【作者】 金靖博；

【导师】 谷会岩；

【作者基本信息】 东北林业大学 ， 森林植物资源， 2008， 硕士

【摘要】 陆地上80%的生态系统都已受到了来自人类和自然的各种干扰,森林生态系统也不例外。干扰影响到森林的各个水平。由于近代人类对森林掠夺性的开发利用,使人为干扰远大于自然干扰。采伐干扰是最重要的人为干扰之一,重点研究采伐干扰对森林生态系统的影响,为森林资源的保护与合理利用提供必要的信息和策略具有十分重要的意义。本文以大兴安岭塔河林业局的兴安落叶松天然林、择伐一次的兴安落叶松林、择伐二次的兴安落叶松林为研究对象,从三种森林类型的林分结构、物种组成、更新、粗木质残体特征、土壤的化学性质方面研究采伐干扰对大兴安岭北坡兴安落叶松林的影响。研究的主要结论有:(1)采伐干扰对森林结构、物种组成的影响:项级树种兴安落叶松的数量在三种森林类型中差异明显。择伐后的森林中山杨和白桦的数量比兴安落叶松天然林中的数量更加丰富,而且它们的胸高断面积在择伐后兴安落叶松林所占的比重也更高。兴安落叶松天然林和伐后兴安落叶松林在物种多样性上或异质性上有差异。(2)采伐干扰对森林更新的影响:采伐干扰影响森林的更新,择伐一次兴安落叶松林在更新个体数量、更新物种组成上都高于天然林,择伐二次兴安落叶松林更新个体数量低于择伐一次兴安落叶松林。(3)采伐干扰对林分、粗木质残体的影响:采伐干扰改变了林分的结构,择伐后森林的蓄积量明显降低,不同树种材积所占比例发生了变化,择伐后兴安落叶松林中阔叶树种材积所占比例有较大程度的增加,而针叶树种所占比例的变化趋势相反。择伐后森林的粗木质残体组成发生了改变,伐桩成为重要的粗木质残体组分,中小径级粗木质残体数量占有绝对的比重。(4)采伐干扰对土壤化学性质的影响:采伐干扰改变了大兴安岭北坡兴安落叶松林土壤pH值、C含量和其它养分含量。随着采伐干扰次数的增加,土壤表层C:N、C:P的比值逐渐升高,但C:K比值逐渐降低。更多还原

【Abstract】 More than 80%of terrestrial ecosystems,including the forest ecosystem,have been influenced by natural disasters,human activities or the combination of both natural and human disturbances.disturbances affect all levels of the forest.For modern human exploration and utilization of the forest,human disturbances are far greater than natural disturbances. Harvesting disturbance is one of the most important human disturbances.Therefore,this paper is focused on the role and effect of harvesting disturbances in forest ecosystem.It is of great significance to provide necessary information and strategy for the protection and rational utilization of forest resources.The subject of this paper is once selective-cutting forest,twice selective-cutting forest and natural forest in Tahe forest bureau,Greater Hinggan Mountains.The impact of harvesting disturbance in the northern slope on Greater Hinggan Mountains forest is studied, including forest structure,species composition,regeneration,stand characteristics of coarse woody debris and soil chemical properties of the three types of forest.The main conclusions are:(1)Impact of harvesting disturbance on forest structure and species composition:The number of climax species Larix gmelini is significantly different for the three forest types. After the selective-cutting,the number of Populus davidiana and Larix gmelini is much greater than that in natural forests,and the proportion of the basal area at chest height after selective-cutting is higher,too.There is much difference in species diversity or heterogeneity for natural and Larix gmelini forest after the cutting.(2)Impact of harvesting disturbances on forest regeneration:Harvesting disturbance affects forest regeneration.Once-selective-cutting forest is much higher than natural forest in the number of individual and species composition of regeneration,and regeneration number of twice-selective-cutting forest is less than once-selective-cutting forest.(3)Impact of harvesting disturbance on the forest stand,coarse woody debris, Harvesting disturbance changed the structure of the forest:the volume decreased significantly after selective-cutting of forests,the proportion of volume of different species changed,the proportion of volume of broad-leaved species increased to a certain degree,while the changing trend of conifer species was opposite.The composition of coarse woody debris after selective-cutting of forests changed,stumps became an important component of coarse woody debris,and the number of coarse woody debris in middle and small class had an absolute proportion.Impact of harvesting disturbance on soil chemical properties:Harvesting interference changed the north slope of in the northern slope on Greater Hinggan Mountains pH value,C content and other nutrient content.With the increase of the times of disturbance,the C: N and C:P ratios of surface soil gradually increased,but C:K ratio decreased gradually.更多还原