Tree Domestication of Indigenous Trees: Experiences, Lessons and Directions

0680-B1

E.L. Tolentino Jr.^[1], M.N.P. Bandian, R.E. Lorida, M.L. Dapdapig and P.V. Quilao

Abstract

A tree domestication trial involving 20 different indigenous tree species was initiated in the Sierra Madre Mountain, Luzon Island, Philippines. Species were prioritized through an ethnobotanical survey. Germination ranged from 0 to 90%. Dormancy was suspected in 12 species while two species exhibited high and rapid germination. Seedlings were grown in polyethylene bags (12.7cm x 20.32 cm) using topsoil or topsoil + chicken manure (10:1 ratio by volume) substrate. Two species were considered relatively fast growing, while most of the species tested were either slow to moderately growing. No serious pest or disease was observed in the nursery. Seedlings were planted in logged and inadequately stocked forest. Survival ranged from 60 to 100%. Lessons gained from the domestication trials were discussed. Future directions for improvement of the program particularly in improving farmers’ conditions were proposed.

Introduction

There are about 50-60,000 plant species in the plant kingdom and approximately 3,000 of these are used in agroforestry farms (Simons & Weber 1999). Exploring the vast plant kingdom for trees with potential uses for timber, food, fruit, fuel, fiber, fodder and other uses is a unique and exciting challenge in this era of rapid natural resource depletion.

Tree domestication manifests a paradigm shift in sustainable agroforestry systems. The active participation of farmers in the project continuum of planning, research, implementation, monitoring and evaluation differentiates it from the traditional “researcher-driven” models. The process is also complemented by the market demand for the product(s). This paper examines a tree domestication trial in the logged-over forests of the Sierra Madre Mountains Luzon Island, Philippines. Specifically, it described how the long-list of potential indigenous tree species (ITS) was short-listed and prioritized. Subsequently, the seed, nursery and plantation practices for these less-used but potentially valuable species were developed. Finally, important lessons and directions of the tree domestication trials were identified.

Materials and Methods

Site Description

The trials were conducted in the two land grants (LGs) of the University of the Philippines (UP): the Laguna-Quezon (LQLG) and the Laguna (LLG) Land Grants. The two land grants are found in the Sierra Madre Mountain Range, Luzon Island, Philippines with an area of 10,000 ha. Legitimate logging operations started in the 60s and ended in 1989. Unfortunately, local residents continued to illegally extract timber, make charcoal and gather other forest products (poles, rattan, wildlife). Shifting cultivation is also a problem.

The area characterized by the absence of a dry season with pronounced maximum rainfall period from October to December. Average total rainfall is approximately 4,000 mm. Approximately two (2) typhoons cut across directly in the area every year.

LQLG has a generally rugged terrain with an elevation ranging from 85 to 560 m asl. The current major landuses are: forested, cultivated and grasslands. The forested area is mainly composed of residual forests with trees mainly belonging to the lower diameter classes (10-30 cm). Soils are classified as Antipolo, Luisiana and Macolod clay series which are very acidic and with low nutrient contents.

The terrain in LLG is generally rolling to moderately rugged. The mean elevation is 360 asl and the highest elevation is 520 m asl. Current land use is similar to LQLG. Forest landuse dominates the area and is classified as residual forests with very few big commercial trees remaining. Soil at LLG is of the Luisiana clay series and is very acidic with poor nutrient status. In both areas, access is very poor (UPLB 1997).

Species Prioritization

A series of informal meetings were held with shifting cultivators and illegal loggers. Sixty-one indigenous tree species were identified. Preference was ranked based on utility and marked value. Only species with sufficient germplasm were included in the field trials.

Seed, Nursery and Plantation Studies

Local knowledge system of the community provided basis for the cultural practices. This was complemented by the observations of the natural growing habits of the species under consideration. Seed collection dates were determined from the knowledge of local people and through regular observations by the forest guards patrolling the area. Most of the collections were ground collections. Seed processing mainly involved pulp removal or drying of dehiscent fruits. Seeds were sown in black polyethylene bags (12.7cm x 20.32 cm) using topsoil or topsoil + chicken manure (10:1 ratio by volume) substrate. Seedlings were raised up to 12 months.

Results and Discussion

Species Selection

The trial veered away from the usual practice of planting exotics. Instead, the trees native to the LGs were considered for the tree domestication trials. Rigorous priority setting requires understanding of user needs and preferences, technological opportunities and systematic methods for ranking species (Jaenicke et al., 1995). A species priority-setting scheme was recently developed (Franzel et al., 1996). The 7-stage system involves long listing and consecutively reducing the number of species through a participatory method. In this study, it was slightly modified. The consultative meetings and informal discussions with upland farmers and illegal loggers yielded a long list of 61 species. Tree species preferred by these people were based on utility (e.g. lumber, furniture, handicrafts, medicine and food) and market value. Only the species with sufficient seeds were included in the trial. Currently, there are about 20 species used in the trials.

