FORRU carries out scientific research to develop the best techniques to grow, plant and take care of indigenous forest tree species, so that forest restoration and biodiversity recovery can be achieved successfully and efficiently on degraded land. As well as being ecologically valid, it is important that the methods developed are cost effective and acceptable to the local people. Therefore, the new techniques developed by FORRU's research are tested for their practicability by villagers at Ban Mae Sa Mai; a local Hmong village (seeModel community).

FORRU's first task was to screen some of the more than 660 tree species that are indigenous to Doi Suthep-Pui National Park (Maxwell and Elliott, 2001) for their ability to act as framework species. Forest restoration begins with seed collection, so FORRU's researchers labelled trees of more than 100 species in the forest around the research station and observed them every 3 weeks, over four years for flowering and fruiting production. This study revealed seasonal patterns of fruiting, enabling seed collection schedules to be devised.
Left: Afzelia xylocarpa flowers

Once the seeds were collected, research continued in the nursery to determine which treatments resulted in the healthiest seedlings (seeFORRU nursery).

Trees grown in the nursery were then planted out in field trials in order to determine which species might act as “framework species” (Elliott et al., 2003). Trees were monitored after planting to determine the survival and growth rates of each species, as well as their ability to shade out weeds and recovery after (accidental) fire. Various silvicultural treatments to maximize field performance of the planted trees were also tested, such as different weeding methods, mulching and fertiliser regimes (Elliott et al., 2000).

An essential characteristic of framework tree species is attractiveness to seed-dispersing wildlife. Therefore, planted trees were checked regularly for production of any resources that might attract birds or mammals (e.g. fruit, flowers, nectar etc.). Surveys to assess the species richness and composition of the ground flora (Khopai, 2000) and bird and mammal communities were also carried out (Chantong, 1999;Toktang, 2005;Thaiying, 2003).

To date, one of the most important outcomes of FORRU's research has been identification of species that can rapidly restore the structure and functioning of upland forest ecosystems (Elliott et al, 2003), whilst enhancing biodiversity recovery.

FORRU carries out tree planting once a year, at the beginning of the wet season, to allow the trees to grow a deep root system before onset of the hot, dry season in January. With each newly planted field plot, experiments are carried out to determine the effective silvicultural techniques to optimize field performance of the planted trees, which are monitored for at least 2-3 years after planting. Right: FORRU research staff Panitnard uses cardboard mulch during planting at Mae Ow.At Ban Mae Sa Mai, Cherdsak Kuaraksa is trailling rare tree species for inclusion in Framework Tree Species plots with early career funding from IFS. More information can be found on the Rare Species page. Research staff wanted to plant rare tree species in order to conserve these species, add biodiversity to the site, and to determine if any might qualify as framework species for northern Thailand. FORRU has also started to test “potential” framework trees species in highly degraded lowlands sites, formerly occupied by deciduous dipterocarp forest. Due to fire and livestock control issues, trials at Mae Ow, Lampan Province and Mae Jo University Phrae Campus have been transferred to Huay Teung Tao Reservoir where FORRU is testing various silvicultural treatments to overcome the poor quality of the soil, including experiments with fertiliser dosage, cardboard mulch and filling planting holes with soil. For more information on these projects see Upland forests and Lowland forests.

FORRU and the Bird Conservation Society of Thailand are assisting the Royal Society for the Protection of Birds (RSPB) with forest restoration research in southern Thailand with funding from Britain's Darwin Initiative (see Gurneys' Pitta).