阔叶红松林不同林层和生长阶段树木生长对采伐强度的响应  

Responses of tree growth to harvesting intensity among forest strata and growth stages in a broadleaved Korean pine forest

作　　者：魏龙鑫 耿燕[1] 崔可达 乔雪涛 岳庆敏 范春雨[1] 张春雨[1] 赵秀海[1] WEI Long-Xin;GENG Yan;CUI Ke-Da;QIAO Xue-Tao;YUE Qing-Min;FAN Chun-Yu;ZHANG Chun-Yu;ZHAO Xiu-Hai(Research Center of Forest Management Engineering of State Forestry and Grassland Administration,Beijing Forestry University,Beijing 100083,China)

机构地区：[1]北京林业大学国家林业和草原局森林经营工程技术研究中心,北京100083

出　　处：《植物生态学报》2022年第6期642-655,共14页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(32171521和32001312)。

摘　　要：采伐是调整林分结构的重要手段。不同林层的树木对采伐强度有着不同的响应方式。但以往考察采伐对树木生长的影响时多采用定性或简单定量的方法(如按树高等距)划分森林的垂直层次,这就忽略了同一林层内不同树种间和不同发育阶段树木生长的差异。该研究在吉林蛟河天然阔叶红松(Pinus koraiensis)林内建立轻度(胸高断面积采伐强度17.3%)、中度(34.7%)、重度(51.9%)采伐以及对照(不采伐)样地,跟踪调查采伐后自然恢复2、4、7年保留木的生长动态。根据不同树种每一个体所处的林层位置和生长发育阶段,将保留木划分为3个组别:林冠层树种的成熟个体(Ⅰ)、林冠层树种的未成熟个体(Ⅱ)以及林下层树种的全部个体(Ⅲ),比较不同恢复时期各组别树木的生长对于采伐强度的响应差异。结果表明,第Ⅱ组树木的平均胸径相对生长速率(0.033 cm·cm^(-1)·a^(-1))显著高于第Ⅰ(0.016 cm·cm^(–1)·a^(-1))和Ⅲ组(0.018 cm·cm^(-1)·a^(-1))。总体来看,采伐促进了大多数林冠层优势树种(第Ⅰ、Ⅱ组)的生长,尤其是第Ⅱ组树木的相对生长速率随采伐强度的增加而增加,但第I组树木的相对生长速率只在重度采伐样地显著高于对照样地。然而林冠层少见种的生长速率并未受到采伐活动的显著影响。值得注意的是,第Ⅰ和Ⅱ组树木生长对于采伐的响应都存在一定的时间滞后,伐后短期内(2年)采伐样地与对照样地的生长速率没有显著差异,而采伐对树木生长的促进效果在伐后2–4年才开始出现,并在随后的监测期内持续存在。各组别树木的相对生长速率均随初始胸径的增大而降低,且这种负相关关系的斜率随采伐强度增加逐渐增大,表明随着采伐强度增加,较小的树木个体从减弱的竞争中获益更多,呈现出更加明显的生长释放现象。Aims Harvesting is an important way to adjust stand structure.Trees in different forest strata have different responses to harvesting intensity.Traditionally,qualitative or simple quantitative methods(e.g.,with equal distance of tree height)were used to identify the vertical layers of the forest,and the impact of harvesting on each layer were analyzed subsequently.However,these methods of specification ignore the differences in tree growth between different tree species and different developmental stages within the same layer.Methods Four permanent plots were established in a broadleaved Korean pine forest in Jiaohe,Jilin Province,ranging in harvesting intensities from low(17.3%of basal area removed),medium(34.7%)to high(51.9%),together with an unharvested control plot.Tree growth rates were documented 2,4 and 7 years after harvesting.According to the position of an individual tree in the forest layer,as well as its development stages,we aggregated all individuals into three cohorts:mature canopy trees(Ⅰ),immature canopy trees(Ⅱ),and understory species of any size(Ⅲ).Tree diameter growth of each cohort were compared during different recovery periods.Important findings The average relative growth rate(RGR)of diameter at breast height(DBH)for cohortⅡ(0.033 cm·cm^(-1)·a^(-1))was significantly higher than that of cohortⅠ(0.016 cm·cm^(-1)·a^(-1))andⅡ(0.018 cm·cm^(-1)·a^(-1)).Overall,harvesting promoted the DBH growth of most canopy dominant tress(ⅠandⅡ).In particular,RGR of cohortⅡincreased progressively with increasing harvesting intensity,while only the greatest harvesting intensity showed a significant positive effect on RGR of cohort I.In contrast,rare species showed weak responses to harvesting treatment.It should be noted that there was a response lag of tree growth to harvesting:no detectable difference in RGR was found between control and harvested plots within the first two years after harvesting,whereas the positive effect of harvesting on RGR began to appear 2–4 years after harvest

关 键 词：阔叶红松林 采伐强度 相对生长速率 林层 个体大小 恢复时期 

分 类 号：S791.247[农业科学—林木遗传育种] S782.1[农业科学—林学]