关帝山林区华北落叶松人工林不同强度间伐的生长效应研究

摘要

抚育间伐是恢复森林生态系统功能、实现森林资源可持续利用的重要森林经营措施。笔者以关帝山林区华北落叶松人工林样地为研究对象，研究不同抚育强度对华北落叶松林生长量变化的影响。研究结果表明：在一定的立地条件下和密度范围内，间伐措施能提高华北落叶松人工林胸径、立木材积的生长量，间伐组胸径年均生长量比对照组增加0．37 cm／a～0．59 cm／a，年均生长率比对照组增加4．05％～5．19％；立木材积的年均生长量比对照组增加0．00109 m3／a～0．00124 m3／a，年均生长率比对照组增加4．48％～5．83％．强度间伐对树高生长有短期促进作用，年均生长量最高达到0．63 m／a，年平均生长率最高达到7．1％，但高生长对间伐效应的长期响应不明显。单位面积蓄积量对间伐强度的响应不明显，但间伐组年平均生长量、年平均生长率均比对照有所增加，以强度间伐效果最好。对初始密度为5000株／hm2～5500株／hm2的20年生华北落叶松人工林的抚育间伐强度进行观测分析，间伐强度最高可达到50％，保守设计适宜强度为40％．%Thinning is the important forest resource management method to rebuild and recover the intrinsic function of for -est ecosystem and achieve sustainable forest management .Larix principis-rupprechtii plantation in Guandi Mountain were used for researching its growth variation under different thinnning intensities .Results showed that after thinning , the DBH and individual volume of Larix principis-rupprechtii plantation increased quickly at the certain site and thinning intensities . The DBH annual growth was turned to be 0.37 cm/a~0.59 cm/a and and annual growth rate was 4.05%~5.19%, annu-al growth of volume was 0.001 09 m3/a~0.001 24 m3/a, annual growth rate of volume was 4.48%~5.83%compared to the control.The height under heavy thinning was growing quickly and the height annual growth was 0.63 m and annual height growth rate was 7.1%.But from the long period observation , the height did not response with thinning .It was no obviously correlated between the stock volume per unit area and thinning , but after thinning , the stock volunme annual growth and annual growth rate were growing quickly .For 20 year-old and the original intensity was 5 000 plants/hm2 ~5 500 plants/hm2 Larix principis-rupprechtii forest,the thinning intensity could be 50%,and 40%conservatively.