rejets racinaires (cas de certains petits arbres et des lianes). L’analyse fine des profils révèle la présence de tous les statuts sociaux parmi les arbres (potentiel, présent, passé, en suppression), avec toutefois une dominance d’arbres du présent. Les éco-unités en phase de maturité sont largement dominantes sur celles en phase d’aggradation ou d’innovation. Les plus grands des chablis (entre 500 et 800 m2) sont colonisées par la clématite, d’autres par de petits arbres ou buissons à propagation végétative active, qui ralentissent pour longtemps la reconquête vers le haut des arbres.

100 Au regard des concepts architecturaux, la forêt à bois dur de Rhinau n’est donc pas le stade terminal d’un seul type successionnel ayant débuté par une forêt à bois tendre, mais le résultat d’une évolution de multiples trajectoires à partir de quelques grandes éco-unités de départ, après 170 ans d’évolution dans un contexte d’inondations régulières, peu énergétiques et fortement chargées en sédiments fins. Les trajectoires de succession ont varié en fonction de la longévité des colonisateurs et les gradients écologiques locaux. Toutes ont passé par des processus successifs de fragmentation en éco-unités de plus en plus petites, à la suite de la Fig. 3. Profil effectué dans l’île de Rhinau (Vandeurssen et Wisse, 1985) disparition des colonisateurs, très différentes dans leur architecture et leur composition spécifique. La plupart ont atteint la phase de pleine maturité et sont en fusion active. Ce sont d’ailleurs ces derniers processus qui expliquent la mise en commun de multiples fonctions (prélèvement des nutriments, microclimat, dispersion des semis…) et l’impression d’être dans une unité forestière homogène, fonctionnant comme une grande éco-unité unique.

Conclusion Il me reste à souhaiter que ces concepts soient davantage considérés dans les interprétations de la sylvigénèse, malgré la lourdeur de leur mise en œuvre, et la difficulté d’appréhension des concepts.

Références Beekmann, F. 1984. La dynamique d’une forêt alluviale et le rôle des lianes. In : Cramer J. (ed). Colloques phytosociologiques. La végétation des forêts alluviales, 9, Vaduz, pp 475-502 Carbiener, R. 1970. Un exemple de type forestier exceptionel pour l’Europe occidentale : la forêt du lit majeur du Rhin au niveau du fossé rhénan (Fraxino-Ulmetum Oberd. 53). Intérêt écologique et biogéographique, comparaison à d’autre forêts thermophiles. Vegetatio, 20, 1-4, 97-148. Dister, E. 1983. Zur Hochwassertoleranz von Auenwaldbaümen an lehmigne Standorten. Verh. Ges. Okol., 10, 325-356. Ernst, W.H.O. 1990. Ecophysiology of plants in waterlogged and flooded environments. Aquatic Botany, 389, 73-90. Koop, H. 1989. Forest dynamics. Silvi-star: a comprehensive monitoring system. Springer, Berlin, New York. Oldeman, R.A.A. 1990. Forests. Elements of silvology. Springer-Verlag, Berlin. Otto, H.J. 1998. Ecologie forestière. Institut pour le Développement forestier, Paris. Peterken, G. 1996. Natural woodlands. Ecology and conservation in northern temperate regions. Cambridge University Press. Schnitzler, A. 1988. Typologie phytosociologique, écologie et dynamique des forêts alluviales du complexe géomorphologique ello-rhénan (plaine rhénane centrale d’Alsace. Thèse, Université de Strasbourg. Schnitzler, A. 1995. Successional status of trees in gallery forest along the river Rhine. Journal of Vegetation Science, 6, 479-486. Schnitzler, A. 1997. River dynamics as a forest process : interaction between fluvial systems and alluvial forests in large European river plains. The Botanical Review, 63, 1, 179-210

101 Schnitzler, A. 2002. Ecologie des forêts naturelles d’Europe. biodiversité, sylvigénèse, valeur patrimoniale des forêts primaires. Lavoisier Tec § Doc. Shugart, H.H. 1984. A theory of Forest dynamics : the ecological implications of forest succession models. Springer-Verlag, New York. Siebel, H.N. et Blom, C.W. 1998. Effects of irregular flooding on the establishment of tree species. Acta Botanica Neerl. 47, 2, 231-240. Splunder, I. van 1997. Floodplain forest. Willows and poplars along rivers. RIZA report Directorate General for Pubic Works and Water Management. Vandeurssen, J. et Wisse, J. 1985. De invloed van fluviatile dynamiek op de groei en structuur een natuurlijk Fraxino- Ulmetum in de Elzas. Thèse, RIN Leersum, AUW Silviculture Wageningen. Walter, J.M. 1979. Etude des structures spatiales en forêt alluviale rhénane. Problèmes structuraux et données expérimentales. Oecologica Plantarum, 14, 3, 345-359. Ward, V., Tockner, K., Schiemer, F. 1999. Biodiversity of floodplain river ecosystem: ecotone and connectivity Regulated River. Research Management 15: 125-139. Wendelberger-Zelinka, E. 1952. Die Vegetation der Donauauen bei Wallsee. Ph. D. Thèse, Université de Linz, Autriche. White, P.F. 1979. Pattern, process and natural disturbance in vegetation. The Botanical Review, 45, 3, 229-299. Winckel, R. van 1984. Le Wylerwald, l’architecture et la dynamique d’une forêt alluviale rhénane sauvage. In : J. Cramer (ed), Colloques phytosociologiques. La végétation des forêts alluviales, pp 503-529.

102 Aan Roelof

Tom Schröder J.P.Thijsselaan 6, Utrecht

Trefwoorden: Leermeester, hoogbos, universeel, oorspronkelijk, uitsteken, onderzoeken, promoveren, schoonschrijven, toonaangeven, systeem, Oûtre-Mer, meedenken, analyse, vernieuwen, internationaal, profiel, voortreffelijk, architectuur, schrijven, evenwicht, doorgeven, tekenen, ambitie, transect, beschouwen, inzicht, hart, luisteren, boekwerken, kennis, vertellen, fractal, wortelstelsel, begrip, épouse, exquise, standhouden, exposé, kijken, auteur, reïteratie, oriënteren, inheems, schoolmaken, Hannibal, historie, mastbos, kronendak, traditie, kroondocent, vooruitstreven, respect, behouden, academisch, natuurlijk, vriendschap, correct, doordenken, eerlijk, bijspringen, eruditie, cortège, omgeving, waarden, Burgot, relaties, tabakspijp, metafysisch, petit-ponch, stijl, open, hamaque, observeren, bosteelt, excelleren, driedelig, Africain, ideeën, belangstellen, logica, polyglot, orde, snellezen, doorzien, diplomatie, integriteit, welspreken, vooraanstaan, francophile, wetenschappelijk, doceren, planten, faam, klassiek, principes, gewicht, grandeur, netjes, vasthouden, trouw, systeem, respect, frustratie, ingenieus, voorbeeld, prestige, structuur, normstellen, helpen, windvangen, rede, toegankelijk, maatschappij, vooruitzien, loyaal, forêt, hutan, rentmeester, traît-d’union, stipt, Kipling, Vrijheid, verantwoorden, bomen, niveau, werkzaam, waarderen, kunstig, schoonheid, modellen, gewetensvol, steungeven, baanbreken, begrip, animeren, voorbeeldstellen, essentie, toewijding, opbouwen, vertrouwen, openstaan, ...

Gebeurtenissen-herinneringen: Opvolging, vakgroepvergadering, voordrachten, studentenoverleg, evaluatie(!), selectie(!), presentatie, acceptatie, inauguratie, college, tentamen, excursie, veldwerk, Air France, ORSTOM-Cayenne, Francis Hallé, Saül, scriptie, symposia, examens, lezingen, “Le Bois et l’Homme”, Citroën, Montpellier, Zeist, Hoogheem, bonbons, promoties, brieven, rapporten, referenties, ontmoetingen, celebreren, aanmoedigingen, correcties, St. BOS, St.Tropenbos, anecdotes, vrolijke noten, LUWperikelen, Hollandse politiek, aansporingen, aanbevelingen, augustus2000: oude boel op de stoep!, Arbre2000 ...... en nog veel meer gezamenlijke belevenissen en conversaties - waarvan jij en vooral Wil de details misschien beter herinneren dan ik...

103 Het grootste deel van mijn loopbaan in tropisch bos heb ik aan de speciale aandacht te danken die je me als je eerste Wageningse afstudeer-student gaf. Mijn vader stierf met een gerust hart na het bericht van slagen voor mijn laatste examen bij jou. Uit je contacten in Montpellier kwam kort daarna mijn eerste (vrijwilligers-)baantje voort: een studie in een CNRS onderzoeksproject naar indiaans bosbeheer in Peru, die mijn verdere leven in Amazonië zou bepalen. Bijgaand plaatje van toen zou er zonder jou niet zijn geweest, evenmin als vele beroepsmatige en vriendschappelijke contacten daarna. Van een van die contacten die ook nog van jouw belangstelling en invloed getuigen, volgt hieronder een recente brief: van een Peruaanse bosbouwer die bijna jouw –zoveelste- promotie-student zou zijn geweest als hij maar was geslaagd voor zijn Engelse test....

Date: Mon, 16 Sep 2002 14:41:53 _0500 Hola Tom: Justo estaba en una reunión ayer con Pilar y su familia y nos acordabamos de ti, sigo aca en Pucallpa, estamos atras de un proyecto con TROPICOS para Iquitos y ya pasamos la primera etapa de calificación (de 2,000 postulante quedamos sólo 40, de los cuales seguramente calificaremos unos 20), osea que probablemente este- mos regresando a Iquitos, pero yo eventualmente. Ahora ya estoy trabajando con una empresa de capital Suizo- Peruano, estamos instalando una planta de 3’500,000 de dólares que trabajará con madera de Bolaina y de Capirona de plantaciones, yo estoy encargado de la parte de manejo, este proyecto es la realización del sueño forestal de un ingeniero peruano, cosechar semillas, germinarlas, sembrarlas, cuidarlas y manejarlas, cosechar árboles, industrializarlos y venderlos, claro en paises de Europa y Asia ya se comenzó esto hace muchos años pero para el Perú es algo nuevo y con especies nativas que es lo mejor, yo comencé con la investigación de estas especies hace muchos años, bolaina hace unos 10 años y capirona recientemente hace unos 4 años.

