【作者】 杨新兵；

【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， 2007， 博士

【摘要】 本文主要研究华北土石山区密云水库流域常见树种的耗水规律和典型林分林木耗水机理,揭示不同树种的耗水特征,在此基础上结合林地土壤水分运移规律,建立森林耗水尺度转换模型。针对密云水库流域现有的植被分布特点,选择22种乔灌木和2个典型林分(油松林和侧柏栎类混交林)作为研究对象,通过盆栽法和典型林分耗水试验,应用数学统计方法,分析了从苗木—林木—林分的耗水规律,得出如下结论:不同树种由于其本身的生物学特性,形成不同的生态适应性。在水分充足条件下,供试22个试验树种苗木蒸腾速率、光合速率与水分利用率日变化曲线呈相似的变化趋势。乔木树种中,阔叶树种的蒸腾速率高于针叶树种,平均水分利用率针叶树种大于阔叶树种。灌木树种中,阳性的蒸腾速率高于阴性树种;平均水分利用率是阴性灌木大于阳性灌木树种。通过蒸腾速率与环境因子的相关性分析,可以得出:太阳辐射和气孔导度是树木蒸腾耗水的重要影响因子。同时,建立了蒸腾速率与环境因子的多元线性回归模型:Y=a+bX1+cX2+dX3+eX4+fX5,相关系数在0.9以上。在控水条件下,比较了各树种的光合、蒸腾和气孔导度变化规律,得出,各树种苗木蒸腾速率随控水时间的延长而下降,侧柏、油松、槲树、栓皮栎、鼠李和平榛等几个树种由于其特殊的生物学结构,控水时间较长,是抗旱树种选择的较好材料。在水分充足条件下,对各树种整株耗水比较得出:7种乔木树种的平均耗水速率为0.071 g·cm-2·d-1,15种灌木的平均耗水速率为0.100 g·cm-2·d-1。树种耗水综合排序为:溲疏>鼠李>荆条>孩儿拳头>黄栌>大油芒>雀儿舌头>绣线菊>元宝枫>栓皮栎>盐肤木>丁香>蚂蚱腿子>槲树>平榛>胡枝子>火炬>紫穗槐>油松>刺槐>花木蓝>侧柏。总体来看:阔叶树种的耗水量大于针叶树种,灌木树种的耗水比乔木树种的单位耗水量大。在微气象条件相对一致条件下,树木的蒸腾作用主要取决于各树种的生物学特性。15个典型林分的试验树种蒸腾速率、光合速率与水分利用率日变化曲线呈相似的变化趋势。针叶乔木树种的最大蒸腾速率油松大于侧柏,阔叶乔木树种的日最大蒸腾速率从大到小的顺序依次:臭椿>麻栎>槲树>刺槐>栓皮栎,灌木树种顺序依次:鼠李>黄栌>酸枣>孩儿拳头>荆条>火炬>花木蓝>雀儿舌头。各树种水分利用效率均表现为下降趋势,乔木树种油松、栓皮栎、麻栎、侧柏水分利用效率最高,针叶树种的水分利用率高于阔叶树种,灌木树种孩儿拳头、花木蓝、黄栌、鼠李等较低。蒸腾速率与环境因子的相关分析表明,树种蒸腾速率与气孔导度和光照强度为显著相关,建立蒸腾速率与环境因子的多元回归模型:Y=a+bX1+cX2+dX3+eX4+fX5,相关系数在0.9以上。蒸腾作用体现树木耗水性的构成指标,并不能完全反映树木的耗水量大小。只有在测定叶片蒸腾速率同时得到树木整株树冠的叶面积,才能进一步得到树木的耗水速率或耗水量。从树种间的耗水量比较发现,刺槐的蒸腾耗水量最大,耗水量排序为刺槐>臭椿>麻栎>槲树>油松>栓皮栎>侧柏通常条件下,林分耗水受气候条件、树种本身生理生态学特性和土壤供水条件的影响。林分耗水的主要途径包括三个方面:林冠截留蒸发、植物蒸腾耗水和土壤物理蒸发。大气降水通过林冠层是一个降水的再分配过程,根据水量平衡原理,忽略水平方向的水分变化,得到树种总的截留率排序为:黄栌>荆条>麻栎>刺槐>油松>槲树>侧柏>臭椿。油松的枯落物年截留量占总降雨量的10.42%,侧柏栎类混交林的年截留量占总降雨量的9.49%,土壤水分蒸发是土壤水分运动过程中的一种特殊形式。土壤月平均蒸发量一年的变化呈波峰曲线。典型晴天条件下,土壤日蒸发主要发生在0～20cm土层。林分耗水量是森林生态系统水量平衡的主要输出项,采用定位通量法和水量平衡法计算了林分总耗水量结果接近,结果为:油松林生长季总耗水为516.52mm,日平均耗水2.74mm,林冠截留占25.63%,土壤蒸发占22.15%,植物耗水占52.22%;侧柏栎类混交林总耗水为527.62mm,日平均耗水2.73mm,林冠截留占23.66%,土壤蒸发占28.38%,植物耗水占47.95%;阴坡裸地的总耗水为499.0mm,日平均耗水2.73mm。树木耗水尺度扩展理论与方法的研究是目前树木蒸腾耗水研究领域的热点问题。树木作为一个独立的个体,是林分的基本单位。土壤水是林木耗水的源泉。建立土壤水分运动、根系吸水和林木耗水三者之间的关联,是建模的思路。本研究在石青(2004)林木耗水模型的基础上进行了改进;利用数学方法,在分析土壤水势变化的基础上,将林木根系作为一个圆锥体,然后,将圆锥体从上到下分解为n个圆台体,分别计算,建立了林分无竞争和竞争耗水林木模型。林分耗水模型Ri为根系中心到影响范围边缘的距离称为影响半径;B为相邻两株树的距离。结合林木或林分的生长模型,可以来模拟从幼龄林开始,不同时段、不同树种、单株或林分的耗水过程,整个生长过程的林分耗水变化,以及林木或林分一生的耗水总量。更多还原

【Abstract】 This article mainly researches water consumption properties of common tree species and the water consumption mechanism of typical stand and tree in Miyun reservoir watershed in Mountain Area of Northern China .Reveal characteristics and rules of water consumption of different species. On the basic of the analytical results, combine soil-water movement in the woodland; establish the scale-transition model of water consumption of forestContraposing the existing vegetation of Miyun reservoir watershed, choosing 22 kinds of shrubs and two pieces of typical forest stand as research object, obtain following conclusion by pot experiment and experiment of typical forest stand, field and experimental research, applying statistical method to analyze water consumption properties from the seedlings to single plant to forest stand. The main conclusion is as follows:Because of biological characteristics of different tree species, form different Ecological Adaptability. At water enough condition, 22 tree species of the young plant used in the experiment whose tendency of transpiration rate, photosynthetic rate and the diurnal changes of water use efficiency are similar. The transpiration rate of arbor trees is higher than Coniferous Trees’, but in the average efficiency of using water, Coniferous Trees is greatly higher than arbor trees’. The transpiration rate of positive shrub species is greatly higher than negative shrubs species’, but in the average efficiency of using water, negative shrubs species is greatly higher than Coniferous Trees’. According to the correlation analysis of transpiration and environment factor, the result is: solar radiation and stomataconductance have a crucial effect to trees transpiration. According to the correlation analysis of transpiration and environment factor, the result is: solar radiation and stomata conductance have a crucial effect to trees transpiration. And meanwhile, Mathematical model of multiple linear regression of transpiration rate and environment factor has been built up: Y=a+bX₁+cX₂+dX₃+eX₄+fX₅.The correlation coefficient greater than 0. 