【作者】 史宇；

【导师】 余新晓；

【作者基本信息】 北京林业大学 ， 水土保持与荒漠化防治， 2011， 博士

【摘要】 植被与水资源之间的关系是华北地区森林植被建设的主要问题。本文以侧柏、刺槐、油松、栓皮栎四类北京山区典型优势树种森林生态系统为研究对象,利用在妙峰山林场的实测数据对不同优势树种森林生态系统各层次的水文过程进行研究,并通过生态水文模型模拟森林植被变化引起的森林生态系统内部水文过程的变化,力求揭示该区域主要优势树种森林生态系统的生态水文特征和规律,为指导该地区森林植被建设提供科学依据。主要研究成果如下：(1)研究期不同树种林分总林内降雨率为侧柏林(71.52%)>刺槐林(68.32%)>栓皮栎林(63.44%)>油松林(62.44%),总干流率为侧柏林(2.61%)>栓皮栎林(2.49%)>油松林(1.73%)>刺槐林(1.52%),总截留率为油松林(35.82%)＞栓皮栎林(34.07%)>刺槐林(30.16%)>侧柏林(25.87%)。降水量、降雨历时和30min最大雨强是影响林冠层降雨再分配的重要环境因子。林外降水量和林内降水量有着非常良好的线性正相关关系,林冠截留量随降水量增加呈增加趋势。建立了4树种的林冠截留模型,经检验具有较高的精度。林内降雨的开始和结束的时间要晚于林外降雨。林内延迟降雨开始时间与延滞期雨强的相关性更为显著,林外降雨与单次累积降水量相关性更强。侧柏林冠对雨滴同时有分散和聚合两种作用。林外雨滴平均直径在中、低强度的降雨中随降雨强度的增加而变大,林内雨滴则变化不大。林内雨滴的终点速度有所减小,表现出林冠层对降雨雨滴降落速度减缓作用。林内降雨的总动能小于林外降雨。(2)各林分枯落物总储量排序为侧柏林>栓皮栎林>油松林>刺槐林。测得林分枯落物层的有效水分拦截量油松林(12.15t/hm2)>侧柏林(10.19t/hm2)>栓皮栎林(7.98t/hm2)>刺槐林(5.40t/hm2)。阔叶树种比针叶树种的枯落物具有更好减流减沙效果。截持降雨能力强的枯落物类型其蒸发能力也较强,排序为栓皮栎>侧柏>油松>刺槐。枯落物蒸发量日变化过程呈单峰状分布,各树种林分的枯落物日间蒸发量明显高于夜间。建立了四个树种枯落物的枯落物降雨截留模型和日蒸发量模型,模拟精度较高。(3)各树种在晴天条件下,树干液流速率的日变化都呈单峰曲线趋势,典型阴天和雨天不同树种树干液流速率变化差异性较大。通过相关分析发现环境因子中气温、太阳辐射、VDP、土壤含水率和土壤水势与树干液流速率呈正相关,而相对湿度与树干液流速率呈负相关关系。利用树木边材面积作为尺度转化中间量,计算各样地6-9月林分蒸腾量油松林为165.28mm,刺槐林为112.82mm,栓皮栎林为218.88mm,侧柏林为214.29mm。4种林分林下灌木6-9月蒸腾总量油松林>刺槐林>栓皮栎林>侧柏林,林下灌木蒸腾量不及乔木的10%。(4)不同树种林分土壤层总持水深的大小排序依次为刺槐林>侧柏林>油松林>栓皮栎林。不同树种林分的土壤入渗规律有一定的差异性,针叶林的土壤渗透能力要明显高于阔叶林。研究期各条件下土壤平均日蒸发量在0.68—1.51mm之间。各个树种整个生长季土壤平均含水率侧柏林为15.58%,刺槐林为15.69%,油松林为15.58%,栓皮栎林为15.03%。侧柏和刺槐林主要土壤贮水层为20-60cm层,油松和栓皮栎为40-60cm以下层。4种林分降雨后的土壤水分消退都体现出了蒸渗型的特征。研究期大部分时间内各树种林分的土壤水分处于中效水和易效水之间,不同树种林分研究期土壤水分有效性状况由好到差排序为：油松林>刺槐林>栓皮栎林>侧柏林。(5)将Brook90集总式生态水文模型应用于描述典型森林样地的生态水文模型,通过两年实测的土壤含水数据对模型进行参数率定和检验,使模型达到较高的模拟精度。用2001--2010年气象数据对4种森林生态系统生态水文过程进行了模拟,分析了其降水输入分配特征、蒸散输出特征和林地产流特征。模型模拟得出年均生态需水量栓皮栎林(954.1mm)>侧柏林(811.0mm)>油松林(498.4mm)>刺槐林(420.1mm)。设定当生态需水满足率为90%和70%时对应的林分LAI和郁闭度数值分别为水源涵养林和水土保持林的最优植被承载力,模拟计算得出了北京山区主要优势树种水源涵养林和水土保持林的植被承载力取值范围。更多还原

