鹤山丘陵草坡的水文特征及水量平衡

 在中国科学院鹤山丘陵综合开放实验站的草坡集水区对大气降水和径流进行了连续4年的观测,并于1994年对该集水区的蒸散进行了测定,结果表明：1)鹤山丘陵区年均降水量1761.37mm,大气降水有明显的干湿季之分,干季降水量占全年降水量的12.47％,湿季占87.53％。年均降水量中有62.24％可引起地表产流,即年均产流降水量1096.3mm。产流降水以中、小雨频度为大,但产流水量主要由大、暴雨供给。文中根据降雨量较大地区的降水、产流特征和规律,提出了产流降水和产流水量的概念。2)鹤山丘陵草坡集水区年总径流系数50.12％,地表径流系数17.33％。地表径流主要集中在湿季产生,与降水量呈二次抛物线型回归关系,与降水强度关系不大。3)1994年水量平衡各分量中,实际降水输入1841.55mm,年径流量970.28mm,径流系数52．69％,径流是系统的最大输出项;蒸散量851.56mm,意味着年降水收入中46.24％的水量以汽态形式返回了大气。蒸散的月变化呈双峰型,不同于降水的季节分配,径流的月变化则与降水同步。系统蓄水年变化量19.71mm,约占年降水量的1.07％,但其月变化却非常大,在一68～104mm之间。草坡集水区的水量平衡是一种收入对支出的补给和收支项目中可变性的动态平衡。4)鹤山丘陵草坡水热季节分配失衡、产流降水量和地表径流量大是这种退化生态系统恢复的3个限制因素;认为退化生态系统恢复过程中系统水量支出和蓄留方式的转变是退化生态系统的恢复机理之一。     

鼎湖山针阔叶混交林生态系统水文效应研究

对鼎湖山针阔叶混交林水文效应的研究表明2002年8月-2003年7月,大气总降水量为1 690mm,林内净降水量为1212.7 mm,占总降水量的72%,其中穿透雨量和茎流量分别为1 125.3和87.4 mm,占总降水量的.66.6%和5.2%.林冠截留量为477.3 mm,截留率28.2%.地表径流量62.1 mm,占总降水量的3.7%.在一定的降水量范围内,林冠对降水的截留量随着降水量的增加而增加,不同的雨量级,林冠截留量变化的趋势曲线不同,且一次截留降水量饱和值约为25 mm;穿透雨量、茎流量均随着林外大气降水量的增加呈线性增加;当日大气降水量在0-30 mm时,地表径流量很小,且呈线性递增;当日大气降水量＞30 mm时,地表径流量随降水量增加以对数递增.与马尾松纯林和季风常绿阔叶林相比,针阔叶混交林在减少地表径流和保持水土等方面具有更好的水文生态效应.     

基于修正的Gash模型对南亚热带季风常绿阔叶林林冠截留的模拟

Gash解析模型及其修正的模型是估算和预测林冠截留的有效工具,探讨其在南亚热带森林植被冠层截留模拟中的适用性,是认识该区域结构相对复杂的自然林分冠层的降雨截留能力及其相关科学问题的重要基础。基于2009年鼎湖山国家级保护区内季风常绿阔叶林样地降雨及其他气象因子的观测数据,采用修正的Gash模型对南亚热带地带性顶极群落季风常绿阔叶林的冠层截留量及其组分进行了模拟量化。结果表明:2009年,季风常绿阔叶林林内穿透雨量、树干径流量和林冠截留量分别为1310.9、85.5和498.9 mm,分别占林外总降雨量的69.2%、4.5%和26.3%。基于修正的Gash模型对林冠降雨截留量的同期模拟值为473.0 mm,模拟截留量比实测值低25.9 mm,相对误差为5.2%。对干季降雨截留模拟的相对误差较小(1.8%),湿季稍大(6.8%)。从林冠截留量的构成来看,降雨停止后的林冠蒸发(231.4 mm)是林冠截留的主要组成部分,占总截留量的48.9%。整体上,国内基于Gash及其修正模型对森林冠层截留的模拟相对误差在0.2%~35.0%。林冠持水能力被视为模型准确估算林冠截留量的先决条件,国内运用不同方法估算的不同林分林冠持水能力大致处于0.23~2.86 mm。修正的Gash模型适用于南亚热带季风常绿阔叶林林冠截留的模拟应用。     

