Microclimate Characteristics Between Low Coverage Sand-Fixing Forest Belts

Low coverage of woodland and scrub drought, the most typical distribution of natural vegetation in semi-arid area, and low coverage belt scheme is a vegetation patterns that can fully fixed a quicksand. In order to reveal the characteristics and mechanism of microclimate under afforestation model with low coverage, this paper selected forest belts which located in southern edge of Horqin Sandy. By comparing the simultaneous observation field date, we analyzed the impact on rainfall, soil moisture、 solar radiation、air temperature、relative humility and other microclimate of forest belts, and compared the characteristics of microclimate in different coverage sand-fixing forest belts. The results showed:(1) Low-coverage sand-fixing forest belts clusters distribution pattern formed a forest rainfall high interception and with glade almost no interception of rainfall capture mode, which made forest belts formed a basic no canopy interception of rainfall fully recharge zone, rainfall recharge can be increased by 20% or more compared to the soil under forest.; Soil moisture was gradually increased with distance away from belts, the trees can reduce the sand soil water content at 0～8 m the outside of border row and gradient of soil water is formed that can make the water permeate from the soil at and beyond 8 m to basal portion of trees; The same time, by observations we found that even when sand fixation forest coverage was reduced to 20% or so, belts windbreak effect was not significantly decreased, Low coverage belts has a significant windbreak effect. so we can conclude that:On the basis of meet the windbreak and sand-fixation, reduce the coverage of sand-fixing forest, can effectively maintain the sand area water balance, promote the interband natural vegetation restoration.(2) On the micro scale, vegetation spatial mechanism is the key factors influencing the climate environment of light, as a kind of zonal distribution pattern, solar radiation was influenced mainly by forest canopy, as to East-West belt, radiation weakened mainly in the north 0.5-1H forest within (tree height) range, with belts spacing decreases, the radiation through the canopy into the forest was less. With the influence of the forest canopy shading shield, temperature and evaporation increased with the distance away from belts, relative humidity diminished with distance away from belts. After afforestation on sand,(3) Represents the surface water and heat condition, air temperature and humidity are important environmental factors affecting vegetation growth, at the same time surface layer air temperature and humidity are influenced by the change of vegetation, due to the changes of vegetation stereo space pattern, local microclimate differences. The reasearch found that during growing season,25m belts plot temperature was lowest and at the same time the relative humility was largest,8m belts plot and 12m belts plot temperature were higher than 25m belts plot and control plot, and the relative humility were lower than 25m belts plot and control plot, when came to the end of growing season, the difference between plots had a narrowing trend, the microclimate characteristics of low-coverage sand-fixing forest belts was much more close to natural restoration vegetation communities.