9.Under the water control condition, comparion the rule of photosynthesis, the rule of transpiration and the change of stomata conductance of different tree species, conclude that different tree species of the seedlings on photosynthesis and transpiration rate descend with the time of water control extending. Because of the special biological configuration and longer time of water control, several tree species are preferable material in choosing fight a drought tree species, such as Platycladus orientalis, Pinus tabulaeformis, Quercus. Dentate, Q. variabilis, Rhamnua davurica and Corylus heterophylla and so on.At water enough condition, in respect of water consumption daily, comparing of Characteristic and law of water consumption day and night, water consumption rate diurnal Course to comparing analysis 22 tree species used in the experiment, conclude that: 7 arbor tree species’ rate are 0.71 g/cm²,15 shrubs species’ rate are 1.00g/cm². The water consumption of Chinese Pine is higher than Chinese Arborvitae. Among them, The comprehensive sequencing on water consumption of kargeleaf arbor tree is: Acer truncatium >Quercus. variabilis >Rhus chinensis >Quercus. dentata >Robinia pseudoacacia. The comprehensive sequencing on water consumption of bushes is: Deutzia scabra>Rhamnua davurica > Vitex negundo Var.heterophylla >Rungia Chinensis >Cotinus coggygria >Spodiopogon sibiricus> Andrachne chinenSis >Spiraea trichocarpa >Syzygium aromaticum >Myripnois dioica >Corylus heterophylla >Lespedeza bicolor>Rhus typhina>Amorpha fruticosa>Indigofera kirilowii. In general, the amount of water consumption of broad-leafed trees’ is bigger than Coniferous Trees’ and the amount of water consumption of shrub species is bigger than arbor trees’.In the similar microclimate conditions, the biological characteristic of variety kinds of trees is the major factor to influence the transpiration of trees. The transpiration rate, photosynthetic rate and water utilization efficiency of 15 kinds of experiment trees of typical forests have the similar change directions of their daily variation curves. The maximum transpiration rate of Chinese Pine is higher than Chinese Arborvitae. The order of daily maximum transpiration rate of broadleaved arborous tree speciesfrom high to low is: Ailanthus altissima> Sawtooth oak> Live oak> Robinia pseudoacacia> Quercus variabilis. The same order of shrub species is: Buckthorn> Cotinus coggygria> Sour jujube> Rungia Chinensis > Heterophyllous negundo chastetree>Rhus typhina>Kirilow indigo> Chinese leptopus. All kinds of trees’ water utilization efficiency were reducing. Some arborous tree species have the highest water utilization efficiency, such as Chinese Pine, Quercus variabilis, Sawtooth oak and Chinese Arborvitae. The water utilization efficiency of coniferous species is higher than broadleaved species. Some shrub species have low water utilization efficiency such as Rungia Chinensis, Buckthorn, Cotinus coggygria, Kirilow indigo and so on. On the basis of analysis of the transpiration rate and environment factor, we can know that transpiration rate and the stomata conductance and the intensity of illumination are significant correlation. So build the multivariate regression model of the transpiration rate and environment factor: Y=a+bX₁+cX₂+dX₃+eX₄+fX₅, the coemcient of association is higher than 0.9.The transpiration rate can express a composing index of water consumption properties of tree species, but cannot completely reflect how large the water consumption properties of tree species are. Only at the same time determining the transpiration rate of leaves and achieving the area of the whole canopy of a tree, can we find the water consumption rate or the water consumption. We can find that from comparing the water consumption among different species, the water consumption of Robinia pseudoacacia is the highest, and the order of the water consumption is: Robinia pseudoacacia > Ailanthus altissima > Quercus