燕山北部白桦林剥皮木的空间分布特征及风折规律  

Spatial Distribution and Patterns of Wind-Breakage of Debarked Betula platyphylla in Northern Yanshan Mountains

作　　者：李永宁[1,2] 刘丽颖[1] 冯楷斌 黄选瑞[1,2] 

机构地区：[1]河北农业大学林学院,保定071000 [2]河北省林木种质资源与森林保护重点实验室,保定071000

出　　处：《林业科学》2016年第1期10-17,共8页Scientia Silvae Sinicae

基　　金："十二五"农村领域国家科技计划"华北土石山区森林可持续经营技术研究与示范"(2012BAD22B0304)

摘　　要：[目的]探讨燕山北部山地白桦林剥皮木的空间分布特征及风折规律,为白桦次生林的健康经营与合理利用提供科学依据。[方法]选取冀北山地典型白桦林,采用空间梯度分析、点格局分析与二项Logistic回归模型等方法研究剥皮木的空间分布特征以及树干风折与剥皮的关系。[结果]从林分边缘到内部,树木剥皮强度逐渐降低,且表现为稀疏区域高于密集区域,平坡、沟底高于斜坡;在林分内剥皮木呈聚集分布,剥皮木与正常木在36~50 m范围内呈负关联,在更小空间尺度内关联性不明显;树干剥皮区的下部和上部平均高度分别为0.52和1.72 m,多在树干的正南及西南方向进行剥皮;剥皮木通常在剥皮后4~9年内从上、下剥皮处风折,倒向方位角多为0~135°,以东偏北方向的最多;白桦剥皮后伤口的恢复生长与裸露木质部的腐朽存在竞争生长关系,木质部裸露的周长比例越大越易风折,二项Logistic回归模型能较好地拟合风折概率与木质部裸露周长比例的关系。[结论]白桦剥皮具有多尺度的空间特征,主要受林木位置、林分密度与地形的影响;剥皮木在林分中呈聚集分布,并与正常木在较大尺度上呈负关联,在剥皮木分布较多的区域剥皮现象有加重的趋势;剥皮对林木的损伤越严重越易风折,风折时间多在剥皮后6年左右。为了减少剥皮情况的发生,需在初春时节加强对敏感地区林分的管理,并注重桦树皮的伐后采集与综合利用。[Objective]The objective of this study was to provide a scientific basis for healthy management and rational utilization of secondary forests of Betula platyphylla. [Methods]A typical debarked B. platyphylla stand was selected in the north region of the Yanshan Mountains. Spatial characteristics and relationships between wind-breakage and debarking were determined using spatial gradient analysis,point pattern analysis and a binary Logistic model. [Results]Debarking intensity reduced gradually from the outer to the inner portions of the stand,and was higher in sparse patches,flat slopes or gully bottoms than dense patches,and slopes. Debarked stems were clustered and were negatively associated with nondebarked stems at scales of 36- 50 m,and there was no association at smaller spatial scales. Average heights of lower and upper borders of debarking area were 0. 52 and 1. 72 m respectively,and debarking occurred on the south-western or southern side of the stem. Debarked B. platyphylla usually suffered from wind-breaking 4- 9 years after debarking and usually broke at lower or upper debarking point on the stem. Most debarked stems fell towards north-east with most falling azimuths ranging from 0° to 135°. There was a competing relation between recovery growth of the stem wound and decay of exposed wood. The greater the percentage of exposed stem circumference of debarked trees,the more vulnerable the debarked stem to wind breakage. A binary Logistic model could be used to depict the probability of wind-breakage of debarked trees,using percentage of exposed stem circumference as variable. [Conclusions]Debarking in B. platyphylla was characterized by multi-scale spatial characteristics and was mostly impacted by tree location,stand density,and topography. Debarked trees were clustered and were negatively associated with non-debarked stems at larger scales.Debarking tended to be more serious in the area with more debarked trees. The more the trees were damaged,the more likely they were broken by wind. Management shou

关 键 词：白桦 剥皮 干扰 点格局分析 二项Logistic回归模型 风折 

分 类 号：S718.55[农业科学—林学]