Deutscher Tropentag 2003 International Research on Food Security, Natural Resource Management and Rural Development Technological and Institutional Innovations for Sustainable Rural Development Georg-August-University Goettingen, October 8 - 10, 2003

A STUDY ON DIVERSITY IN ASSOCIATION WITH VARIABILITY OF IRONWOOD (Eusideroxylon zwageri T. et B.) IN JAMBI,

Bambang Irawan1 and Franz Gruber2 1 Agriculture Faculty Jambi University – Indonesia and a Ph.D candidate at Forest Botany Institute, Goettingen University – Germany. Email: [email protected] 2 Forest Botany Institute, Goettingen University – Germany

Abstract A study on tree diversity in association with variability of ironwood has been conducted at Senami forest stand in Jambi, Indonesia. Senami is one of natural forest stand that dominated by ironwood (Eusideroxylon zwageri T. et B.) species. The researches have been conducted from October 2002 to November 2002 using systematic plot sampling. The field research found that ironwood grows associatively with more than a hundred tree species. At tree stage, species number that were recorded are 99. At pole stage, ironwood grows associatively with 90 species. At sapling stage, it grows with 125 species while at seedling stage ironwood grows with 92 species. The most important species for wood production are Eusideroxylon zwageri, Palaquium hasseltii, Litsea spp., Ochanostachys amentacea, and Shorea spp. All of the species belong to 28 families. The most dominant families are Lauraceae followed by Moraceae, Euphorbiacea, Anacardiaceae, Caesalpinaceae and Burseraceae. The study also revealed that each ironwood variety grows in some small clusters. It can be found in about 68 % of forest area. The alternatives of cluster composition of ironwood variety are daging, kapur and sirap (4.69 %), daging and sirap (9.38%), and sirap and tanduk (4.69%). Sirap is the variety that able to form cluster with any other varieties. The Sørensen coefficient index between ironwood communities obtained that the most similar communities are the communities of daging and sirap with index of 0.792, followed by daging and kapur (0.569), sirap and tanduk (0.497), kapur and sirap (0.488), daging and tanduk (0.478), and kapur and tanduk (0.364).

Keywords: ironwood, tree diversity, variability

1. Introduction The lowland rain forests of support 111 dipterocarp species, including six endemics. The emergent , which can reach 70 m tall, are also dipterocarps (Dipterocarpus spp., Parashorea spp., Shorea spp., Dryobalanops spp.) and, to a lesser extent, species in the Caesalpiniaceae family (Koompasia spp., Sindora spp., and Dialium spp.). Dipterocarps dominate

1 Deutscher Tropentag 2003 International Research on Food Security, Natural Resource Management and Rural Development Technological and Institutional Innovations for Sustainable Rural Development Georg-August-University Goettingen, October 8 - 10, 2003 the canopy layer as well. Other canopy and understory tree families that are common include Burseraceae, Sapotaceae, Euphorbiacae, Rubiaceae, Annonaceae, Lauraceae, and Myristicaceae. Sumatra once contained pure stands of ironwood forests (Whitten et al. 2000). Jambi is one of 32 provinces in Indonesia which is situated in the southern part of Sumatra. It is geographically located between 0° 45′ and 2° 25′ latitude South and 101° 10′ and 104°55′ longitude East. It is bordered by Riau province in the North, Berhala gulf in the East, South Sumatra in the South and West Sumatra in the West (Anonymous, 1997). According to Governor of Jambi’s decree No. 108, 1999, the forest area in Jambi province is 2,179,440 ha (42.73% of the total land area). 870,250 ha of this is protection forest (17% of land area) and about 1,320,700 ha production forest (25.67% of total area). In the past ironwood grew at almost every part of Jambi forest except in Kerinci District but due to over exploitation, nowadays, this species can be found only in some forest areas such as Senami forest, Sengkati, Durian luncuk and some areas in Merangin, Sarolangun, Bungo and Tebo Districts. Local people recognized four varieties of ironwood namely daging, kapur, sirap and tanduk (see Irawan and Gruber, 2002). However, there is no further information on the ironwood’s variety distribution and their association with other tree species in natural forest. The study has been conducted to obtained this information since it is useful for future management of ironwood. 2. Research methods 2.1. Time and study site The field research has been conducted from October 2002 to November 2002 at Senami natural forest stand Jambi - Indonesia. Senami forest stand is located at Tembesi resort forest on Batanghari district forest in provincial forestry service of Jambi. Field condition of Senami forest is flat to undulate with elevation of 0 – 5 %. According to Schmidt and Fergusson (1951) The climate is type A with annual precipitation of 2662 mm. Senami forest is dominated by ironwood associatively with medang (Litsea sp.) and balam (Palaquium sp.). 2.2. Materials and Methods The materials that were used were forest stand and samples of trees and seedlings. While, the instruments were compass, GPS (Geographical Positioning Systems), Camera, rope and stationery. The research has been conducted using systematic plot survey. The size of sample plot is 20 m 20 m for tree, 10 m x 10 m for pole, 5 m x 5 m for sapling and 2 m x 2 m for seedling observation. Each variety of ironwood was noted according the investigation results. The variety

