采伐对天然云冷杉针阔混交林半分解层凋落物现存量、含水率及林分郁闭度空间异质性的影响

目的]以吉林省汪清林业局金沟岭林场4块天然云冷杉针阔混交林为研究对象,探究不同采伐强度下重度(采伐强度21. 21%),中度(采伐强度11. 22%),轻度(采伐强度6. 29%)和对照(未采伐)]凋落物半分解层现存量、含水率与林分郁闭度的空间异质性。方法]采用地统计学方法,对各样地凋落物半分解层现存量、含水率与林分郁闭度数据进行普通克里金插值,得到3个指标的空间分布格局图。结果]表明:在10 100 m的尺度上,采伐使得凋落物现存量由离散型分布转变为聚集型分布,而对凋落物含水率的空间格局影响不大;所有样地的郁闭度均表现为聚集型分布,采伐一定程度上影响了其在中度采伐与重度采伐样地的空间异质性;凋落物现存量与林分郁闭度之间不存在相关性,而在对照样地,凋落物现存量与含水率存在显著的负相关,但相关程度较弱(r 0. 3)。结论]采伐对凋落物半分解层含水率空间异质性影响不大;中度采伐与重度采伐样地的郁闭度异质性可能是由于采伐不均匀所导致;采伐使凋落物现存量空间异质性程度降低。

Effect of Cutting on Spatial Heterogeneity of Standing Crop and Water Content in Semi-decomposition Litter Layer and Canopy Density in Natural Spruce-fir Mixed Forest

Objective] Four 1-hectare plots of natural mixed spruce-fir coniferous and broadleaf forests located in Jin''gouling Forest Farm of Jilin Province were investigated to explore the spatial heterogeneity of standing crop and water content in semi-decomposition litter layer and forest canopy density under different cutting intensities21.21% of volume removed (heavy cutting), 11.22% (medium cutting), 6.29% (light cutting) and the control (no thinning)].Method] An ordinary Kriging interpolation was performed on the data of the standing crop and water content in semi-decomposition litter layer and forest canopy density, and then their spatial distribution pattern was obtained using geostatistical methods.Result] At the scale of 10XC~.TIF]100 m, cutting resulted in the standing crop of litter from a discrete distribution to aggregated distribution but with little effect on the spatial heterogeneity of water content. The canopy density of all plots showed an aggregated distribution and cutting affected the spatial heterogeneity of medium and heavy cutting plots to some extent. There was no correlation between the standing crop and canopy density. However, there was a significant negative correlation between the standing crop and water content in the control and the moderate cutting stands, but to a lesser degree (r<0.3).Conclusion] Cutting has little effect on the spatial heterogeneity of water content in semi-decomposition litter layer. The heterogeneity of forest canopy density in the plots under medium cutting and heavy cutting may result from uneven cutting. Cutting reduces the degree of spatial heterogeneity in the standing crop of the semi-decomposition layer.