黄土高原半干旱区油松人工林林冠截留模型及其参数特征研究

利用2008—2011年定位观测数据,采用回归分析方法对黄土高原半干旱区油松人工林林冠截留与林外降雨之间的关系进行建模研究,并运用Bootstrap方法,对模型参数特征进行分析。结果表明:林冠截留量(I)与林外降雨量(P)可用非线性模型I=a Pb进行回归模拟,回归方程为I=0.584P0.576;该模型不仅具有较高的拟合精度,且拟合方程参数稳定性良好,经检验,方程均达到显著性要求,可在该区域油松人工林应用。     

内蒙古蛮汉山典型森林植被土壤层和枯落物层的水文特征研究

森林植被的土壤层和枯落物层具有重要水文功能,以内蒙古中部地区的蛮汉山5种森林植被(樟子松人工林、油松人工林、华北落叶松人工林、白桦次生林和山杨次生林)为研究对象,从土壤层和枯落物层两方面分析5种森林植被的水文功能。结果表明：不同森林植被土壤的最大贮水深存在差异,由大到小依次为华北落叶松人工林(525.28 mm)、油松人工林(511.70 mm)、山杨次生林(490.63 mm)、白桦次生林(489.12 mm)、樟子松人工林(448.79 mm);土壤有效贮水深由大到小依次为：油松人工林(40.34 mm)、华北落叶松人工林(31.25 mm)、白桦次生林(30.69 mm)、山杨次生林(28.34 mm)、樟子松人工林(24.35 mm)。5种森林植被的枯落物现存量变化幅度为2.77～15.60 t·hm^-2,枯落物最大持水深的变化幅度为0.42～2.78 mm,枯落物总持水深、半分解层持水深和未分解层持水深均呈现为：樟子松人工林>华北落叶松人工林>山杨次生林>白桦次生林>油松人工林。     

云南元谋干热河谷区加勒比松人工林枯落物层的水土保持功能研究

对云南元谋干热河谷区加勒比松人工林枯落物层水土保持功能的模拟试验结果表明:该河谷区的加勒比松人工林枯落物层具有截留降雨的作用,其降水截留率可达73.48%,且滞缓林地地表径流的效果显著;厚度为3 cm的枯落物层能抑制林地土壤水分的蒸发率达54.5%;加勒比松人工林的枯落物层能防止林地土壤的击溅侵蚀,当枯落物层厚2.0 cm时,林地土壤的滴溅侵蚀业已停止。     

长沙市郊枫香人工林水文生态效应的研究

为了科学评价城市景观公益林的生态效益,采用森林水文定位观测、样品采集和实验分析相结合的方法,从森林林冠层、林下枯落物层、土壤层3个生态作用层对长沙市郊枫香人工林水文生态效应进行研究并以荒地作为对照。结果表明:观测期内林冠截留量占平均总降雨量的22.37%,穿透雨、树干茎流与林外降雨存在线性关系,林冠截留量与降雨量具有显著的幂函数关系;林下枯落物贮量为4.56 t.hm-2,枯落物最大持水量为6.79t.hm-2;林地土壤容重小于荒地,非毛管孔隙度是荒地的2倍,林地0～45 cm层土壤最大持水量为197.80 mm;枫香人工林能够改善土壤结构,相对于荒地具有明显的水土保持作用。     

贡嘎山暗针叶林生态系统枯落物截留特征研究

充分考虑不同林型下枯落物的特性和降雨特性,采用现场模拟方法观测枯落物截留,以浸水法观测枯枝落叶层的最大持水量,观测了贡嘎山不同演替阶段的暗针叶林群落林内枯落物的截留特征.结果表明,贡嘎山暗针叶林生态系统中不同群落的枯落物截留降水量与林外降雨量有不同程度的线性相关关系,而林内降雨量与枯落物截留量之间存在幂函数关系.同林型内,由于枯落物数量与组成成分、分解程度等不同,其持水能力也存在着较大的差异:过熟林中枯落物吸水饱和时间最短,最大持水率最低,枯落物与林下厚厚的苔藓层混杂在一起,截留水分的能力相对较弱;幼龄林中枯落物饱和需要时间最长,最大持水率也最高,对林下降雨的再分配作用也相应最大.同时,枯落物层的截留作用及截留量的大小,除去枯枝落叶层的数量和质量外,与枯落物的湿润程度相关.     

