云冷杉过伐林主要树种结构特征分析

Analysis of Structure Characteristics of Main Tree Species in Spruce-Fir Overcutting Forest

选择长白山针阔比9∶1、8∶2、7∶3的云冷杉过伐混交林,探讨直径结构、空间格局、蓄积生长、林下更新以及植物多样性等林分结构问题,为恢复红松为主的针阔混交林,提出结构调整思路。研究表明:由于过去以不合理的非经营性采伐,红松成主要择伐对象,红松不同年份各径阶株数变化幅度较大,直径18 cm开始出现缺损株数现象,缺乏中、大径组株数,导致母树数量、结实量和种源减少,造成在主要树种中红松更新最差的问题,不利于林分正向演替。不同针阔比混交林空间格局与其主要树种空间格局并非完全一致,在同一林分不同树种间存在差异。针阔比9∶1、8∶2、7∶3的混交林空间格局分别为随机分布、聚集分布和均匀分布。其中,红松分布格局主要呈聚集分布。因此,恢复以红松为主的针阔混交林,以红松和珍贵阔叶树种作为目标树种,采取目标树培育方法,伐除影响其更新和生长的林木,而将云冷杉和一般阔叶树作为伴生树种,逐渐减少云冷杉的优势,最终逐渐恢复成红松阔叶混交林;对针阔比8∶2和7∶3混交林红松分布格局,采取人工补植、间伐等措施,结合天然更新,向随机分布进行调整;采取人工补植、清理母树周围枯枝落叶层等措施人工辅助红松天然更新。

In order to propose new design ideas of recovering mixed stand whicn mainly by Pinus Koraiensis, some issues about stand structure were discussed and analyzed, such as diameter, spatial pattern, stand volume growth, regeneration and plant diversity, based on three types of overcutting spruce-fir forest on Changbai Mountains. The most difference among the forests was the ratio of conifer trees to broad-leaved trees, with stepped-rates of 9： 1,8：2 and 7： 3. The results showed that： P. koraiensis forest became cutting object because of unreasonable and non-operating cutting in the past. The amount of P. koraiensis trees greatly changed among different diameter intervals, and loss happened when diameter greater than 18 em, which led to the decline of parent tree, seed and provenance, contrary to positive evolution. The spatial pattern of mixed stand was not exactly the same as that of the main tree species, and showed difference among different trees in the same stand. The three forests with different needle/broadleaf ratios followed a random, aggregation and uniform distribution. P. koraiensis assumed aggregation distribution. So the following should be done to recover mixed stand which mainly composed of P. koraiensis. 1. Taking P. koraiensis and precious broadleaf species as the goal, adopting the target tree cultivation method, removing the trees affecting the renewal and growth of target trees, taking spruce fir and broad-leaved tree as accompanying species, weakening the dominance of spruce and fir, and eventually restored the stand gradually to the P. koraiensis and broad-leaved mixed stand; 2. For the stand with conifer tree and broadleaved tree mixed in the ratio of 8：2 and 7： 3, changing aggregation distribution into uniform distribution through repair planting, intermediate cutting and combined with natural regeneration; 3. Adopting artificial supplementary interventions to help the natural regeneration of P. koraiertsis, such as repair planting, litter cleaning and so on.