The Application of Competition Indexes on Individual Tree Growth Models for Predicting the Growth of Taiwania Cryptomerioides

• Main Authors: Tu, Chia-Wei, 杜加維
• Other Authors: Wen-Liang Lin
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/83880330261109981291

碩士 === 國立臺灣大學 === 森林學系 === 86 === Abstract In the forest management stressing ecological principles, whole- stand growth models offering information of stands can''t meet our requirements in some aspects. In order to get more quintessential information of trees like the variations of the growth of the different trees in the same stand, developing individual-tree growth models is an important issue in forestry. The competition is very important in many ecological relations affecting the growth of an individual tree, and the intertree competition is just the most important factor for a tree in a stand. We can derive the growth of the trees according to the quantifying of competition. This thesis used 15 size-ratio competition indexes representing intertree competition to derive individual-tree growth models. Mathematical functions of these models were established with multiple regression empirical models and non-linear semi-empirical models. The models will predict periodic increments of diameter at breast height(DBH) and those of basal area(BA) from 23-year-old to 32-year-old Taiwania cryptomerioides in the Experimental Forest of National Taiwan University. The different competition indexes, formulas for determining the competitors, and evaluations of the models will be compared and analyzed. The study result showed, compared with original empirical models, the models established by stepwise regression could determine the independent variables more effectively. Among growth models deriving from competition indexes of 15 types, the non-linear semi-empirical model deriving from Hegyi''s competition index was the best; the search radius using DBH angle gauge method was better than the fixed radius method.