【作者】 玉宝；

【导师】 王百田；

【作者基本信息】 北京林业大学 ， 生态环境工程， 2010， 博士

【摘要】 在干旱半干旱区,水分已成为人工林培育关键限制因子。必须遵守水资源环境容量原则,根据林地水量调控林分密度和结构,才充分发挥人工林各项效益。笔者认为有必要深入研究水分生产函数等围绕水分因子的密度调控技术,弥补传统密度调控技术不足,有利于缓解人工林地力衰退、林地干化、地下水位下降等生态问题加剧。本研究在山西省方山县和吉县,以刺槐(Robinia pseudoacacia Linn.)和油松(Pinus tabulaeformis Carr.)人工林为研究对象,根据调查样地、解析木和气象资料,估算气候生产力,揭示气象因子对年轮影响机制。在全面分析不同结构林分生长、耗水及密度效应规律基础上,建立了人工林水分生产函数。旨在为干旱半干旱区人工林经营管理、抚育间伐、密度调控及碳循环研究提供依据。其主要结论为：1.研究区人工林生长受密度、坡向、坡位等因子综合影响。同密度及坡向林分生长与坡位有关；同密度及坡位林分生长与坡向有关。密度对林分生长影响,因坡向、坡位和密度大小而不同。密度多大将会影响林分生长,须分坡向、坡位进行量化。这对人工林集约经营有指导意义。以林龄和密度建立了单株生长模型。2.月降水和月湿润指数对年轮宽度影响有滞后效应。建立了年轮宽度指数模型。月湿润指数在研究气象因子对年轮影响方面,较降水和温度优越。方山县和吉县气候生产力分别达8.688 t·hm-2·a-1,9.314 t·hm-2·a-1。实测最高生产力分别占气候生产力的31.6%和59.8%。3.现降水条件下,人工林耗水量达不到需水量。将生长季按耗水量从高至低的排序为：7月,6月,8月,5月,9月,10月。随林龄增加,人工林耗水量增加,达一定林龄后将超过降水量。这林龄为：方山县刺槐15a；吉县刺槐5a,油松23a。以林龄和密度建立了人工林耗水模型。4.初步界定了人工林水分生产函数。以林分年耗水量为自变量,以林分生物量及蓄积量年增量为因变量,建立了人工林水分生产函数,填补了相关研究空白。为人工林合理利用水分,调控密度,提供理论依据。5.建立了人工林密度效应模型。随林龄增长,密度效应越显著,林木胸径生长与密度负相关系数增大。达一定林龄后,相关系数增幅变小,这林龄为：方山刺槐阳坡13a,半阳坡10a；吉县半阳坡刺槐8a；方山县半阳坡及阴坡油松13a。不同坡向对密度响应不同。方山刺槐阳坡相关系数较半阳坡小；方山油松阴坡相关系数较半阳坡小。6.研究区人工林直径分布顶峰多数偏左,现密度普遍偏大须间伐。间伐对林分更新和植被多样性有显著影响。间伐林多样性指数较未间伐林高。林下死地被物厚度、间伐林密度与辛普森、香农多样性指数显著负相关,与生态优势度显著正相关。间伐林随密度增加,更新密度和均匀度指数均减小。7.建立了以单株及林分生长量为因变量,以林龄、密度、林分耗水量为自变量的密度调控模型。可为人工林密度管理提供参考依据。更多还原

【Abstract】 Moisture has become the key limiting factor of cultivating forest plantation in arid and semi-arid regions. All of benefits of forest plantation can be fully realized if people abide water resource environment capacity principle according to forest land water control standing forest density and structure. The author thinks it is necessary to deeply research density adjust and control technology of moisture factor such as moisture production function to make up the deficiency of traditional density adjust and control technology, which will be good for remitting more and more severe ecological problems such as deterioration of soil fertility of forest plantation, drying of woodland and decline of groundwater level.This research analyzes wood and meteorological data, estimates climate productivity and shows the mechanism of meteorological factor’s effect on annual-ring according to investigation plot with forest plantation of Robinia pseudoacacia Linn and Pinus tabulaeformis Carr as research subject in Fangshan County and Ji County of Shanxi Province. Forest plantation moisture production function is established based on comprehensively analyzing growth of standing forest in different structures, water consumption and density effect rule, aiming at supplying basis for forest plantation operation management, intermediate cutting, density adjust and control and carbon cycle research in arid and semi-arid regions. Its main conclusion is:1 The growth of forest plantation in research region is affected by many factors such as density, slope and slope position. The growth of standing forest with the same density and slope is related with slope position; the growth of standing forest with the same density and slope position is related with slope; the effect of density on standing forest growth is different due to different slope, slope position and density. Density will affect the growth of standing forest and shall be quantized according to slope and slope position. It has guidance meaning for intensive operation of forest plantation. Single-tree growth mode is established with forest age and density.2 Monthly precipitation and monthly moisture index have lag effect on width of annual-rings. Annual-ring width index model is established. Monthly moisture index takes better effect on annual-ring in terms of meteorological factor, compared with precipitation and temperature. The climate productivity in Fangshan County and Ji County has reached 8.688 t·hm-2·a-1,9.314 t·hm-2·a-1,respectively. The actually-measured supreme productivity in such two counties has taken 31.6% and 59.8% of climate productivity, respectively.3 Under the condition of precipitation, the water-consuming quantity can’t reach the water-requiring quantity. The sorting of water-consuming quantity in growth reasons according to the descending order is:July, June, Aug, May, Sept., Oct.. The water-consuming quantity of forest plantation increases with the increase of forest age. The water-consuming quantity will exceed the precipitation when the forest age reaches certain standard. The forest age is:15a Robinia pseudoacacia Linn. in Fangshan County; 5a Robinia pseudoacacia Linn. in Ji County and 23a Pinus tabulaeformis Carr. The water-consuming model of forest plantation is established with forest age and density.4 The moisture production function of forest plantation is initially defined. The moisture production function of forest plantation is established to make up relevant research vacancy with standing forest annual water-consuming quantity as independent variable, standing forest biomass, accumulation quantity and annual increment as dependent variable, which supplies theory basis to rational moisture utilization and density adjust and control of forest plantation.5 Forest plantation density effect model is established. The density effect becomes more and more obvious with the increase of forest age, breast diameter in growth progress and negative correlation coefficient of density increases. When the forest age reaches certain standard, the correlation coefficient growth rate becomes small, the forest age is:13a Robinia pseudoacacia Linn of north-facing slope; 10a semi-north-facing slope;8a Robinia pseudoacacia Linn of semi-north-facing slope in Ji County; 13a Pinus tabulaeformis Carr of semi-north-facing slope and south-facing slope in Fangshan County. Different slopes give different responses for density. The correlation coefficient of north-facing slope Robinia pseudoacacia Linn in Fangshan County is smaller than that of semi-north-facing slope; the correlation coefficient of south-facing slope of Pinus tabulaeformis Carr in Fangshan County is smaller than that of semi-north-facing slope.6 Most of the diameter distribution peak of forest plantation in research region is in the left, the current density tends to be thinning commonly. Thinning has obvious effect on standing forest renewal and plant diversity. Diversity index of thinning forest is higher than that of non-thinning forest. Thickness of plants under the forest and thinning forest density are in obvious negative correlation with Simpson’s diversity index and Shannon diversity index and are in obvious positive correlation with ecological dominance. The renewal density and evenness index of thinning forest reduces with the increase of density of thinning forest.7 The density adjust and control model is established with single-tree and standing forest growth as dependent variable as well as forest age, density and standing forest water-consuming quantity as independent variable. It can supply basis for forest plantation density management.更多还原