I have spent eight years working in the floating villages of Tonle Sap Lake, one of the world’s largest freshwater fisheries.
Almost all of the families I know make their living in some way from the lake where they live, which provides two-thirds of Cambodia’s protein consumption. But I was recently surprised to learn that one of the species they’re the most dependent on is not a fish, but a tree.
The flooded forest grows in the lowlands of Tonle Sap Lake, stretching over 300,000 hectares (741,000 acres). The forest is known to contain more than 200 species of tree within gallery forest and bush shrub habitats.
The dominant species present along rivers, streams and canals is a tree known in the Khmer language as raing (Barringtonia acutangula). A tall tree that can reach up to 20 meters (66 feet) high, raing can survive in the water for up to nine months at a time.
This one species of tree provides a remarkable range of direct and indirect benefits for local people, including:
- Fish nurseries: Tree roots and branches shelter young fish from predators and keep overall fish populations healthy. In return, herbivorous fish help disperse the tree’s seeds.
- Medicine: Leaves and bark are used to treat diarrhea and stomachache.
- Food: The tree’s young leaves can be added to meals as a vegetable supplement.
- Firewood: Dead raing trees have been recognized as good firewood for smoking fish, one of the primary sources of livelihood on the lake.
- Windbreak: Due to the size of these trees, they act as a wind barrier that protects the fishermen’s boats and houses from storms, a role that will become even more important as climate change strengthens the intensity of storms.
- Housing anchors: Residents of floating houses have to tie their homes to treetops in order to keep them from drifting. The strength of raing trees makes them popular choices for this job.
- Rope: Local people use the young tree’s bark to make string or rope for fishing and other uses.
- Erosion Protection: This type of tree, along with others in the inundated forest, plays a very important role in protecting the lake and river from erosion.
- Wildlife habitat: In addition to fish, these trees provide habitat for waterbirds and mammals. The region’s unique species have recently attracted more international tourists, so this tree indirectly supports local livelihoods derived from tourism.
Despite — or perhaps because of — the flooded forests’ value for nearby communities, they are greatly threatened by human activities like overexploitation for firewood, overfishing and deforestation to make way for agriculture plots. Recent water level changes in the Mekong River due to dams are also predicted to have a huge impact on the lake’s ecosystems, even further reducing the size of the flooded forest. In fact, more than 95 percent of the lake’s flooded forest has already been destroyed.
Fortunately, local communities are taking action. Since 2010 three community fisheries — Kompog Prak, O’taprok and Kompong Lor — have strongly collaborated with CI’s project to protect, maintain and replant flooded forest.
With technical support and materials from CI, these three communities have each created tree nurseries. Over the past four years, they have replanted more than 120 hectares (296 acres) with 75,000 seedlings.
Members of the community fisheries have been strong participants in these activities, voluntarily contributing labor, patrolling and guarding replanted areas from fire, chasing domestic animals from replanting sites and removing weeds. When CI assessed the survival rate of the trees planted during the first year, we found that more than 60% of the seedlings survived.
In just a few years of replanting, the landscape is visibly greener with the young trees, some of which have grown to over a meter in height. Our reforestation effort will benefit over 200 nearby families, allowing them to continue their livelihoods and become more resilient to the predicted impacts of climate change.
As we’ve seen, raing trees impact the lives of the people living in and around Tonle Sap Lake in a myriad of ways, from food security to human health. Imagine what would happen if all the raing trees disappeared tomorrow — and keep in mind this is the story of just one species.
Biodiversity forms the building blocks of all life on Earth; the loss of one species can have unpredictable, wide-ranging impacts. By preserving and restoring ecosystems as a whole, we are giving all of Earth’s living things — including ourselves — the best chance of survival.
Sokrith Heng manages CI Greater Mekong’s work in the Tonle Sap Lake region. Thanks to Chanthorn Srorn, Kriya Sith, Vann Layhim, Tangkor Dong and Rachana Seng for their contributions to this blog.