Institute of Silviculture A Literature and Interview Based Approach to Identify Less Known Understory Species for the Enrichment of Different Shade Stages of Agroforestry Systems in Panama Master’s Thesis at the Institute of Silviculture, Technische Universität München Submitted by Ludgera Ewers Freising, 24 January 2013 1st Examiner: Prof. Dr. Dr. Michael Weber 2nd Examiner: Dr. Bernd Stimm Supervisor: Dipl.-Ing. silv. Carola Paul _____________________________________________________________________Acknowledgements Acknowledgements There are several persons who contributed to this Master’s Thesis in one or another way which I would like to thank sincerely: Prof. Dr. Dr. Weber of the Institute of Silviculture at Technische Universität München for offering the supervision of the thesis and accepting the topic. Dr. Stimm for agreeing to be the second examiner. The company Forest Finance for financial support, the provision of valuable contacts and the very friendly assistance in Panama. The experts for taking their time to patiently answer the detailed question- naire and thereby providing crucial information for the investigation. Friends in Panama and different countries in the world for helping me out with translations and corrections, especially Fernando Lopez, Yariv Kav, Johanna Schmid-Lindner, María Isabel Paredes Saénz, Andrea Ewers and Therese Hertel. My family for mental and financial support. Special thanks to Dipl.-Ing. silv. Carola Paul for feedback, input and ideas, motivating words and generally for the very committed, professional yet per- sonal supervision of this thesis. iii iv ________________________________________________________________________Abstract- English Abstract - English The increasing world population and rising living standards demand more agricultural areas for food and energy production, because existing agricultu- ral areas are not sufficient anymore while at the same time land is degraded at an accelerating rate. The need to diminish climate change and secure biodiversity as well as the shift to renewable resources requires a reduction of deforestation and the facilitation of reforestation and restoration. Agro- forestry systems can contribute to both aspects, as trees and understory plant species and/or livestock are grown simultaneously. Therefore it is sug- gested to be a promising and sustainable alternative to common and wide- spread agricultural monocultures. However, one obstacle which keeps small- scale farmers from implementing agroforestry systems on their fields is the fact that with an increasing canopy closure trees do not permit the growth of most staple food crops (e.g. Maize, Beans, Yucca or Rice), because they need full sun. Therefore they are only suitable for the first years of an agro- forestry system in the tropics. The Institute of Silviculture of Technische Uni- versität München has been conducting a research project in the Eastern part of Panama, where valuable native timber tree species have been combined with common local staple food crops like Maize, Beans, Yucca and Rice dur- ing the establishment phase of an agroforestry system. However, so far there are no systems which systematically include economically valuable shade tolerant plant species for later stages of the agroforestry system. For this reason local small-scale farmers in the tropics are usually not motivated to grow trees in a systematic way apart from fruit trees or shelter-trees for live- stock which they include to a small extent. They are lacking financial returns from agricultural crops when trees produce shade. A closed cycle of understory plant species for different shade conditions will enable local small-scale farmers to generate income at any time of the agro- forestry system and thereby may encourage them to systematically include trees on their fields. Given their number small-scale farmers bear a great potential for fostering reforestation and reducing deforestation. Therefore this study aims at identi- fying shade tolerant understory plant species known in Panama that might be suitable for different designed shade stages of an agroforestry system. It was meant to be a theoretical baseline study and thus excluded practical trials. A triangulation was chosen as the methodological approach which consists of literature research, elaboration and application of a criteria checklist to nu- v ________________________________________________________________________Abstract- English merically assess plant species for their theoretical appropriateness, as well as expert interviews. It was suggested that the needed information could be found best in different, partly unpublished sources which were most success- fully accessed by this methodological approach. In order to allow a systematic