【作者】 曹恭祥；

【导师】 王彦辉；

【作者基本信息】 中国林业科学研究院 ， 生态学， 2014， 博士

【摘要】 为认识水文要素的空间变化，量化其对水文过程影响及坡面尺度效应，本文于2012年和2013年生长季在六盘山香水河小流域对典型坡面和主要植被类型进行了立地因子和林分结构特征的调查，并利用传统水文学方法研究了林分生态水文过程。研究结果量化了植被的水文影响及坡位差异，分析了坡面尺度效应，加深了对植被系统结构的水文影响及坡面尺度效应形成机理的认识，可为发展森林生态水文学理论和促进林水综合管理提供科学指导。1.主要植被类型结构特征及蒸散差异香水河小流域内主要森林类型的结构特征差异较大。林分树高、胸径等分布存在明显差异。在整个生长季，华山松林、白桦林、辽东栎林的冠层LAI动态表现为生长初期快速上升，生长中期保持稳定，生长后期缓慢下降；油松林的冠层LAI变化幅度较小。本文研究的所有森林样地的土壤均为灰褐土，土壤石砾含量大于20%。华山松林、油松林、白桦林、辽东栎林的土壤特征指标存在差异，0～100cm土层的土壤容重分别为0.83、1.04、0.79、1.14g·cm-3；总孔隙度分别为66.5、59.6、68.0、56.4%；田间持水量分别为47.1、32.9、62.4、35.2%。在2012年生长季观测期（5月11日—10月18日），林外总降雨量507.2mm，属于平水年。受树种组成、林冠郁闭度、植被垂直分层等林分结构特征差异影响，各林分的蒸散量大小和组分差异较大，华山松林、白桦林、辽东栎林、油松林、华北落叶松林的蒸散量（和组分）分别为413.2、480.7、389.0、377.6，541.4mm分别占同期降雨量的81.5、94.8、76.7、74.4和106.7%。2.不同密度华北落叶松结构特征及蒸散（组分）差异在2007年间伐后形成的不同密度（1811、1556、1134、1033、844株·hm-2）华北落叶松林平均树高相差不大（13.8～14.8m），但平均胸径随林分密度降低而逐渐增大（16.3～18.1cm）。不同密度的华北落叶松林的林冠LAI变化趋势一致，表现为生长初期快速上升，生长中期保持稳定，生长后期缓慢下降；林冠LAI随林分密度增大呈直线上升。林分密度对土壤物理性质无显著影响。在不同密度的华北落叶松林样地，其总蒸散量（和组成）分别为614.9、549.6、531.7、500.7、466.9mm，分别占同期降雨量的121.2、108.3、104.8、98.7、92.0%，表现为蒸散量随林分密度增大而增加，即在间伐降低林分密度的5年后还可明显观测到其降低林分蒸散耗水的作用。3.不同坡位华北落叶松结构特征、蒸散（组分）差异及坡面尺度效应选择分布华北落叶松的半阳坡作为典型坡面，坡面林分胸径主要分布在16～24cm，树高均在11m以上。不同坡位的（坡顶、坡中上、坡中、坡中下、坡底）华北落叶松林生长季平均LAI依次为2.97、3.14、3.20、3.19、3.24，随坡位降低逐渐增加，从坡顶向下的坡面滑动平均值随水平坡长增加而增加。7从坡顶开始坡长为200m时（水平坡长395m），树高、胸径、LAI等结构指标的滑动平均值近似于整个坡面的平均值。为评价不同坡位处的林分结构对整个坡面的代表性及其随坡长的变化规律，建立了不同坡位处林分结构指标与坡面平均值的比值沿从坡顶向下的水平坡长的数量关系。在2013年生长季观测期（5月16日—10月19日），林外总降雨量为815.9mm，属于丰水年。在典型坡面上，各坡位的（坡顶、坡中上、坡中、坡中下、坡底）华北落叶松样地的林分蒸散量（和组分）依次为425.7、440.7、449.8、448.8、486.1mm，分别占同期降雨量的52.5、54.0、55.1、55.0、59.6%，其占同期降雨量比例明显低于往年。林分蒸散及组分均存在坡位差异，冠层截留和蒸腾量随坡位降低呈增加趋势，林下蒸散趋势相反；总蒸散量随坡位降低逐渐增大。森林的水文影响存在坡面尺度效应。从坡顶向下计算的2013年生长季森林蒸散及其分量的坡面滑动平均值，随水平坡长增加，冠层截留量表现为先减小后持续增加，林下蒸散表现为先增加后持续降低，乔木蒸腾量和总蒸散量表现为持续增加；当坡长约200m时，森林的冠层截留、乔木蒸腾、林下蒸散、总蒸散量的坡面滑动平均值分别为140.5、119.7、181.0、441.2mm，比整个坡面的平均值分别低3.9%（5.6mm）、低9.4%（12.4mm）、高5.6%（9.6mm）、低1.9%（8.4mm）。建立了森林蒸散及其分量的样地测定值与坡面平均值的比值随离开坡顶水平距离而变化的统计关系，依此可将任一特定坡位分样地测定值尺度上推为坡面平均值，从而在减少工作量的同时还提升调查精度。4.不同森林样地的产流特征对2012年生长季森林样地的水量平衡计算表明，并非各林分样地均有产流，其中华山松林和辽东栎林分别产流16.6和54.7mm，但油松林和白桦林的水量平衡项分别为-6.6和-82.1mm，需消耗土壤水分。随着华北落叶松林的林分密度由高至低，其计算产流量分别为33.1、31.9、68.5、85.9、89.5mm，密度减少53.5%，产流量增加幅度为170.3%，表明在间伐降低林分密度的5年后还可明显观测到其增加产流效果。在降水丰富的2013年生长季，在典型坡面上位于坡顶、坡中、坡底的华北落叶松林样地的水量平衡计算所得的产流量分别为353.7、344.4、301.4mm。5.冠层LAI与水文过程的关系冠层LAI与其他林分结构指标（郁闭度、树高、密度、胸高断面积）存在较高相关性，且LAI直接影响林分的各个水文过程。为了认识林分结构对水文过程的影响，利用2012年各样地生长季冠层平均LAI和水文过程观测数据，进行了相关分析。结果显示：冠层LAI与总蒸散（R2=0.56）、冠层截留（R2=0.59）、乔木蒸腾（R2=0.52）呈正相关且相关性较高，与林地产流量负相关且相关性较高（R2=0.53），但与林下蒸散呈负相关且相关性较低（R2=0.12）。说明，林分结构是水文过程主要影响因素。更多还原

【Abstract】 For understanding space changes of the hydrological elements, to quantify its impact onthe hydrological processes and the slope scale effect. Based on the measurements of vegetationstructure and site factors of the typical slope andmain vegetation types,and the observations offorest ecological and hydrological processes using the traditional hydrology method from2012to2013two years growing season (May to October) in Xiangshuihe watershed of LiupanMountains, Ningxia. We quantified the hydrological effects of vegetation and it’s slopedifference and analyzed the slope scale effect. This study is helpful to understand thehydrological effect of vegetation system structure and its formation mechanism form samplescale to slope scale, and to promote the development of forest ecological hydrology theory, andto provide scientific guidance for regional forest integrated water management.1. The differences of vegetation structure characteristics and evapotranspiration invegetation typeThe structure characteristics of main forest type in Xiangshuihe watershed are different.Significant differences were diameter at breast height and tree height. The season change trendof canopy LAI of Pinus armandii forest, Betula platyphylla forest and Quercus