油松人工林碳汇功能的研究

对木兰林管局油松人工林19块标准地分林木层、灌木层、草本植物层、枯落物层和土壤层进行了生物现存量的实测与碳储量的研究,结果表明林木层和土壤层的碳储量构成了林分碳储量的主体.分配次序为土壤层＞林木层＞地表枯落物层＞草本层＞根桩＞灌木层,林木层碳储量分配次序为干＞枝＞根＞叶.建立了林木蓄积与生物量、碳储量的回归模型,认为幂函数形式有较好的适用性.以林龄(A)和3株优势木平均高(H)建立了土壤有机碳密度(Soc)拟合方程,可用于具体小班土壤碳密度的估测.木兰林管局油松人工林林分碳密度为76.586 2～284.417 8t/hm2,平均值为143.1 t/hm2,其中林木平均碳密度为30.454 5t/hm2,土壤平均碳密度为110.773 5t/hm2;现有油松人工林碳储量估测结果为983 314.0 t,其中林木碳储量为208 923.0 t,占总碳储量的21.25%,土壤碳储量为760 881.0 t,占总碳储量的77.38%.     

油松人工林单木树高生长模型研究

使用Richard,Logistic,Korf,Mitscherlich,Schumacher,weibull等6种理论生长方程拟合了不同立地条件下油松人工林单木树高生长过程,从中选出模拟效果最优的生长方程。研究结果显示:三参数理论生长方程Lo—gistic、weibull、Richard、Korf对油松树高生长拟合的精度基本相近,明显高于二参数的Mitscherlich、Schumach—er方程;立地指数显著影响各方程渐进线参数和形状参数,将立地指数引入各理论生长方程中,构建了模拟油松人工林单木树高生长精度最优的预测方程为Logistic式;使用未参加建模的油松解析木数据对构建的预测方程进行T检验,发现预测值与实测值之间无显著差异(P=0.6213>0.05)。可见,本文构建的预测方程可以准确预测油松人工林单木树高生长过程,为油松人工林科学经营提供重要参考。     

辽东山区不同森林植被类型枯落物层截留降雨行为研究

对辽宁东部山区具有代表性的油松林、落叶松林、红松林、柞木林及杂木林5种森林植被类型枯落物层截留降雨行为进行了比较研究。结果表明，枯落物截留量随林内雨量的增加而增加，呈显的线性关系；枯落物截留率在低的林内雨量级时下降梯度较大，以后随林内雨量增大而逐渐减少，最后趋于某一定值，枯落物截留达到饱和。曲线估计的饱和截留率为：杂木林30％，柞木林23％，落叶松林20％，油松林15％，红松林10％。林冠层与枯落物层截留量依林外雨变化呈显的线性关系，总截留率在低雨量级时保持在较高的水平，随后急剧下降，并逐渐趋于某一稳定性，达到最大截留能力。由曲线推算的最大总截留率，杂木林和 柞木林为45％，落叶松林为40％，红松林和油松林约为30％。枯落物生长季相对于林内雨的截留率为14．31％－43．15％，平均值为31．15％，相对于林外雨量的截留量为11．15％－32．30％，平均值为24．05％。     

内蒙古大青山白茬子沟小流域典型森林植被的冠层降水再分配特征

利用生长季观测的降雨数据,分析了内蒙古大青山白茬子沟小流域白桦次生林和华北落叶松人工林林冠降雨截留、穿透雨及树干径流与降雨量的关系,以及降雨林冠截留过程的特征。结果表明:两种林分林冠截留量与降雨量的关系吻合对数回归模型;穿透雨量、树干径流量与降雨量均呈明显的一元线性关系,穿透雨量和树干径流量均随着降雨量的增加而增加。不同林分的林冠截留量、穿透雨量和树干径流量的月动态变化与总降水量的月变化基本一致;林内穿透雨率超过73%,冠层截留率9.81%~26.22%,树干径流0.72%~9.10%。     

两种经济林中的穿透雨与茎流特征研究

本文观测了桃李两种经济林的穿透雨和茎流特征。结果表明,两种经济林的穿透雨量、林冠截留量、茎流量与降雨量均存在极显著的正相关关系。用幂函数方程能较好的拟合林冠截留量与降雨量之间的关系,而用线性方程能较好的拟合穿透雨量、茎流量和降雨量之间的关系;桃李两种经济林穿透雨量分别占降雨量的93.29%、85.34%,林冠截留量分别占降雨量的5.60%和12.04%,茎流量分别占降雨量的1.11%和2.62%。     

