| The Western forest area of Tianshan located in the Yili river valley is one of the three important forest areas in Xinjiang.After the implementation of the natural forest protection project for more than 20 years,the current situation of the communitv structure of the Picea schrenkiana var tianschanica forest and its relationship with environmental factors need to be further clarified,which is also the important basis and basis for the implementation effect evaluation of the Xinjiang natural forest protection project and the scientific management of regional forest resources.In this paper,the typical sample method was used to research the structural characteristics,the quantitative classification and ordination of the community,the correlation evaluation between the community distribution and the environmental factors of the Picea schrenkiana var tianschanica forest in the QiaXi Forest Park of Gongliu branch of the state-owned forest administration of Western Tianshan,this paper revealed the structural characteristics of the Picea schrenkiana var tianschanica forest and assessed the interaction between forest communitv and environmental factors in the Western Tianshan.The main results were as follows:1.The analysis of stand structure showed that different cutting methods had obvious influence on the diameter,height and age structure of the Picea schrenkiana var tianschanica forest in Mountain Tianshan.With the decrease of the interference intensity(clear cutting→selective cutting→no cutting),the distribution of diameter,height and age structure presented a trend from single peak to multi peak,and the distribution range of diameter,height and age of the Picea schrenkiana var tianschanica forest expanded obviously,meanwhile the heterogeneity of stand structure enhanced as the number of trees with different diameter,height and age increased.In the early stage of clear cutting,the number of small-diameter timber was the most,the number of large-diameter timber was relatively wide in the early stage of selective cutting,and the number of medium diameter timber was relatively large in the early stage without cutting interference;the regeneration of Picea schrenkiana var tianschanica forest in Tianshan under different cutting modes were also different,the mode of early clear cutting forest was artificial regeneration.While there was a large number of natural regeneration young trees in the early stage of selective cutting,there was a certain number of natural regeneration young trees in the felled forest,which showed that moderate cutting disturbance was helpful for the natural regeneration of Picea schrenkiana forest.2.The results of vegetation composition,classification and ordination showed that there were 131 species of vascular plants,93 genera and 42 families in the study area.The Picea schrenkiana var tianschanica forest community in Western Tianshan could be divided into 8 forest community types by TWINSPAN classification.The DCA ordination was consistent with TWINSPAN classification,which revealed that the environmental gradient mainly based on water heat coupling played a leading role in the distribution of Picea schrenkiana var tianschanica forest community in Tianshan.The significant environmental factors were the elevation and slope of terrain,as well as the contents of zinc,iron and total nitrogen in soil nutrients.3.The analysis of community distribution and environmental interpretation showed that the community distribution of Picea schrenkiana var tianschanica forest in Western Tianshan was affected by both environmental factors and cutting intensity.There were 37.8%explained by environmental factors,5.2%by cutting intensity factors,39.1%by mutual interpretation,82.1%by environmental factors and cutting intensity factors,and 17.9%by unexplained factors.In the practice of forestry production,cutting interference should not only be a way of resource utilization,but also a way of adjustment and promotion of forest ecological management in the new era. |
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