Por otra parte como te decía al principio sigo con lo de TROPICOS, que probablemente se haga socia de la Empresa en algún momento para llevar adelante todo lo que es medio ambiente y desarrollo rural con los campesinos, pues las plantaciones de Bolaina se desarrollan en tierras de agricultores, además tambien tenemos tierras propias. Al menos ya tengo para pagar las cuentas estuve casi 8 meses sin trabajo gastándome todos mis ahorros, felizmente cuando estaba al borde de la quiebra salió algo de plata para este proyecto, yo aposté a él y ellos apostaron a mi cuando no tenían ni un centavo ahora es la vedette de los proyectos en el Perú, ya ganó dos premios internacionales (antes de iniciar), Bueno todos aca ahora bien, Te recordamos siempre, osea que cuando vengas avisanos o visitanos, No se que más contarte para ponerte al día.

Boswetenschap en Maatschappij Het begon simpel: hoe een hogere bomenproductie per hectare te halen - zoals bij de teelt van een landbouwgewas. Met dat te onderzoeken en te onderwijzen, begon ruim honderd jaar geleden “Bosbouw” in Nederland, en eerder al elders in Europa. In de eeuwen daarvóór was het natuurlijke bos hier al vrijwel geëlimineerd. Boeren en landeigenaren plantten daarna bomen voor eigen gebruik, en de Overheid ging bos aanleggen voor het algemeen belang. Zo’n bomenaanplant werd bos genoemd, en kreeg plaats in een cultuurlandschap, voor de mens.

De relatie tussen bomen en de mens was in de eerste plaats van economische aard, en onderzoek en onderwijs waren daarop gericht. Materialisme, eigen aan de westerse cultuur, was grondslag en doel van het bomenbeheer: op efficiënte wijze zoveel mogelijk hout produceren en oogsten, om het geld. Het belang van andere bosprodukten en -functies kreeg een lager hiërarchisch niveau: het direct economische belang ervan was immers geringer.

104 Allengs echter deden toegenomen materiële welvaart, milieubehoeften, en contact met andere culturen en levenswijzen elders in de wereld, deze materiële doelstelling verschuiven. Ook de Bosbouwwetenschap moest daarin mee. Aanpassingen in het onderwijs gingen daarbij echter niet vanzelf van binnenuit. De systeeminertie en het houtbolwerk kwamen onder druk te staan van de maatschappij, en van eigen studenten die verandering van het curriculum vroegen ten gunste van een meer ecologische dan materiële benadering.

Juist in die tijd ging de “belangrijkste” bosbouwhoogleraar: die in de Houtteelt, met emeritaat, en werd een opvolger gezocht. Die gebeurtenis maakte ik mee als student en studenten-vertegenwoordiger in de Vakgroep Houtteelt. Ook studenten hadden in die jaren na 1968 invloed op het bestuur van de toenmalige Landbouw Hogeschool gekregen, en vroegen medezeggenschap bij de benoeming van een nieuwe hoogleraar. Zo was er een bijeenkomst van bosbouwstudenten in studentencafé “Nolleke Prop”, waar een kandidaat-hoogleraar zich presenteerde aan deze kritiese studentengeesten.

Deze kandidaat bleek goede papieren te hebben voor de functie en een nieuwe richting voor te staan die aansloot bij de veranderde tijden. Hij kwam niet uit het nationale houtproductie-establishment maar uit het buitenland, en was in de eerste plaats onderzoeker. Afgestudeerd in Wageningen, maar daarvan los- en doorgegroeid in de Franse onderzoekscultuur, in Ivoorkust, Guyane en korte tijd Ecuador. Met uitstekend gevolg gepromoveerd in Montpellier, en daar benoemd tot hoogleraar. Veel internationale ervaring, ecologisch georiënteerd - er woei een nieuwe wind door Hinkeloord.

Inhoudelijk en didactisch totaal vernieuwd eigentijds collegemateriaal, een persoonlijke benadering en motivatie van studenten, nieuwe ideeën en publikaties, innovatieve boeken bij een prestigieuze uitgever), voortgaande internationale bekendheid, en de komst van Bosbouwpromovendi voor het eerst weer sinds decennia, deden de faam van de nieuwe Professor verder groeien. Klein defect: minder aanpassing aan de lokale smaak en cultuur van die tijd, die deze nieuwe wind al spoedig wat te fris vonden. Boven het maaiveld uitsteken en succesvol zijn wekt jalouzie, en ecologie moest de Hogeschool commercie niet overgroeien! Lokaal bestuur, over-heidsbezuinigingen en politieke trends spanden nu samen tegen de nieuwlichter. Dat vervolgens met de persoon ook de Leerstoel in de Bosbouwwetenschap werd weggewerkt, was dan helaas een gevolg van “de conjunctuur”... Maar dat deze lokale politiek later leidde tot een historische daling van het aantal LUW-studenten - en dus van LUW inkomsten en prestige -, bleek een streep door de Hoge-schoolse Handelsrekening.

Het nieuwe bosbouwzaad was echter in de voorgaande jaren gezaaid in studenten, ingenieurs, promovendi en Doctores Philosophiae, tot ver over de Wageningse grenzen.

105 Supernova

Jane Shaw Natural Resources Conservation Service United States Department of Agriculture 2796 Christiansburg Pike, Floyd, Virginia, 24091, USA

Ruurdtje Boersma said, ‘Be there!’. And so I was. Professor Oldeman strode in and proceeded to talk to us as if we had been conversing yesterday and he had just remembered some topics he forgot to introduce into the conversation and wanted to bounce off our minds. I listened and knew I wanted to listen again but I did not know just yet how this bright star would guide me in the year to come.

I had never met Professor dr. Roelof A. A. Oldeman and ignorantly did not know of what he had accomplished, but the class he offered intrigued me and though my mind was not quite agile enough to fully understand the offering, I knew I would gladly spend many hours trying. A three piece suit in dashing colors, a neatly trimmed beard, books that you couldn’t put down and picture and tales of discoveries faraway and near…our class stimulated in ways you couldn’t have imagined and I quickly knew if I could sit at this one teacher’s knee, if only briefly, my mind would expand and grow and my thoughts would gain clarity and incredible knowledge. He was kind enough to say yes. Discussions with Professor Oldeman are like yoga for the mind. Backbends, cartwheels and then flying to an unbelievable dismount to end up in a pose you did not know existed. You couldn’t take your mind off it. I left class and went on with the weeks’ activities but everytime I stepped outside I searched trees, examined landscapes, reaching my thoughts around these new propositions. He guided me through my first significant research, gently shaping and pulling me back on course often by way of undeniable examples. The glittering brilliance of the ideas he shared with me is matched only by the boldest courage with which he proposes and adheres to them. He teaches by example, never forcing you to accept an idea but simply putting forth irrefutable proof and challenging you to find your own answers which he hopes are new and different. And when you do, he will help you to defend yourself from the sticky hobgoblins of discovery. He is a true professor in all the glory of the idea of the word. He may excuse himself from the official duties of academia, but his star will shine brightly yet and I dare to say he will be right in the thick of the new frontiers of science still. It is an honor to know him. It is an excitement to wait for the next idea I have to share and debate with him.

Professor Oldeman stands like a California Redwood in the forest of inquiry. He seems to somehow know the road to the secrets of the ancients and stands tall, pointing the way towards a rigorous and principled struggle for truth. He is now, and I am sure was long before I had the pleasure of knowing him, a beacon on a dark and foggy beach. We can all surely thank providence to have had the opportunity to think with him and for the promise of his challenging ideas now and in the times to come; we can look forward to the next notion, insight, question or controversy we have to put forth for his comment. Thank you, Professor Oldeman, for teaching me how to stand on my toes and reach. Your supernova is unique because it shines on.

106 He started it

dr. ir. Willie Smits Director Gibbon Foundation/ Chairman Balikpapan Orangutan Survival Foundation P.O.Box 7610 JKP, Jakarta 10076, Indonesia

Wageningen, 1978 I was about to become a drop out from Wageningen Agricultural University when coming out of the office of the “studentendekaan” I noticed the announcement for the very first lecture by the newly appointed professor of Silviculture, Prof.dr.ir. R.A.A.Oldeman. To distract my rather upset mind, I decided to drop in at Hinkeloord, after all it was on the way and the lecture was to start in five minutes, less than the time needed to get there on my bike from Hotel de Wereld.

I listened as someone who had nothing to loose or to gain, and I just looked at the many slides Prof. Oldeman showed the fully filled, small “grote collegezaal” at Hinkeloord. Slowly his words started catching my attention, all the things he showed from these pictures with tropical plants. I found the interactions and connections as well as the simple but good observations on architecture of plants fascinating. After the meeting I shook hands with him and told him how interested I was. He was very kind and said “well there are still many treasures to be found in the tropical forests”. That very moment I decided to start doing something with my life and study silviculture with Prof. Oldeman.

Thanks to the fact that an examination period was about to start I managed to quickly catch up with the study and was allowed to keep my fellowship. With the help of Prof. Oldeman and Jan Boerboom I got to work in Indonesia in a timber concession. From here I brought back some dipterocarp seedlings, which became the start of much work related to mycorrhizae, root investigations, physiology, silviculture, plant propagation. Together with Prof. Oldemans’ loyal friend, our greenhouse keeper Bob Schalk, a range of investigations lead to many interesting breakthroughs.

After finishing my studies I was appointed in the department of Prof. Oldeman to develop the “perforons” further and to continue work on the Dipterocarpaceae. All of this again would have been impossible without his never flagging support. He was always there for stimulating discussions and to encourage his students. For me this was great, to have positive stimulation and at the same time much freedom to develop my ideas and inven- tions with his support.

A visitor that happened to pass by was brought to the greenhouse. Prof. Sukiman from Indonesia was highly surprised to find what had been done with the Indonesian Dipterocarpaceae at Hinkeloord. Soon another visitor came over from Jakarta and he also showed great interest. A week later again an invitation letter came for me to come to Indonesia and try to put into practice some of the findings from the greenhouse and laboratory.