acutissima > Q. dentata > Pinus tabulaeformis > Quercus variabilis > Platycladus orientalis.The main approach of the water consumption of forest stand contains three factors, such as crown interception evaporation, transpiring water-consumption of plants and soil water physical evaporation. Atmospheric precipitation gets through forest canopy, which is a redistribution process about rainfall. According to water balance principle and ignore water change in horizontal direction, conclude the sequence of the interception rates as follows: Cotinus coggygria>Vitex negundo Var.heterophylla > Quercus acutissima >Robinia pseudoacacia >Pinus tabulaeformis >Quercus. Dentate >Platycladus orientalis > Ailanthus altissima. The litter layer interception of Pinus tabulaeformis is about 10.42% in whole precipitation, and Platycladus orientalis is about 9.49% in whole precipitation. Soil water evaporation is a special form during soil water movement. Average evapotranspiration per month of thesoil water whose change assume peak curve in the year. Under the typical clear day condition, daily evaporation of soil water mainly happens in horizon of soil from 0 to 20cm.Water consumption of forest stand is a main output in water balance of forest ecosystem. According to oriented flux method and water balance method accounts measuring water consumption of forest stand. The conclusions are as follows: total water consumption of the Pinus tabulaeformis is 516.52mm in growing season,and the average daily water consumption is 2.74mm, and crown interception is about 25.63% in whole interception, and soil evaporation is about22.15% in whole evaporation, and water consumption of plants is 52.22%in whole water consumption of plants; total water consumption of the mixed forest of the Arborvitae and oak is 527.26mm, and the average daily water consumption is 2.73mm, and crown interception is about 23.66% in whole interception, and soil evaporation is about28.38% in whole evaporation, and water consumption of plants is 47.95%in whole water consumption of plants; total water consumption of the shady slope is 499.0mm, and the average daily water consumption is 2.73mm.The water consumption of forest stand is the chief output item of water - balance of the forest ecosystem. The calculation results is nearly the same though two methods that oriented flux method and water balance method, the result is: the amount water consumption of Chinese pine forests in growing season is 515.3mm, daily average water consumption is 2.74mm, canopy interception account for 25.69%, soil water evaporation account for 22.20%, plants’ water consumption account for 52.35%; The amount water consumption of the mixed forest of Chinese arborvitae with oak is 512.8mm, daily average water consumption is 2.73mm, canopy interception account for 24.33%, soil water evaporation account for 29.96%, plants’ water consumption account for 49.31%; The amount water consumption of schattenseite bare soil is 499.0mm, daily average water consumption is 2.73mm.Build the relationship in forest stand water consumes, soil water and water movement is the line of thought of module construction. This research improve on the forest water consume model from PhD Shi Qing. On basis of analysis the alteration of the soil water potential, use math method, make forest roots system into a circular cone, and then divide this circular cone into n circular truncated cones. Calculate them separately. At last, a forest consume model （including competition model and no competition model） has been built up.Forest water consume model:Ri is the distance from the center of root system to the edge of area of influence, named influenced radius; B is the distance of the neighboring two trees.Using it with the growing model of forest or forest stand can simulate single tree or forest stand’s process of water consumption in different time slot and different tree species from young growth. It can also simulate the alteration of water consumption of forest stand, and the gross quantity of water consumption of forests or forest stand during their whole life.更多还原