Fallen Forest: Cambodia’s Political Reforestation Unlikely to Survive

Outdated reforestation tactics are dooming Southeast Asia’s ecosystems and carbon capture efforts. However, new research shows a better way forward.

Monks Sot Phally and Yoeun Socheat crossing the cleared Phnom Tamao Forest just 40 kilometres from Phnom Penh. The forest was hastily reforested and designated an arboretum, a botanical garden for trees.
Monks Sot Phally and Yoeun Socheat crossing the cleared Phnom Tamao Forest just 40 kilometres from Phnom Penh. The forest was hastily reforested and designated an arboretum, a botanical garden for trees.

Sand fills and spills from Sot Phally’s sandals as the chief monk carries an alm bowl from his pagoda through what was once Phnom Tamao Forest.

‘I used to walk under the shade of the trees. There were fresh, green woods, but now it is just cleared land,’ Phally said about the renamed Phnom Tamao Arboretum. Six months earlier, he’d silently watched from his meditation space at the top of Tmor Antong Pagoda as bulldozers toppled hundreds of hectares of forest.

Just southwest of Cambodia’s capital Phnom Penh, this forest was controversially earmarked for development despite being a ‘protected area’ by a wildlife rescue centre. As clearing began in August, public outcry prompted Prime Minister Hun Sen to reverse his council’s approval of the project.

But by then, half the forest was gone.

With a newfound green thumb, Hun Sen rushed to reforest. His tycoon allies and personal bodyguards led the effort to plant a sparse array of limited tree species. While considered a textbook approach often repeated across Southeast Asia, a growing body of research suggests these tactics usually result in nearly half of replanted trees dying within a decade, even under the best circumstances, and Phnom Tamao was hardly in ideal conditions.

Experts at the Forest Restoration Research Unit in Thailand say these failures bring into question if or how Southeast Asia can recover lost landscapes. Since 1994, these researchers have fine-tuned an alternative method of ecosystem restoration that co-founder Stephen Elliott claims ‘sucks up carbon like there is no tomorrow’ through dense, diverse planting. But this process is failing to take root across the region. That’s especially true in Cambodia, where Phnom Tamao’s reforestation excluded forestry officials directly trained by Elliott.

‘When you are trying to do something a little new, there is resistance,’ Elliott said. ‘It is only laziness. People can’t be bothered to do something which is hugely more beneficial but takes a bit of effort.’


‘It’s a ‘difficult, high ambition to reconstruct nature. […] It even sounds a bit arrogant. The truth is we can’t reconstruct forest ecosystems exactly the way they were before deforestation.’ — Stephen Elliot

An evolving strategy for thicker forests

Perched atop his meditation boulder, Phally could only hear a gentle breeze across the flattened forest, where bird song and the buzz of insects once filled the air.

‘It has been silent since [the deforestation],’ he said. ‘I have no idea where the animals are.’

The hullabaloo at Phnom Tamao, where conservation groups had been releasing rescued animals for nearly two decades, marks an increasingly precarious time for Cambodia’s natural resources. In November, Hun Sen signed a sub-decree marking nearly a million hectares of protected area eligible for privatisation. A month later, the Ministry of Environment proposed legalising ‘game hunting’ on forest reservations. In early 2023, a separate ministry awarded its first land concession in nearly a decade, despite a moratorium on these long-term leases, which are infamous for causing land conflicts. In early March, Hun Sen urged for a Forestry Administration law amendment to allow private citizens to raise endangered animals. Forestry Administration Director Keo Omaliss, who was indicted in the U.S. for wildlife trafficking in November, and Phnom Tamao Director Nhek Ratanapich, have declined to comment since Southeast Asia Globe first began its investigation in July.

The startling speed of Phnom Tamao’s deforestation came to an equally sudden halt when a Facebook post from Hun Sen, which is effectively law in Cambodia, cancelled the development. Reforestation began 22 hours later.