杉木人工林水量平衡和蒸散的研究

 本文根据我们严密设计的小集水区径流场连续6年的水文测定数据,进行了杉木人工林水量平衡和蒸散的研究。结果表明：集水区年平均降雨量1065.5mm, 在林冠作用面降雨量的分配中,林冠截留雨量264.6mm,截留率24.8%;穿透过林冠层的雨量799.82mm,树干径流量1.08mm,分别占降雨量的75.1%和0.1%。林内降水到达林地时,在枯枝落叶层这个作用面上净降水进行再分配,其中,地表径流量9.27mm,地下径流量203.00mm,总径流系数0.199。土壤蓄水量月变化较大,但年变化很小,占降雨量的1.2%。系统水量最大的输出是蒸散,每年以气态形式返回大气的水量866.03mm,占降雨量81.3%。在蒸散的水量中,林冠截留雨量的直接物理蒸发量为264.6mm,占总蒸散量的31.6%。     

中国东部森林样带典型森林水源涵养功能

通过对我国东部森林样带四个森林生态系统定位研究站（长白山站、北京站、会同站和鼎湖山站）的九种森林类型水源涵养监测数据的分析,研究了水热梯度下不同森林生态系统水源涵养功能。结果表明：在生长季的5-10月份,各森林类型的水源涵养特性表现出较大差异。林冠截留率的大小依次为：阔叶红松林＞杉木林＞常绿阔叶林＞针阔混交林＞季风常绿阔叶林＞落叶阔叶混交林＞马尾松林＞落叶松林＞油松林,最高的长白山站阔叶红松林的截留率是最低的北京站油松林的2.2倍。森林降雨截留量与林外降雨量呈显著的正相关,林冠截留率与降雨量呈显著负相关。枯落物最大持水深（5-10月份）以北京站落叶阔叶林最大,为6.0mm;鼎湖山站的季风常绿阔叶林最小,为1.0mm。0-60cm土层蓄水量最大的是会同站的人工杉木林,为247mm;最小的是北京站的落叶松林,仅为45.5mm;林分总持水量依次为：杉木林＞阔叶红松林＞常绿阔叶林＞针阔混交林＞季风常绿阔叶林＞落叶阔叶混交林＞马尾松林＞落叶松林＞油松林。各林分总持水量主要集中在土壤层,占总比例的90%以上。     

南亚热带季风常绿阔叶林水文功能及其养分动态的研究

 根据在鼎湖山季风常绿阔叶林集水区3年的观测结果,对这一南亚热带地带性植被的水文功能进行了较深入的探讨。由于林分结构复杂,季风常绿阔叶林对大气降水具有较高的林冠截留率,截留率的季节变化动态与降水量的季节分配有关。该森林土壤结构良好,其渗水速度快,加上有较厚的枯落物层,对于减缓地面径流,减少水土流失,功效甚大。但由于土层较薄,其蓄水功能有限。该森林的径流量占总降水量的比例特别是地表径流所占比例较小,分别为50.22％和14.19％。其季节分配有利于保持水土和植物生长。由于土壤蓄水量变化出现负值,用水量平衡法计算得出鼎湖山季风常绿阔叶林年蒸发散量为1323.98mm,占大气降水量的51.81％。该森林的降水中主要营养元素浓度较高,降水带来大量的养分,特别是氮素的年输入量高达35.29kg·hm-2。淋溶也给该森林带来较高的养分归还量,其中钾的淋溶量高达35.65kg·hm-2;镁的淋溶量高达8.9kg·hm-2,为林外雨输入的2.37倍。径流中的氮输出为28.35kg·hm-2,降水中的氮素净输入量为6.94kg·hm-2;但镁的净输入呈负值。     