The results revealed that species preference by upland farmers is based on the utility of the tree or its market value. This thinking could have been influenced by the previous logging operations in the area, which have shaped the minds of the local people that the forest is mainly for production purposes, e.g. timber. None of the respondents valued the trees for conservation purposes.

A problem encountered in the study is the use of local names for the species causing problems in the actual identification of the trees, e.g. dipterocarps^[2].

Seed technology

Most of the seeds used for the trial were collected from natural seed fall. This resulted in a higher incidence of decayed seeds. The small volume of the fruits/seeds collected did not require the use of special equipment for processing and cleaning. Most of the processing procedures were manually performed with the aid of water particularly for species with fleshy fruits (e.g. Litsea leytensis) or fruit drying.

Dormancy was observed in several species (Table 1). Germination in these species is either low (3-70%) and/or with germination periods lasting for 28 to 97 days. Only two species exhibited a relatively high percent germination achieved in 14 days: namely Dysoxylum altissimo (90%) and Calophyllum glabrum (76%). The presence of dormancy in most of these species has important implications on the soil seed bank. Continuous natural regeneration is highly possible. Additionally, the findings indicate the need to determine treatments to hasten the germination of these species.

Table 1. Germination performance of selected indigenous tree species at the LGs.

Nursery Studies

All the seeds were directly sown in pots. Slow seedling growth was observed in five (5) species (Table 2). The slowest among the species tested, Litsea leytensis reached only an average height of 1.2 cm in 4 months. On the other hand, Syzygium nitidum, was rated as fast growing after it reached an average height of 17 cm in two months (Table 2). The infestation by a larva could be a reason for the slow growth but improved cultural treatments could possibly increase growth.

Seedling pest and disease was not very serious, in fact, the two species of Syzygium which was reportedly attacked were able to recover even without the application of insecticides (Table 2). This observation is another evidence that indigenous species are more resistant to the potential infestation or infection compared to their exotic counterparts.

Most of the tested species are shade demanding. Only Syzygium nitidum and Aglaia luzionensis could survive without shade in the nursery. Since most of the ITS are climax species such light requirement is obvious.

Alternative soil substrate could be investigated since the topsoil available in the LGs is highly acidic (pH 4.5). This could probably explain some of the observed slow growth performance of some seedlings. The study was not able to verify if indeed the acidic soil was the causal factor for the poor performance of some species.

Table 2. Growth performance or requirements of selected indigenous tree species in the LG nursery.

Tree Management

Average survival rate ranged from 60 to 100%. The vines strangling the seedlings are the main source of mortality. Teijsmaniodendron ahernianum showed the fastest height and diameter growth. Average monthly height increment is approximately 6.3 cm. Diameter is similarly the highest (2.6 cm) in two years. Sandoricum sp. is second with an average monthly height increment of 5.6 cm. Castanopsis philippinensis averaged 4.3 cm height increase in 34 months. Another species, Dysoxylum altissimum, averaged 3 cm in height per month. Four other species has monthly height increment of more than 2 cm. Another four have increments less than 2 cm. Litsea leytensis averaged only 0.8 cm per month (Table 3). This was consistent with the nursery performance of the species confirming that the species is slow growing.

The findings address the criticism that ITS are slow growing. Obviously, not all ITS are slow growing, and with better silvicultural treatments and site conditions, performance could have been much better.

Table 3. Height and diameter growth performance of selected tree species at the UP LGs.

Lessons Learned

The tree domestication trial yielded some important lessons critical to its success. Below is a discussion of the lessons that could be useful for similar tree domestication projects.

Germplasm availability. This is a limiting factor in the large-scale use of these indigenous tree species. The previous logging operations and the continuous illegal logging activities have eliminated considerable number of mother trees in the LGs. Germplasm sources are limited. Further, logging operations are dysgenic in nature since the best trees are frequently harvested.

The study identifies the potential role of asexual propagation in complementing the germplasm requirements of ITS plantations. The common pitfall with most reforestation programs in the Philippines is that when confronted with the inadequate germplasm situation, management becomes predisposed to select exotics which have abundant seed sources.

Indigenous Knowledge System(IKS). This has been the rich source of basic information in the seed source, propagation and tree management of the ITS. In fact, it was confirmed that what may be lacking in the libraries was available in the hearts and minds of the local people who have known, used and valued these species as part of their culture and way of life. The people knew the uses and marketability of the species. They know the best trees in terms of durability, hardness and strength. In addition to their utility, local people are also familiar with the seed germination, grow habits (open or shaded) and growth rates (fast or slow growing) of ITS. The study confirmed that IKS should always be considered when reforestation and agroforestry projects are planned and implemented in upland communities.