2 Deutscher Tropentag 2003 International Research on Food Security, Natural Resource Management and Rural Development Technological and Institutional Innovations for Sustainable Rural Development Georg-August-University Goettingen, October 8 - 10, 2003 of ironwood was recognized based on experience and knowledge of local people and verified by comparing to other morphological structures (see Heyne 1927; De Wit, 1949; Kostermans et al., 1994; Irawan and Gruber, 2002).

2.3. Statistical analysis Species Important Value (SIV) and Family Important Value (FIV) were calculated from the formula below according to Curtis and McIntosh (1950,1951) and Mori et al. (1983) respectively. Relative frequency Number of sample units containing a species = X 100 Sample units for all species Relative density Number of individuals of a species = X 100 Number of individuals of the sample Relative dominance Basal area of a species = X 100 Total basal area of the sample

SIV = Relative frequency + Relative density + Relative dominance Relative diversity Number of species of a family = X 100 Total number of species of the sample Relative density Number of individuals of a family = X 100 Total number of individuals of the sample Relative dominance Basal area of a family = X 100 Total basal area of the sample FIV = Relative diversity + Relative density + Relative dominance

To obtain similarity between communities of each ironwood variety based on species composition, Sørensen coefficient index is used. The formula is as follows (Sørensen, 1948): 2 X number of shared species Sørensen coefficient = Species of community 1 + species of community 2

3 Deutscher Tropentag 2003 International Research on Food Security, Natural Resource Management and Rural Development Technological and Institutional Innovations for Sustainable Rural Development Georg-August-University Goettingen, October 8 - 10, 2003

3. Results and discussions 3.1. Species richness The field research found that ironwood grows associatively with more than a hundred tree species. Species number that were recorded are 99 species of trees, 90 species of poles 125 species of saplings and 92 species of seedlings From those number of species only some species that economically important for wood production namely Eusideroxylon zwageri, Palaquim sp., Dyera costulata, Litsea sp., Shorea sp., Hopea mengarawan, Tetramerista glabra, Ochanostachys amentacea, Peronema canescens, Koompassia malaccensis.

Table 1. Economically important tree species for wood production at study site Local name Scientific name Mean diameter Mean SIV Basal area Volume (m) height (m) (m2/ha) (m3/ha) Balam Palaquium sp 0.33 21.40 9.21 0.77 12.42 Bulian Eusideroxylon zwageri 0.26 24.68 19.98 1.10 5.18 Jelutung Dyera costulata 0.33 12.0 1.16 0.09 0.72 Kacang-kacang Strombosia javanica 0.20 8.00 0.91 0.03 0.18 Keruing Dipterocarpus sp. 0.37 17.00 1.26 0.11 1.28 Medang Litsea sp 0.29 15.60 19.02 0.99 11.07 Meranti Shorea sp 0.26 24.00 6.72 0.39 6.58 Petaling Ochanostachys amentacea 0.36 19.50 7.14 0.65 8.83 Kempas Koompassia malaccensis 0.22 15.00 1.97 0.04 0.38 Sungkai Peronema canescens 0.22 16.00 1.46 0.08 0.85