南亚热带鹤山5种生态系统的地表径流

运用“小集水区径流场”技术对山丘陵试验站5种生态系统地表径流进行了连续5年的观测与实验,结果表明：a.5种系统的地表径流系数马占相思林＜果园＜豆科混交林＜草坡＜林草苗系统,分别为2．3％,6．97％,13．30％,17．90％,22．16％;径流模数变率差马占相思林＜豆科混交林＜林果苗系统＜草坡＜果园,分别为0．46,0．57,0．63,0．65,1．68,可见两种人工林生态系统在蓄留水分,调节水量上均优于草坡,而两种农林复合生态系统有所欠缺;各系统的地表径流系数均有明显的干,湿季差异,表现为湿季＞全年＞干季,径流模数变率差的季节变化则恰好与此相反。b.5种系统每场降水的地表径流量与降水量间存在着二次抛物线型回归关系,地表径流量随降水量的增加是非匀速的,年地表径流量主要由几场大的降水所决定;地表径流量与降水强度的关系不大。c.5种系统发生产流的最小降水量马占相思林＞果园＞豆科混交林＞林果苗系统＞草坡,辚15．9,13．28,8．1,6．71,5．21mm;各系统对产流和洪峰的滞后约为10－30min,马占相思林滞后时间最长,其含蓄水分,削减洪峰和调节地表径流的作用最为明显,文中讨论了造成林果苗和果园系统水文功能缺陷的一些原因,肯定了亚热带丘陵区上坡构建马占相思林在恢复生态学上的重要意义。     

中国主要森林生态系统水文功能的比较研究(英文)

 基于中国不同区域生态站的观测资料,着重从降雨截留（林冠截留、枯枝落叶层截持和土壤蓄水）、调节径流和蒸散等3个方面对我国主要森林生态系统的水文生态功能进行了比较研究。各生态系统林冠年截留量在134～626 mm间变动,由大到小排列为：热带山地雨林,亚热带西部山地常绿针叶林,热带半落叶季雨林,温带山地落叶与常绿针叶林,寒温带、温带山地常绿针叶林,亚热带竹林,亚热带、热带东部山地常绿针叶林,寒温带、温带山地落叶针叶林,温带、亚热带落叶阔叶林,亚热带山区常绿阔叶林,亚热带、热带西南山地常绿针叶林,南亚热带常绿阔叶林,亚热带山地常绿阔叶林。枯落物持水量可以达到自身干重的2～5倍,但也因林型而异。土壤非毛管持水量变动在36～142 mm之间,平均89 mm。常绿阔叶林的非毛管持水量通常高于100 mm,而寒温带/温带落叶阔叶林和常绿针叶林通常低于100 mm. 土壤的非毛管持水量通常占生态系统中截持水量的90%,其次是枯落物和林冠层。这说明,森林土壤在调节降雨截留中占有重要地位,其水文功能的大小取决于土壤结构和空隙度,而这些恰恰又受枯落物和森林植被特征的影响。森林皆伐后,一般地表径流会显著地增加,而适当抚育措施则对地表径流影响不大。流域径流受诸多因素的影响,包括植被、土壤、气候、地形、地貌以及人类影响导致的流域景观变化,比较研究表明森林变化对流域径流的影响尚未得到一致的规律性的结果。通过对比研究不同森林的蒸散变化,发现随降雨量的增加,森林蒸散量略有增加,而相对蒸散率却在下降,相对蒸散率在40%～90%间变动。     

鼎湖山季风常绿阔叶林及针阔叶混交林节肢动物群落多样性调查

20 0 1年 5月和 10月在自然保护区鼎湖山季风常绿阔叶林和针阔叶混交林的灌木层和草本 -苗木层对节肢动物多样性进行了调查。结果表明 ,5月份的灌木层 ,季风常绿阔叶林的节肢动物物种数和个体数 >针阔叶混交林 ,相反 ,在草本 -苗木层 ,针阔叶混交林的物种数和个体数 >季风常绿阔叶林。 10月份 ,针阔叶混交林节肢动物物种数和个体数与季风常绿阔叶林间无明显差异。两林分中 ,天敌占总物种数的 2 7.5 0 %～ 87.5 0 % ,蜘蛛类群占总物种数的 18.18%～ 6 6 .6 7%、占天敌物种数的 5 3.33%～ 90 .91%。除 5月份的草本 -苗木层外 ,节肢动物的丰富度指数、多样性指数均是季风常绿阔叶林 >针阔叶混交林 ,优势集中性指数则是针阔叶混交林 >季风常绿阔叶林。     

