【作者】 史振华；

【导师】 王百田；

【作者基本信息】 北京林业大学 ， 生态环境工程， 2009， 博士

【摘要】 干旱半干旱地区占我国国土面积的52.5%,植被覆盖率较低,生态环境脆弱。而植被恢复与生态环境改善又受到可利用水资源(降雨、地下水、地表水)的制约,人工恢复或者重建植被必须按照“量水种植”的基本原则,才能达到预期的生长效果,形成与地理气候带相适应的植被群落结构,增强植被的稳定性,提高其生态效益、经济效益与社会效益。本文以森林生态学、测树学、数理统计学等理论为依据,以样地调查、标准木与优势木解析材料以及试验地气象资料为基础数据,从探讨黄土高原半干旱区刺槐(Robinia pseudoacacia L.)生长和降水量关系入手,在对刺槐生长规律全面分析的基础上,确立了评价指标,采用图表、数据、相关分析、回归拟合等统计方法分析刺槐不同生长指标与不同降水量指标之间的关系,阐释了黄土半干旱区刺槐人工林在不同降水资源条件下的生长状况,为半干旱区刺槐林的营造提供可靠的基础数据和研究方法上的突破。其主要研究结果与结论如下:(1)研究区1957～2007年的气象观测资料显示:降水资源总体上有下降趋势;而温度有上升态势,这种变干变热的局面对当地植被的生长极为不利。气候的变化势必成为半干旱区人工林营造的最重要考虑因素之一。(2)通过刺槐连年生长量和降水量的关系分析得出,树高连年生长量同前一年降水量和当年降水量的平均值存在显著正相关关系;胸径和材积的连年生长量受前一年降水量的影响较大,而且这种关系随着造林密度的增加表现的更为明显;从总生长量与降水量指标的关系研究中得出,刺槐树高生长量和其速生期的降水积累量呈正相关关系:胸径和材积生长量与其生长期降水总量呈正相关关系。(3)建立了研究区以Sloboda模型为基础的刺槐人工林多形立地指数表;通过与1982年资料做对比,在年均降水量下降100 mm的情况下,研究区优势木的基准年龄(14年)高普遍下降了1 m左右。(4)建立了研究区刺槐人工林降雨指数表,并论证了其可行性和实用性,降雨指数表借鉴的是立地指数表的构建理论和方法;在此基础上结合密度效应,建立了研究区刺槐单木水分密度生长函数。以期为不同年均降水量水平下的刺槐林营造提供理论依据。更多还原

【Abstract】 52.5%of the territory of China is arid or semi-arid area with low vegetation coverage,which is the main ecologically and environmentally fragile region.Vegetation restoration and the improvement of ecological environment are constrained by limited available water resources(precipitation,groundwater, surface water).The artificial restoration and reconstruction of vegetation should be carried out in accordance with the basic principle-"Planting according to moisture".Only in this way can we achieve the anticipated growth effects and form the suitable vegetation community structure for the geographical and climatic conditions.Simultaneously,we can also enhance the stability of vegetation as well as the ecological,economic and social benefits.This thesis was based on forest ecology,tree measurement science,statistics and Other mathematical theory.All the basic data was from sample field investigation,standard and advantage wood analysis,and meteorological data in the research area.The study was explored from the relationship between locust(Robinia pseudoacacia L.) growth and precipitation.Based on the comprehensive analysis of locust growth,the evaluation index was created,and the relationship between different indicators of locust growth and different indicators of precipitation was established by different statistics methods such as charts,data,correlation analysis,and regression fitting.This thesis interpreted locust growth conditions under a particular precipitation level in semi-arid area of Loess Plateau,and provided a reliable breakthrough of basic data and research method for creating Locust stand in semi-arid area.The followings are the major findings and conclusions:1.The meteorological observation data after 1957 shows:the overall precipitation in the study area was decreasing,and the temperature was rising.This hot and dry situation in study area is extremely detrimental to vegetation growth of local area.The trend of climate change has become an important consideration for creating plantations. 2.Through the analysis of the relationship between locust growth and precipitation,we found tree height annual growth was affected by both previous year and this year’s precipitation,there was a significant positive correlation between them.The precipitation of the past year had a big effect on annual growth of DBH and volume,and this effect became more obvious along with the increase of density.From the study of the relationship between growth indexes and precipitation indexes,it is positive correlation between tree height growth and accumulation of precipitation in fast growing period. Furthermore,it is positive correlation between dbh and volume growth as well as accumulation of precipitation in growth period.3.In the same study area,dominant tree height of standard age(14a) generally declined around 1m when an average annual precipitation declined 100m.The multiple form site index table of locust artificial forest in research area is established based on Sloboda model.4.By using the theories and methods of building site index table,we established the precipitation index table of locust artificial forest in research area.We further demonstrated its feasibility and practicality,then combined with the density,established a growth founction including density and precipitation of locust in study area.This provides a guided theoretical basis for locust stand management under different average annual precipitation.更多还原