六盘山华北落叶松人工林生长规律研究

A study on the characteristics of stand growth of Larix principis-rupprechtii plantation in Liupan Mountains

采用标准地调查和标准木树干解析法调查林龄为31年的华北落叶松人工林,对解析木资料进行综合汇总、计算,绘出华北落叶松树高、胸径、材积的生长曲线图,揭示华北落叶松在六盘山区的生长动态规律.结果表明：华北落叶松的胸径、树高、材积总生长量随着林龄增长,呈明显的上升趋势,胸径、树高连年生长量呈明显的波浪型增长趋势,胸径快速增长主要集中在6—16年;第7年时,胸径生长量达到连年生长量的最高峰.华北落叶松树高快速增长主要集中在6—14年,第12年时,达到连年生长量的最大值;材积连年生长量快速生长期主要集中于12—29年,材积生长量保持在0.007-0.031 m^3;第29年时,达到材积生长量的最高峰.材积连年生长量的快速生长期较胸径连年生长量、树高连年生长量迟.第11年、14年时,林分的高生长、胸径生长均有明显下降,可将第11—14年,定为对华北落叶松开展首次抚育间伐的最佳时间段,之后应当按森林经理期5-8年,定期对华北落叶松人工林开展森林抚育间伐措施,以保证其胸径、树高的正常生长.华北落叶松为早期速生型树种,其材积生长率曲线随着林龄的增长呈明显的下降趋势.

This paper is based on the calculation of data of sample trees by means of plot investigation and stem analysis the growing curves of tree height, diameter of breast height（DBH） and volume of timber were drawn to determine the characteristics of the stand growth of 31 a Larix principis-rupprechtii plantation in LiuPan Mountains.The results show that：The growth of tree height, DBH and volume of Larix principis-rupprechtii increased significantly with the age of plantation. The growing curves fluctuated in the processes of increase in tree height, DBH. Growth of DBH was quickly at age of 6-16 a, and reached its peak of annual growth at age of 7a. In similar, growth of tree height was quickly at age of 6-14 a, and reached its peak of annual growth at age of 12 a. However, growth of volume of timber was quickly at age of 12-29 a, then kept annual growth with 0.007-0.031 m^3, and reached its peak of annual growth at age of 29 a. The quick growth of volume of timber was delayed compared to that of tree height and DBH. And the growth velocity of tree height and DBH decreased apparently, thus optimal phase for primary thinning of Larix principis-rupprechtii plantation could be determined during this stage. After that,proper thinning of the plantation should be carried out, at period of management cycle of 5-8a, to insure the normal growth of tree height and DBH. Larix principis-rupprechtii is a tree species of early-stage-quick-growth, the growth velocity of volume of timber presents a trend of drop with the age.