More than 70 million people live in Southeast Asia's Mekong region, where trees and forests have multiple benefits for people and biodiversity. Trees lock soils in place, preventing landslides and protecting crops, while forests help regulate rainfall and water cycles. Wood and other forest products provide millions of people with food, materials and economic opportunities in rural communities across Myanmar, Vietnam, Cambodia, Laos and Thailand. The entire planet relies on the Mekong's forests to store carbon and mitigate climate change.

But these forests are under threat. Expansion of agriculture and heavy logging have led to extensive forest loss and degradation in the past few decades. As much as one-third of the region's forest area was lost between 1973 and 2009. Between 2010 and 2017, the five countries of the Mekong lost 300,000 hectares of forest — an area four times the size of New York City.

At the same time, deforestation is only half the story. New trees are also appearing throughout the region, both inside and outside the forest — on farmland, shrubland and in towns and villages. A new WRI analysis, part of the New York Declaration on Forests Five-Year Assessment Report led by Climate Focus, used satellite data to assess forest change in the Mekong, as well as — for the first time ever — change in tree density (the number of trees per hectare) outside the forest.

Across the Mekong, Trees Outside Forests Are Increasing

Our analysis found that forest loss is still outpacing forest gain in the Mekong region. Vietnam, Laos and Cambodia experienced the greatest losses, while Myanmar had a slight net loss. Thailand was the only country with a net gain. Commercial tree plantations, where gain and loss happens in regular cycles, were not counted as either deforestation or restoration in our analysis.

But the good news is that outside of forests, such as in agricultural areas and around settlements, all countries except Laos had a net gain in tree density, with Myanmar experiencing the highest net gain. These trees provide food and fuelwood for homesteads, protect hillsides from erosion and filter sediments to improve water quality. In total, 4.68 million hectares of non-forest lands had an increase in tree density between 2010 and 2018 — an area slightly smaller than Switzerland.

Thailand: More Trees Inside and Outside the Forest

Thailand is a bright spot regarding forests and trees. Although it has lost significant forest — an estimated 43% of its forest area between 1973 and 2009 — the country is reversing this trend. We found that between 2010 and 2017, Thailand was the only Mekong country to experience a net gain in both forest area and trees outside the forest. Its forest area grew by 1.7% and the presence of trees by 1.2%. Outside of forests, lands considered barren in 2010 saw an increase in tree density of 4.5% in 2018. On farms and croplands, where trees mix with or border crops to stabilize soils and protect yields, tree density increased by 0.6%.

As part of a new national strategy, Thailand recently announced ambitions to increase its forest area by 23% before 2030, as part of its Nationally Determined Contribution under the Paris Agreement. The country has gained recognition for several innovative projects, from mangrove restoration to community-led reforestation. Our estimates indicate that Thailand has added nearly half a million hectares of forest area since 2010.


A mangrove restoration project in Mahachai, Thailand. Photo by Dow Maneerattana/WRI.
A mangrove restoration project in Mahachai, Thailand. Photo by Dow Maneerattana/WRI.

How Do We Measure Restoration?

Measuring increased tree cover on an international scale is extremely challenging. While deforestation is highly visible from space — it happens quickly and leaves a stark footprint — measuring restoration is more difficult. Trees grow slowly and are often widely spaced apart, especially in rural landscapes. Measuring this growth requires higher-resolution satellite data and different methods of interpreting satellite imagery.

Forty-one countries have endorsed the New York Declaration on Forests since its inception in 2014, including Thailand and Vietnam. Its goals include halving deforestation by 2020 (and ending it by 2030) and restoring 150 million hectares of degraded land by 2020 (increasing to 350 million hectares by 2030). To assess progress toward these goals, our team investigated two questions: How much tree cover has been lost? And how much land is actually under restoration?

For this analysis, we combined novel satellite-based algorithms from the University of Maryland's GLAD Lab and data collection techniques from the Food and Agriculture Organization's Collect Earth tool to produce the first-ever assessment measuring changes in tree cover on all types of land. This method captures multiple types of restoration activities: from dense, natural tree cover inside forests to the sparse tree cover on farms, shrublands and settlements outside forests. While this research only assessed countries in the Mekong region, the method can be applied globally.

Forest Landscape Restoration Pays Off for People


A farmer in Myanmar harvests green beans in a landscape of mixed crops and trees. Photo by James Anderson/WRI.
A farmer in Myanmar harvests green beans in a landscape of mixed crops and trees. Photo by James Anderson/WRI.

The new report shows that monitoring restoration is critical to achieving real progress. Thailand and Vietnam have shown leadership as the region's two signatories to the New York Declaration on Forests. They also have some of the most promising statistics on increased tree cover. But monitoring is not just about holding countries accountable to their pledges. Keeping track of where and how land is regenerating provides governments, experts and on-the-ground stakeholders like communities, NGOs and businesses with valuable information on how their investments in restoration are paying off.

Measuring progress encourages communities to restore land because it provides evidence that restoration efforts work. By visualizing where trees are growing, we can go to those places and see if people there are benefitting from pay-offs in water quality, food productivity and livelihoods. Often, they are. In fact, new analysis by the Food and Land Use Coalition shows that forest restoration alone provides an economic opportunity of $175 billion globally, much of which will flow directly to rural communities that rely on and care for the land.

The future of the world's forests is in our hands, and it's time to act. Measuring tree restoration, both inside and outside forests, is a crucial first step toward achieving the goals that the New York Declaration on Forests set out five years ago. By doing so, we can ultimately beat deforestation and climate change.