I showed the letter to Prof. Oldeman and two weeks later I could leave with his full support to try to set up a dipterocarp research program in Indonesia. Thanks to his help and that from Joop Hildebrand I managed to find my niche and start working on large scale reforestation programs supported by practical research. I worked hard but my reporting was erratic, and there were many problems in getting the program started, but always Prof. Oldeman backed me up and let me develop the program as I saw fit and stimulated me to think “out of the box”. After that I did my doctorate with Prof. Oldeman, I started working for the Tropenbos program he had

107 initiated, again being accepted on his recommendation. I ended up becoming Team Leader of that program and eventually personal advisor to the Minister of Forestry of the Republic of Indonesia, writing several of the national forestry rules and regulations in the process. In the mean time I have lived more than two decades in Indonesia and do not intend to ever leave it again, except for short travels.

That one lecture made all the difference. How could this farmers’ son that wanted to become a vet ever imagine to end up in tropical forestry as I did if it had not been for that very first lecture. I have my whole career in the tropics not because of the pictures or because of what Prof. Oldeman told at that lecture, but because of how he motivated me with his sincerity and creative thinking.

As may be clear from the above Prof. Oldeman was the perfect person to guide me as a lecturer, a promotor, my boss and mentor. He has the rare capability to stimulate almost anyone to dig deeper and to achieve more. You still have to do it yourself, but if I for instance had been caught up in the red tape of bureaucracy and not been supported in the trusting way Prof. Oldeman did, I would never have become what I have. For this Prof. Oldeman, I owe you my eternal gratitude!

Through my being in Indonesia and our friendship the links between Prof. Oldeman and many Indonesian students and other activities there found many new fertile foundations that have led to many Indonesian students coming to Wageningen and getting their degrees here. All of these Indonesians that I know so well speak very highly of Prof. Oldeman. They of course mention his wide knowledge, his high level of English in the corrections of their theses, as well as the difficulties they sometimes have in understanding the free associative thinking behind the many recommendations he gave to add to or improve their theses. But most of all his way of respecting these students from such diverse backgrounds and how he motivated them, encouraged them is what touched their hearts and minds most.

It was everywhere the same where I went. When I spend time at Harvard Forest in Petersham Massachusetts, the coffee lady, the lady of the library, they would speak fondly of this kind and pleasant Prof. Oldeman who once was there to write a book. When you speak to anyone of the staff in the gardens or greenhouse at Hinkeloord there is nothing but praise for Prof. Oldeman. He always makes time for people, he shows respect and he always stimulates people with interesting facts, nice stories and the beauty of our world. This is a quality not found in many professors. Most of them tend to be much more focused on facts and rules. Prof. Oldeman can see the person in anyone he meets, and because of that he has uncountable many friends around the world.

It therefore hurt me to see how such a kind and trusting person, used to working amongst all kinds of cultures, picking up their languages as easily as their cultural backgrounds, had to work in such a cold and bureaucratic place as The Netherlands. How few people could understand his thinking which was so often far ahead of other people with less experience. The initiatives he developed, so varied, never afraid to learn new things, to explore and always so quick to see the bigger picture and the interactions. I guess it is no wonder that the rule based bureaucratic culture under the reorganized university structure did not fit this academic thinker and explorer. The old style professorship with room for academic freedom started disappearing around the time Prof. Oldeman started in Wageningen.

No wonder many people that could not understand his visions and that were not willing to invest in trying to understand them, ran into less pleasant situations with him. I have often felt the same problems, but still I try to follow the style of Prof. Oldeman, trying to encourage people to feel amazed at nature’s beauty and complexity, and to encourage them to see the bigger picture and to think out of the box. Even if this means running into conflicts with more bureaucratic persons in the establishment, your daring style is the one I prefer and hope to continue for another 25 years in Indonesia.

Prof. Oldeman has done so much in his distinguished career, so much that so few people know about, that it

108 is virtually impossible to start even summarizing them. Other friends will probably do this. I personally want to thank him for the root box work, the Mycorrhizae in Tropical Forests project, Tropenbos, the Hutan Lestari program and all the other guidance in many other projects.

Willemien, with your absolute loyalty, dedication and energy, I wish you enjoyable times after Prof. Oldeman’s retirement. I know my students from Indonesia, and I can tell you that they all admire you and Prof. Oldeman. Your energy and never faltering support for your husband must have been the basis for his perseverance to go on even in the face of many adversities. Prof. Oldeman’s dedication to you, and your dedication to him, were always the perfect example of how it should be for our Indonesian friends. You have sacrificed much for the hard work of your husband over these many years. It is time to enjoy now.

Prof. Oldeman, I don’t know where to start to thank you personally. The scientific books I inherited from you and that I will put to good use for Indonesia’s forests, the appointments you gave me, the hammock, the many gifts, the many dinners together, they are all great but pale in comparison to what is most important. You gave me the chance to develop, to become a creative thinker, a person that dares to go against the stream and that wants to motivate other people to see beautiful things in the forests of this world, and to see the potential that is in everyone of us. The few little things I can now do for you pale in comparison with that gift. For that I will forever be grateful. Persahabatan kita tidak akan putus. Selamat jalan!

A picture of our getting together with Minister Djamaludin Suryohadikusumo who expresses his thanks as well for all you have done, here in Burgers Bush (another project supported by Prof. Oldeman). From left to right: Ir. Djamaludin Suryohadikusumo, Mrs. Djamaludin, Mrs. Oldeman, Mrs. Smits, Willie Smits, Prof. Oldeman.

109 Oldeman, mens en Wetenschapper

Mr Chris T.F. Thurkow (In memoriam) Erevoorzitter Sitchting Het Kronendak

Het pensioen kan voor een man als Prof. Dr Ir R.A.A. Oldeman niet het einde van zijn carrière zijn. Immers, hij heeft de zeldzame gave bij velen met wie hij verkeert verborgen talenten te wekken. Ook is hij er diep van doordrongen, dat de mensheid gebaat is bij ontwikkeling van toptalent. Dit geldt voor allen, voor Oost en West, voor Noord en Zuid. Cultuur- en mentaliteitsverschillen zijn voor hem dan geen probleem. Met eindeloos geduld en een groot inlevingsvermogen weet hij ook bij zijn niet-westerse discipelen met grote overtuigingskracht het sluimerende wetenschappelijk toptalent tot volle bloei te brengen.

Toeval bracht mij in contact met Roelof Oldeman. Ruim vijftig jaar geleden werd ik als beginnend diplomaat geplaatst in Zuid-Afrika, waardoor ik als vanzelf het ecotoerisme beleefde in de toen nog vrij primitieve wildparken. Geleidelijk aan werd dit een passie, waaraan men zich bijna overal ter wereld kon overgeven . Dit bracht mijn vrouw en mij ertoe na het pensioen op de LUW colleges ecologie en natuurbeheer te gaan volgen. Mijn hoogleraar bracht mij in contact met Prof. Oldeman, die het wetenschappelijk onderzoek in het kronendak van het regenwoud verder wilde ontwikkelen, bij voorkeur door middel van een onafhankelijke instelling. Omdat ik, wederom toevallig, betrokken was bij enkele familiestichtingen en geholpen had met de herziening van de statuten van die stichtingen groeide de gedachte ook het kronendakonderzoek de stichtingsvorm te geven, hetgeen in 1989 heeft geleid tot de oprichting van de Stichting Het Kronendak.

Van de aanvang aan was Oldeman voorzitter van de stichting en inspirator van het onderzoek. Geheel in de stijl van Oldeman, de begenadigd leermeester, werd het door de stichting gestimuleerde onderzoek vaak afgesloten met een promotie of een ander afgesloten studieonderdeel. Kenmerk van alle inspanning van de stichting is dat het onafhankelijk, soms baanbrekend onderzoek betreft en dat financiering door de stichting zelf of extern geheel belangeloos geschiedt. Een bijzondere bijdrage aan de financiële kracht en onafhankelijkheid van de stichting werd geleverd door Dr Jakoba Ruinen, die een groot deel van haar actieve leven als wetenschapper heeft gewijd aan het onderzoek aan de fyllosfeer en op hoge leeftijd in de kronendakstichting zoveel verwantschap met haar levenswerk herkende, dat zij de stichting eerst een belangrijke gift deed toekomen en vervolgens per testamentaire beschikking nog een aanzienlijk deel van haar spaarkapitaal. Te harer ere besloot de stichting bij het 10-jarig bestaan in 1999 een bijzonder hoogleraarschap in te stellen. Op 26 oktober 2001 sprak Prof. Dr Jan H.D. Wolf onder de titel “Juwelen in de Kroon” de rede uit, waarmede hij het ambt van bijzonder hoogleraar op de Mejuffrouw Dr Jakoba Ruinen leerstoel Fyllosfeerwetenschappen vanwege de Stichting Het Kronendak aanvaardde.

Het stemt allen, die kennis van de immense biodiversiteit en van de vele nog onopgeloste levensprocessen van het regenwoud een goed hart toedragen tot grote voldoening, dat Professor Oldeman ook na zijn emeritaat, naar wij mogen hopen nog vele jaren in goede gezondheid, door het instrument van de Stichting Het Kronendak zijn bijdrage aan dit grote doel mag blijven leveren. Het is goed om te weten, dat vele van zijn discipelen klaar staan om te zijner tijd de fakkel van hem over te nemen.

110 Adaptive or adjustive… yet a luminous modelling tool !

Emmanuel F. Torquebiau CIRAD, Department TERA TA 60 / 15 34394 Montpellier CX5 France [email protected]

Climbing up trees. Be it in real terms or as a metaphor, this is what Roelof Oldeman made me do. It all started with a word. A strange, somehow old-fashioned, resonant, strong, fascinating word. But neat. Neat as the concept behind it. “Reiteration”. For the group of neophyte students at the Montpellier tropical botany lab in 1977, the word sounded like a mystery to be unravelled. It sounded like an entire story hidden in the intricacies of forest architecture. However, 25 years later, I’m still amazed that it took me but a few walks through a pristine forest, but a few drawings of trees in their natural environment, to quickly grasp the luminous concept of the “reiteration of the initial architectural model”. A simple, yet powerful determinant of forest architecture. When you’re there, amidst straight, long boles, looking upwards: a demonstration, a proof, a modelling tool. Indisputable.

