基于树木年轮信息的宝天曼不同径级华山松碳储量动态变化

Carbon storage dynamics of Pinus armandii forest at different diameter levels based on tree ring data in the Baotianman National Nature Reserve, central China

基于树木年轮学方法,本文分3个不同径级研究了宝天曼自然保护区华山松碳储量的动态变化.研究发现:(1)随着径级的增大,小径级A(DBH?15 cm)、中径级B(15<DBH?25 cm)和大径级C(DBH>25 cm)华山松碳储量分别为2.757,9.211,15.408 t/hm2,它们年均增加的碳储量分别为0.0685,0.1535,0.136 t/hm2;(2)中径级华山松林分密度和径向生长量最大,其年均碳储量增长量大于大径级华山松和小径级华山松;(3)大径级华山松每年碳储量增长量决定着华山松林总碳储量的变化.个体死亡率是限制中小径级华山松碳储量增长的重要因素,树木生理生长的影响是限制大径级华山松碳储量增加的主要因素.研究结果表明,利用树木年代学序列能较好地探讨宝天曼华山松生长趋势和评估碳储量的动态变化.

Based on tree-ring analysis, Pinus armandii trees were divided into three classes（A, DBH≤15 cm; B, 15 cm〈DBH≤25 cm; C, DBH 〉25 cm） to study carbon storage dynamics of Pinus armandii populations in the Baotianman National Nature Reserve. Comparison of these three diameter classes revealed three major findings.（1） The carbon storage of P. armandii trees in small DBH class A, intermediate class B and large class C were 2.757, 9.211 and 15.408 t/hm2, respectively, with corresponding annual carbon increments of 0.0685, 0.1535 and 0.136 t/hm2.（2） The intermediate class（15 cm〈DBH≤25 cm） had the highest stand density, diameter increment and carbon storage among the three DBH classes in the P. armandii forest.（3） Trees in the large DBH class（DBH〉25 cm） had the greatest contribution to total carbon storage of the P. armandii forest. Tree mortality was the main factor limiting carbon storage within small and intermediate DBH class P. armandii trees, whereas physiological growth was the restrictive factor for large DBH class trees. Our results demonstrate that dendrochronological analysisis is an important method to evaluate growth trends and to assess the carbon storage dynamics of the P. armandii forest in the Baotianman National Nature Reserve.