Biodiversity and Genetic Resources Conservation. Tree domestication that focuses on indigenous tree species is an essential approach to biodiversity and genetic resources conservation. The planting of these tree species in ecosystems that they normally inhabit will support an "ecosystems" approach to biodiversity conservation. In fact, the overuse of exotic could be perilous for the existence of native species, whether flora or fauna.

Implication to Reforestation and Agroforestry Programs. Tree domestication offers farmers, foresters and researchers with a manifold list of species for food, wood, fuel and other uses. The planting of ITS not only promotes biodiversity but becomes a buffer for the abrupt changes in the wood market demand and environmental conditions. These indigenous tree species are generally adaptable to the selected site thereby obviating the need for intensive studies on site-species adaptability. Some of ITS are potentially fast growing. Resistance to pest and diseases is another desirable feature of domesticated indigenous trees. Consequently, lower maintenance and protection costs are incurred.

Implications to Community Forestry. Growing tree species familiar and valuable to the community insures the active participation of local communities in upland development. Instead of strategizing technology transfer schemes for community forestry, the community becomes the source of the technology to be used in the project. This does not only reduce project costs but also reinforces the goal of participatory approach in upland development.

Future Directions

To insure the continued success of tree domestication, the following proposals are suggested.

(1) Complete implementation of the community-based forest management program. It was observed that farmers really care for lands and trees that they know are "theirs". Secure land tenure results in effective upland natural resources management.

(2) Institution of on-farm trials. Participatory researches on the various aspects of tree domestication should be instituted for interested farmers preferably in steward managed farms. Farmers-stewards are enthusiastic in researching technologies or analyzing problems that will improve or innovate their farm practices.

(3) Identification of alternative germplasm sources. Alternative sources of germplasm should be identified. This will not only insure adequate quantity of planting stocks but also maintain appropriate genetic diversity. This should include the use of vegetatively propagated planting stocks.

(4) Screening of fast growing species. To burst the "fast-growing" myth of exotics, fast growing indigenous species have to be properly identified. From this study, four species are potentially fast growing. There were claims of fast growth of other ITS, but the absence of germplasm has prevented the inclusion of these species in this study.

(5) Product testing. Testing for the identified uses of the trees should be done to determine their actual suitability, serviceability, durability and other desirable properties for its intended use.

Conclusions

Tree domestication offers a myriad of options for a revitalized reforestation and agroforestry programs. It could also have potential impacts on biodiversity and genetic resources conservation, and community forestry. The Land Grant experience affirmed that indigenous knowledge system is a rich repository of information on natural resources management. The absence of formal scientific literature need not be a limiting factor for the use of indigenous tree species. The study has proven that local people are "scientists in a special way". However, common sense and basic forestry science principles will have to be employed to bridge information gaps. Tree domestication programs will also be successful if participatory approach is adopted. This is not only in conducting on-farm trials but more importantly in providing secure land tenure for the upland farmers. Lastly, tree domestication will certainly be critical in addressing the tree species needs of farmers for improved upland cultivation and better quality of life.

References

Franzel, S., Jaenicke, H. & Janssen, W. 1996. Choose the right tree species: Setting priorities for multipurpose tree improvement. ISNAR Research Report No. 8. The Hague, 87 pp.

Jaenicke H., Franzel, S. and Boland, D. 1995. Towards a method to set priorities amongst multipurpose trees for improvement activities: a case study from West Africa. Jour of Trop For Sci 7:490-506.

Simons, A. and Weber, J. 1999. Concepts and principles of tree domestication. Lecture material used for the Training Workshop on Tree Domestication 8-13 November, 1999. ICRAF, Nairobi, Kenya.

Tolentino, E. L. 2000. The paradigm shift in silviculture: indigenous tree species. Second Lecture for the Mr. and Mrs. Guillermo Ponce Professorial Chair Lecture in Silviculture and Forest Influences delivered at the Operations Room Tamesis Hall, College of Forestry & Natural Resources, University of the Philippines Los Baños on June 23, 2000.

Tolentino, E.L., Carandang, W.M. and Roshetko, J.N. 2002. “Selection of Agroforestry Tree Species: Domestication of Indigenous Tree Species”. Paper presented in the National Symposium on Forestation Research and Practices. April 16, 2002, College of Forestry and Natural Resources, UP Los Baños, College, Laguna.

University of the Philippines Los Baños. 1997. UP’s Environmental Heritage for the 21st Century”: The Laguna-Quezon and Laguna Land Grants Master Plan. 150 pp.