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Common goals ensure forest restoration success in northern Thailand

Tree nursery

Chotgun Prapatsit, Ban Mae Sa Mai tree nursery manager, potting on some tree seedlings to supply nearby reforestation initiatives in northern Thailand. Image courtesy of © Anthony Bouch

  • Twenty-five years ago, the Hmong community of Ban Mae Sa Mai village in northern Thailand began a collaboration with researchers and national park authorities to restore agricultural fields to natural forest.
  • Between 1997 and 2013, they honed methods of assisted regeneration while restoring 33 hectares (82 acres) of upland evergreen tropical forest in Doi Suthep-Pui National Park.
  • Monitoring teams documented the return of biodiversity and ecosystem services to the restored land, and participants founded a tree nursery that continues to supply thousands of native tree seedlings each year to nearby initiatives inspired by the Ban Mae Sa Mai model.
  • However, the Hmong community face the prospect of eviction from their ancestral land, which lies within a protected area. Experts warn that disputes between authorities and the community, coupled with an increasing risk of fire due to climate change, could jeopardize the survival of the recovering forest.

CHIANG MAI, Thailand — Chotgun Prapatsit takes a handful of topsoil and deftly sprinkles it into a small cylindrical potting bag containing a tiny tree seedling. The spindly stem sports its first set of fresh green leaves, which bob merrily as he tucks the soil in around its base, as if settling it down for a cozy night’s sleep.

“In the tree nursery, we live with our hearts,” Chotgun tells Mongabay during a visit to the Ban Mae Sa native tree nursery in Chiang Mai province, northern Thailand. As co-manager, he nurtures roughly 20,000 tree saplings each year for planting in local forest restoration projects. He says he feels connected to each individual specimen, watching them develop from seed to seedling in the nursery, and then from sapling to tree in the forest. “Each tree is different,” he says, “so if one is lost, we know.”

He nestles the newly prepared seedling into a tray amid a dozen others. At first glance, the young trees seem to be nothing more than a haphazard tangle of wispy stems and outsized leaves, but closer inspection reveals them to be a carefully curated assortment of 20 to 30 species native to the region’s biodiverse upland evergreen forests.

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The tree nursery, on the outskirts of the Hmong village of Ban Mae Sa Mai, was established in 1997 as part of the community’s effort to avoid resettlement after their ancestral land was designated a protected area. By restoring areas of watershed forest that had been cleared for agriculture, the community hoped to demonstrate good faith with park authorities and simultaneously address problems with their water supply.

Over the next 16 years, the Hmong villagers restored 33 hectares (82 acres) of upland evergreen tropical forest within the upper Mae Sa valley in collaboration with national park authorities and researchers from Chiang Mai University’s Forest Restoration Research Unit (CMU-FORRU) who were beginning to experiment with methods of assisted regeneration at the time.

Northern Thailand village
Ban Mae Sa Mai village lies within the Mae Sa valley, a mosaic of forest, agricultural fields and villages in northern Thailand. Photo by Carolyn Cowan for Mongabay

The reforestation project now serves as a research and demonstration site, where university students monitor biodiversity recovery and carbon sequestration, and local, regional and international delegates train in reforestation methods and community-led ecosystem restoration. Meanwhile, the nursery supplies tree-planting initiatives around the Mae Sa valley with locally grown saplings that are equipped to cope with the region’s soils and conditions.

However, the recovering forests face an uncertain future. The village population is growing, and with it, demand for land for housing, businesses and cultivation. But there’s very little land left in the valley to accommodate this expansion, placing intense pressure on forests. Furthermore, ebbing enthusiasm for conservation and conflict with park officials has at times led to abandonment of forest management practices that curb forest fires, an increasingly significant threat in the face of climate change.

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Tree planting to repair relationships

Overlooking the Mae Sa valley, the restored tracts of forest lie within Doi Suthep-Pui National Park, a 26,500-hectare (65,500-acre) range of forested mountains west of Chiang Mai city. More than 2,000 plant species have been documented in the park, around 340 of which are trees typical of Thailand’s upland evergreen forests. Roughly 350 bird species, 70 types of amphibians and reptiles, and several dozen mammals also call the park home, including elusive marbled cats (Pardofelis marmorata) and threatened species, such as dholes (Cuon alpinus) and Sunda pangolins (Manis javanica).

The valley itself is a mosaic of forest, agricultural terraces, and the villages of Ban Mae Sa Mai and Ban Mae Sa Noi, which, with a combined population of 1,800, represent the largest community of Hmong people in northern Thailand.

Although the Hmong have lived in and farmed the Mae Sa valley for more than a century, the inclusion of their customary land as part of Doi Suthep-Pui National Park in 1981 led to concerns over the legal threat of eviction. Thailand’s law on national parks forbids land possession, clearing and burning in protected areas. Furthermore, in the late 1990s, national park authorities began a nationwide campaign of forced resettlement for communities living within park boundaries.

