【作者】 李俊；

【导师】 曾思齐； 佘济云；

【作者基本信息】 中南林业科技大学 ， 森林经理学， 2012， 博士

【摘要】 世界范围内的生态环境正在不断恶化,而森林作为可以对抗生态环境问题的最大陆地生态系统,正面临着持续不断的破坏和经营管理无力的两难境界,致使天然林面积迅速减少,人工林品质不断下降,森林功能逐渐退化。森林结构是森林的内在本质,森林功能是森林的外在表现形式,结构决定功能。如何明晰森林的结构?理解结构与功能的耦合关系?调整森林结构实现功能的最优化等等问题便成为了当前林学界最关键的问题?本文属于国家林业公益性行业科研专项“南方集体林区次生林抚育间伐与高效利用技术研究(项目编号201004032)”的部分研究内容。本文从林分结构(直径结构、树高结构、冠幅结构、林木水平分布格局、林木空间隔离程度及林木大小分化程度等)研究出发,利用基于不固定对象木空间分析方法下的大小比数对单木生长模型进行分类,并通过单木生长模型模拟林分生长及直径结构变化,构建基于直径结构形状参数和林分平均年龄的全林分生长模型。最终利用全林分生长模型实现林业生产从林分密度调整向径阶调整的转变。直径结构方面：3种林分类型(南酸枣、苦槠和檫木)中混交林中小径阶所占比重普通低于45%,纯林中所占比重更小普通在20%以下；苦槠林一般都在15%以下。林分天然更新能力及群落演替稳定性均一般,特别是纯林已经出现不良趋势。形状参数在1.01-3.13之间,拟合后直径分布形状基本为左偏单峰山形。树高结构方面：混交林的树高跨度及标准差均高于纯林,林层数一般也多于纯林,混交林的垂直结构较复杂,对垂直空间的利用率要高于纯林。形状参数在1.49-3.99之间,混交林基本为左偏单峰形,而纯林基本为右偏单峰形。冠幅结构方面：形状参数在1.28-2.43之间,分布形状基本为左偏单峰山形。混交林的冠幅跨度及标准差均高于纯林,混交林的空中水平结构较复杂,对水平空间的利用率要高于纯林。林木水平分布格局方面：3种林分类型的平均角尺度分别为0.61、0.62、0.55,均为聚集分布。林木中处于随机分布的比例一般都在20%以下,发展趋势是由均匀分布和随机分布向聚集分布转化。林木空间隔离程度方面：3种林分类型的平均混交度分别为0.47、0.25、0.51,除苦槠林为弱度混交外,其他2种类型均属中度混交。平均混交度与树种配置比例成正相关。纯林中同类树种大都成聚集分布,树种配置极其不合理的现象明显。林木竞争态势方面：南酸枣林中南酸枣和枫香均处于竞争优势地位,而杉木及檫木整体表现出竞争劣势地位；苦槠林中枫香处于微弱竞争优势地位,而苦槠整体上处于中庸偏劣势地位。檫木林中檫木、南酸枣、鹅掌楸、马尾松和苦槠均处于竞争优势地位,而杉木表现出竞争劣势地位。不固定对象木的空间分析方法在3种空间分布结构方面的结果上均存在显著性或极显著性差异,且该方法下的对象木数与直径、树高、冠幅及大小比数均存在显著性或极显著性相关,从而认为基于不固定对象木的空间分析方法与基于固定4株对象木的空间分析方法为相互独立的方法,且基于不固定对象木的空间分析方法的结果更具说服力。以林木竞争态势对单木生长模型进行分类拟合,将单木模型划分为竞争优势木(大小比数≥0.5)和竞争劣势木(大小比数<0.5)两大类,从而更加精确的表达现实林木的生长状态。在模型选择方面,综合考虑现有数据拟合效果、模型复杂度及未来预测效果,单木模型中南酸枣以Gompertz模型为最佳,檫木以Gauss模型和Logistic模型为最佳,苦槠以Logistic模型和Schumacher模型为最佳,马尾松以Schumacher模型和Logistic模型为最佳,杉木以Gauss模型和Gompertz模型为最佳,枫香以Gompertz模型为最佳。林分生长模拟方面：随着林分平均年龄的不断增长,整体上看连年生长基本上是先升后降,拐点基本出现在50年左右；中龄林(南酸枣林和檫木林)中,在排除林分平均年龄的影响,形状参数与连年生长成显著负相关。成熟林(苦槠林)中,形状参数与连年生长成极显著正相关。全林分模型构建上,2参数(林分平均年龄和形状参数)的生长模型均优于1参数(林分平均年龄)的生长模型。中龄林中林分平均年龄与林分连年生长成正相关,但贡献权重较小,形状参数整体表现为负相关,贡献权重较大；成熟林中林分平均年龄与林分连年生长成负相关,但贡献权重较小,形状参数整体表现为负相关,贡献权重较大；在混交林表现的更加明显。该研究的主要创新点有以下3个方面：1、利用影响圈界定对象木,构建了基于不固定对象木的空间分析方法,对南方集体林区3种典型林分类型空间结构进行了研究。2、利用竞争态势对单木生长模型进行分类,更加符合林木现实生长。同时在对现有数据拟合效果的基础上,结合未来预测结果,进行模型最优选择。3、基于林分直径结构的形状参数与林分平均年龄构建了南方集体林区3种典型林分类型6种子类型的全林分生长模型,实现了林分生产实践的林分密度调整向前迈进一步,发展到林分径阶调整的目标。更多还原