liaotungensisforest was similar, the dynamic of canopy LAI was showed for growing rapidly rising in earlygrowth stage, remain stable in mid growth stage, and slow decline in later growth stage. but theseason changing scale of canopy LAI of P. tablaeformis forest was small.The forest soil types are mostly black brown soil and gravel content is higher inXiangshuihe watershed. The soil characteristic of B. platyphylla forest, P.tablaeformis forest,P.armandii forest and Q.liaotungensis forest was similar, bulk density was0.83、1.04、0.79、1.14g·cm-3, total porosity was66.5、59.6、68.0、56.4%, field capacity was47.1、32.9、62.4、35.2%in0-100cm soil layer, respectively.Rainfall is507.2mm in the growing season (May11to October18) of2012inXiangshuihe watershed. The results showed that forest evapotranspiration and its components difference were mainly affected by species composition, canopy density, the stand verticalstructure. The stand evapotranspiration of P. armandii forest, B. platyphylla forest,Q.liaotungensis forest, P. tablaeformis forest and Larix Principis rupprechtii forest were413.2,480.7,389.0,377.6,541.4mm, respectively accounted for81.5,94.8,76.7,74.4and106.7%ofthe rainfall at the same period, but it’s components are different.2. The differences of Larix Principis rupprechtii forest structure characteristics andevapotranspiration (components) in different densityDifferent density of Larix Principis rupprechtii forest were thinning in2007(1811、1556、1134、1033、844tree·hm-2), the average tree height of different density of Larix Principisrupprechtii forests were similar(13.8～14.8m), but the DBH is increased with the decrease ofstand density (16.3-18.1cm).The season change trend of LAI of Larix Principis rupprechtiiforests with different density were similar, the dynamic of canopy LAI was showed forgrowing rapidly rising in early growth stage, remain stable in mid growth stage, and slowdecline in later growth stage. and LAI were positively correlated with forest density.The soil hydrological-physical properties of Larix Principis rupprechtii forests withdifferent density had certain difference, but there was no significant change rule.The evaporation of L. Pricipis-rupprechtiis with the density of1811、1556、1134、1033、844tree·hm-2were614.9,549.6,531.7,500.7,466.9mm, respectively accounted for121.2,108.3,104.8,98.7and92.0%of the rainfall (507.2mm) at the same period, and the value ofevaporation was positively correlated whit stand density. The results show that thinningtreatment reducing stand density after5years was an observed effective measure for reducingthe stand evapotranspiration.3. The differences of Larix Principis rupprechtii forest structure characteristics andevapotranspiration (components) and slope scale effect in different slpoeHalf-sunny slope as a typical slope was choose that distribution of L pricipis-rupprechtii,DBH had mainly distributed in16-24cm, and an average value of tree height more than11m.The average value of LAI of different slope (top,upper, middle,lower and bottom slope position) was2.97,3.14,3.20,3.19,3.24in growing season, respectively.Moving average increase withthe of level of slope length from the top downward slope.The soil hydrological-physicalproperties of Larix Principis rupprechtii forests with different slope position had certaindifference, but there was no significant change rule.The result showed that stand structurefeatures (Tree height, DBH, LAI) can represent the entire slope forest stand structurecharacteristics when investigating slope length was200m.To evaluate the representation ofstand structure to total slope and change rule stand structure with the slope length in thedifferent slope position, the quantitative relationship was established between the ratio of standstructure in different slope position