Among ironwood variety, sirap variety is the most common species that followed by daging, kapur and tanduk variety. The species important index of those variety are 4.15, 1.03, 12.69 and 2.11 respectively. Total SIV for this species is 19.98. The SIV of those varieties is low because most of big trees at the study area have been felled by illegal logging (Irawan, 2002). Other researchers mentioned that the major traits to ironwood are over-exploitation, shifting cultivation, the introduction of chain saws and extensive road systems by the timber industry, selective logging, infrastructure (roads, dams, power lines etc.) especially since the 1998-1999 economic crisis (Peluso, 1992; Kostermans et al., 1994; IUCN, 2001; WWF, 2001). Even ironwood is still one of the dominant species in the study site but the number is quite different to results obtained by research that conducted at unexploited forest. Whitten et al. (2000) wrote that ironwood forest can vary from forest in which it is virtually the only species of large tree present, to forest in which it is one of many species but clearly the dominant one. An example of the former was investigated by a team from CRES in Rimbo Kulim near the river Kahidupan, Muara Tembesi in Jambi. The sample size was 0.5 ha of undisturbed forest. A total of 84 trees of 15 cm diameter at breast height were found and 81 (96%) of these were ironwood.

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Two of remainder were unidentified, and the other was a specimen of Koompasia sp. Additionally Greeser, (1919) found that ironwood, formed the main canopy of the forest. Koompasia, Shorea or Intsia were the main emergent and ironwood was a subdominant species. Some other species produce and vegetable that economically important especially for local people. Those species are Nephelium sp, Artocarpus rigida, Baccarurea crassifolia, pauciflorum,, Archidendron microflorum, and Parkia speciosa. Species that produce traditional medicine are Eurycoma longifolia, and E. zwageri. Table 2. Tree species that produce non timber forest products at the study area No Local name Scientific name Products Fruit Vegetable Medicine Others 1 Bulian Eusideroxylon zwageri v 2Durian Durio zibhetinus v 3Jelutung Dyera costulata Latex 4 Jengkol Archidendron pauciflorum v 5Kabau Archidendron microcarpum v 6 Kemang Mangifera kemanga v 7 Petai Parkia speciosa v 8 Pasak bumi Eurycoma longifolia v 9 Rambutan Nephelium sp. v 10 Tampui Baccaurea crassifolia v 11 Tempunek Artocarpus rigida v

3.2. Family richness The vegetation analysis revealed that in the study site could be found about 28 families of tree species. The dominant families at tree stage are presented in table 3. Table 3. The family of tree species that grow at the study site No Family Relative Relative density Relative Family important diversity (%) (%) dominance (%) value 1 Lauraceae 12.50 16.26 10.42 39.18 2 Moraceae 3.85 12.80 20.97 37.62 3 Euphorbiaceae 10.58 10.03 7.93 28.54 4 Anarcadiaceae 6.73 5.54 4.42 16.69 5 Caesalpinaceae 4.81 4.15 5.65 14.61 6 Burseraceae 2.89 5.89 5.75 14.50 7 Sapotaceae 3.85 3.11 3.97 10.93 8 Sterculiaceae 1.92 3.46 4.70 10.09 9 Annonaceae 2.89 3.46 3.22 9.57 10 Mimosaceae 2.89 2.77 1.47 7.12 11 Dipterocarpaceae 1.92 2.77 2.32 7.00 12 Myrtaceae 1.92 2.77 2.13 6.82 13 Myristaceae 2.89 1.04 2.33 6.25 14 Meliaceae 0.96 2.42 2.49 5.88 15 Fagaceae 0.96 2.77 1.84 5.57 16 Ulmaceae 0.96 2.08 1.32 4.36 17 Verbenaceae 1.92 1.04 0.50 3.46 18 Unidentifed Family 12.50 6.57 6.04 25.11