Cabbage fields, Thailand
Fields of cash crops dominated the upper watershed areas of the Mae Sa valley prior to the start of reforestation efforts in the late 1990s. Photo by Carolyn Cowan for Mongabay

To assert their right to remain, the villagers formed the Ban Mae Sa Mai Natural Resources Conservation Group (NRCG) and began planting trees to restore their watershed forests.

A member of the NRCG, Chotgun recalls when there was no forest at all along the watershed before they began collaborating with CMU-FORRU. He says that as a child, he ran and chased wild animals across the open hillsides for fun. Now, having been involved in forest restoration over the past two decades, he says he’s happy to see the recovery of forest wildlife and crucial ecosystem services.

“The trees have grown so fast that the forest has already filled,” he says. “Now, our water source is not cloudy, and when it rains the water doesn’t wash away, so we can use it comfortably. Even the weather is getting better because we have a forest. We have moisture in the air and wild animals around us — the ecosystem began to recover.”

Reforestation plot, Thailand
A forest plot planted in 1997 in the upper Mae Sa valley, northern Thailand. Photo by Carolyn Cowan for Mongabay

Wildlife recovery

Looking toward the restored forest plots at the summit of the valley reveals a stark contrast. To the south, the sun-drenched land rolls downhill in a swaths of cabbage, corn and carrots; and to the north, trees reach up to 30 meters (100 feet) skyward, casting dappled shade on an understory of saplings and forest herbs.

Prior to planting in 1998, this patch of forest was still a field, says Aom Khuanphirom, a field research officer at CMU-FORRU, during a site visit to collect tree seeds to supply the village tree nursery. Stepping from the field margins into the regenerating forest, the reek of agrochemicals is replaced by the earthy aroma of leaf litter and fresh foliage, and the baking heat of open ground by cool, moist air.

Aom points out the wrinkled seeds of Sapindus rarak, a light-demanding tree that only grows around the forest edges, contrasting them with a thicket of young Castanopsis calathiformis, a type of oak, growing in the center of the plot, where only shade-tolerant species thrive.

Hiking downslope through a “chrono sequence” of progressively younger restored forest plots, the revival of biodiversity is palpable: trilling songs of seed-dispersing bulbuls and other birds reverberate across the forest crown, termite colonies busily recycle nutrients on the forest floor, and mushrooms peep through the leaf litter all around.

Reforestation plot, Thailand
Biodiversity recovery is well underway in reforested plots, including birds, fungi, lichens and carbon sequestration levels. Photo by Carolyn Cowan for Mongabay

A ‘special case’

The Ban Mae Sa Mai project was recently highlighted by Restor, an ecological restoration network, as an example of best practices out of more than 700 initiatives globally.

“The association between the Hmong community and the researchers from FORRU make this a very special case,” Robin Chazdon, a forest restoration expert at U.S.-based consultancy Forestoration International and co-author of a case study on the project, told Mongabay in an email. “Working together, the two groups learned from each other and complemented their skills and knowledge.”

For instance, the community shared traditional knowledge about the location of seed trees and use of forest species, and the researchers in turn shared their knowledge of how to grow the young trees for planting.

“This type of collaboration can be difficult to achieve, but where there is a dedicated research group working in an area and a motivated community, strong ties can be established that enable long-term forest restoration for multiple benefits,” Chazdon said.

In addition to an enhanced water supply and improved relations with park authorities, community members were given training and support to adopt local restoration-based livelihoods and were included in all stages of forest planting, maintenance and monitoring. “This engagement increased knowledge within the community and contributed to a strong connection with the reforestation project,” Chazdon said.

Tree seeds, Thailand
Aom Khuanphirom, a field research officer at CMU-FORRU shows a fleshy tree seed from a framework species cultivated at the tree nursery. Photo by Carolyn Cowan for Mongabay

The project also pioneered new methods of restoring forests in Southeast Asia using the “framework species” approach, a method first devised in Australia that centers around planting a subset of native tree species that are ecologically resilient, grow quickly, and attract seed-dispersing animals that in turn boost natural regeneration processes.

“About 85% of [upland evergreen] tree species are animal-dispersed,” Stephen Elliott, co-founder and research director of FORRU-CMU, tells Mongabay. “So you need [to plant trees that] produce flowers with plenty of nectar to bring in the bats or the birds, and you need them to produce fleshy fruits, like the wild cherry trees, so that birds, civets and hog badgers come in.” By transporting the seeds of a multitude of other tree species in the surrounding landscape, Elliott says, the animals help restored sites to regenerate naturally, “so you’re not completely relying on every single planted tree making it.”

When the project began in 1997, Elliott said the team used trial and error to find out which of the 350 species native to the region’s upland evergreen forest performed best as framework species. “When we started, we were just testing everything,” he says. “We were going out and collecting the seeds of everything, growing it all in the nursery, then planting it in the field.”

Gradually, they identified 20 to 30 suitable framework species, honed tree-care techniques to maximize sapling growth and survival, and monitored the recovery of forest biodiversity. Within just two to three years, the young forest canopy closed over, blocking out competitive weeds. And within six years, the bird community increased, from roughly 30 species prior to planting, to 88 species. Seed-dispersing animals brought in at least 73 new types of trees from the surrounding natural forest, and lichens, mycorrhizal fungi and carbon sequestration levels eventually returned to, or even exceeded, levels typical of natural forests.