Put it as you will. Once you’ve understood that trees initially grow according to a genetically determined growth pattern (Hallé and Oldeman’s Architectural models), once you’ve become familiar with the twenty or so different models, and once you’ve seen that the model grows in size or repeats itself (according to species and / or environmental conditions: Oldeman’s reiteration), then you have it. You have a ready-to-use visual modelling device which allows you to analyse, represent and model forest patterns through a few observations. And tell whether you’re in a calm or dynamic forest zone, whether some disturbances have occurred in the past or not, whether a new forest structure is emerging or an old structure dying, etc. Believe it or not, it is as simple as that. Just one precaution, however: do not try to understand tree architecture in a book. As a concept borne in the field, it will unravel only in the field. A guarantee of seriousness.

Induced by changes in forest microclimatic parameters, reiteration appears in most forest trees when they reach or approach the upper canopy and its open conditions. A fork on the main trunk will remain there for ever. More forks will eventually appear upwards when the process repeats itself, and forklets will finally mark partial reiterations in the upper tree crown. Simple again. And what do you do when you want to better observe this and understand how it is related to microclimatic changes? You climb. Up trees. No choice. To see. To measure. Looking for sequential and reiterated branches. Fixing light sensors in the canopy. And you find that reiteration and microclimate are correlated indeed, as Oldeman rightly hypothesized (Torquebiau, 1988). Up trees. This is what Oldeman made me do. As a metaphor and in real terms.

Reiteration allows trees to adapt themselves to forest environmental growth factors. Adaptive reiteration hence initially came as a natural denomination: a way for trees to adapt their architecture according to changing environmental factors, as opposed to traumatic reiteration, similar, but in reaction to a violent event such as a broken trunk or branch. Sounds simple, doesn’t it? Yet in a 1984 letter, Oldeman suggested to me to opt for adjustive reiteration, as the word adaptive could have an evolutionary meaning. So I did (Torquebiau, 1986), though convinced by then that the distinction was somehow spurious. A few years later, puzzled by observations on genetic variations in tree crowns, I realized how premonitory was the distinction: if such variations do exist, then reiterations, because they emerge from the dedifferentiation of meristems, are likely to be the preferred axes where such a variability will occur. Multiple reiterations in a tree crown can hence be seen as a population

111 where Darwinian selection can take place, and in this sense, can be described as adaptive. Remember also that reiteration is not uniformly present among different tree taxa (mostly absent in gymnosperms, common in angiosperms, except some primitive families such as Myristicaceae or Annonaceae) or among different ecological niches (rare in pioneer trees, the rule in mature forest trees). All in all, I wouldn’t be surprised if one day it is demonstrated that reiteration has played a role in tree evolution. Adaptive and adjustive and luminous.

The reader will hopefully forgive me for having conceded to a somewhat pompous prose for the start of this modest note in homage to Roelof Oldeman. Memories of endless discussions are many: at Hinkeloord or in a pub in Wageningen, in the Kebun Raya in Bogor or in the streets of Bandung, in the corridor of the defunct botanical institute of Montpellier, in the forest of Central Kalimantan, at the world congress of ecology in Yokohama in 1990, etc. Every time a new idea; every time a thorough discussion; and not necessarily related to trees or forests, far from it!

Beyond the emblematic reiteration and its dual nature, Roelof Oldeman has regularly thrown ideas around, indefinitely stimulating thoughts of his readers. Here are some of my favorites:

• Applying fractals to agroforestry design, “…because methods of forecasting and design used in monocultures are not relevant … and the production geometry of agroforestry mosaics can be expressed mathematically by the fractal geometry … of a Menger sponge” (see Oldeman, 1992). • Coining the word “silvology” (“the theoretical basis for understanding of forests and designing silvicultural systems… and a special branch of ecology”) as a wink (or a pleasant gibe?…) to conventional foresters caught in forest management techniques and forestry plans (see Oldeman, 1990). Fig. 1. Architectural integration levels from cell / tissue (p.m.), through • Defining the “inversion surface”, i.e. the organ (a), organ complex (b), branched complex exemplified by Rauh’s, junction of the inversion points marking the Massart’s and Troll’s models (c) and reiterated complex (d), to the collective levels (e) to (g). Note organ complex as subsystem of either first persistent reiteration (the main fork of eco-unit (palm, seedling) or branched complex (branches, trunk). In the trunks), “…under which the vegetative eco-unit (e) p = trees of the present; f = trees of the future. In the chrono- unit (f) an aggrading phase is organizing itself under the degrading one; complex is distinguished by a single large this links chrono-units of different kinds in the silvatic unit (g). Systems unit, the trunk; and beyond which appear at each level figure in higher-level systems as symbols. Broken line separates individual from collective systems (Oldeman, 1983). successive series of smaller and smaller reiterated complexes… as is self evident when one examines tree form”. Large trees below, small trees above! (see Oldeman, 1974, and Hallé et al, 1978). • The amazing Figure 1 in Oldeman (1984; here reproduced as Fig. 1), which takes you in a glance from leaves to large size silvatic units through 7 levels all integrated one into the other (organ; organ complex; branch complex; reiterated complex, eco-unit; chrono-unit; silvatic unit). If at all a University Professor should aim at producing powerful syntheses which could mark their time, this is, in forest ecology, one of the most exhaustive I’ve ever seen.

112 Dear RAAO, I hope these few lines will reach your heart; but I hope overall that they will give readers the will to go back to your writings and read them again and again; looking here for an unconventional idea, discovering there a new word, an iconoclast paradigm. There are many such exciting discoveries to be made in RAAO’s writings and drawings: look for them in and between the lines. Look for them in any figure: in RAAO’s drawings, you won’t miss the forest for the trees.

I am not sure the style of these few lines is adequate for a “Liber amicorum”. Such books have become rare in France: I must confess that I have not read one for many years and, of course, that it is the first time I am contributing to one. Only you, the Dutch, will ever stick to these old-fashioned traditions, as only you, the Dutch, are probably able to combine so elegantly tradition and modernity. And among those able to smoothly run this combination, RAAO is probably a model.

Acknowledgements Blackwell Scientific Press (http://www.blackwell-science.com/) gave permission for the reproduction of figure 1.

References Hallé, F., Oldeman, R.A.A. and Tomlinson, P.B. 1978. Tropical trees and forests: an architectural analysis. Berlin: Springer- Verlag, 441 p. Oldeman, R.A.A., 1974. L’architecture de la forêt guyanaise. Mémoire ORSTOM N° 73. Paris : ORSTOM, 204 p. Oldeman, R.A.A., 1983. Tropical rainforest architecture, silvigenesis and diversity. in Sutton, S.L., Whitmore, T.C. and Chadwick, A.C. Tropical rain forest: ecology and management. Special Publication Number 2 of the British Ecological Society. Oxford: Blackwell Scientific Publications, 139-150. Oldeman, R.A.A., 1990. Forests: elements of silvology. Berlin: Springer-Verlag, 624 p. Oldeman, R.A.A., 1992. Architectural models, fractals and agroforestry design. Agriculture, Ecosystems and Environment 41 (2): 179-188. Torquebiau, E. 1986. Mosaic patterns in Dipterocarp rainforests in Indonesia and their implications for practical forestry. Journal of Tropical Ecology 2: 301-325 Torquebiau, E. 1988. Photosynthetically active radiation environment, patch dynamics and architecture in a tropical rainforest in Sumatra. Australian Journal of Plant Physiology, 15: 327-342.

113 Bosologie, of de wetenschap van het bos

Henricus F.M. Vester El Colegio de la Frontera Sur AP 424 Chetumal Quintana Roo 77000 Mexico [email protected]

De term Bosologie —het klinkt een beetje plomp en nogal onwetenschappelijk in het nederlands, daarom— liever gezegd Silvology (Oldeman, 1990) doet zijn oorsprong vermoeden in de ecologie, en lijkt te verwijzen naar een soort gespecialiseerde tak van wetenschap in de meer algemene discipline van de ecologie. Niets is echter minder waar. Het accent van de ecologie ligt heden ten dage vaak meer op fysische dan biologische vraagstukken, hetgeen een vernauwing betekent van de oorspronkelijke, ruime en meer holistische definitie van ecologie (Haeckel, 1866) waar de uitvinder van de term “silvology” zich wellicht meer in zal vinden.

Om bossen te leren kennen heeft men bossen afgebroken, eerst letterlijk, en geprobeerd die bossen weer op te bouwen uit losse onderdelen, zoals dat in de plantage bosbouw gebeurt. Met weinig kennis krijg je dan eenvoudige bossen, met veel empirische kennis complexe plenterbossen. Maar hoe moet je door eeuwen heen vergaarde kennis op een bepaalde plaats met een specifieke soorten samenstelling en dynamiek nu vergelijken met kennis opgedaan in een bossysteem in een ander werelddeel? Silvology geeft daar een antwoord op.

Een grote stap vooruit in het wetenschappelijk benaderen van bossen en bosbouw was het analytisch en abstract kunnen werken met bomen en bossen, dat wil zeggen in tekeningen en op schaal (Fig. 1), als een echte ingenieur. De ruimtelijke en temporele aspecten van de groei en ontwikkeling van bossen kunnen dan namelijk in aanmerking genomen worden. En de ingenieur kan zich daarmee een voorstelling maken van veranderingen. Ruimtelijk inzicht is een pre voor een “bosoloog”, maar ook een gevoel voor vorm en systematiek, want bomen groeien volgens patronen. De wetenschap van bossen, of silvology heeft zich ontwikkeld op het raakvlak tussen botanie en bosbouw.

Het gebruik van beelden naast of in plaats van, maar in ieder geval voorafgaand aan, het gebruik van getallen maakt niet alleen het modelleren en abstract bewerken van bossen mogelijk, het stimuleert ook het geheugen van de bosingnieur of onderzoeker. Buzan & Buzan (1996) laten zien dat beelden veel gemakkelijker opgeslagen en herinnerd worden dan woorden of getallen. Mijn eigen ervaring heeft me geleerd dat de transecten die ik ooit getekend heb met veel aandacht voor de architectuur, gemakkelijk weer terug komen in de herinnering, vaak met veel details.

