【作者】 段劼；

【导师】 马履一； 贾黎明； Andrew McMahan；

【作者基本信息】 北京林业大学 ， 森林培育， 2010， 博士

【摘要】 森林未来的生长情况如何?采用何种措施才能将森林培育成用材林、公益林、碳汇林?气候和环境变化能在多大程度上影响森林生长?这些都是林学家和森林经营管理者想要知道的问题。森林生长模型是用来预测森林发展变化情况的重要工具,与一般的经验生长收获模型相比,加入了气候、立地条件及生理学模型和参数的过程模型成为当前模型界研究的重点和热点问题,既能模拟森林经营措施又能模拟树木生理生态生长过程的混合模型应运而生。本研究以引自美国的基于混合模型的森林生长模拟系统FVS-BGC为研究对象,在充分解析原系统的基础上进行了消化吸收,并以北京市油松、侧柏两个试验树种为例建立起适合北京地区试验树种的FVS-BGC系统,得到的主要结论有：(1)解析了FVS-BGC系统的组成、执行过程及主要生长模型。系统运行需要5类输入数据：单木数据、林分数据、气候数据、立地数据和树木生理数据,能够输出5类单木、林分在日、年水平上的生长及生态生理学预测结果。生长模型是FVS-BGC系统的核心组成部分,系统共包括7类经验生长模型：胸径—树高模型、树冠率模型、冠幅模型、树冠竞争因子模型、胸径生长模型、树高生长模型和枯损率模型；6类生理生态学模拟模块：辐射模块、水分模块、光合作用模块、呼吸作用模块、气孔导度模块、生产力模块。(2)研究了系统生长模型关键自变量,结合前人研究对系统主要生长模型进行了优化,具体内容包括：1)优化了油松地位指数表；2)建立了林分平均木—优势木树高生长模型；3)建立了树冠竞争因子模型；4)优化了油松、侧柏林分密度指数模型,并计算出两树种最大林分密度指数；5)优化了胸径—树高模型、树冠宽(冠幅)模型和胸径生长模型,采用相关指数作为所建各模型的拟合效果评价指标,结果表明各模型相关性较高,优化后模型的相关指数较前人有所提高。(3)确定了FVS-BGC系统需要的3类参数,气候参数、立地参数和树木生理参数。FVS-BGC系统共需要5类日水平的气候参数：最高温度、最低温度、相对湿度、降雨量、总辐射和大气透射率。在确定立地参数和树木生理参数时采用了试验结合参考文献的方法。试验确定了油松、侧柏4种立地类型0～30cm的土壤饱和含水量,并据此计算出绝对水体积参数。确定了树木生理参数中油松、侧柏两树种的最高光合作用速率分别为7μmol·m-2.s-1和5μmol.m-2·s-1；光合作用最高温度和最适温度分别为25℃和45℃；比叶面积分别为11m2／kg和17m2／kg,冠层消光系数分别为0.8和0.7；叶、干、根生物量占全株比例分别为：叶15%、68%、干17%、29%和根59%、12%；各器官含碳率均为50%。(4)本文建立的北京地区油松、侧柏生长的FVS-BGC系统可以同时输出经验生长收获模型和过程模型两种预测结果。使用20年的固定复位样地数据(间隔5年)对系统进行了检验,两种系统预测结果均与实测值接近,模拟效果良好。分别使用了2块油松、侧柏典型样地对系统预测效果及灵敏度进行了评价,从模拟结果可以看出经验生长收获模型模拟结果比过程模型模拟结果要高出28%,结果和国外有关研究类似。最后使用FVS-BGC系统模拟了油松、侧柏两块高密度林分经胸径下层疏伐和树高上层疏伐后林分生长情况,并根据预测结果确定出最佳的经营措施。本文深入研究了FVS-BGC系统,首次从源代码水平解析了系统生长模型,总结出了区域FVS-BGC系统构建方法；首次使用该系统进行了北京市油松、侧柏单木及林分水平生理生态过程的模拟,并对比研究了对同一对象采用不同模拟方法的预测结果,分析了经验生长收获模型与过程模型预测结果的差异。本研究为建立我国区域森林生长模拟系统提供了参考,研究结果有一定的理论实践意义。更多还原