The “Framework Species” approach to forest restoration aims to plant trees that produce nectar and fleshy fruits to attract seed dispersing animals, such as bats, civets and birds like the red-whiskered bulbul pictured here. Image by alain01789 via Creative Commons (CC-BY-NC-ND 2.0)

Breakthroughs go global

According to Chazdon, since the foundational work at Ban Mae Sa Mai, the framework species approach has become a widespread practice in forest restoration projects around the world, particularly in biodiverse tropical forest ecosystems. It’s currently practiced in projects from Malaysian Borneo and Cambodia to Madagascar and Tanzania.

Kitiya Sophonpanich, secretary-general of the Rajapruek Institute Foundation, which supports the Ban Mae Sa Mai tree nursery, said the collaborative project has inspired many initiatives in Thailand to adopt similar methods that focus on a subset of locally grown native trees, rather than eucalyptus and pine, which have historically been the basis of many failed schemes.

The proven success of the framework species approach “made us aware of the importance of good quality indigenous saplings in forest restoration,” Kitiya told Mongabay in an email. “We have even come to the conclusion that for a forest restoration project to work, we need to have our own nursery, or at least an access to quality saplings.”

Kitiya added that her team is now applying these approaches to many other projects aiming to restore watershed forests in the north and northeast of Thailand, where many of the country’s most important rivers originate, and also in the south of country, where communities are restoring mangrove forests. “We have adapted [the methods] a bit to fit with different contexts,” she said. “We also use their monitoring methods to validate our successes.”

Tree nursery, Thailand
The Ban Mae Sa Mai project has inspired many initiatives in the region, which focus on planting locally grown native trees. Photo by Carolyn Cowan for Mongabay

Long-term sustainability

Given that reforestation goals are now part of national climate change mitigation strategies, community-led forest management and restoration are becoming increasingly important. At Ban Mae Sa Mai, the Hmong community takes a leading role in forest management by cutting fire breaks and carrying out fire outbreak monitoring throughout the dry season. But the motivation to carry out these tasks ebbs and flows, according to Elliott.

The zoning of the Mae Sa valley as part of Doi Suthep-Pui National Park precludes the villagers’ rights to use resources from the forests they helped to restore. This prevents local people from earning a living through the sale of non-timber forest products — a common means of making restoration initiatives financially self-sustaining. Therefore, there’s increasing pressure on the valley’s forest land as the population expands.

Furthermore, in recent years, Thailand’s forestry authorities have renewed their efforts to clamp down on communities living within park boundaries. “In a way, we’re right back to the situation we had in the 1990s: It’s circled right back,” Elliott says. He warns that past conflicts between park officials and villagers have led to disillusionment and abandonment of important tasks like cutting fire breaks, leaving the recovering plots vulnerable to fire. As recently as 2020, forest fires raged across the Doi Suthep-Pui National Park, generating air pollution levels in Chiang Mai up to 40 times higher than international safe standards.

Northern Thailand
The Mae Sa valley in Chiang Mai province, northern Thailand. Photo by Carolyn Cowan for Mongabay

With forests in the region facing increasing drought and other effects of climate change, Elliott says finding ways to engage the community over the long term to protect the restored forests, particularly through fire prevention, is vital.

One way could be to elevate the status of forest restoration to a financially viable livelihood, akin to a farmer, through leveraging carbon markets and other payments for ecosystem services like water purification. “When you look at the value of the forest, about a third is in carbon, and about a third is in watershed services,” Elliott says. “So you have multiple opportunities to monetize it, [what we need now] is the institutional structures and policy mechanisms to put it in place.”

For nursery manager Chotgun, the restored forest is a constant in the landscape, and also a gift that can be passed down from one generation to the next to ensure the community’s future. He says that although it will be up to future generations to decide how to carry on the legacy of their ancestors, in a valley with limited space and a growing population, they might need a helping hand.

“In order to keep the forest alive, we need to cultivate awareness among children and make the rules for using our limited space clear,” Chotgun says. “We instill the history of the conservation group and the forest in children’s consciousness to allow them to cherish what they have. And that will allow them to stay in this area without any problems.”

Banner image: Chotgun Prapatsit, Ban Mae Sa Mai tree nursery manager, potting on some tree seedlings to supply nearby reforestation initiatives in northern Thailand. Image courtesy of © Anthony Bouch


Chazdon, R. L. (2021). Case Study #2: Restoring native forest with Ban Mae Sa Mai Village, Chiang Mai, Thailand. Crowther Lab. ETH Zurich. Retrieved from

Elliott, S., Chairuangsri, S., Kuaraksa, C., Sangkum, S., Sinhaseni, K., Shannon, D., … Manohan, B. (2019). Collaboration and conflict — Developing forest restoration techniques for northern Thailand’s upper watersheds whilst meeting the needs of science and communities. Forests, 10(9), 732. doi:10.3390/f10090732

Carolyn Cowan is a staff writer for Mongabay. Follow her on Twitter @CarolynCowan11

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