Verder kijken dan bladeren en bloemen en het eenvoudigweg voldoende kenmerken verzamelen om een plant te determineren was nodig om patronen in de ontwikkeling van bomen te zien. Samen met Francis Hallé heeft Prof Oldeman in 1970 een boek geschreven, waarin op systematische wijze, of, zoals hen zelf voor ogen stond, als in het periodiek systeem der elementen, de basisvormen, of architectuurmodellen van bomen in de tropen zijn geordend. Tot nu toe zijn er in de natuur geen modellen gevonden die wezenlijk anders zijn dan de in het boek beschreven modellen. Daarentegen zijn er in de natuur wel voorbeelden gevonden van de twee destijds op theoretische gronden voorspelde modellen.

Er is ondertussen veel meer bekend geworden over de ontwikkeling van bomen en de patronen daarin. Beschrijvingen worden nu meestal toegespitst op soorten en erg gedetailleerd uitgevoerd. Dit neemt echter niet weg dat het periodiek systeem der architectuur modellen een groot potentieel heeft wat nog steeds niet ten volle

114 Figuur 1. Profiel van een lijntransect van 50 m lang, op schaal getekend in 1999 in natuurlijk bos in de botanische tuin “Dr. Alfredo Barrera Marin” waar in 1988 de orkaan Gilbert veel schade aan bomen heeft aangericht. In boom nr 1, geheel rechts zijn duidelijk de plaatsen van takbreuk en de reacties van de boom daarop te zien. Soorten samenstelling: 26, 33, 80, 85, 89, 98, 101, 103, 104, 105, 106: Astronium graveolens Jacq.; 70: liaan sp. Onbekende Bignoniaceae; 7, 67,74, 93, 97, 113: Brosimum alicastrum Sw.; 6: Bunchosia swartziana Griseb.; 69: Bursera simaruba (L.)Sarg.; 62: Chamaedorea seifrizii Burret; 3, 28, 35, 90, 107: Coccothrinax readii H.J. Quero R.; 34, 52, 64: Cordia gerascanthus L.; 5, 13, 38, 40, 42, 45, 46, 47, 51, 54, 57, 75, 81, 83, 84, 87, 95, 99, 102, 108, 116: Drypetes lateriflora (Sw.) Krug & Urb.; 17, 20: Eugenia capuli (Schltdl. & Cham.) Hook. & Arn.; 21: Guettarda combsii Urb.; 117: Gymnanthes lucida Sw.; 15, 25, 50: Malvaviscus arboreus Cav.; 11, 61, 110, 36, 55: Manilkara zapota (L.) P. Royen; 1, 29, 30, 42, 44, 60, 72, 79, 86: Sideroxylon foetidissimum Jacq.; 18, 48, 114: Myrcianthes fragrans (Sw.) McVaugh; 12, 41, 27, 53, 100: Nectandra coriacea (Sw.) Griseb.; 63, 78: Ottoschulzia pallida Lundell; 49: Picramnia antidesma Sw.; 8, 88: Pouteria reticulata (Engl.) Eyma; 31: Sabal yapa C. Wright ex Becc.; 68, 96: sp. onbekende Sapindaceae; 2, 22, 58, 59, 66, 109, 112: Talisia oliviformis (Kunth) Radlk.; 10, 56: Thevetia gaumeri Hemsl.; 16, 19: Thrinax radiata Lodd. ex Schult. & Schult. f.

is benut, en nog menig proefschrift verbergt waar de systematiek op zijn minst zijn voordeel mee kan doen.

Architectuurmodellen zijn niet alleen interessant voor de systematicus, maar ook voor ecologen. Dit heeft Prof Oldeman heel duidelijk aangegeven in een aantal publicaties (Oldeman & Fundter, 1986; Oldeman & van Dijk, 1991; Oldeman & Sieben-Binnekamp, 1994), die allen handelen over “boomtemperamenten”. Deze term was al sinds mensenheugenis in gebruik onder bosbouwers en is door Oldeman en van Dijk (1991) uiteindelijk gedefinieerd als: “de verzameling van eigenschappen die een boom laat zien als reactie op veranderingen in zijn omgeving”. De kracht van deze publicaties zit hem niet in het bedenken van nieuwe termen en het nieuw inhoud geven aan oude termen, maar in de relatie die wordt gelegd tussen de architectuur kenmerken van een boom en zijn ecologie. Prof Oldeman geeft hiermee niet alleen de bosbouw een ecologie component, maar gebruikt ten volle de ecologie als wetenschap van de interactie tussen organismen onder elkaar en met hun natuurlijke omgeving.

Met het formaliseren van de term temperament heeft Prof Oldeman nieuw inzicht gegeven in de relatie tussen bomen en omgeving. De basis voor dat inzicht is gelegd in zijn proefschrift en in het artikel “Ecotopes des arbres et gradients ecologiques verticaux en foret guyanaise“ (Oldeman, 1974). Daarin werd al duidelijk dat de omgeving van de boom nodig een speciale aandacht behoefde. De concepten als “niche”, “habitat” en “ecotope” waren duidelijk toegesneden op dieren en ontoereikend om het dynamische aspect van de omgeving van een boom gedurende zijn leven duidelijk te kunnen karakteriseren. In latere stukken spreekt Prof Oldeman over de “directe omgeving” (Oldeman & van Dijk, 1991; Oldeman & Sieben Binnekamp, 1994).

Het nadenken over de omgeving van een boom leidde er ook toe dat Prof Oldeman het concept eco-unit invoerde (Oldeman, 1983). Overigens, de publicatie is uit 1983, maar in 1981 werd dit werk gepresenteerd op het internationale congres over onderzoek in “agroforestry” in Nairobi.

115 De uitvinding van de nul door de arabieren was een mijlpaal in de ontwikkeling van de wiskunde. Zonder een nul is er geen referentiepunt, is alles continu. Zonder nul is de afstand tussen één en min één ongedefinieerd. Zonder nulpunt kun je vraagstukken als: “wat was er eerder, de kip of het ei?”, eindeloos oplossen. In America is de nul door de mayas uitgevonden. Het symbool dat zij gebruikten voor de nul lijkt op een oog maar is volgens de archeologen een schelp. Het definiëren van een nulpunt, of een nul gebeurtenis (zero-event) in de dynamiek van het bos (Oldeman, 1983), is een grote stap voorwaarts geweest in de bosecologie. Het maakt het analyseren van bossituaties aan de hand van architectuur kenmerken in bomen mogelijk.

Die grote stap voorwaarts heeft niet zozeer geleid tot het kunnen optellen of aftrekken van stukken bos of gebeurtenissen in het bos. Levende systemen laten zich nu eenmaal niet eenvoudigweg optellen. Tussen levende systemen ontstaan interacties, waardoor de samenwerkende systemen een nieuw systeem vormen. In silvology heeft Oldeman (1990) heel duidelijk laten zien hoe bossystemen hiërarchisch georganiseerd zijn, overal op aarde, daarmee heeft hij de basis gelegd voor een boswetenschap die botanie en ecologie in zich verenigen en instrumenten aanreikt aan de bosingenieur.

Maar, Prof. Oldeman heeft niet alleen een bijdrage geleverd aan het inzicht in bossen, hij heeft ook sterk bijgedragen aan de vorming van mensen, de manier waarop mensen naar bossen kijken: met respect. Het ontwerpen van technische hoogstandjes, of het organiseren van observaties en feitjes is één, maar het omgaan met bos is iets heel anders. De bijdrage van Oldeman in deze dilemma’s is vervat in een aantal heel duidelijke uitspraken “Wanting a product, first forget the product and mind the forest” (Oldeman, 1991). En in het slot van het boek “Struggle of life” waar staat: “Let us always join in the struggle of life, not struggle against it. “(Rossignol et al., 1998).

De “vorming” van mensen had niet de vorm van “kneden” zoals een aantal politici eens formuleerde in een kranten publicatie die we samen met afgrijnzen lazen. In zijn studie tijd was het respect voor vrijheid al vooraanstaand; hij dankte in zijn werkstuk “ Shifting cultivation and field rotation” (1964) Prof Kools “...for the freedom he gave me to tackle this subject”. Prof Oldeman sprak in zijn inaugurele rede over de “boom der vrijheid” (Oldeman, 1977). Dit respect voor de vrijheid van denken, de vrijheid voor het ontwikkelen van eigen ideëen en eigen kennis heeft vorm gekregen in zijn onderwijs en de vrijheid die hij zijn studenten gaf hun kennis te ontwikkelen. Hierbij denk ik terug aan de presentatie die Prof Oldeman in 1994 gaf aan de Universidad Nacional in Bogotá, Colombia. Na een voortreffelijke rede in niet merkbaar ongeoefend spaans werden kritische vragen op onze Prof afgevuurd. Daaronder de vraag: Wat denkt u welke richting wij hier in Colombia met onderzoek op moeten gaan? (vrije formulering, HFMV). Daarop gaf Oldeman het volgende antwoord: “Elke generatie en elk land worstelt met zijn eigen vragen en heeft het recht ook om die vragen naar eigen inzicht op te lossen; elke generatie vormt zijn eigen wetenschap.” (vrije formulering, HFMV).

Als docent was Oldeman een echte Prof, die aandacht besteedde aan de presentatie van zijn materiaal, die probeerde concepten tot leven te brengen, en vooral een man die respect toonde voor zijn medemens en een voorbeeld was. Zijn colleges waren inspirerend en gaven te denken. Zijn dictaten waren heel dicht met informatie, waardoor het veel tijd kostte ze door te werken. Zijn evaluaties gekenmerkt door het “éénzinsexamen”. Als docent-af zal hij zeker mensen blijven inspireren en doorgaan die prof te zijn die wij kennen en Hoogachten.

