300 hectares of forest collapse in UNESCO reserve in Vietnam's Mekong Delta

At U Minh Ha National Park in Vietnam's Mekong Delta, about 300 hectares of melaleuca forest have toppled, a decline park officials link partly to years of holding water back to prevent fires.

Stretches of dried-out, dead melaleuca mixed with fallen, broken trunks at U Minh Ha National Park.

In the distance, a band of forest remains healthy and green. According to the park, the decline has unfolded over roughly the past 10 years and has grown increasingly pronounced in sub-zones 1 and 3.

U Minh Ha National Park is one of three important wetland conservation areas in the Mekong Delta and forms the core zone of the UNESCO-recognized Ca Mau Cape World Biosphere Reserve.

Large melaleuca trees, completely uprooted, sit interspersed with grassy mounds and stumps left soaking underwater for long stretches.

A mass of melaleuca roots torn from the ground, dragging up a thick layer of black peat. According to the U Minh Ha National Park management board, as the dry season sets in, the peat layer loses its cohesion, leaving many old melaleuca trees unable to anchor themselves and prone to toppling in large numbers.

Rangers managing and protecting U Minh Ha National Park survey the deteriorating melaleuca trees. Because the area is a strict conservation zone, measures that directly intervene in the forest are limited.

A melaleuca seedling about 30 centimeters tall, at risk of dying. Under prolonged high water, young melaleuca cannot rise above the water line to photosynthesize and die off in the earliest stage of growth.

Beyond the 300 hectares already degraded, about 400 more hectares are at risk of further decline if adverse conditions persist.

As the melaleuca forest has declined, open gaps have formed and are gradually being taken over by plants such as grasses, spikerushes, reeds and swamp ferns. This is regarded as a sign of structural change in the ecosystem if the forest is not restored.

The core zone of U Minh Ha National Park spans more than 8,500 hectares. Of that, over 2,500 hectares fall within the zone for conserving the peatland melaleuca forest ecosystem, and more than 5,190 hectares belong to the zone for restoration and sustainable use of the wetland ecosystem.

U Minh Ha's melaleuca forest in decline. Video by Chuc Ly