With our own hands, we can help the planet by planting trees, returning greenery to deforested areas. But with a trick or two, the greenery can more quickly return to a natural forest that a range of wildlife can call home.
This is what has happened in the upper Mae Sa valley, in the heart of Chiang Mai's Doi Suthep-Pui National Park, 1,328m above sea level.
Here, a 21 hectare section of the 4,480 hectares of spoiled forest has been brought back to life, thanks to a reforestation programme using what experts call the "framework species method".
Contrary to most state reforestation programmes, which simply fill areas with a single species of tree, this reforestation plot in the upper Mae Sa valley is rich in biodiversity.
"The trees we planted have attracted wildlife and accelerated the regeneration of the natural forest," said Steven Elliot, an expert from the UK at the Forest Restoration Research Unit of Chiang Mai University (Forru-CMU).
Forty years ago, the upper Mae Sa valley was an abundant tropical forest that protected the rain-catchment areas of the Sa River, which flows into Chiang Mai's Ping River, a main tributary of the Chao Phraya.
The forest, however, was cleared for farming, and subsequently abandoned after it became infertile. Consequently, the rain-catchment area almost died.
Since 1996, however, Forru-CMU has been working with local villagers at Ban Mae Sa Mai and the Doi Suthep-Pui National Park officers to save their forest, using the framework species method.
The trick is to grow fast-growing pioneer trees together with shade-tolerant climax trees, which not only help accelerate regeneration but also attract seed-dispersing wildlife and birds to accelerate the return of biodiversity to the forest.
According to Elliot, pioneer trees were selected from northern Thailand's indigenous tree species. They grow rapidly, are resilient to forest fires and form an upper canopy that creates dense shade and attracts seed-dispersing wildlife.
The shade-tolerant climax trees, meanwhile, grow slowly in the pioneer trees' shade, to form an under-storey. As these trees grow, more indigenous seeds will be brought in by birds and wildlife to naturally grow in their shade.
Using this system, the pioneer trees will begin to die after 10 to 20 years, but the dead wood will enrich the soil, providing food for invertebrates. While the planted climax trees grow to form the main canopy, the naturally established trees form an under-storey, ready to return the forest to its former glory.
Since the technique has identified the pioneer and climax trees suitable for the ecosystems of northern Thailand, the success in the upper Mae Sa valley will help other communities revive their degraded forests more effectively.
According to Elliot, each site must be cleared of weeds while preserving any existing tree seedlings or saplings. The next step is planting a mixture of 20 to 30 native tree species, including both pioneer and climax species, 1.8 to 2m apart.
Between 20 and 30 species will be planted on each site and maintained through weed control and the use of fertilisers for a few years, until they are well-established. Throughout this time, fires must be prevented. With these species, natural regeneration processes should further help the forest's recovery.
Elliot, also a Chiang Mai University biology professor, claimed the project a success for bringing back 87 species of birds and 61 species of plants after the 30 chosen framework species were planted here 10 years ago.
Seeds were also brought by various birds and fruit-eating Indian civets (chamod) who come from the nearby Dong Seng Forest.
"These plant seeds came in here on the wind. They are normally stronger than those planted by us," the expert said.
According to Elliot, the trees that his team planted changed the conditions in the forest. In the 6th to 10th years, cogongrass (ya kha) will no longer exist in the shade of trees grown to help re-establish the self-sustaining forest ecosystem.
"Biodiversity here is very high. Apart from two types of lichen, the forest is also home to barking deer, wild pigs, Burmese ferret-badgers and pangolins. The fruit bats are also coming to the field plots and bringing more seeds," the PhD from the University of Edinburgh said.
Follow-ups and statistical findings by Forru have confirmed the return of biodiversity in terms of wildlife and trees in the area. The 2nd and 3rd years saw a rapid increase in canopies. In the 3rd year, 14 species of trees began to bear fruit and become shelters for wild animals. It also saw the return of mammals like large Indian civets, hog badgers, barking deer and wild pigs.
In the 6th year, multiple tiers of canopies caused many leaves to replace weeds and ensured appropriate environment for seeds to grow as saplings naturally. In the 7th year, 44 species of plants became habitats and food sources for wildlife.
Cherdsak Kuarak, a Forru researcher working on the project, is proud to see the renewed biodiversity in the area.
"We grew 30 kinds of plants here and later found some 90 more types. It's incredible to find some important species like agarwood (mai krisna). This is our success. More animals will come here and the forest will grow on its own," he said enthusiastically.
The biggest obstacle to the project is fire. However, the area has fire watch towers, a forest fire watch team of 15 villagers and teams to create and maintain six- to eight-metre-wide fire breaks.
To guarantee the forest's survival, the Forru team has solicited the co-operation of the villagers and strengthened local children's love of nature by regularly taking them trekking and bird-watching.
Chote Parasidh, assistant headman of Baan Mae Sa Mai, said the villagers, all Hmongs, have been working to revitalise the forest since 1991 and have willingly joined Forru to help save their forests since 2001.
"Now, we can hear and see more wildlife, including boars, barking deer, nocturnal animals and pheasants. They have come back.
"We also saw barking deer running along the village road, last rainy season," he added.
This is why the villagers want to continue the reforestation project even if financial support might someday come to an end. They also plan to promote ecotourism and homestays for tourists to learn about their lifestyle and local nature.
So far, over 200 families in Baan Mae Sa Mai and Baan Mae Sa Noi, who mostly earn livings by growing lychee, have joined the project with the goal to cover 800 hectares, he said.
The villagers and volunteers usually start planting trees early in the rainy season. This year, nearly 100 Thai and foreign volunteers worked on 3.2 hectares at Baan Mae Sa Mai.
Among the volunteers are Phutthamon Somjai and Sutthida Samerjai, 4th year students of Chiang Mai University.
Both looked happy planting trees, but they voiced concerns about Chiang Mai's unsolved environmental problems like rubbish, forest fires and water pollution, as well as many locals' negligence.
Since 1961, Thailand has lost nearly two-thirds of its forests, mainly due to land clearance for logging and agriculture.
Despite the project's success, Supol Jitvijak, acting head of the forest resources management unit at WWF Thailand, said the framework species method should be expanded slowly due to the shortage of researchers and villagers who know trees scientifically and have time to take care of them.
Therefore, only 21.5 hectares of the "new forest" have been planted in the past six years, or 3.2 hectares a year of the 4,480 hectares of destroyed forest here.
The reforestation project from 2006 to 2008, which will cover a 9.6 hectare plot, is supported by WWF Thailand and King Power Duty Free with a budget of three million baht.
Although the technique has proved successful in restoring tropical forests in northern Thailand, more research is required to find appropriate pioneer and climax trees to restore different forest ecosystems in other parts of Thailand, according to the Forru.
Elliot cautioned that overenthusiasm and planting more trees than a community can maintain would eventually allow pests to grow faster than trees.
The success in the upper Mae Sa valley, however, has strengthened the determination of both the locals and the conservationists to revive the watershed forest of the Ping River.
"And we are on the right track," said Supol.Bangkok Post
