The relationship between tree productivity and biomass not only reflects plant adaptation and the interaction of plants and the environment, but also has significant implications in global carbon cycling, climate change, and forest management. However, how biotic factors (e.g. tree age, diameter at breast height [DBH], height) and abiotic factors (e.g. elevation, latitude, and longitude) influence this correlation has not been well investigated.

Prof. REN Hai, from South Chinese Botanical Garden and Dr. HUI Dafeng from Tennessee State University, USA jointly studied the relationship between the two variables based on 6153 records from tree productivity and biomass database in China. The trees were divided into 8 groups along with single group variable gradient (e.g. age) and then both linear regression model and allometric equation (i.e. power function) were applied to determine the correlation between productivity –biomass relationship and the group variable. Same procedures were performed to each of the group variables (i.e. age, DBH, height, density, elevation, latitude and longitude) Differences in model parameters among groupings indicated significant productivity—biomass correlation which, nevertheless, varies with group variables. The result revealed that, to improve the estimate of tree productivity based on biomass, tree age and size are expected to be considered, which was overlooked in previous researches.

This work was supported by the "Strategic Priority Research Program" (No.XDA05050206) of the Chinese Academy of Sciences, and has been published online by the international journal, Forest Ecology and Management (http://www.sciencedirect.com/science/journal/03781127/264).