search for suitable plant species four different shade stages of agroforestry systems in Panama were determined. These stages are 1) full sun, when tree species are only small seedlings which do not produce any shade, 2) 20 - 30% of shade when trees reach a height of about 2 - 3 meters, 3) 50 - 60% of shade with trees of about 7 m and 4) a closed canopy with hardly direct sunlight reaching the understory. This will be the case when the trees reach their final height and di- ameter of the canopy. The literature review resulted in a pre-selection of six possibly suitable un- derstory plant species. In order to include different kinds of experts in the investigation, 23 Panamanian and international experts were divided into four expert groups: local practitioners (mainly farmers), employees of Pana- manian governmental institutions, scientists as well as non-local practition- ers. They were interviewed for their feedback regarding the preselected plant species, as well as for recommendations of further plant species for the four designated shade stages. In total 104 different plant species were analyzed for their potential suitability, out of which 100 were recommended in expert interviews. 86 had to be neg- lected due to different reasons, e.g. because they were exotic to Panama, invasive or toxic. 18 plant species were analyzed in more detail, because they were considered appropriate for Panama, which were: Noni (Morinda citrifolia), Arazá (Eugenia stipitata McVaugh), Borojó (Borojoa patinoi Cu- atrec), Ginger (Zingiber officinale), Cananga (Cananga odorata), Cat’s Claw (Uncaria guianensis), Aloe Vera (Aloe Vera Auth), Cayenne Pepper (Capsi- cum frutescens), Panama Hat Palm (Carludovica palmata), Ipecac (Cepha- elis ipecacuanha), Abuta (Cissampelos pareira L.), Coriander (Coriandrum sativum), Caña Agria (Costus scaber), Lemon Grass (Cymbopogon citratus), Garlicvine (Mansoa alliacea), Bitter Melon (Momordica charantia L.), Orchids (Orchidaceae spp.), Guaraná (Paullinia cupana) and Vanilla (Vanillia plani- folia). vi ________________________________________________________________________Abstract- English According to the applied criteria checklist the best performing plant species were Ginger (Zingiber officinale), Cananga (Cananga odorata), Coriander (Coriandrum sativum), Garlicvine (Mansoa alliacea) and the Panama Hat Palm (Carludovica palmata). When considering the different shade stages separately, the species that are suggested most appropriate are for stage 1) • Ginger (Zingiber officinale), • Cananga (Cananga odorata) and • Lemon Grass (Cymbopogon citratus), for stage 2) • Ginger (Zingiber officinale), • Cananga (Cananga odorata) and • Coriander (Coriandrum sativum), for stage 3) • Cananga (Cananga odorata), • the Panama Hat Palm (Carludovica palmata) and • Garlicvine (Mansoa alliacea), and for stage 4) • the Panama Hat Palm (Carludovica palmata), • Caña Agria (Costus scaber) and • Ipecac (Cephaelis ipecacuanha). Further investigation in practical trials will be needed in order to assess the species’ practical suitability for agroforestry systems in Panama, to determine best tree/understory combinations and densities, and especially in order to obtain economic data so that the profitability of the scenarios can be evalu- ated. The chosen method appears to be appropriate for the set goal, but it did not allow for feedback by experts regarding those plant species which were rec- ommended in the interviews. Therefore especially local practitioners shall be consulted once again and asked for their feedback regarding these plant species in question before conducting practical trials. vii viii ______________________________________________________________________Abstracto- Español Abstracto - Español La creciente población mundial y el incremento del nivel de vida de las per- sonas exigen más áreas agrícolas para la alimentación y la producción de energía, pues los campos existentes ya no son suficientes y la tierra se de- grada a un ritmo acelerado. La necesidad de reducir el cambio climático, asegurar la biodiversidad y el cambio hacia fuentes renovables de energía, requieren reducir la deforestación y facilitar la reforestación y la restauración. Los sistemas agroforestales pueden contribuir a ambos aspectos, pues árbo- les, plantas y animales del sotobosque crecen a la par. Por lo tanto, se su- giere que es una alternativa prometedora y sostenible frente a los monoculti- vos agrícolas comunes y generalizados. Sin embargo, un obstáculo que de- tiene a los pequeños agricultores en la implementación de sistemas agrofo- restales en sus campos es el hecho de que con un aumento de los árboles de cierre del dosel se impide el crecimiento de la mayoría de cultivos de ali- mentos básicos (por ejemplo, maíz, frijoles,