森林的风/雪灾害研究综述

风／雪灾害不仪极大影响木材生产，同时对森林生态系统的稳定性也造成很大影响。森林风／雪危害的主要类型有树干弯曲、干(冠)折、掘根以及后续危害等；其发生主要依赖于气象条件、立地因子、树木和林分特征及其之间的相互作用。其中．林木尖削度(胸径／树高)和林分结构特征(树种、组成、密度等)是控制树木和林分对风／雪荷载抵抗的主要特征量。因此．通过造林、调整林分结构．加强林分管理如间伐、施肥等措施一直是用来减少林木的风／雪灾害的主要措施。另外．林木或林分发生风／雪害的模型分析研究也取得了很大进展，但由于森林风／雪害受诸如地形、天气等多种因素影响、目前所建立的模型系统在实际应用中普适性较芹。通过综述以往研究结果认为：在气象和立地条件难以控制的情况下．通过改变可控因子林分结构来减少森林风／雪害是可行的。因此．研究如何加强森林经营管理，尤其是不同形式的间伐技术和不同处理的造林措施与风／雪灾害发生的关系、如何增加林木和林分抵抗风／雪灾害的能力等是今后该研究领域的重点和难点。与此同时．应加强风／雪灾害危险率评估研究．进而对森林进行风／雪灾害危险率管理；并注重对受灾前后林地内生态效应的研究，以便为灾后的森林经营管理和调控提供坚实的理论依据。

Forest damage induced by wind/snow: A review

Wind/snow damage not only threatens the productivity of forests, but also has a significant impact on forest stability. Forest damage induced by wind/snow is characterized by stem bending, crown breakage, uprooting and the consequential effects of the damage. Earlier study related to this aspect showed that the existence of such damage depends on the meteorological condition of the forest area, site factors and certain extant of species specific in nature. However, stem taper and characteristics of tree crown are the main characters controlling the tree resistance to wind/snow loading. Though the site factors and meteorological conditions can nearly not be controlled by human beings, forest damage induced by wind/snow might be reduced by forest management techniques such as regeneration, thinning, fertilization and stand structure adjustment. Studies on models for analyzing the occurrence of tree or stand wind/snow damage have greatly progressed, but the evaluation models were not applied commonly in practice because forest wind/snow damage was affected by some other factors such as topography and weather conditions. Moreover, most of the researches were focused on the plantation forest, few of them on the natural forests. Therefore, we believe that it is the viable way to reduce the stand wind/snow damage through changing the controllable factors i.e., tree characters or stand structures, because the meteorological phenomena and site environments are hardly controllable. Based on the certain results, we concluded that studies on the relationships between different thinning levels and afforestation measures with wind/snow damage as well as the techniques for improving the resistance ability of tree against to wind/snow should be paid more attention. In addition, the ecological processes of wind/snow damage for natural forest and their evaluation should be recommended in the future research.