【作者】 王小云；

【导师】 叶功富；

【作者基本信息】 福建农林大学 ， 水土保持与荒漠化防治， 2008， 硕士

【摘要】 本文论述了生态场理论的研究现状和存在的问题。从生态场的角度初步探讨了防护场理论,构建了防护场的相关特征函数和简单模型。对防护场理论的研究内容、意义以及防护场的特点进行了阐述。讨论了防护场理论在沿海防护林中的应用,并对不同发育阶段的木麻黄林分进行了风速测定和温度测定。从防护场的角度分析了不同发育阶段木麻黄基干林带、木麻黄片林和木麻黄农田防护林的防风效应场和温度效应场。防护场是防护林体系所产生的防护效应在时间域与空间域的分布。防护场的特征函数包括防护场势、防护场强度、防护场变化梯度和防护距离等。防护势是指防护林体系单位域内潜在的防护能力;防护场强度是指防护林体系所表现出的实际防护能力,即现时的防护能力:防护梯度是指单位时间空间域内防护场强度的变化;有效防护距离指防护林体系所形成的最大有效防护范围。当达到最大防护距离时,防护场强度为零,防护场梯度也为零,也就是当防护因子的变化梯度为零时的距离。本试验选取了福建省东山岛大帽山一带不同发育阶段木麻黄基干林带、片林和农田防护林做为研究对象。分别测定了2006年11月到2007年3月大风季节林内外不同点的风速,以及2007年11月林内外的温度变化:对数据进行了克里格插值计算,并应用surfer软件绘制了风速和温度的等值线图、三维表面图和变化率图。研究结果表明:(1)木麻黄基干林带内风速成逐渐下降趋势。幼林和中幼林风速削减率在1h和5h间达到最大值,分别为58%和71%:中林在10h处达到最大值为70%;成熟林和过熟林在林20h处达到最大值,分别为74%和69%。空间表面图为两边高中间低的凹面。(2)木麻黄基干林带后风速成逐渐增长趋势,25h处已经接近空旷处风速。局部区域又有下降,幼林、中幼林和中林下降点在林后5h到8h之间;成熟林和过熟林下降点在林后12h到18h内;各点风削减率分别为32%、10%、11%、0%和3.8%。木麻黄基干林带各测点风速成开口向上的抛物线状,即符合方程:y=0.1125 x~2-1.9799x+9.6244,在林内成下降趋势,林外又逐渐增加的趋势。(3)木麻黄片林和木麻黄基干林带有相似的规律,拟合函数为:y=0.3638x~2-3.6141x+910.548。片林内10h处风速达到最小值,各发育阶段风削减率分别为100%、75%、67%、50%、48%。木麻黄片林后风速成增加趋势,在林后10h左右风速接近空旷地。(4)木麻黄农田防护林各测点风速分析得出:中林、成熟林和过熟林,风速值在林后10h左右达到最小值,风削减系数分别为33%、32%和25%。从空旷地到林后10h间风速成下降趋势,在林后10h到25内风速成上升趋势。其关系式为:y=0.2327x~2-2.3387x+9.6018。(5)多元多次统计分析得出,木麻黄基干林带和片林在林内5h内林分密度、枝下高和冠幅对风速削减率的影响比较大,林内5h到林后10h之间枝下高、密度和树高是主要影响因素。木麻黄农田防护林内外树高和密度是农田防护林风速削减率的主要影响因子。(6)对木麻黄基干林带、片林和农田防护林1m高处各测点温度分析得出:基干林带和片林内形成一个温度低压槽,外围形成一个温度高压脊,边缘地带温度变化比较剧烈,是个过渡区,温度差值在1℃-2.5℃之间。农田防护林带内形成一个带状的低温区,带外形成一个面积较大的高温区,类似于水槽状。农田防护林从内到外的温度成逐渐增大的趋势,其中在边缘地温度增长最快,林带内外温差在0.96℃到1.54℃之间。依据上述防护场效应的观测结果,探讨了防护场理论在沿海防护林体系建设中的应用前景。防护场理论在沿海防护林的建设和经营管理中有着重要的指导作用,对研究沿海防护林的防护效能等方面也有一定的启发意义。在沿海防护林的管理中应重视种苗培育,根据防护功能的要求注意选用具有较强生长能力,能够有效抵抗风沙等不良因素和病虫害的优良种苗。通过木麻黄海岸防护林的试验结果表明,采用多树种混交、合理间伐、修枝、林下套种等措施,对于提高沿海防护林的防护效应具有显著的影响。更多还原