不同密度毛竹林枯落物层水文特性研究

对黄山区4种密度毛竹纯林枯落物层的储量、最大持水量、最大持水率、吸水速率、有效拦蓄量等水文特性参数进行了研究。结果表明:(1)不同密度毛竹林枯落物储量、厚度及自然含水率均存在较大差异;不同林分枯落物储量为3.98 6.00 t·hm-2,其中,以3 000株·hm-2的林分枯落物储量最高。(2)4种密度毛竹林下枯落物最大持水率为317.09%347.58%,密度为3 000株·hm-2时,毛竹林枯落物层最大持水量达到20.70 t·hm-2。(3)4种密度毛竹林枯落物层持水量(S)与浸泡时间(t)的关系为S=alnt+b(a为方程系数,b为方程常数项),其吸水速率(V)与浸泡时间(t)的关系为V=ctd(c为方程系数,d为方程指数);在0 4 h内枯落物吸水速率急剧下降,4 h后明显减缓。(4)密度对毛竹林枯落物水文特性有一定影响,选择适宜的营林密度对于提高毛竹林枯落物层水文生态功能具有重要的作用。     

闽北毛竹林枯落物层持水功能研究

以杉木林和常绿阔叶林为对照,对闽北典型毛竹林(杉竹混交林、毛竹纯林、竹阔混交林)林下枯落物储量、持水特性及其对降雨的拦蓄能力进行研究,结果表明:(1)各林分未分解层、半分解层和已分解层枯落物储量、最大持水量和有效拦蓄差异较大,但均以半分解层最高,分解层次之,未分解层最小;杉木纯林枯落物总储量、最大持水量和有效拦蓄均最高,分别为14.6 t·hm^-2、2.668 mm和1.43mm,竹阔混交林次之,分别为7.0 t·hm^-2、1.298 mm和0.76 mm,毛竹纯林最低,分别仅为4.7 t·hm^-2、0.916 mm和0.58 mm。(2)5种林分各层枯落物持水量与浸泡时间的关系为:S=k ln(t)+p,在0 - 2 h内,枯落物持水量迅速增加,此后增加速度逐渐减缓;其吸水速率与浸泡时间的关系为:V=at^-1+b,在0 - 1 h内,枯落物吸水速率迅速下降,2 h后下降速度逐渐减缓。(3)竹阔混交林枯落物持水能力虽小于杉木纯林但在竹林中最强,对此,在竹林改造和竹林经营过程中应加以重视。     

Rainfall interception in a moso bamboo (Phyllostachys pubescens) forest

In recent years, moso bamboo (Phyllostachys pubescens) forest areas in Japan have rapidly expanded, and bamboo is now invading nearby natural or plantation forests. To date, only one study has examined the rainfall interception of a moso bamboo forest. In that study, it was reported that the interception ratio (interception/rainfall) of the bamboo forest did not exceed the interception ratios of other natural and plantation forests (n = 4) in Japan. To expand the current state of knowledge about rainfall interception of bamboo forests, we measured throughfall and stemflow at another bamboo forest site. Annual rainfall (Rf), throughfall (Tf), and stemflow (Sf) during the measurement period were 2,105, 1,556, and 322 mm, respectively. Annual rainfall interception at the plot (I) was 228 mm. Tf/Rf, Sf/Rf, and I/Rf were 73.9, 15.3, 10.8%, respectively. I/Rf was less than 20% throughout the year except in October, the month with lowest rainfall. We also summarized rainfall interception data from 19 other natural and plantation forests. The I/Rf value of our site did not exceed the I/Rf values of these natural and plantation forests (n = 19). Our data will be useful for assessing changes in water resources that result from replacement of natural or plantation forests by bamboo forests.     

Characteristics of canopy interception and its simulation with a revised Gash model for a larch plantation in the Liupan Mountains,China

Canopy interception is a significant proportion of incident rainfall and evapotranspiration of forest ecosystems. Hence, identifying its magnitude is vital for studies of eco-hydrological processes and hydrological impact evaluation. In this study, throughfall, stemflow and interception were measured in a pure Larix principis-rupprechtii Mayr.(larch) plantation in the Liupan Mountains of northwestern China during the growing season(May–October) of 2015, and simulated using a revised Gash model. During the study period, the total precipitation was499.0 mm; corresponding total throughfall, stemflow and canopy interception were 410.3, 2.0 and 86.7 mm,accounting for 82.2, 0.4 and 17.4% of the total precipitation, respectively. With increasing rainfall, the canopy interception ratio of individual rainfall events decreased initially and then tended to stabilize. Within the study period, the simulated total canopy interception, throughfall and stemflow were 2.2 mm lower, 2.5 mm higher and0.3 mm lower than their measured values, with a relative error of 2.5, 0.6 and 15.0%, respectively. As quantified by the model, canopy interception loss(79%) mainly consisted of interception caused by canopy adsorption, while the proportions of additional interception and trunk interception were small. The revised Gash model was highly sensitive to the parameter of canopy storage capacity,followed by the parameters of canopy density and mean rainfall intensity, but less sensitive to the parameters of mean evaporation rate, trunk storage capacity, and stemflow ratio. The revised Gash model satisfactorily simulated the total canopy interception of the larch plantation within the growing season but was less accurate for some individual rainfall events, indicating that some flaws exist in the model structure. Further measures to improve the model's ability in simulating the interception of individual rainfall events were suggested.     