Goede Prof en Beste Vriend, Met grote dankbaarheid denk ik terug aan alles wat u mij geleerd heeft, het geduld en de aandacht besteed, de kansen gecreeerd. Onze afspraken voor bespreking van de voortgang van het proefschrift heeft u altijd aan het eind van de middag gepland om uitlooptijd te hebben, die ook altijd werd gebruikt. Het waren bijzondere bijeenkomsten. Vaak kwam het woordenboek tevoorschijn om de precieze betekenis van woorden na te kijken; altijd werden er boeken uit de kast gehaald, en soms lagen ze al klaar. De momenten die markeerden dat wetenschap en menselijkheid hand in hand gaan zijn niet alleen gemarkeerd door de bijeenkomsten op uw werkkamer. Ook was daar uw bezoek aan Araracuara, de motor die op het water afsloeg, een sigaar die uitkomst

116 bracht tegen de muggen; een wandeling door Amsterdam, met een bezoek aan Hajenius; en onlangs nog de cursus in Spanje. Ook gaat mijn dank uit naar uw vrouw die altijd onafscheidelijk naast u staat. De dank die ik u beiden graag wil overbrengen staan niet in een woordenboek, maar komen uit het diepst van mijn hart.

Hans Vester, September 2002

Dankbetuiging Het veldwerk voor het transect in figuur 1 werd verricht met financiele steun van CONACYT (project nr. 25035N) en met medewerking van Francisco Javier Xuluc Tolosa.

Literatuur referenties Buzan, T. & Buzan, B. 1996. El libro de los mapas mentales. Ediciones Urano, Barcelona, España. Haeckel, E. 1866. Generelle Morphologie der Organismen. Reimer, Berlin. Oldeman, R.A.A. 1974. Ecotopes des arbres et gradientes ecologiques verticaux en foret guyanaise. La terre et la vie 28(4): 487-520. Oldeman, R.A.A. 1977. De boom der vrijheid. Landbouw Hogeschool, Wageningen, 42 pp. Oldeman, R.A.A. 1983. The design of ecologically sound agroforests. Pp.173-207 In: Huxley, P.A. Plant research and agroforestry. ICRAF. Nairobi, Kenya. Oldeman, R.A.A. and Fundter, J.M., 1986. Diptero-Vochysian tree strategy. Naturalia Monspeliensia, speciale uitgave (L’arbre symposium) pp191-208. Oldeman, R.A.A. 1990. Forests: elements of silvology. Springer, Heidelberg. Oldeman, R.A.A. 1991. The paradox of forest management. Paris, Proc. Xth World For. Congr., 4: 153-188. Oldeman, R.A.A. and van Dijk, 1991. Diagnosis of the temperaments of tropical rain forest trees. In: Gomez Pompa, A., Whitmore, T.C. & Hadley, M. (eds.): Rain forest regeneration and management. MAB series vol 6. UNESCO, Paris, France & Parthenon, Park Ridge, USA. Pp. 21-65. Oldeman, R.A.A. and Sieben-Binnekamp, A. 1994. Timber trees: architecture and ecology. In: Leakey, R.R.B. & Newton, A. C. (eds.): Tropical trees: the potential for domestication and the rebuilding of forest resources. HMSO, London. Pp. 25-33. Rossignol, M, Rossignol, L, Oldeman, R.A.A. and Benzine Tizroutine, S. 1998. Struggle of life or the natural history of stress and adaptation. Treemail, Heelsum, Nederland

117 From Walled Garden to Rainforest

Anne M. Visscher MSc-student WU P.C. Hooftlaan 31 3705 AE Zeist The Netherlands [email protected]

My search for knowledge on the growth of plants started in a walled garden in the Netherlands, and continued in the rainforests of the Carib- bean and South-America.

The Walled Garden Amongst their diverse and colourful array of beans, fruits, herbs and flowers, or just the seeds, Taco IJzerman and Esther Kuyler exchanged a supay piña wealth of stories with me that revealed some of the little-known phenomena on this planet. I was attracted by their initiative to continuously experi- ment with and enable the integration of plants, animals, fungi or microbes, and people and the ideas they portray. Their recognition of my interests led them to introduce me to professor Oldeman.

Rainforests Complex systems can be observed from an architectural perspective, outlining new insights that take shape along the way. I had been shown a method of observation by professor Oldeman and practised this in Puerto Rico, formulating what I saw as patterns of hardwood growth.

Then on to Peru, where the entire forest became a central point of attention, each plant potentially, or already known to be, medicinal. The bark of trees and lianas, the leaves, fruits and flowers of herbs and shrubs were applied regularly and discovered and observed with ease, compared to the flowers, fruits and leaves of trees, and the epiphytes growing in their crowns. A selection of these medicinal plants of the canopy has been documented and can be seen on the web at http://www.treemail.nl/kronendak/visscher/ or can be accessed from http://www.treemail.nl/kronendak/publicat.htm. My interest for these higher and less known regions of the forest was stimulated by Professor Oldeman and the Canopy Foundation. The next step will be to assess the possibility of enclosing a compartment of the canopy and thereby taking the observation of the forest to a higher level of integration.

With gratitude I look back at several years of creative conversation and subsequent research in the field, be it focussed on plants, soil or the system as a whole, where no interest can be rendered unimportant.

118 Phorocantha sp. ex Fraxinus excelsior

Hans van der Wal El Colegio de la Frontera Sur Campeche

In 1993 leerde ik Prof. Oldeman kennen, in de barak naast agronomie. Ik was opgetogen, mijn voorstel voor promotieonderzoek was in goede aarde gevallen.

Mijn idee van wetenschap was toen wat beperkt, denk ik nu, terugkijkend. Het protestantse erfgoed zat diep en voedde een zekere dogmatiek, wellicht in velerlei opzichten “juist”, maar arm in andere: wetenschap moest de armen dienen – dat was veelal niet het geval. Fout, het is nodig daar wat aan te doen. Punt.

Wetenschap zag ik louter als een instrument en daarmee ging ik voorbij aan de inhoud, aan de onmiddellijke vraag naar “wat voor wetenschap?” Die vraag kon ik slechts beantwoorden met degelijke maar beperkte instrumenten als factoriële veldproeven en extrapolaties – naar wat? Ik zat koppig in de val, gebouwd van de regressielijnen van een gefragmenteerde werkelijkheid, inadequaat voor de werkelijke complexe werkelijkheid. Om een complexe werkelijkheid te benaderen, zijn, naast kennis en toewijding, vooral creativiteit, durf en speelsheid nodig. Zien, intuyeren van verbanden, systematiseren, beoordelen, ordenen. Succes wordt verder bevorderd door een gevoel voor “ m o o i ”. Speels de werkelijkheid even vervangen door een fantasie, een beeld; en dat een duw te laten zijn in de gestage opbouw van een visie met nieuwe elementen en een nieuwe samenhang...

In “Forests: Elements of Silvology” (Oldeman, 1990, uitgeverij Springer) springt dit steeds weer naar voren in de vormgeving van de dia-dynamische visie die daar uitgewerkt wordt (dia, grieks voor “door”), door vormen, tijd en schaal heen. Een speciale illustratie daarvan is te vinden op pagina 41-42, figs 3.10 en 3.11 B. De australische kever Phorocantha sp. komt voort uit Fraxinus excelsior in Oost Flevoland. Dia-kijk de pagina maar, tegen het licht. (reproductie van de figuur met toestemming van Springer Verlag (http://www.springer.de/rights/index.html).

Zoveel verbanden zijn er over het hoofd gezien in de industriele waan, dat het verantwoord, gewenst is om er eens één te boek te zetten die nog nooit overwogen is. Naast al die andere, die pagina na pagina draden tot een begrip en systematiek van complexiteit samenweven zonder steken te laten vallen.

En een zekere mate van dat begrip, die verbazing en speelsheid, dat zijn nu precies de dingen die mijn dagelijks werk nu, na de Oldemanniaanse begeleiding van mijn promotiewerk, rijk maken. Elke dag weer.

119 De l’architecture à la géométrie des forêts

Jean-Michel N. Walter Université Louis Pasteur _ Institut de Botanique _ 67070 Strasbourg F [email protected]

Rendre hommage au Prof. Roelof Oldeman est pour moi un honneur et une joie. Je vais d’abord évoquer les années de ma découverte des concept nouveaux sur l’architecture de l’arbre et de la forêt, qu’il a forgés avec son collègue et ami le Prof. Francis Hallé, puis les années au cours desquelles, sur ces fondements, j’ai pu développer mes propres thèmes de recherche.

De retour à l’Institut de Botanique de l’Université de Strasbourg à la fin des années 60, après deux ans passés au Brésil auprès des vestiges de la Forêt Atlantique et de la forêt d’Araucaria, je découvrais une nouvelle approche de l’arbre et de la forêt dans l’Essai sur l’architecture et la dynamique de croissance des arbres tropicaux (Hallé et Oldeman, 1970). Le concept d’ «architecture de l’arbre» était né. Celui, complémentaire, d’ «architecture de la forêt» suivait, avec L’architecture de la forêt guyanaise (Oldeman, 1974). Dès le début des années 70, j’avais commencé à enseigner, avec enthousiasme, ces concepts à mes étudiants de botanique et d’écologie.

À cette époque, j’étais affecté au Laboratoire d’Écologie Végétale, dirigé par le Prof. Michel Gounot. Le Laboratoire de Morphologie Expérimentale était dirigé par le Prof. Jacques Roux, «Prof». Ces Laboratoires étaient devenus, au cours des années 70, des pôles d’enseignement et de recherches sur la morphologie et l’architecture des végétaux. C’est là que j’ai rencontré Roelof. L’échange universitaire triangulaire entre Strasbourg, Clermont-Ferrand et Montpellier était ancien : il datait de l’époque des Prof. Henri-Jean Maresquelle, Paul Champagnat et Louis Emberger. À présent, il devenait quadrangulaire, en s’étendant à Wageningen où Roelof avait été nommé Professeur lors d’une mémorable cérémonie d’intronisation en 1978. En cette même année, la publication de Tropical Trees and Forests (Hallé et al., 1978) allait renforcer mes «convictions architecturales». L’année d’avant, j’avais organisé à Strasbourg un Colloque sur l’Analyse structurale quantitative des forêts, auquel Roelof avait apporté une remarquable contribution (Oldeman, 1979).