【Abstract】 The status and existed problems were discussed in this paper.Based on the ecological field discipline,demonstrated the shelter field theory,and established the definitions and sympols model about shelter field and it’s eigenfunction.Furthermore,discussed the content,significanace and charactiristic of shelter field.Discussed the application of shelter field on coastal protectiv forest,surveyed the wind speed and temperature,and analysized the wind cut effect field and temperature effect field about shelterbelt of Casuarina equisetifolia.The thesis defined the shelter field as the distribution and effect in the time and spatial domain generated by shelter forest.The eigenfunction of shelter field contain shelter potential, intensity of shelter field,gradient of shelter field,and domain of shelter field.Defined potential shelter field as potential function of shelter-belt;Intensity of shelter field was the current function of shelter-belt;Gradient of shelter field was the change ratio of intensity of shelter field;Domain of shelter field was the biggest influence area of shelter-belt;The Intensity of shelter field and Gradient of shelter field were not exits while the domain of shelter field to was maximum.The experiment was done by selecting trunk shelter-belt,forest bands and farmland shelter-belt of Casuarina equisetifolia at different development stages as targets in Damao mountain area of Dongshan in Fujian Province.Measured the wind speed from Nov.2006 to Mar. 2007and temperature in Nov.2007 on different sites inside and outside of the selected targets. Datas was interpolated calculation with Kriging software,and draft contour maps,3D surface map and change ratio map of wind speed and temperature.The main experiment results were as follows:(1)Wind speed in trunk shelter-belt of Casuarina equisetifolia is in declining trend.The wind speed cut ratio respectlly reach the max at 1h and 5h in young and middle young stages of development,while the value respectly were 58%and 71%.The wind speed cut ratio respectlly were 70%,74%and 69%reach the max at 10h,20h and 20h while at middle,mature and super-mature stages of development.3D surfer map was cancave as two sides high and low in the middel.(2)Wind speed behind the trunk shelter-belt of Casuarina equisetifolia is in a rising trend. wind speed at 25h is nearly the speed at spacious place,but it declined at some sites.Declining sites are between 5h and 8h while at young,middle young,and middle forest,while mature and over-mature forest are at 12h to 18h.the wind speed cut ratio are respectlly 32%,10%,11%,0%and 3.8%.wind speed tendency in trunk shelter-belt of Casuarina equisetifolia is parabola of opening upward and described as:y=0.1125x~2-1.9799x +9.6244.decling in forest and rising out of forest.(3)Trunk shelter-belt and forest bands of Casuarina equisetifolia have the same discipline rules,and the fitting function is y=0.3638x~2-3.6141x+910.548.the wind speed reach the minimum at 10h in forest bands and the wind speed cut ratio is respectlly 100%,75%,67%50%,and 48%at different developed stands.The wind speed behind the forest bands is in a rising trend,and wind speed at 10h is maximum which is nearly the speed in specious place.(4)Analyzing the wind speed at all sites in farmland shelter-belt shown that wind speed at 10h reach the minimum at middle,mature and over-mature developed stages,and the wind speed cut ratio were respectilly 33%,325,and 255.It is fitting functin is y=0.2327x~2-2.3387x+9.6018.(5)Statistical analysis shown that:density,Under branch height and width canopy have a main relationship with the wind speed cut ratio within 5h in trunk shelter-belt and forest bands of Casuarina equisetifolia,but within 5h to 10h,tree height,density and under branch height are major effect factors of wind speed cut ratio.In farmland shelter-belt,tree height and density have mainly relationship with the wind speed cut ratio.(6)Analyzing the temperature at all survey sites in trunk shelter-belt and forest bands of Casuarina equisetifolia shown that:inside which the temperature was a temperature low-pressure zone,and outside was temperature high-pressure ridge.the edge was a transition area and the temperature difference was 1℃-2.5℃.Temperature in farmland shelter-belt forming a belt-shaped low temperature area while the outside forming a big high temperature area.the edge area have a more acute temperature change than other areas.The difference inside and outside was from 0.96℃to 1.54℃.Shelter field theory play an important role in the establishment and management of coastal protective forest,it put forward some new requests to the seedling cultivates,growth and frame of trees,and have a great deal of enlightening significance for the building and management of coastal proeetive forest of Casuarina equisetifolia.We shoule pay attention to cultivate trees seed which have more ability of growth ability,resistance sandstorm and insect pest.Experiment and analysized indicate that:Shielding effect have Remarkable advanced by the ways of mixed forest of Multi-tree species,intermediate cuttings,belt cuttings,interplanting and density adjustment.更多还原