New advance in the cooperative research on net forest primary production on the big sampling plot of temperate forest on Changbai Mountain
Net primary production (NPP) of forest is the production of forest in the natural environment and it reflects also the ability of forest in carbon accumulation. The research in forest NPP has been a major aspect of ecology and a focus in the global change study. Though we have got many understandings in forest production on various scales, there has been no unanimous conclusion on the scale of individual trees. Many authors reported that the growth rate of trees decreased with the increase in tree size (trunk diameter). The estimation was mostly drawn from data in photosynthesis measurement on individual leaf level. However, according to metabolic scaling theory, the growth rate in plant biomass should be increase with the size of the plant.
So as to assess the changes in carbon accumulation rate in relations to tree trunk diameter(DBH), Dr Stephenson in Unites States Geological Survey and 38 scientists from 30 institutions investigated 672127 big trees of 403 species on permanent sample plots globally. The results show that the trees with DBH over 100cm fix 103 kg carbon per year. It is 3 times that of trees with diameter 50cm. The mentioned big trees in more than 96% surveyed species still accumulate carbon and the rate increases with increase in DBH ( and age). The results were published on January 1st in Nature on line, entitled as “Rate of tree carbon accumulation increases continuously with tree size”.Prof Zhanqing Hao and Prof Xugao Wang in our institute are the working team members and coauthors of the published paper.