【Abstract】 How the forest growth in the future? Which method was suited for cultivating the forest to timber forest, public welfare forest or carbon sick forest? In which extent the climate or the environmental change could affect the forest growth? Forest scientists and forest managers wanted wishfully to find out the answers of all these questions. Forest growth model is an important tool for forecasting the forest development and the process-based model with climate, site and physiology factors was became the focus point in the model research scope. Hybrid model which could model the forest management measures and the tree physiological ecology growth processes in the same time was emerged as the times require.Process-based models forest growth simulation system FVS-BGC (Forest vegetation simulator & Bio-Geochemical Cycles) was studied in deeply level for building a FVS-BGC system for Beijing area with two experimental species Pinus tabulaeformis and Platycladus orientalis. The valuable experiences in this researching process could been very useful and set a strong foundation for building a regional or a nationwide FVS-BGC system. Four major conclusions in this study were in below part.(1) The system components, executive process and key growth models were analyzed. The system running needs five type data, tree-level data, stand-level data, climate data, site data and tree physiology data. Also, five output data of tree or stand level in daily or yearly growth and physiological ecology data could be predicted. Growth models were the mainly component of FVS-BGC, there are seven types experienced models includes DBH-H model, crown ratio model, crown width model, crown competition factor model, DBH model, height models and mortality model. There are six type physiological ecology modules in FVS-BGC, radiation module, water module, photosynthesis module, respiration module, stomatal conductance module and NPP module.(2) Key independent variables were researched and the mainly growth models were optimized rebuilt based on previous studies and the primary works included:1) rebuilt the site index table of Pinus tabulaeformis,2) built the height model of mean tree and the dominant tree, 3) built the crown competition factor model,4) rebuilt the stand density index model of Pinus tabulaeformis and Platycladus orientalis and figured out the maximum stand density index of the two species,5) rebuilt the DBH-H model, crown width model and DBH growth model. Correlation index was used for evaluating the model fitting effect and the results showed that all models had a highly predictive validity.(3) Three type parameters of FVS-BGC were determined which includes climate parameters, site parameters and tree physiology parameters. There are five climate parameters in daily level were maximum temperature, minimum temperature, relative humidity, precipitation, total radiation and transmissivity. Two methods of doing experiment and reading references were used for determining the site parameters and the tree physiology parameters. The maximum soil water content of 0-30cm and the absolutely water volume in four site types of Pinus tabulaeformis and Platycladus orientalis were determined by doing experiment. The maximum photosynthesis rate were 7μmol·m-2·s-1and 5pμmol·m-2·s-1, the maximum temperature and the optimum temperature were 25℃and 45℃, the specific leaf area were 11m2/kg and 17m2/kg, the crown extinction coefficient were 0.8 and 0.7 of Pinus tabulaeformis and Platycladus orientalis. The proportion of leaf, stem and root biomass in whole tree was 15%,17%,12% of Pinus tabulaeformis, for Platycladus orientalis the proportion was 15%,17% and 12% respectively. The carbon content rate of each organ set 0.5 forcibly.(4) The Beijing FVS-BGC was built based on above works.20 years with 5 yearly repetition measurement fixed plots’data were used for testing the FVS-BGC predicted values and results showed that predicted values were closed to the measured values. The predicted effect and system sensitivity were also tested with 4 typical plots,2 plots for each species, the predicted results showed that experience based values were exceeded the process based values with about 28% which most similar contrasted with other foreign studies. At last, we used FVS-BGC to simulated lower level thinning depended on DBH and upper layer thinning depended on Height with two highly density stands of Pinus tabulaeformis and Platycladus orientalis respectively with the target of selected the optimal forest management decision and we achieved the goal.In the new century, the hybrid model became the focus both in forest ecosystem modeling and forest management modeling scope. In this study, we analyzed the growth models in source code level, simulated the physiological ecology growth condition of Pinus tabulaeformis and Platycladus orientalis in both tree level and stand level, contrastive analyzed the predicted results of same object but with different model methods and researched the differences between experienced based model and the processed based model by using the FVS-BGC for the first time. This study provided a reference for building a regional or nationwide forest growth simulation system FVS-BGC and also has a valuable significance of theory and practice.更多还原