with slope average value and the slope horizontal distanceform top to bottom.Rainfall is815.9mm in the growing season (May16to October19) in2013, belong to thewet year. The evaporation of L. Pricipis-rupprechtiis in different slope positions (from topslope to bottom slope) were425.7,440.7,449.8,448.8mm,486.1mm, on typical slope,respectively accounted for52.5、54.0、55.1、55.0and59.6%of the rainfall at the same period.Accounting for the proportion of rainfall was decreased obviously, because of effected byrainfall and meteorological conditions. The evapotranspiration and its components existedslope position differences. Interception and transpiration was increase with lower slopepositions, contrary trend of floor evaporation; Total evapotranspiration was increase with lowerslope positions.The effect of forest to hydrological exist slope scale effec. Calculation of the slpoemoving average value of the stand evapotranspiration and its components form top to lower ingrowing season in2013, canopy interception showed reduced first and continue to increaseafter, floor evaporation showed increase first and continue to reduced after, tree transpirationand total evapotranspiration showed continue to increase with the slope horizontal distanceincrease. Compared to the average value, the moving average value of canopy interception, treetranspiration, understory evapotranspiration and total evapotranspiration was respectively lower3.9%(5.6mm), lower9.4%(12.35mm), higher5.6%(9.6mm) and lower1.9%(8.4mm) when slope length was200m.Relationships between ratios of forest evapotranspiration and its components measured ina specific position of a slope to the slope average and the horizontal distance from the slope topwas obtained in this paper. Therefore, the average of an index for a whole slope can beupscaled from the value measured in any given slope position. That would lessen the workloadand improve the accuracy.4. The flow characteristics of different vegetation typesWater balance calculation of forest plots in growing season in2012, the results showed:not all stand sample has water output. The capacity of water output of P. armandii forest and Q.liaotungensis forest was16.6and54.7mm, water output of P. tablaeformis forest and B.platyphylla forest was-6.6and-82.1mm, consumption of soil moisture.The water flow of L. Pricipis-rupprechtiis forest with density from high to low were:33.1,31.9,68.5,85.9, and89.5mm, runoff increased by170.3%when density decreased by53.5%.The results showed that thinning treatment reducing stand density after5years was an effectivemeasure for increasing the runoff production.The water flow of L. Pricipis-rupprechtiis forest in top, middle and bottom slope positionwere353.7,344.4,301.4mm respectively in2013year growing season, runoff decreased fromtop slope to bottom slope.5. The relationship between leaf area index and hydrological processBetter correlations between LAI with other forest structure, and LAI was direct effecedthe hydrological process of stand. In order to understanding the effected of forest standstructure for hydrological processes. The correlation analysis was used the average value ofLAI in growing season and data of hydrological process in2012, the results showed: the totalevapotranspiration, canopy interception and tree transpiration was positively related with leafarea index (LAI), and the correlation coefficients (R2)were respectively0.61,0.50and0.45.However, understory evapotranspiration was negatively related with leaf LAI, with a low correlation coefficient of0.12. There was a liner relationship between LAI and forest waterflow and the correlation coefficient (R2) was up to0.58. The results showed that foreststructure characteristics were the important influence factors of forest evapotranspiration andrunoff.更多还原