【Abstract】 The relationship between vegetation and water resources is the main problem of forest vegetation construction in north China. In this paper, taking Platycladus orientalis, Robinia pseudoacacia, Pinus tabulaeformis and Quercus variabilis, these four typical forest ecosystems as the research object, using the measure data of Miaofeng Mountain to research the hydrological processes of different forest ecosystems of major dominant species and simulate the hydrological processes changes caused by the forest vegetation various, seeks to reveal eco-hydrological disciplines of the different forest ecosystems of this area, to provide the scientific basis for guiding the construction of forest vegetation. The main results are as follows:(1) The ranking of the total throughfall percentage of different tree species during research is: Platycladus orientalis (71.52%)> Robinia pseudoacacia (68.32%)> Quercus variabilis (63.44%)> Pinus tabulaeformis (62.44%); total stem flow percentage is Platycladus orientalis (2.61%)> Quercus variabilis (2.49%)> Pinus tabulaeformis (1.73%)> Robinia pseudoacacia (1.52%); and the total interception percentage is Pinus tabulaeformis (35.82%)> Quercus variabilis (34.07%)> Robinia pseudoacacia (30.16%)> Platycladus orientalis (25.87%). Rainfall quantity, rainfall duration and rain largest intensity within 30min are the important environmental factors of forest canopy rain redistribution. Precipitation outside the forest and inside the forest has very fitting linear positive correlation, canopy interception increase with increasing precipitation. Establish 4 tree species canopy interception model, which has a high accuracy upon examination. The start and end time of rain inside of the forest is generally later than the outside. The correlation between the start time of delayed rain inside the forest and rainfall intensity of the delayed period is more significant, and rainfall outside the forest and one single accumulated precipitation are more relevant. The canopy of Platycladus orientalis has dispersion and aggregation two functions simultaneously to the rain. The ultimate speed of the rain under the forest has been reduced, showing that the forest canopy reduced speed function to rainfall drops. Total kinetic energy of outside rainfall is larger and inside rainfall.(2) The ranking of forest litter total reserves is:Platycladus orientalis> Quercus variabilis> Pinus tabulaeformis> Robinia pseudoacacia. As measured, the ranking of forest litter layer effectively water blocking amount is of Pinus tabulaeformis (12.15t/hm2)> Platycladus orientalis (10.19t/hm2)> Quercus variabilis (7.98t/hm2)> Robinia pseudoacacia (5.40t/hm2). Broad-leafed tree species have better flow and sediment reduction effect than coniferous tree species. The litter type with stronger rainfall interception has stronger evaporation capacity, and the ranking is Quercus variabilis> Platycladus orientalis> Pinus tabulaeformis> Robinia pseudoacacia. Litter evaporation process changes at daytime is a single peak-like distribution, every species of litter evaporation was higher at the daytime than the night. Establish rainfall interception model and daily evaporation model of four litter species, which have high simulation accuracy.(3) Each tree species in sunny conditions, diurnal variation of sap flow rate is a single peak curve trend, sap flow rate of different species changes greater at typical cloudy and rainy weather. Through correlation analysis, it showes that among environmental factors, temperature, solar radiation, VDP, soil moisture and soil water potential and sap flow rate correlate positively, while the relative humidity and sap flow rate correlate negatively. Using the tree sapwood area as the scale transformed middle amount, calculating forest plots transpiration from June to September, Pinus tabulaeformis is 165.28mm, Robinia pseudoacacia is 112.82mm, Quercus variabilis is 218.88mm, Platycladus orientalis is 214.29mm. The ranking of 4 stand shrub total transpiration from June to September is: Pinus tabulaeformis> Robinia pseudoacacia> Quercus variabilis> Platycladus orientalis, which is less than 10% of arbors.(4) The ranking of soil layer total water-holding the depth of different species stands is Robinia pseudoacacia> Platycladus orientalis> Pinus tabulaeformis> Quercus variabilis. Soil infiltration of different species has some differences, coniferous forest soil infiltration capacity is significantly higher than that of broad-leaved forest. During research, of the average soil daily evaporation is between 0.68-1.51mm under various conditions. As to the average soil moisture throughout the growing season, Platycladus orientalis is 15.58%, Robinia pseudoacacia is 15.69%, Pinus tabulaeformis is 15.58%, Quercus variabilis is 15.03%. Main water storage layer of Platycladus orientalis and Robinia pseudoacacia is 20-60cm layer, pine and cork oak is the layer under 40-60cm. 4 kinds of soil moisture receded after rain reflected the dissipatedinfiltration type features. Most of the time within the study period, the soil moisture of different forest tree species in between the medium efficiency water and readily available water, and the ranking of soil water effectiveness status of different forest tree species in study period is:Pinus tabulaeformis> Robinia pseudoacacia> Quercus variabilis> Platycladus orientalis.(5) Use Brook90 lumped hydrological model to describe a typical plot of forest eco-hydrological model, by two years measured data on soil moisture calibrating and testing model parameter to make the model achieve high simulation accuracy. With 2001-2010 meteorological data simulated 4 kinds of eco-hydrological process in forest ecosystems, analysis of its characteristics of the input precipitation distribution, characteristics output evapotranspiration and forest runoff characteristics. According to Model simulations, it shows that average ecological water demand is of Quercus variabilis(954.1mm)> Platycladus orientalis(811.0mm)> Pinus tabulaeformis(498.4mm)> Robinia pseudoacacia(420.1mm). When setting the ecological water demand was 90% and 70%, the corresponding value of stand LAI and canopy density are the optimum vegetation carrying capacity of water conservation forest and the soil and water conservation forest, simulation calculated the vegetation species carrying capacity range of the water conservation forest and soil and water conservation forest main building group in Beijing mountainous area.更多还原