Invité à Wageningen pour des conférences à ‘Hinkelord’, je recevais en retour, les années suivantes à Strasbourg, cinq élèves de Roelof pour des stages sous ma responsabilité. L’architecture et la dynamique des forêts alluviales du Rhin, celles-ci menacées de destruction totale, étaient alors les thématiques majeures de nos recherches (Walter, 1982). Pendant les années 70 et 80, j’allais aussi porter la «bonne parole» successivement au Laboratoire de Botanique Tropicale à Paris, invité par le Prof. Raymond Schnell, et à l’ENGREF de Nancy, invité par le Prof. Jean-Claude Rameau.

Pendant cette période, de nombreuses thèses et des mémoires avaient été soutenus sur l’architecture et la dynamique des arbres et des forêts, tant à l’Université Agronomique de Wageningen qu’aux Universités de Montpellier et de Toulouse. Certains de ces travaux me parvenaient. Ils sont restés parmi les plus précieux documents de ma bibliothèque personnelle. J’ai eu l’insigne chance, grâce à Francis, de me rendre en 1976 pendant un mois à Saül, en Guyane Française, sur les «traces d’Oldeman». Cela a été une formidable démonstration des thèses de «Hallé et Oldeman». Les noms de «Plateau de la Douane», de «Mont Belvédère», de «Crique du Bœuf Mort», de «Montagne La Fumée», retentissent encore maintenant comme les étapes d’un parcours initiatique. C’est au cours de cette longue période que j’ai découvert la richesse de l’approche holistique dans l’œuvre de Roelof. Un aspect particulièrement symbolique, que j’ai intégré à ma façon, fut une vision à la fois globale et

120 détaillée de la voûte forestière de Guyane. Il s’agissait d’une photographie hémisphérique apparaissant sur la page de couverture de la thèse de Roelof. Elle était prise de manière tout à fait inhabituelle, du haut en bas de la canopée. Quelle n’a pas été ma surprise de retrouver sur la page de couverture de L’Arbre 2000 (Oldeman, 2001), trente ans plus tard, cette autre vision hémisphérique de la forêt guyanaise, mais cette fois de bas en haut! Coïncidence ou choix? Cette inversion des termes est familière à la pensée de Roelof, comme par exemple dans la définition qu’il propose de l’arbre et de la forêt, l’un par rapport à l’autre et vice-versa, ou dans l’aller-retour entre systèmes et sous-systèmes. Toujours est-il que j’avais été impressionné et inspiré par la première image hémisphérique. Elle était le déclic qui orienterait désormais mes recherches sur les voûtes forestières : d’architecturales qu’elles étaient, elles seraient dorénavant géométriques.

En effet, l’architecture et la géométrie peuvent être considérées comme deux approches complémentaires de la structure forestière. D’un côté, l’approche architecturale tente d’intégrer différents niveaux hiérarchiques. Elle est basée sur la dynamique de croissance des arbres individuels, caractérisée par l’arrangement spatial des axes portant les organes photosynthétiques et reproducteurs, ainsi que sur leur distribution au sein d’un réseau d’unités écologiques correspondant à des phases de développement, dont l’ensemble compose la mosaïque forestière. De l’autre côté, l’approche géométrique cherche à quantifier la surface, l’agrégation et l’orientation d’organes -feuilles, fleurs, fruits, troncs et branches - d’arbres individuels et de groupes d’arbres, ainsi que la taille, la morphologie et la dispersion spatiale des trouées qui les séparent. Ces propriétés sont reliées à la physique des transferts de matière et d’énergie. Leur analyse statistique conduit à une importante réduction des données d’observation. Seuls, quelques descripteurs synthétiques en sont extraits: l’indice foliaire, l’inclinaison Figure 1. Interactions lumière/ombre, humidité/sécheresse, vent/tranquillité, entre des éléments du feuillage, écounités au sein d’une mosaïque forestière. D’après Oldeman, 1992 Fig 4 (La forêt de la Sihl: nostalgie ou avenir ?). l’ouverture relative de la voûte, le degré d’agrégation du feuillage et la distribution de la lumière associée à ces éléments. Ces variables clefs sont largement utilisées dans la modélisation du fonctionnement des écosystèmes et pour expliquer les réponses des plantes et des animaux aux ressources en espace et en énergie. Analyser la géométrie des canopées, revient donc à relier l’échelle des éléments du feuillage à celle de la forêt.

C’est dans cette direction: tenter de faire le lien entre l’architecture et la géométrie des canopées forestières, que j’ai orienté mes recherches. Ces travaux ont été à la base de développements théoriques et pratiques sur la photographie hémisphérique des canopées, auxquels je me suis consacré, en partie, les dernières années. D’abord, ce fut «la lumière et la forêt» (Walter, 1993; Walter & Torquebiau, 1997; Fig. 1), que je ne détaillerai pas ici. Puis, ce furent les «effets de pente» et l’ «agrégation des éléments du feuillage», chacun dans un contexte particulier basé sur des intuitions de Roelof.

L’ «effet de pente» sur l’architecture et la géométrie des canopées forestières avait été négligé jusqu’alors. Constatant que la majeure partie des forêts sur Terre survit désormais sur des pentes, souvent fortes, il était évident que le comportement des forêts sur pente demandait à être mieux compris. Roelof a esquissé de manière graphique, par le dessin architectural (Fig. 2), un modèle de réponse de la forêt au relief. J’ai repris l’idée féconde d’ «imbrication forestière sur pente», en mettant au point, avec Emmanuel Torquebiau, une méthode permettant d’intégrer l’ «effet de pente» au calcul de l’indice foliaire par la méthode des photographies hémisphériques

121 (Walter & Torquebiau, 2000). Cet effet était jusque-là ignoré, soit qu’il eut été simplement oublié, soit qu’il n’y eut pas de méthode fiable pour l’aborder.

L’effet d’ «agrégation des éléments du feuillage» sur l’estimation de l’indice foliaire est un thème récurrent dans l’analyse géométrique des voûtes forestières. Cette agrégation s’exprime à toutes les échelles: rosettes de feuilles, ensembles de rameaux et de branches, groupements d’axes séquentiels et de réitérations, bouquets de cimettes formant la couronne, arbre individuel et groupes d’arbres. Cette structure contagieuse est tout à fait générale dans la plante et dans le tapis végétal. Elle est l’expression morphologique, difficile à traiter quantitativement, Figure 2. Imbrication forestière sur pente. D’après Hallé, Oldeman & Tomlinson, de l’optimisation des échanges de matière et d’énergie. 1978. Grâce à son intuition, Roelof a construit un modèle établissant un pont entre l’architecture et la géométrie des forêts (Fig. 3): la «forêt froncée, ou la hiérarchie de systèmes vivants en fractale biologique à limites floues» (Oldeman, 2001). J’ai pu contribuer à ce thème par mes recherches, en collaboration avec Richard Fournier, sur l’effet de l’agrégation du feuillage dans l’estimation de l’indice foliaire (Walter et al., 2003).

Je ne voudrais pas terminer sans relever des traits qui me paraissent essentiels dans l’héritage scientifique de Roelof. Tout d’abord, l’invention d’une méthode originale de dessin architectural de la forêt, remarquable par sa lisibilité et son adéquation aux concepts qu’il a développé. Ensuite, la clarté du langage, notamment dans la construction de termes nouveaux, loin de tout jargon technique. Qui n’emploie maintenant couramment les mots «arborigenèse», «sylvigenèse», «réitération», «éco-unité», parmi bien d’autres? Et surtout, la clarté de la construction hiérarchique (Oldeman, 1990; Rossignol et al., 1998), la formulation et l’utilisation de concepts qui, loin de constituer un encombrant appareillage, rendent mieux compréhensibles la dynamique et le fonctionnement des forêts, de toutes les forêts de la planète.

Enfin, audelà de toute admiration, je voudrais évoquer la haute stature de Roelof, dans le sens le plus noble du terme ; sa capacité de synthèse hors pair ; sa culture hors du commun , intégrant tous les aspects de la vie ; son don des langues, qui permet à l’orateur passionnant qu’il est d’alterner instantanément l’anglais, le hollandais, le français, l’allemand, l’espagnol, avec Figure 3. Plis photosynthétiques. La forêt froncée. D’après aisance et naturel. Je suis confiant dans la valorisation Oldeman, 2001. [La forêt de la Sihl: nostalgie ou avenir?, de l’immense héritage que constitue son œuvre, dont Fig 5] l’influence se poursuivra sur des générations de scientifiques, jeunes botanistes, écologues et forestiers. Mais pardelà ces qualités, je n’oublierai jamais sa générosité, la chaleur de son accueil, son amitié, à laquelle j’associe son épouse Wil, rencontrée ici et là, à Strasbourg, chez nous à la maison, au Laboratoire, mais aussi dans la forêt du Rhin et, en famille, à Wageningen.

122 Acknowledgements We thank Springer verlag (http://www. springer.de/rights/index.html) for their permision to reproduce Fig 2

Références Hallé, F. et Oldeman R.A.A. 1970. Essai sur l’architecture et la dynamique de croissance des arbres tropicaux, Masson, Paris. Hallé, F., Oldeman R.A.A. and Tomlinson P.B. 1978. Tropical Trees and Forests. An Architectural Analysis, Springer, Heidelberg. Oldeman, R.A.A. 1974. L’architecture de la forêt guyanaise, Mémoires ORSTOM Nº 73, Paris. Oldeman, R.A.A. 1979. Quelques aspects quantifiables de l’arborigenèse et de la sylvigenèse. In: Analyse structurale quantitative des forêts, Colloque DGRST (Strasbourg, 19-21 Octobre 1977). Oecologia Plantarum 14(3): 289-312. Oldeman, R.A.A.1990. Forests: Elements of Silvology, Springer, Heidelberg. Oldeman, R.A.A. 1992. La forêt de la Sihl: nostalgie u avenir? Lecture Stadtfortamt Zürich for visiting French foresters, Oct. 1992. Handout, 6 pp. Oldeman, R.A.A. 2001. Arbres, architecture, évolution. In: Labrecque M., L’arbre 2000, IQ, Collectif Institut de Recher- che en Biologie Végétale (4e Colloque international sur l’arbre, Montréal, 20–25 Août 2000), 2001, p. 364-374. Rossignol, M., Rossignol, L., Oldeman, R.A.A. and Benzine-Tizroutine, S. 1998. Struggle of Life, or The Natural History of Stress and Adaptation, Treemail Treebook1, Heelsum. Walter, J.M.N. 1982. Architectural profiles of flood-forests in Alsace. In: Dierschke K. (coord.). Struktur und Dynamik von Wäldern (Rinteln 13-16 Avril 1981), J. Cramer, Vaduz. Pp.187-234. Walter, J.M.N. 1993. Canopy geometry and the interception of PAR in a temperate deciduous forest: an interpretation of hemispherical photographs. In: Varlet-Grancher C, Bonhomme R. and Sinoquet H. (coord.). Crop structure and light microclimate, INRA Editions, Science Update, Paris. Pp.373-384. Walter, J.M.N. and Torquebiau, E.F. 1997. The geometry of the canopy of a dipterocarp rain forest in Sumatra. Agricul- tural and Forest Meteorogoly 85: 99-115. Walter, J.M.N. and Torquebiau, E.F. 2000. The computation of forest leaf area index on slope using fish-eye sensors. Comptes Rendus de l’Académie des Sciences, Paris, Sciences de la Vie 323: 801-813. Walter, J.M.N., Fournier, R.A., Soudani, K. & Meyer, E. 2003. Integrating clumping effects in forest canopy structure: an assessment through hemispherical photographs. Canadian Journal of remote sensing 29 (3): 388-410

