采伐对蒙古栎次生林林分生长和林分结构的影响

Effects of the Cutting Intensity on Stand Growth and Structure for Querus mongolica Secondary Forests

探讨不同采伐强度下林分生长和林分结构的变化,对于实现森林的可持续经营具有重要意义。以辽东山区52a生蒙古栎天然次生林为研究对象,分别设置强度采伐(40%)、中度采伐(29%)和对照(0%)3块固定样地,利用伐后7年长期连续观测数据,分析不同采伐强度对林分生长和林分结构的影响。结果表明:1)采伐促进了林分平均胸径和单株材积的增长。采伐7年后,强度、中度采伐林分平均胸径分别比对照增长6.9cm和5.2cm,单株材积分别为对照的1.8倍、1.5倍(P<0.05)。2)采伐降低了林分蓄积量,提高了林分蓄积生长率,7年间林分蓄积年均生长率表现为中度采伐>强度采伐>对照。3)采伐降低了林分平均混交度,使林分整体趋向于纯林。在林分空间分布格局方面:中度采伐提高了随机分布林木比例,林分整体呈随机分布;强度采伐反而降低了随机分布林木的比例,林分整体呈聚集分布。采伐促进了蒙古栎天然次生林的生长,优化了林分结构,综合考虑宜采用中度采伐强度。

It is of great significance to study the changes of stand growth and stand structure under different cutting intensities for sustainable forest management.In this study,a natural secondary forest of 52 years old Quercus mongolica in mountainous area of eastern Liaoning was studied,and three fixed sample plots of high intensity(40%),medium intensity(29%)and control(0%)were set,respectively.Based on the long-term continuous observation data of 7 years in the after-cutting period,the effects of different cutting intensities on growth and stand structure were compared and analyzed.The results showed as follows:(1)cutting promoted the increase of mean DBH and individual volume.After 7 years of cutting,the average DBH of high intensity and medium intensity stands increased by 6.9cm and 5.2cm,respectively,and the individual volume was 1.8 times and 1.5 times than that of the control,respectively.(2)The cutting reduced the stand volume and increased the stand volume growth rate.The average annual growth rate of the stand volume during the 7-year period was medium intensity>high intensity>control.(3)The cutting reduces average value of mingling degree of stands,which makes the whole stand tend to be pure forest.In the spatial distribution pattern of stands,medium intensity increased the proportion of randomly distributed trees,and the whole stand distribution pattern showed randomly distribution;On the contrary,high intensity reduced the proportion of randomly distributed trees,and the whole stand distribution pattern showed aggregated distribution.Cutting promoted the growth of natural secondary forest of Quercus mongolica,optimized the stand structure,and medium intensity should be adopted.