Study On Structure And Growth Of Shelter Forest In Maowusu Sand

The Maowusu sand is one of regions that the desertification occur seriously in our country, which also is one of the key regions that the desertification researching, the sandstorm endanger seriously very much. For easing and repressing the sandstorm endangerment, established a shelter forest system of sand from the seventies. This paper research on the shelterbelt structure and growth in the Maowusu sand, the result show that the pure forest of Pinus sylvestris .var. the structure of chest diameter and tree height is more regular than that of the mingled forest, and match the variety regulation that general trees growth in the structures that density of tree quantity such as the pure forest of the Pinus sylvestris .var. , the mingled forest composed with Pinus sylvestris .var., Chinese pine and poplar, banding pure forest of Pinus sylvestris .var. and banding pure forest of Chinese pine. In leaf layer structure, the leaf layer peak value of Pinus sylvestris .var. pure forest and shelterbeh both are lower than that of the mingled forest and Chinese pine forest belt, and it's relative tree quantity decrease with the tree height increasing, thus form the thicker leaf layer, we can draw a conclusion, in the shelter forest system that constructed in that region, the group and banding structure of Pinus sylvestris .var. forest is reasonable.The trunk resolution result of pure forest and mingled forest indicate that, the growth condition of chest diameter,tree height,and volume is resemble in pure forest and mingled forest of Pinus sylvestris .var. , and the growth condition of chest diameter.tree height,and volume is better than that of Chinese pine in mingled forest. In 23 year,the average chest diameter of Pinus sylvestris .var. is 12.4cm, average tree height is 8.4m , average volume is 0.0591 m~3, but the chest diameter of Chinese pine is 10.1cm, tree height is 7.4m, volume is 0.0316m~3. Analyze from the structure and the growth conditions of the shelter forest, Pinus sylvestris .var. has powerful adaptability in this area, the construction of pure forest or mingled forest that most composed by Pinus sylvestris .var.should be aggressive developed in the shelter forest system, which improve the ecological benefit and windbreak and sand-fixation results of the shelter forest.