鼎湖山南亚热带森林细根生产力与周转

 报道了鼎湖山季风常绿阔叶林和针阔叶混交林群落0～40cm土层中细根(≤2mm和2～5mm)的现存量、死亡量、生产力和周转率,并比较了用“连续钻取土芯法”和“埋无根土柱法”来估算表层土(0～20cm)细根生产力的差异。结果表明：在0～40cm土层中,季风常绿阔叶林≤2mm和2～5mm细根现存量分别为6.59t·hm-2和4.81t·hm-2,死根比率各为29.9％和22.9％;针阔叶混交林≤2mm和2～5mm细根现存量分别为5.35t·hm-2和4.24t·hm-2,死根比率各为34.4％和24.0％。细根现存量的季节性变化不显著。季风常绿阔叶林细根年分解量、年死亡量和年净生产力分别为0.90,1.59,2.65t·hm-2·a-1 (≤2mm)和0.41,0.63,1.25t·hm-2·a-1(2～5mm),针阔叶混交林的相应数值各为0.80,1.4l,2.42t·hm-2·a-1(≤2mm)和0.37,0.62,1.21t·hm-2·a-1(2～5mm)。季风常绿阔叶林细根年周转率为0.57 (≤2mm)和0.34次·a-1(2～5mm),针阔叶混交林分别为0.69(≤2mm)和0.38次·a-1(2～5mm)。     

鼎湖山人工松林生态系统蒸散力及计算方法的比较

Based on the consecutive measurement (1995-1997) of meteorology and microclimate of artificial Pinus forest in Mount Dinghu, we calculated the potential evapotranspiration by using four different methods to discuss the method which is fit for forest ecosystem. The results are given as follows.1) In terms of the enviromental conditions of forest ecosystem, we redefined some parameters in Penman equation and used it to calculate the potential evapotranspiration of artificial Pinus forest ecosystem in Mount Dinghu.Preliminary result is that Penman equation is worth spreading for calculating the potential evapotranspiration of forest ecosystem,compared with several other methods.2) The annual average potential evapotranspiration of the artificial Pinus forest in Mount Dinghu is 937.55mm,according to Penman equation. It is 50% of the rainfall in the corresponding period. The highest mean monthly potential evapotranspiration is July and the lowest mean monthly potential evapotranspiration is January. This is completely consistent with the variations of temperature.     

The fate of rainfall in a mallee and heath vegetated catchment in southern Western Australia

Mallee, a shrub-eucalypt association, once covered large areas of the cereal growing land in Western Australia. The hydrologic consequences of land development have been more than a doubling of water yield and increased deep drainage beyond the plant-root zone. The latter has led to large areas of soil salinization. The uncleared catchment studied was covered with mallee vegetation (65%) and a heath association (35%). Over 12 years of measurement, runoff from the catchment has averaged 0.025 mm per annum with a mean annual rainfall of 376 mm. Half of the runoff resulted from two major events totalling 0.15 mm. Since there was no evidence of groundwater accession in the catchment, the rainfall was balanced by evapotranspiration. Despite virtually no runoff from the whole catchment, considerable internal redistribution of surface water occurred, with localized overland flow in some areas as high as 7.7 mm from 30.9 mm of rainfall in one day. Rainfall penetrated rapidly under the mallee vegetation and the rate of penetration observed could not be achieved solely through the soil even if there was saturated flow. A typical stand of native mallee trees (Eucalyptus pileata and E. eremophila) in the catchment effectively redistributed 8% of the annual rain falling on the stand with 3% lost as interception and 5% going to stemflow. However, on an individual tree basis some 15% of the rain falling on the canopy was lost as intercepted water and 25% ran down the stem. The stemflow caused saturated conditions around the bole of the mallee and dye tracing showed that the water penetrated the soil via the annular pathways of the soil-root interface. Roots of mallee trees were found at 28 m depth and it is postulated that the mallees are adapted to the semi-arid environment by virtue of their ability to store water deep in the soil profile for use during the dry summer months.     

Phytoplankton response to changed nutrient level in Lake Peipsi (Estonia) in 1992–2001

To clarify the sediment yield processes following a disturbance by a forest fire in a mountainous catchment, and considering the hydrological and geomorphological processes in the headwater, we measured bedload sediment yield at rainfall events in disturbed and secondary forest catchments in the western part of Japan. The three catchments were under different hydrogeological conditions. The IK, TB and TY catchments were disturbed by forest fires in 2000, 1994, and 1978, respectively. In the IK catchment, although runoff response to rainfall was fastest with high peak flows, the catchment also had the highest base flow. Moreover, the annual sediment yield there was about ten times as high as in the other two catchments, and it was found that there was a steep linear curve in the relationship between precipitation and bedload sediment yield. This is thought to be caused by overland flow generation following water repellency on the slopes, and by the accumulated sediment that forms the thick soil layer on the valley bottom. On the other hand, in the TB catchment runoff experienced high peak flows at rainfall events and low base flows, and there was a gradual linear curve in the precipitation–sediment yield relationship. This might be the result of there being a thin soil layer on the hillslope and on the valley bottom because of successive erosion after the fire. In the TY catchment, runoff had a low peak flow at rainfall events and a high base flow; and the bedload sediment yield increased exponentially with increasing precipitation. Therefore, sediment yield in the TB catchment was more than that in the TY during storm events with precipitation of less than 100 mm, whereas it was the opposite during heavier rainfalls. It indicates that there is a thick soil layer on the slope and a thin soil layer on the valley bottom in the TY catchment following the recovering of vegetation, and that the sediment yield process predominates only during big rainfall events, only then does subsurface flow generate.     

