Buttress trees in a 20-hectare tropical dipterocarp rainforest in Xishuangbanna, SW China

Abstract

AimsButtresses are prevalent and are important to many ecological processes in tropical rainforests but are overlooked in many rainforest studies. Based on a buttress survey in a 20-hectare plot, this study aims to answer the following questions: (I) Is buttress forming a fixed species characteristic? (ii) Is there any phylogenetic signal for buttress forming across a broad taxonomic scale? (iii) Is buttress forming an inherent feature or simply induced by environmental factors, and how is this relevant to the size of the tree?MethodsWe surveyed buttresses for all 95940 trees with diameter at breast height (DBH) ≥10mm in a 20-ha tropical dipterocarp rainforest in Xishuangbanna, SW China. The occurrence of buttresses was compared across different taxa and across different tree-size classes. A phylogenetic analysis was conducted among buttressed and non-buttressed species in order to understand the evolutionary background of buttress formation.Important FindingsThis preliminary study showed that buttress trees are very abundant (making up 32% of trees with ≥100mm DBH) in this 20-ha tropical rainforest situated at the northern edge of the tropics. Fifty-one percent of the 468 tree species in the plot had stems that produced buttresses. Large trees were more likely to develop buttresses than smaller ones. We found that although buttress formation is not a fixed species characteristic, there is a strong phylogenetic signal for buttress formation in larger species. © 2012 The Author 2012. Published by Oxford University Press on behalf of the Institute of Botany, Chinese Academy of Sciences and the Botanical Society of China. All rights reserved.