The Forest Restoration Research Unit: FORRU

Lowland Forest Restoration

FORRU has successfully carried out forest restoration, using the framework species method, in upland forests at Ban Mae Sa Mai. One of FORRU's current objectives is to determine the best techniques for the restoration of degraded lowland areas in northern Thailand, formerly covered by deciduous forests. In these areas, natural forest recovery it severely constrained by 3 major factors: 1) high fire risk, ii) presence of domestic cattle and iii) severely degraded soils.

With support from Thailand's Biodiversity Research and Training Program (BRT), FORRU has been working to optimise theframework species method to restore biodiversity in degraded deciduous forests at lowland sites. This project commenced at two sites, the Phrae Campus of Mae Jo University and Mae Ow Watershed Development Project in Lamphun Province. The site at Mae Ow was abandoned due to forest fire and cattle damage in the hot season of 2007, and experiments were tranferred to Huay Tung Tao reservoir in Chiang Mai province, where experimentation continues. Left: Site on Phrae Campus at Mae Jo University

Lowland deciduous forest tree species are different from those that have been proved to be successful framework species at higher elevations. The first and most critical step in adapting the framework species methods to any new forest type is tree species selection. Therefore, we used existing data to select candidate framework species most suited to the harsh conditions of the lowland sites. This project involves two tree nurseries, which are now growing a total of 64 tree species for testing as framework tree species. Suitable seed germination treatments are being tested and production schedules are being researched and developed to ensure that trees are ready for planting in the early rainy season.

Before tree planting, surveys were carried out to determine the initial condition of the vegetation, bird communities and soil conditions, so biodiversity levels can be compared between before and after planting. Ten rai of experimental plots were established at both Mae Jo and Mae Ow in July 2006, including planting 15 candidate framework species. An additional four rai were planted at both Mae Jo and Huay Tung Tao in June 2007, and four rai at Huay Tung Tao in June 2008, adding up to a total of 22 rai of experimental plots planted.

Germination trials were carried out to determine the most effective techniques to propagate potential framework tree species for deciduous forests. Silvicultural treatments tested included filling the planting hole with compost (right) and various fertiliser application regimes.
Monitoring results at the end of the first rainy season indicated that good survival and growth rates had been achieved. Initial indications are that more intensive treatments (compost in the planting hole and high rates of fertilizer application) are likely to achieve the best results.

By working closely with the Royal Thai Army, local NGO’s and schools, the plots at HTT are now beginning to fulfill their secondary role as educational facilities for forest restoration. The site was used a venue for the field trip of the workshop “The Future of Forest Restoration Research in Indochina” held in March 12-14th 2008. About 50 international delegates were able to observe the high growth rates. In addition, CMU and the Royal Thai Army have worked on a proposal to manage this area as a bird corridor, adjoining Doi Suthep Pui National Park. Plans are underway to create more bird habitats in this area, increase forest cover and create educational trails and signs for visiting students. The bird sanctuary proposal is copied in the appendix. Furthermore, about 40 children from Prem International Centre joined in the planting event as part of their environment group’s extracurricular activities. Several interns (university students) at FORRU-CMU have joined in the maintenance and monitoring activities at the plots. The demonstration plots at MJU Phrae Campus have also been used for class work for about 200 students, for forest restoration lessons and field labs work. The plots were visited by teachers from Vietnam and local villagers also received training in tree propagation methods at the nursery.

The progress of the planted trees has been monitored at regular intervals since planting. The forest fire at Mae Ow provided the opportunity to study the fire resistance of the tree species. For more details, the final report (March 2008) to BRT is available below.
Lowland Framework Species Report 2008

Devising a framework species system to restore deciduous forests in northern Thailand has become a far more challenging task than expected. In evergreen forest, framework species were easy to identify, and we had identified a functional range of species and achieve impressive demo plots within 3-4 years after starting nursery and field work. This was probably because i) there are more species to choose from in evergreen forest; ii) conditions for tree growth are much better above 1,000 m elevation than in the lowlands and iii) human disturbance, especially cattle and fire, was less intense. In deciduous forest, the main problem has been fire and cattle destroying the planted trees before completion of field trials, despite considerable expenditure on fire break cutting and employment of local people for fire prevention and suppression. Having shifted the field trial plot system to Huay Tung Tao has allowed the project to progress with less difficulties with cattle and fire so FORRU will continue to expand the field trial plots in this region.