Analyses of landuse change impacts on catchment runoff using different time indicators based on SWAT model

Previous researches mainly focused on the runoff responses to landuse change based on annual, seasonal or monthly time scales, there are few studies based on daily scale. We conducted a comprehensive investigation into runoff responses on the daily scale as well as annual and monthly time scales using SWAT, and compared the impacts of time scales with different time indicators quantitatively. Jinjiang, a coastal catchment of southeast China with a humid sub-tropical climate, was used for simulations. A calibrated SWAT model produced satisfactory reproduction of annual, monthly and daily runoff processes over a nine-year (2002–2010) period at three gauging stations. Runoff was then simulated and compared using the same meteorological input but two different landuse scenarios (1985 and 2006, with reduced forest and increased cropland and urbanized area). The results showed varying change in runoff among three time scales and three catchments. The annual runoff had the smallest increase between two scenarios, monthly runoffs had medium rates (increasing in all months except October–November), and daily runoff had the largest rates with the increase in flood peaks but decrease in drought flows, because of the variable influence on interception/evapotranspiration loss, percolation and antecedent soil water storage. Indicators of different time scales (annual runoff, monthly runoff, maximum 1-day and 5-day flood runoff, minimum 1-day and 7-day runoff) proved appropriate for analysing landuse change impacts.     

泾河流域上游土石山区和黄土区森林覆盖率变化的水文影响模拟

泾河流域上游是黄土高原的重要水源地和退耕还林工程区,在较大空间尺度上定量评价区内森林覆盖增加的水文影响对科学指导林业生态环境建设、保障区域水安全和可持续发展均有重要意义。为了在尽量排除地形、土壤、气候等作用的基础上定量评价森林的影响,将泾河上游划分为土石山区和黄土区,分别制定了多种森林恢复情景,利用分布式流域生态水文模型(SWIM)模拟评价了森林覆盖率及其空间分布变化对流域年蒸散量、年产流量、年地下水补给量、年土壤深层渗漏量及日径流洪峰的影响。土石山区模拟结果表明,增加森林覆盖将增加流域蒸散和减少流域产流,如现有森林覆盖(占全流域面积比例为13.8%)情景与现有森林变为草地(占全流域面积比例为0)情景相比时,流域年蒸散量从445.4 mm变为427.7 mm(减少了17.4 mm和4%);年产流量从42.4 mm变为53.5 mm(增加了11.1 mm和26.3%),年地下水补给量从61.6 mm变为76.9 mm(增加了15.3 mm和24.8%),年深层渗漏量从72.9 mm变为88.3 mm(增加了17.7 mm和24.3%);平均森林覆盖率每增加10%,导致流域年蒸散量增加12.8 mm,年产流量减少8.0 mm,年地下水补给量减少11.1 mm。在比较干旱和土层深厚的黄土区,增加森林覆盖将同样增大流域蒸散和减少流域产流,但变化幅度明显小于降水相对丰富和土层浅薄的土石山区,平均森林面积增加10%导致流域年蒸散量增加9.0 mm,年产流量减少4.5 mm,年地下水补给量减少8.8 mm;此外,在较缓坡面造林的水文影响大于较陡坡面造林。从森林水文影响的年内变化来看时,森林覆盖率升高的水文影响在土石山区和黄土区也有差别,如土石山区5—7月份的蒸散显著增加,5—10月份的深层渗漏均有减少;而黄土区是蒸散量在5—10月均有增加,深层渗漏在7—10月份显著减少。另外,土石山区森林覆盖率增加对日径流峰值的影响不显著,而黄土区则能明显削弱,这可能主要是因土石山区的高石砾含量土壤的渗透性能明显高于黄土区的黄土,而黄土区的森林能够明显改善土壤入渗性能和减少地面径流形成。     

