Research towards the restoration of northern Thailand's degraded forests

Throughout northern Thailand, large areas of land within national parks and wildlife sanctuaries are deforested or degraded and require reforestation. Within such protected areas, where the primary objectives are conservation of biodiversity and watershed protection, reforestation should aim to recreate the original forest ecosystems. Recently, many community groups have organized tree plant events to restore forests to about 8,000 sq km degraded land, to mark the golden jubilee of His Majesty King Bhumibol Adulyadej. However, such tree planting projects are often constrained by lack of knowledge of the habitat requirements of the several hundred native tree species being used. Knowledge of how to germinate the seeds and raise healthy seedlings is also limited and there is no identification manual for tree seedlings.

The Forest Restoration Research Unit (FORRU), a joint initiative between the Royal Forest Department and Chiang Mai University, with sponsorship from Riche Monde (Bangkok) Ltd., was established in November 1994 to determine the most effective methods to complement and accelerate natural forest regeneration in deforested areas, to increase biodiversity and protect watersheds. Its objectives are: 1) to develop tools for studying the restoration of natural forest ecosystems, such as a seedling identification handbook, seedling herbarium and databases of seed, fruit and seedling morphology; 2) to determine how the ecological processes of natural forest regeneration might be accelerated; 3) to identify which tree species are suitable for planting to complement natural seedling establishment; 4) to develop appropriate methods to propagate such tree species and carry out experimental planting trials and 5) to teach interested groups about appropriate forest restoration techniques.

Current research at FORRU includes a study of the fruiting phenology of 94 tree species to provide information on the seasonal availability of seeds for planting. Fruit and seed characteristics are entered into a computer database to enable correlation between seed characteristics and germination success. More than 200 tree species have been tested for germination in partial and deep shade, to determine which might be suitable for planting in the hot, partially shaded conditions found in deforested gaps. One of the major tasks of FORRU is to photograph, draw and describe seedlings at all stages of development to compile a seedling identification guide. Seedling planting trials are being carried out to determine the performance of a wide range of native forest tree species under various conditions. Some preliminary results on phenology, seed germination and seedling performance in a deforested gap are presented. Initial results indicate that several primary forest tree species can grow well in gaps and that planting them would not only increase the biodiversity of regenerating forest, but also accelerate forest succession.