Far East's rainforests shaped by humans for the last 11,000 years

Researchers have shown that the tropical forests of South East Asia have been shaped by humans for the last 11,000 years.

A major analysis of vegetation histories across Borneo, Sumatra, Java, Thailand and Vietnam has revealed a pattern of repeated disturbance of vegetation since the end of the last ice age approximately 11,000 years ago.

Queen's Palaeoecologist Dr Chris Hunt, who is Director of Research on Environmental Change at Queen's School of Geography, Archaeology and Palaeoecology, said that it has long been believed that the rainforests of the Far East were virgin wildernesses, where human impact has been minimal but their findings indicate a history of disturbances to vegetation.

He said that while it could be tempting to blame these disturbances on climate change, that is not the case as they do not coincide with any known periods of climate change. Rather, these vegetation changes have been brought about by the actions of people.

Hunt said that there is proof that humans in the Kelabit Highlands of Borneo burned fires to clear the land for planting food-bearing plants. Pollen samples from around 6,500 years ago contain abundant charcoal, indicating the occurrence of fire. owever, while naturally occurring or accidental fires would usually be followed by specific weeds and trees that flourish in charred ground, they found evidence that this particular fire was followed by the growth of fruit trees. This indicates that the people who inhabited the land intentionally cleared it of forest vegetation and planted sources of food in its place.

He said that one of the major indicators of human action in the rainforest is the sheer prevalence of fast-growing 'weed' trees such as Macaranga, Celtis and Trema. The research has been being published in the Journal of Archaeological Science.