Large Trees In Tropical Rain Forests Require Big Plots

Societal Impact StatementGlobally, the conservation value of big trees is linked to biodiversity and carbon sequestration. We studied trees, greater than 80 cm in diameter, in a forest in the Republic of Congo. We found that more than 100 species reach this size and the most abundant species is Sapele (Entandrophragma cylindricum), which is exploited for global timber markets. More than 40% of the large tree species are used by local people for food. Our results show that big trees are important to local people in the Congo Basin in addition to being the focus of industrial logging and in many areas the basis for the formal economy.SummaryThe main aim of this paper is to establish standard techniques for surveying the biggest trees in tropical rain forests. One hundred and thirty hectares (13 plots of 10 ha) of unlogged mixed species terra firma forest in the Republic of Congo were surveyed for trees greater than 80 cm in diameter. More than 100 species of tree exceed 80 cm in diameter and one species, Entandrophragma cylindricum (Sapele or Sapelli), dominates this size class. Obtaining comparable data of big trees from different sites across the tropics is a priority. We propose a standardised plot size of 10 ha, replicated 10 times for each forest type at different study sites and a minimum trunk diameter of 70 cm at breast height or above buttresses.