To speed up reforestation, Hun Sen sent more than a thousand members of his personal security unit to Phnom Tamao, where they simultaneously facilitated the replanting and detained five journalists and four activists visiting the forest. By the end of August, the paramilitary force reported 96% of reforestation was complete. Guards planted roughly 200 saplings per hectare, an average of about 7.5 metres apart.

Employees of the tycoon who volunteered to assist the reforestation declined to be interviewed. One cheerful worker, however, shared both a chocolate pudding cup and the names of the three luxury-grade tree species being replanted: Siamese RosewoodCambodia Beng, and Burma Padauk.

‘Oh my God,’ Elliott muttered when told about Phnom Tamao. His process follows a very different track than the ‘arboretum’ model, aiming to restore some semblance of a natural forest ecosystem. He breaks that down into biomass, structural complexity, biodiversity and ecological functionality. This begins with an assessment of still-standing forests around a deforested area. Only the seeds of the trees with high growth and survival rates are selected to be replanted, with a typical diversity of about 30 species—10 times the species planted in Phnom Tamao. Trees are then replanted almost exactly 1.8 metres apart to avoid competition between saplings. On average, this should equal out to roughly 3,000 trees planted per deforested hectare, 15 times more than what was planted at Phnom Tamao.

There are Forestry Administration leaders in Cambodia who are well-aware of this—because Elliott himself trained them over the course of nearly six years.

Kim Sobon is one of them. He often leads government reforestation projects with the Department of Forest Plantation and Private Forest Development as a deputy director. He confirmed the department was not involved in the reforestation of Phnom Tamao and declined to share more.

Seab Kimsrim, who manages a Forestry Administration research station and tree nursery in Siem Reap, said the nursery donated more than 2,000 Siamese Rosewood and Cambodia Beng to Phnom Tamao.

‘We are conservationists, so we are happy to restore our land, our forest area,’ Kimsrim said about Phnom Tamao. ‘But we also want development in that area. We cannot just do conservation without development.’Elliott’s research unit, based at Chiang Mai University, is regionally renowned for its expertise in tropical forest ecosystem restoration that goes against the grain in Southeast Asia. According to Elliott, the unit’s partnership with the Forestry Administration assisted with the development of ‘sensible forest ecosystem restoration practices’. This included establishing Kimsrim’s research station and nursery in Siem Reap, as well as creating technical manuals in the Khmer language.

Seab Kimsrim manages Khun Ream Forest Research Station’s tree nursery, which raises more than 10,000 saplings annually, mostly of Siamese Rosewood.

At a reforestation site directly behind that nursery, Kimsrim said the replanting at Phnom Tamao loosely fit the modus operandi of the Forestry Administration. The 100-hectare plot he was in was reforested only with Siamese Rosewood, planted in 3-metre intervals.

After learning about how Phnom Tamao was reforested, Elliott said it was ‘disappointing that the training provided does not seem to have been applied.’ Even so, Hun Sen’s bodyguards did do some things by conventional standards. The lack of species diversity across a low number of widely spaced saplings might be commonplace, but recent studies find that many trees planted this way are unlikely to survive. This traditional reforestation runs contrary to almost everything Elliott’s restoration unit has learnt in the past three decades.

‘The more diversity you put in in the beginning, the faster the diversity comes back,’ Elliott said. ‘How can you write a symphony with one note?’

‘Ambition to reconstruct nature’

An example of that mindset has played out on Mon Jam Mountain, on the outskirts of Chiang Mai. In a haze of smog from the agricultural burning season, a trail of students struggle to keep up with Elliott as he leads them to different forest restoration plots.

While Elliott agrees that planting trees is better than cutting them, he admits it’s a ‘difficult, high ambition to reconstruct nature’. ‘It even sounds a bit arrogant. The truth is we can’t reconstruct forest ecosystems exactly the way they were before deforestation,’ he stated.

