Biomass study warns against large tree logging

Forest management and climate change mitigation have come under scrutiny after a study found that up to half of the aboveground biomass found in tropical forests is stored in a selection of big trees.

Ferry Slik, a scientist at the Centre of Integrative Conservation, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, led the study, Reuters reports, which was published in Global Ecology and Biogeography. Forest locations in South America, Africa and Asia were examined for the study.

The researchers found that bigger trees (>28" in diameter at breast height) store more biomass than previously thought. 'Only 3% of the forests are made up of big trees, but these trees store up to half the biomass,' Slik was reported to have said. 'If just a few of these large trees die, it immediately has a major impact.'

Additionally, changing climatic conditions impact the storage of tropical forest biomass. Slik explains: 'If temperatures keep rising – a 2-6°C rise is predicted over the next century – it will likely negatively affect these big trees.'

But learning that large trees play a key role in tropical forest biomass storage is just the beginning. 'Now we know these big trees are important for biomass but we still don't know much about the dynamics of these trees – how fast they grow, how old they get – because researchers have been concentrating on relatively small plots which contain few big trees due to their low density, Slik was quoted as saying.

He concluded: 'Logging usually concentrates on larger trees. Maybe it's better to focus on intermediate-size trees. Logging could be managed in a more environmentally friendly way. The biggest threat to these large trees is human intervention in forests. As soon as logging or agricultural activities begin, these trees are usually the first to disappear. It takes a very long time to get them back.'