Hainan Island, The Western Coastal Shelterbelt, Windbreak And Sand-benefit Studies,

On the basis of commenting domestic, outside and Hainan Island coastal shelter forest ecological benefits research results, the simulated test of wind-tunnel of benefit, and the shelter forest and sand ground spatial relationship of sand ground that 6 issues have been coastal in the past 70 years through checking winds and fix drifting sand to shelter forest, this text have summarized and analysed benefit of checking winds and fix drifting sand of the coastal shelter forest.Test simulation different kinds of littoral zone and prosperous to take through wind-tunnel regional sand blown by the wind shed field, preliminary can get the following conclusion : Sand kind by the coast, because a foot-path is thick, it starts wind speed to exceed 10m/s, and increase with increase of its humidity. Wind erosion modulus M on the sand ground instructs the wind speed at the same time on the coast u(?) becomes logarithm growth, increase M that and is up to sand one kind of water contents |O (% ) drops fast; And as the water content increases, the sensitive degree that M varies with u(?)is reduced relatively.Blow wind that come from sea , through sea beach and sea shore sand dune area , form sand blown by the wind shed, while mounting the coast , produce backset current is it pile up to subside , after land first distance, produce the sand blown by the wind and meet and hinder the course of depositting etc. while flowing and transmitting in succession. If there are forest belts or a stretch of forest on the bank, the function of obstructing flowing in sand blown by the wind is more obvious, and forest land it covers to be heavy degree, check winds and fix drifting sand benefit to be the more obvious. Through studying about the shelter forest and sand ground spatial relationship of six period sand ground have been coastal of the past 70 years, get the following conclusion:The total variation tendency that the coastal land utilizes in the west of Hainan Island is: naked sand ground and other land reduce; half-naked sand ground , shelter forest land , other forest land , farming land increase. According to violent change degree, the change course of forest land , farming land and other land iscomparatively violent ,the change course of sand ground , half-naked sand ground and Shelter forest land is comparatively relax .In the past 70 years ,the big period of the study district sand blown by the wind land (naked sand ground + half-naked sand ground ) area appeared in 1986, the half-naked shape of sand ground is mainly, the second peak period when the sand blown by the wind phenomenon appeared is in 1964, the naked sand ground accounts for over half. In respect to the shelter forest land ,now is its last most period ,distribute at north and middle segment mainly.Through making a relevant analysis to find with shelter forest land to the sand ground of different periods, according to whole research district, benefit is comparatively obvious that shelter forest and fixes the sand. North segment regional shelter forest fix the sand benefit to be most heavy, south segment take second place, China sections of area protect forest land fix the sand benefit to be least obvious.