123 Aanmoediging

Martijn Weterings & Suzanne Schonck Studenten tropische ecologie Duyvekotstraat 13 5066 BP Moergestel

In deze maatschappij te leven, waar geld en macht vooraan staan, met financiële groei als streven, waar bomen, dieren ten onder gaan.

In deze maatschappij te leven, waar men heel graag veel bezit, en nemen makkelijker is dan geven, waar ieder op zijn eiland zit.

In deze maatschappij te leven, te voldoen aan wat men verwacht, je niet in ‘extremen’ te begeven, is vaak moeilijker dan ik dacht.

Maar als ik er over nadenk nu, dan vind ik het leven fijn, Met aanmoediging van mensen als U, behoud ik mijn ideeën, mijn zijn.

124 Prof. Dr. Ir. R.A.A. Oldeman; personal reflections on a non-canonical scientist

Jan H.D. Wolf Professor Miss Dr Jakoba Ruinen Chair 'Phyllosphere Sciences' Universiteit van Amsterdam Institute for Biodiversity and Ecosystem Dynamics (IBED) Postbus 94062 1090 GB Amsterdam The Netherlands e-mail [email protected]

I shall never forget June 18th, 1993. On that day I defended my Doctor’s thesis on ‘Ecology of epiphytes and epiphyte communities in montane rain forests, Colombia’ from the pointy questions posed by Prof. Oldeman. I vividly remember a lengthy discourse by my esteemed opponent on the meaning of the word ‘canonical’ as in Canonical Correspondence Analysis, one of the techniques I had used to analyze my data. In my somewhat awkward reply I focussed on the mathematic meaning of the word as in canonical matrix. In the calm after the storm of the public defense, I realized that I had missed a great opportunity. Why hadn’t I thought to dodge the question by focussing on another meaning of the word canonical: conforming to a general rule or acceptable procedure, or orthodox? After all, wasn’t my opponent a great example of a non-canonical scientist? In his own words, he had still lived the time when ‘scientists were free to wonder and select their own subjects, ways and methods’. Addressing this topic would have given my opponent the room to express his concerns about the changing practices within the scientific community and would have given me breathing space.

We will never know for certain if the scientific freedom enjoyed by the young postwar scientist Roelof Oldeman has been crucial for the development of his ideas. That his ideas were innovative and have changed the biological landscape, however, is beyond question. He shaped the field of tree architecture, and concepts like eco-units and silvatic mosaics are engrained in modern forestry and landscape ecology. One of the reasons why Oldeman’s ideas have much impact is that they present a framework for the first step in any scientific research protocol: recognizing patterns and forms. In Oldeman’s words ‘recognizing form is one leg on which biological architectural analysis stands’ and ‘to be understood the tree must be sketched, mapped, and measured so as to calculate images rather than formulae’. But be aware: a visit to any forest is never the same again, after one has become familiar with the forms and patterns described by Oldeman and his co-workers. For example, one can not help spotting reiterations everywhere, where before only branches grew.

In view of the foregoing it is not surprising that my esteemed opponent regarded the drawings of the described epiphyte communities as the highlights in my doctoral thesis. It is my pleasure to include one as part of this liber amicorum.

Finally, his non-canonical outlook has also helped shape the newly developing field of canopy biology. The promising concept of ‘canopy farming’ as a tool for biodiversity conservation is receiving ever more attention and pilot projects are currently underway in several tropical countries.

After his retirement, I sincerely hope that in his capacity of director of the Stichting Het Kronendak, Roelof Oldeman will continue to stimulate canopy research for many years to come. I thank him for his guidance and particularly look forward to a continued cooperation with a respected friend.

125 Epiphytic vegetation in the Central Cordillera, Colombia; altitude 1980 m. (From PhD thesis Wolf, 1993; drawing G. Oostermeijer.

Acknowledgement The copyright holder of the figure “Epiphytic vegetation in the central Cordillera, Colombia”, Borntraeger Publishers (http://www.schweizerbart.de) gave its permission for reproduction.

126 127 128 129 130 Professor R.A.A. Oldeman: more than a lecturer

Dr. Ir. Irsyal Yasman PT INHUTANI I, Manggala Wanabhakti Bldg, Block VII 12th fl., Senayan – Jakarta 10270 INDONESIA

My first meeting with Professor R.A.A. Oldeman in 1987 took place when he came with a “small project” for East Kalimantan from The Netherlands to Indonesia. This grew out to a Cooperative Research Project of Wageningen Agriculture University, Ministry of Forestry, PT Inhutani I and PT Inhutani II at Wanariset I Samboja, and a site of Tropenbos was established through the Kalimantan Project in Indonesia. It was my good friend Dr. Willie Smits who first introduced me to Professor Oldeman when he supervised the project that had a wide impact for further research concerning Dipterocarpaceae in Indonesia. And that for such a tiny project.

Professor Oldeman is a friendly and pleasant person almost to everybody who knows him and has been working with him in the field. Working with such an experienced professor in the forest brought a lot of challenges, especially for young researchers who were motivated by him to keep studying in order to understand all those mysteries of Wanariset research forest. He tried to explain the Kalimantan forest phenomenon based on his long-term experiences in Latin American and European forests. Discussions we had along the journeys often resulted in new ideas on how we could design research for the Dipterocarp forest. When everybody in the team started to get exhausted, the professor made such funny scientific jokes that excitement on what we worked on came back. We finally realized that he truly is a professor with such abundant field experiences and such deep concerns about humanity. Many colleagues of mine, either Indonesian or of other nationalities, have confirmed the outstanding qualities of our professor.

He also has a clear vision on the future of forestry. Once he made a comment, when visiting a forest plantation newly promoted by the government of Indonesia. The comment later turned out to be completely true. During his visit, a hot topic in forest plantation establishment was discussed: is it desirable for the tropical forest to use an exotic species to Kalimantan like Acacia mangium Wild.? Instead of taking a definite stand in the exotics issue, he told us not to look at what we planted at that time when it had not yielded yet, but that instead we should imagine what would be on the place after ten or fifteen years. That formula stimulated us to establish plantations, thinking of the future benefits the timber estates would bring. Currently, Acacia mangium has been recognized as a very important species for forest plantations in Indonesia, and its wood is used not only in pulp and paper industries but also for furniture industries with their own market.

In his field of expertise, Professor Oldeman has an excellent reputation. His thoughts and concepts have been referred to by many people in their writings. To understand those thoughts and theories required dedication. Often more than one reading was necessary to understand his articles, and this is confirmed by all my colleagues. Professor Oldeman coined many useful terms. Examples are the terms of ‘Eco-unit’ and ‘Mosaic’ discussed in his book titled: “Forests: elements of SYLVOLOGY”, or the term ‘temperament’ as referred to plant character and behavior. He had the gift to simplify complicated explanations to his students by using spontaneous illustrations and examples.

Professor Oldeman has a very special personality which has allowed him to build extensive relationships with many students from many nations. He opened networking and communication in a simple and very impressive way, indeed. When he scheduled meetings in his agenda, he always looked for opportunities to introduce one student to another. This often proved very useful and promoted new networking among the students from different countries. His initiatives and roles in the establishment of international foundations such as Tropenbos, Hutan Lestari International and others, showed his eagerness and capacity to open networking opportunities

131 between scientific workers.

I also would like to forward some comments on some issues which are not directly related to his expertise, but which left me truly impressed. I still remember when I went to The Netherlands for the first time and had to arrange a meeting with him. My friends told me that if I wanted to be for sure that the professor was in his room at ‘Hinkeloord’ (the name of the Forestry Department Building at Wageningen Agricultural University), I just had to recognize the typical cigar smell. Another thing which also impressed me, was that he often offered me a cup of strong black coffee made by himself before scientific discussion started. He scheduled meetings usually in the afternoon after lunch, at a time later than most Dutch because of his very strong French cultural traits. Prof. Oldeman likes the French culture very much, and he is really as Dutch as he is French. This is what I sensed when I followed a presentation given by Prof. Oldeman in a seminar in 1991 at Montpelier, where he used a very attractive and theatrical French language and style.

The professor also likes to study language and culture from the countries he has visited. This helps him to ‘break the ice’ in discussions and talks with people. In Indonesia he pronounced perfectly the terms “Bir Botol Besar” and “Bir Botol Kecil”, meaning Big Bottle of Beer and Small Bottle of Beer. He used these terms whenever he went to restaurants in Indonesia. There were so many other words he learned, just to please people and make them feel comfortable.

Many of the things I have learned, I learned them from him. As time goes by, the professor is now entering his pension. But I am sure his contributions to the world of science will stand forever. From the first time we met and established friendship until his supervision of my dissertation, I have come to think that his role is more than that of a lecturer, who teaches sciences to his students: he showed so many things that probably can’t be formally learned.

Jakarta, November 2002 Dr Ir. Irsyal Yasman Director PT INHUTANI I

132 133 134