The decade-old reforested plot on Mon Jam was once a dense and active habitat, with camera-trap images of wildlife to prove it. In contrast, the plot in Siem Reap is more like a neat and spacious orchard, void of most other vegetation and wildlife.

The downsides of the Thai unit’s process are perhaps obvious in its explanation: it is more expensive, complicated, and time-consuming. While companies planting trees solely for public relations may not be interested in this long-term approach, Elliott hopes the method’s unintended benefits of restoring ecosystems that store large quantities of carbon will encourage them to reconsider.

‘Carbon was a minor consideration when we started 30 years ago,’ said Elliott, over an instant noodle lunch on the mountain. ‘Global warming, or the greenhouse effect, was hardly on the political agenda. By sheer accident, we created a system that just sucks up carbon like there is no tomorrow.’

The ability of forests to act as a ‘carbon sink’ is a key way Southeast Asian nations receive climate finance funds from governments and companies trying to counter their emissions. In the past three decades, organisations participating in tree-planting rose by 290%, according to a 2021 report.

‘Carbon storage is a really important piece of the reforestation puzzle. But that should always be married up with other ecosystem services,’ said Lindsay Banin, a statistical ecologist for the U.K. Centre for Ecology and Hydrology, listing soil and water protection, as well as biodiversity conservation as additional measures.

study Banin co-authored earlier this year synthesised regional reforestation efforts, and found nearly a fifth of planted trees die within the first year, which came with a rising mortality rate to almost half of the trees obsolete in a decade. Across more than 170 reforestation sites in Southeast Asia, the study found an average of three tree species planted per site, identical to Phnom Tamao.

‘I was surprised the average was so low,’ Banin said. ‘By having greater diversity, you have opportunities for plants that function a bit differently to perform better in future climates. There are options for nature going forward.’


‘A study Banin co-authored earlier this year synthesised regional reforestation efforts, and found nearly a fifth of planted trees die within the first year, which came with a rising mortality rate to almost half of the trees obsolete in a decade. Across more than 170 reforestation sites in Southeast Asia, the study found an average of three tree species planted per site, identical
to Phnom Tamao.’

The study concluded that ‘the uncertainty in planting outcomes also emphasises the critical value of protecting remaining, functionally-intact forests.’ These results weren’t meant to be a ‘doom and gloom’ prediction, Banin insisted, but rather a push for improving regional reforestation and forest protection. This would rely on buy-ins from local communities, because ‘the things they value will be what keeps forests standing’.

The little that is left standing at Phnom Tamao Arboretum continues to provide for surrounding villages. Almost six months after reforestation began, cut grass, the ideal cattle feed, overflow from baskets on Chip Korb’s dusty Honda motorbike. Earlier that day, brothers Kun and Ton Il also came to the arboretum to stack dried logs, perfect for fencing and cooking, on a pair of carts.

‘As long as we do not destroy the small trees, we are allowed to take from the forest,’ Ton said. ‘I’m so happy they let me. At least we can still use the forest.’

The sand path Phally takes back to Tmor Antong Pagoda is a bleached contrast between Phnom Tamao’s surviving forest and the sterile arboretum. The success of the rushed reforestation is now up to prayers and faith, he believes.

‘This still is a sacred place for people to pray for happiness. I call for every country to protect their forest. Nature is the root of Buddhism, religion, and life,’ Phally said. ‘I hope the small trees will grow taller in the next decades, maybe I will meditate under them in this life.’

Fragmented forests and wilting saplings pock-mark the desolate Phnom Tamao Arboretum, which was suddenly cleared and then rapidly replanted in August.
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About the author

Anton L. Delgado

Anton L. Delgado is a fellow with The Pulitzer Centre’s Rainforest Investigations Network. He was most recently a senior reporter at Southeast Asia Globe where he spearheaded the newsroom’s environmental coverage from in Phnom Penh. Before moving to Cambodia, Delgado was an environmental reporter at The Arizona Republic with the USA TODAY network.

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