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

Growth Effect Research of Thinning on Larix Principis-rupprechtii Plantation in Guandi Mountain Forest

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0.001 09 m3/a^0.001 24 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5 000株/hm2~5 500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.