Selection of quadrat for biomass harvesting and model of Eupatorium adenophorum in Xishuangbanna

Biomass and carbon stock of grassland vegetation are important components of terrestrial carbon sequestration, to reinforce the research of biomass of grassland vegetation can increase the precision of estimating regional vegetation carbon stock. Based on time and labor consumed, this paper studied selection of optimum size and number of the sampled quadrats in estimating Eupatorium adenophorum biomass under the standard error of mean needed to control, furthermore, an optimum independent variable was chosen to simulate prediction equation of estimating biomass of E.adenophorum. And the results indicated that, 1) the suggested optimum size of E.adenophorum biomass sampling was 2.00 m2, and the suggested sampling number was 15; 2)During the three selected combination variables D2H (the square of the plants basal diameter multiplied by the hight); CH (the width of the plant's crown multiplied by the hight);PH (the cover of the plant multiplied by the hight) for establishing biomass estimation models, CH was better than the other two variables for its correlation with biomass and simulation of linear regression equation.