By Nay Tun Lin, Htet Aung Khant (Scott) & Phyo Thet Naing (Jerry)
With the support of THE NEXT FOREST under THE BKIND PROJECT, we studied the long-term effects of forest restoration on carbon, stored in trees and soil, and the recovery of bird and mammal communities at restored forests in the upper Mae Sa Valley from May to November 2024.
We collected our data from 4 study sites; 2 restoration sites, 12 and 24 years after tree planting, least-disturbed, mature, natural forest (the reference forest) and an avocado field as a control site (original vegetation before restoration). The fascinating results we obtained from these studies show that the Framework Species Method (FSM) of forest ecosystem restoration is working; the restored forest are healthy, with various wildlife species thriving in them.FORRU field team together with BKIND research students.
Tree carbon
In the forest carbon study, we measured tree sizes and calculated tree carbon content using allometric equations developed for northern Thailand trees by Pothong et al. (2022). The results showed that after 12 years and 24 years, restored forests stored 48% and 84% respectively of the carbon found in natural forests. The study also predicts it will take about 34 years for restored forests to fully match natural ones. Such tree-carbon studies can be quite beneficial regarding carbon sequestration and carbon credit markets as they can prove the value of forest restoration as a climate-change solution and a financial opportunity through carbon markets.Pyae Shan and FORRU field officer Som measuring trees in 12-year-old restored forest.
Soil carbon
Jerry and Scott preparing to collect soil samples. 8 sampling units with 5-meter radii were established in each plot, and soil samples were collected at three depths (0–5 cm, 5–10 cm, 10–15 cm) using a split-core sampler.For soil organic carbon (SOC), we collected soil samples in each plot and analyzed them in a lab using the Walkley-Black method. Soil carbon increased in the 12-year-old restored site, reaching 86% of natural forest levels. Total SOC of this site was also 28.2% higher than that of the control habitat. However, the 24-year-old site had lower-than-expected soil carbon possibly due to the lingering effects of over cultivation and soil degradation (perhaps a land slide) in the past. Such past land-use impacts may not yet have been counteracted by inputs of carbon from the trees above. Yet, the restored forests still showed a great potential for carbon sequestration and the findings highlight the effectiveness of forest restoration, particularly the FSM, in enhancing SOC and improving soil fertility.
We used birds and mammals as indicators to assess the effects of restoration on biodiversity recovery.
Birds
Scott with his binoculars in the control site. Bird-watchers worked in pairs; a spotter identified the birds seen whilst a recorder recorded the species and time.Bird monitoring was done by birdwatching; bird species being recorded by direct observation with binoculars or by their songs. Birds were observed for 3 hours before sunset and 3 hours after sunrise, since they are most active during such hours. A total of 140 bird species were recorded across all study sites. Restored forests had bird communities similar to natural forests, showing a recovery of biodiversity towards the reference condition. Some bird species, like bulbuls and barbets spread tree seeds from remaining forest fragments into restoration sites, thus aiding recovery of plant communities during restoration.
Mammals
Nay setting up a camera trap in a reference forest. Camera traps were installed for over 700 trap nights through out the study and moved monthly to maximize area covered.Since most mammals are nocturnal and very shy, observing them directly is almost impossible. Consequently, we used camera traps to find out which mammal species were present. They are handy and are commonly used for surveying mammals. A total of at least 18 small and medium-sized mammal species were recorded with the camera traps, including the critically endangered Sunda Pangolin. Mammal activity levels in 12- and 24-year-old restored forest were 43% and 55% that of the reference forest, respectively, showing ongoing ecological recovery. Both restored sites supported more than half the number of species recorded in the reference forest. The most frequently detected species was the common palm civet. It is an efficient seed disperser, thus providing opportunities for forest trees to establish on open sites and helping to increase tree-species richness in restoration plots.
Common palm civet, an excellent seed disperser, was the most detected species and found in all study sites including the control site.
The Sunda pangolin was found in the reference forest and 12-year-old forest. Pangolins are one of the most trafficked animals in the world, as their scales are valuable and highly prized especially for Chinese medicine. Presence of such endangered animal suggests that the study area is well protected and that hunting in the area is less than in the past.
In conclusion, the findings from this research indicate that forest restoration using FSM was effective for carbon capture and biodiversity recovery.
