海南岛西部沿海防护林防风固沙效益研究

【作者】 尹秋菊；

【导师】 孙武；

【作者基本信息】 华南师范大学 ， 自然地理学， 2005， 硕士

【摘要】 本文在评述国内外以及海南岛沿海防护林生态效益研究成果的基础上,通过对防护林防风固沙效益风洞模拟试验,以及近70年米6期沿海沙地防护林与沙地空间关系,总结利分析了沿海防护林的防风固沙效益。 通过风洞试验模拟不同类型海岸带,初步可以得到以下结论: 海岸边的沙样由于粒径粗,其起动风速超过10m/s,且随其湿度的增加而增大。海岸上沙地的风蚀模数M随指示风速u_∞成对数增长,而随沙样含水量ω(%)的增加M快速地下降;且随含水量增大,M随u_∞变化的敏感程度相对降低。 从海面吹来的风,经过海滩和海边沙丘地带,形成风沙流,在登上海岸时,产生回流沉降堆积,在陆地一段距离后,相继产生风沙流和传输中遇阻沉积等等过程。如在岸上有林带或片林,风沙流的受阻作用就更明显,而且林地覆被度越大,防风固沙效益越明显。 通过对近70年来6期沿海沙地防护林与沙地空间关系研究,得到如下结论: 海南岛西部沿海土地利用状况总的变化趋势是:裸沙地和其它地类减少,半裸沙地、防护林地、其它林地和农用地增加。从变化的剧烈程度来看,林地、农用地和其它地类的变化过程较为剧烈,沙地、半裸沙地和防护林地变化过程较为缓和。 近70年来研究区风沙化土地(裸沙地+半裸沙地)面积最大时期出现在1986年,主要以半裸沙地形态出现,风沙化现象出现的第二个高峰期在1964年,裸沙地面积占到一半以上。就防护林地而言,目前是其面积分布最大时期,主要分布在北段和中段地区。 通过对不同时期沙地和防护林地面积作相关分析发现,从整个研究区来看,防护林的固沙效益较为明显。北段地区防护林的固沙效益最大,南段次之,中段地区防护林地固沙效益最不明显。更多还原

【Abstract】 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.更多还原