The Facts That Led The Degradation Of Artificial Sand-fixation Pinus Sylvestris Var.mongolica And Its Prevention Measures

At present, the recession of pinus sylvestris var.mongolica man-made sand-fixation forest has harmed the natural growing of realistic standing forest, which will cause enormous loses to the"three norths"forest belt system project. So problem concerning improving recession pinus sylvestris var. mongolica man-made sand-fixation forest has become an important problem which can strong the"three norths"forest belt achievement.We define five pieces of standard field, 35 pieces of temporary standard field according to different site-type, different standing forest density and different recession level and continually using 2 pieces of fixed field which has been set in 1980 and each piece of field's area is (20m X 20m) 0.50 hectare. After researching drying condition, climate discrepancy of natural pinus sylvestris var. mongolica and pinus sylvestris var. mongolica man-made forest in Zhang Gu Tai etc. and the soil moisture condition of Zhang Gu Tai man-made sand-fixation forest, we find that the vertical distribution of moisture content of pinus sylvestris var. mongolica sand-fixation forest soil is influnced by precioitation, site-type, evapotranspire and buried ancient soil, and soil moisture content of root system (20-50m) is less than flowing sand field. During growing period (5-9 months), May, June and September are soil moisture losing period, July and August are soil moisture storage period and soil moisture storage of June is the lowest.So far, there are many reasons for the recession of pinus sylvestris var. mongolica man-made sand-fixation forest, such as climate discrepancy (most of them are heat quantity), manage mistake (high density of pure forest and standing forest), unreasonable soil moisture using, pine plant diseases and insect pests and pine spike top, etc. Therefore, in order to enhance the stability of pinus sylvestris var. mongolica man-made sand-fixation forest, we should take different measures according to growing condition of pinus sylvestris var. mongolica man-made sand-fixation forest, that is, taking measures such as intermediate cuttings of keeping health & moving weakness, intermediate cuttings of narrow-band management and intermediate cuttings of wide-band management to adjust standing forest structure which can prevent presenility of pinus sylvestris var. mongolica man-made sand-fixation forest. So we can get the conclusion that to develop foster intermediate cuttings according to forest differentiation is the most effective way.