Rainfall redistribution of a virgin Pinus koraiensis forest and secondary Betula platyphylla forest in Northeast China

A virgin Pinus koraiensis forest in the Xiaoxing’an Mountains was selected to study its rainfall redistribution effect via 97 rainfall occurrences during a growing season. The following results were obtained: 1) The canopy interception of the P. koraiensis virgin forest amounted to 98168 mm during a growing season (May to September), which was 19.6 per cent of the total rainfall and 1.3 times that of a secondary Betula platyphylla forest. Compared with other forest types in China (11.4%–36.5%), the ratio of the canopy interception in the virgin pine forest was at a medium level. 2) The throughfall of the virgin pine forest was 395.77 mm, which accounted for 78.7% of total precipitation, and the stem-flow was 8.78 mm, accounting for 1.74% of total precipitation. Compared with the secondary birch forest, the virgin pine forest had lower throughfall but higher stem-flow. 3) Cubic regression equations (p < 0.01) which describe the relation between throughfall, stem-flow and canopy interception in the virgin pine forest and rainfall in an open field were fitted. A linear regression equation (p < 0.01) was found to be a better fit for the relationship between throughfall of the secondary birch forest and rainfall outside the forest. Factors affecting throughfall and stem-flow were analyzed, with results providing a good reference to the study of rainfall redistribution in coniferous and broadleaved mixed forests. __________ Translated from Science of Soil and Water Conservation, 2006, 4(6): 61–65 [译自: 中国水土保持科学]     

滇西南巨尾桉人工林木根径、胸径与树高模型研究

为研究巨尾桉人工林林木根径、胸径与树高数学模型,在滇西南的双江县选取138株（其中建模样本103株,检验样本35株）树干健全、通直圆满、无分杈的巨尾桉人工林样木,采集其根径与树高、胸径与树高成对数据。利用SPSS 21.0回归分析,分别建立线性方程、对数曲线、指数曲线和Logistic曲线等11个数学模型,以决定系数（R²）、估计值的标准误（SEE）、均方差（RMSE）、平均绝对偏差(MAD)、相对误差（RS）、模型预估精度（P）、显著性(Sig)P值作为模型评价指标,对比11个模型的拟合效果。结果表明,11个根径—树高模型显著性（Sig）P<0.001,其中有9个模型的预估精度大于97%,回归方程达到极显著水平,拟合效果较好;11个胸径—树高模型显著性（Sig）P<0.001,其中9个模型的预估精度大于97%,回归方程达到极显著水平,拟合效果也较好。通过对各项评价指标进行比较分析,确定三次项曲线H=a₀+a₁DR+a₂DR²+a₃DR³是拟合效果最好的根径—树高数学模型,代入拟合参数后的根径—树高数学模型表达式为H=11.069901-0.729389DR+0.096782DR²-0.001984DR³;线性方程H=a₀+a₁D是拟合效果最好的胸径—树高数学模型,代入拟合参数的胸径—树高数学模型表达式为H=4.818702+0.891217D。     

Incident rainfall partitioning and canopy interception modeling for an abandoned Japanese cypress stand

Interception loss (E _i) in forests has been studied widely. However, E _i parameters and modeling as well as spatial patterns of throughfall (TF) in abandoned Japanese cypress (Chamaecyparis obtusa) plantations remain poorly documented. In this study, gross precipitation (P _G), stemflow (SF), and TF were monitored in an unmanaged 32-year-old Japanese cypress stand throughout the 2011 rainy season. Results indicate that P _G partitioning into TF, SF, and E _i were, respectively, 64.2 ± 3.6, 10.6 ± 0.6, and 25.2 ± 1.1 % of the 880.8 mm cumulative P _G from 29 rainfall events. Direct throughfall proportion (p) and drainage from the canopy contributed about 14 ± 7 and 50 ± 21 % of the total TF for the events, respectively. The mean canopy storage capacity (S) was 2.4 ± 0.7 mm. The coefficient of variability (CV) of TF rate decreased asymptotically with increasing P _G amount, ranging from 16 to 56 % with median 26 %. The CV of TF rate was not significantly correlated with canopy cover (r = 0.152, P = 0.521, n = 20) and distance from the nearest trunk (r = 0.196, P = 0.408, n = 20). Based on the revised Gash analytical model, the total simulated E _i was close to the observed, with a general underestimation magnitude of 5.7 %. The E _i components were quantified, and most of the interception loss (62.9 %) evaporated during rainfall, while 26.8 % evaporated after rainfall ceased. Climatic and forest structural parameters required by the model were identified and analyzed by sensitivity analysis, implying that the revised Gash analytical model is robust and reliable enough for abandoned Japanese cypress plantations in a maritime climate.     