亚热带常绿阔叶林的水文生态特征

对日本冲绳岛亚热带天然次生常绿阔叶林的水文生态特性进行了为期3年的定位观测.结果表明,观测期间年平均降雨量高达3325mm,台风降雨(包括直接和间接影响)占年降雨量的42.3%;穿透雨量和树干流量分别为年降雨量的53.9%和30.9%,较高的树干流量可能与高风速、强度降雨以及优势树种的树冠构造紧密相关.林冠截留损失占年降雨量的15.2%,低于世界范围内其它多数常绿阔叶林(15%～30%).年平均地表径流和壤中流量分别是1092mm和613mm,分别占年降雨量的32.8%和18.4%;较高的径流量可能是由不良的土壤物理性质引起的.试验林土壤尤其是下层土壤非毛管孔隙度低(8%～12%)、粘粒含量极高(51.9%～60.5%),水分渗透缓慢(12ml·min^-1).0～70 cm土层的有效蓄水量和最大蓄水量分别为85 mm和324mm,林地凋落物层的最大持水量为2.8 mm,接近或低于中国亚热带和热带山地雨林.     

北亚热带3种森林群落对大气湿沉降重金属的调控

森林群落截留消纳沉降重金属的能力影响着森林集水区溪水输出重金属的情况,决定着小流域的水质安全。为评价北亚热带地区典型森林生态系统对大气降水中主要重金属离子的截留能力和分配特征,以浙江庙山坞林场3种典型森林群落(毛竹林、杉木林、青冈阔叶林)和森林集水区-小溪为研究对象,于2018年7月—2019年6月监测了12次降水事件,分析、比较和讨论了大气降水、林内穿透雨、树干茎流、枯透水、地表径流和集水区溪水中7种重金属(铅(Pb)、锌(Zn)、镉(Cd)、铜(Cu)、砷(As)、镍(Ni)和锰(Mn))的质量浓度和通量的动态变化。结果表明,大气降水中7种重金属,Pb、Cd、As、Cu、Zn、Mn和Ni的年均浓度分别为0.974、0.124、0.512、3.42、36.7、8.48和1.94μg/L,3种森林群落林冠层截留的干沉降重金属中Zn和Mn的比例最高,林冠层降水对重金属Mn和Zn的淋溶量极高,超过大气降水沉降量的2.78倍和54.2倍,同时截留了降水中的As和Ni;枯落物层对Mn、Cd和Zn表现出截留作用,对Cu和Ni有淋溶或释放的作用;3种森林群落的地表径流中Pb、Mn、Cd和Zn浓度明显降低,As和Ni的浓度略高于枯透水,但由于地表径流量非常小,土壤表层对降水中重金属均表现出极强的截留作用。3种森林群落对大气降水中的重金属均表现出极高的截留率,森林群落之间没有显著差异,其中青冈阔叶林的截留能力最强,杉木林较弱。而地表径流及土壤渗透水等汇集到森林集水区后,溪水中重金属Mn、Ni、Cd和Zn的浓度和通量均有大幅的增加,仅对重金属As和Cu呈现截留的作用,这可能与森林土壤重金属本底值偏高以及森林长期接收的重金属沉降在降水淋溶下从酸性土壤中大量溶出有关。     

宁夏六盘山人工林和天然林生长季的蒸散特征

为了系统地认识森林生态系统结构对蒸散特征的影响,2009年5-10月,应用热扩散技术和传统水文学方法,对六盘山香水河小流域华北落叶松人工林和华山松天然林的蒸散及分量进行对比研究.结果表明: 华北落叶松人工林生长季总蒸散量为518.2 mm,是同期降雨量的104.6%,远高于天然林蒸散量420.5 mm.两种林分总蒸散量在其垂直层次上的分配比例相近,表现为冠层蒸腾量>草本+土壤层蒸散量>灌木蒸腾量,但林分各组成分量占总蒸散量的比例明显不同.其中,人工林冠层月均截留量和蒸腾量为19.6和25.2 mm,分别是天然林的1.2和1.9倍;人工林灌木层月均蒸腾量为 4.4 mm,占天然林的23.4%;人工林草本+土壤层月均蒸散量为37.1 mm,是天然林的1.8倍.采用Penman-Monteith方程对林分的实测蒸散量进行对比检验,两种方法对林分蒸散量的估计值基本接近.