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Lauraceae is the most important family. It consists of some tree species that produce economically important for wood production namely E. zwageri, Litsea spp. Moraceae is the second dominant family, it consists of some pioneer species namely Artocarpus elasticus and Artocarpus rigida that produce edible fruit for local people. Euphorbiaceae is also dominated by pioneer species such as Macaranga spp. However this family also produce important wood species namely Ochanostachys amentacea and planted species that produce latex, Hevea brasilensis. Other families that produce economically important for wood production are Caesalpinaceae that consists of koompasia sp., Dipterocarpaceae that consists of Dipterocarpus spp. and Shorea spp., Sapotaceae is composed by Palaquium spp., and Verbenaceae that consists of Vitek sp. and Peronema canescens.

3.3. Ironwood distribution Table 4. Ironwood distribution and harvesting status of the sample plots No Variety Plot that obtained ironwood (%) Harvesting status 1 Daging 15.63 Destroyed 2 Kapur 9.38 Destroyed 3 Sirap 35.94 harvested to destroyed 4 Tanduk 6.25 harvested 5 No ironwood 32.81 No influence to destroyed

Table 4. shows that the sirap is the most dominant among ironwood varieties not only on density but also on the distribution across forest area. It could be found on 35.94 % out of total plots followed by daging, kapur and tanduk variety. The harvesting status of the forest area is between stand harvesting and destroyed area. Daging and kapur variety could be found on the forest area that already destroyed, sirap variety is on forest stand that already harvested to destroyed forest areas while tanduk variety could be found on stands with harvesting status of harvested. The different harvesting status of forest areas from where the ironwood variety was obtained possibly due to the ironwood variety itself. Ironwood is the main wood that harvested by local people in the study site. According to local people, tanduk is the most difficult ironwood variety to manage due to wood structure. It has interlocked grain. Most local people have used a traditional tool like a wedge to split wood into smaller pieces therefore, at the beginning they have chosen the wood that easier to utilize. It is a possible explanation why the plots where tanduk variety could be found is the only plots that are not destroyed yet.

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In the study site, ironwood grows in small cluster (see table 4) about 32 % of the study site is the forest areas where ironwood is absent. The alternatives of cluster composition of ironwood variety are daging, kapur and sirap (4.69 %), daging and sirap (9.38%), and sirap and tanduk (4.69%). Sirap is the variety that can form cluster with all other varieties. This distribution pattern tends to influence the morphological characters of ironwood varieties.

Table 5. The Sørensen coefficient index between communities and cluster formation of ironwood varieties No Communities Sørensen coefficient Cluster formation cluster formation (%) index 1 Daging-kapur 0.569 Daging +Kapur + sirap 4.69 2 Daging-sirap 0.792 Daging + sirap 9.38 3 Daging tanduk 0.478 Sirap + tanduk 4.69 4 Kapur-sirap 0.488 5 Kapur-tanduk 0.364 6 sirap-tanduk 0.497

The Sørensen coefficient index between the communities of ironwood variety is presented in table 4. The most similar communities are communities between daging and sirap with index of 0.792, followed by daging and kapur (0.569), sirap and tanduk (0.497), kapur and sirap (0.488), daging and tanduk (0.478) and kapur and tanduk (0.364). It means that daging and sirap communities are composed by 79.2 % of the same species while the lowest index is obtained by kapur and tanduk communities that have 36.4 % of the same species composition.

4. Conclusions 1. The field research found that ironwood grows associatively with more than a hundred tree species (99 species at tree stage, 90 species at pole stage, 125 species at sapling stage, and 92 species at seedling stage). 2. The species belong to 28 families. The most dominant families are Lauraceae followed by Moraceae, Euphorbiacea, Anacardiaceae, Caesalpinaceae and Burseraceae. 3. Ironwood variety grows in some small clusters. The alternatives of cluster composition of ironwood variety are daging, kapur and sirap (4.69 %), daging and sirap (9.38%), and sirap and tanduk (4.69%). Sirap is the variety that able to form cluster with any other varieties.

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