降雨特征对兴安落叶松林降雨再分配过程中钾元素影响分析

[目的]以大兴安岭地区兴安落叶松林为研究对象,分析降雨特征对兴安落叶松林降雨再分配过程中K~+的影响。[方法]对林外降雨、穿透雨、灌木穿透雨、树干径流和枯透水进行了野外观测、取样和室内实验测定。[结果]结果表明:(1)研究期间兴安落叶松林林外降雨总量为266.0 mm,平均次降雨强度0.074 mm·min~(-1);降雨再分配过程中K~+含量平均值排序为枯透水树干径流灌木穿透雨穿透雨林外降雨,其中林外降雨中K~+含量在0.227 2.631 mg·L~(-1)之间,变化幅度较大,穿透雨中K~+含量波动在2.198 3.053 mg·L~(-1)之间,枯透水中K~+含量波动较小,稳定在3.077 3.281 mg·L~(-1)之间。(2)降雨量和降雨历时对降雨再分配过程中K~+含量均表现为正相关,随降雨量和降雨历时的增加K+含量的增加幅度呈上升趋势;而降雨强度和降雨间隔期对K~+含量增加幅度的影响则反之,但当降雨强度大于0.041 mm·min~(-1)时,K+含量的增加幅度开始出现转折,呈上升趋势;当降雨间隔期增大至233.28 h时,K~+含量的增加幅度趋于稳定。(3)影响林外降雨中K~+含量的主导因子是降雨间隔期,影响穿透雨、灌木穿透雨和树干径流中K~+含量的主导因子均为林外降雨量,而对枯透水中K~+含量起主导作用的则为降雨强度。[结论]降雨量、降雨历时、降雨强度以及降雨间隔期均会对降雨再分配过程中各个层次的K~+含量产生不同程度的影响。降雨再分配过程中K~+含量平均值大小排序为枯透水树干径流灌木穿透雨穿透雨林外降雨,其中大气降雨中K~+含量在5月和9月较高,穿透雨中K~+含量在5—10月呈波动式变化,灌木穿透雨中K~+含量变化幅度较大,而树干径流和枯透水中K~+含量较稳定。降雨量和降雨历时对降雨再分配过程中K~+含量的影响均表现为正相关。对林外降雨中K~+含量影响程度由大到小排序依次为降雨间隔期降雨强度降雨历时降雨量,穿透雨中K~+含量与各影响因素的灰关联度大小顺序依次为降雨量降雨历时降雨强度降雨间隔期,灌木穿透雨和树干径流中K~+含量与各影响因素的灰关联度排序和穿透雨一致,影响的主导因子均为降雨量,枯透水中K~+含量与各影响因素的灰关联度大小顺序依次为降雨强度降雨间隔期降雨历时降雨量。     

麻竹人工林水文生态效应

在福建南靖连续4a对1995年春在杉木采伐迹地上营造的株行距为3m×4m、4m×5m和5m×6m3种密 度的麻竹试验林进行水文生态效应观测。结果分析表明:(1)麻竹林冠截持量与降水量和林分密度均呈正相关,而 秆茎流和林内降水量与降水量呈正相关,与林分密度呈负相关。密度为825丛·hm-2的麻竹林的年林冠平均截持 量和截持率为155.2 mm和14．61％,林内平均降水量和降水率为829．0 mm和78．11％,竹秆茎流量和茎流率为 77.3mm和7.31％。(2)麻竹林地表枯落物具有吸持其自身干质量2．8倍水量的潜在能力。(3)3种密度麻竹林的 0-60 cm土壤层最大潜在蓄水量为315．3-326．3 mm,略低于毛竹林367．9mm。(4)麻竹林地表径流和泥沙流 失量与降水量呈正线性相关,与林分密度呈负相关;竹林密度为825丛·hm-2的麻竹林年地表平均径流量、土壤侵 蚀模数是密度为330丛·hm-2的麻竹林的0．55、0．45倍,其NO3-、NH4 、PO43-、K 等养分年流失量则分别是密 度为330丛·hm-2的麻竹林的0．58、0．49、0．36、0．49倍。