【Abstract】 In the worldwild scalse ecological enviroment is worsening constantly and the forest system,as the largest ecological mainland ecosystem resisting ecological enviromental problems,was confronting the dilemma of continuous destruction and management asthenia,which made the decline of natural forest area,reduction of the planted forest quality and gradual degradation of forest function. The forest structure was the intrinsic nature, while its function was the external manifestation, thus structure determined function. How to clear forest structure? How to understand coupling relations between the structure and the function? It was the most essential question that realized the problems such as function optimization, and so on, by adjusting forest structure. This article’s content is a part of the public welfare industry of the state forestry administration research projects:"Southern collective secondary forest tending and thinning and efficient use of technology research (The Item Number:201004032)".With the study of stand structure(such as diameter structure, tree height structure, crown width structure, horizontal distribution patterns of forest, space isolation degree of forest and size differentiation of forested.),the whole stand models based on the parameters of diameters structure shape and forest mean age were constructed in this article, by classifying individual tree growth models through neighbourhood comparison on the basis of the space analysis methods of non-fixing subject tree, simulating stand growth and changes of diameter structure through individual tree growth models. Finally, the transformation which was from adjustment of stand density to adjustment of diameter class, could be realized by using the whole stand models.Diameter structure aspect was as followed:among3kinds of stand types (Choerospondias axillaris forest, Castanopsis sclerophylla forest and Sassafras tzumu forest),the specific gravity of small diameter class was generally lower than45%in mixed forest, while it was normally below20%in pure forest; and it was under15%in Castanopsis sclerophylla forest. Stand natural renewal capacity and stability of community succession appeared normal, especially there being adverse trend in pure forest. Shape parameters were between1.01and3.13, diameter distribution shape was basically leftist unimodal montiform after fitting. Tree height structure aspect was as followed:the tree height span and standard deviation of mixed forest were both higher than those of pure forest, so as the number of forest stories, the vertical structure of mixed forest was more complicated, and its utilization ratio to vertical space was higher than pure forest. Shape parameters were between1.49and3.99, the image of mixed forest was basically leftist unimodal montiform, whereas that of pure forest was basically rightist unimodal montiform.The crown width structure aspect was as followed:the shape parameters were between1.28and2.43. and distribution shape was basically leftist unimodal montiform.The crown width span and standard deviation structure of mixed forest was more complex, the utilization ratio to level space was higher than pure forest.Forest level distribution pattern aspect was as followed:the mean uniform angle index of the3kinds sand types was respectively0.61,0.62,0.55,all for aggregation distribution. The proportion under random distribution of forest was generally below20%,the development trend was the transformation from even distribution and random. distribution to clustered distribution. The isolation degree of forest space aspect was as followed:the average mingling degree of3kinds stand types was respectively0.47,0.25,0.51,except for light degree group mixture of Castanopsis sclerophylla forest, the other two types both belonged to moderate group mixture, There was a positive correlation between average mingling degree and proportion of species configuration. The same kind of species almost appeared clustered distribution in pure forest, of which the species configuration had obvious unreasonable phenomenon. Forest competition situation aspect was as followed: Choerospondias axillaris and Liquidambar formosana in Choerospondias axillaris forest were both in competitive advantage position, whereas Cunninghamia lanceolata and Sassafras tzumu were in competitive disadvantage in whole appearance; and in the whole, the Liquidambar formosana in Castanopsis sclerophylla forest was in weak competitive supriority,while Castanopsis sclerophylla was in partial inferior position. In Sassafras tzumu forest, Sassafras tzumu, Choerospondias axillaris, Liriodendron chinensis,Pinus massoniana and Castanopsis sclerophylla were all in competitive superiority, while Cunninghamia lanceolata showed a competitive inferior.In the respect of3kinds space distribution structure, the results of non-fixing subject tree space analysis methods had significant or extremely significant, and in which there was a significant or extremely significant correlation between the numbers of subject tree and dianmeter,tree height, crown width and heighbourhood comparison. It was found that the space analysis methods based respectively on non-fixing subject tree and fixing4strains subject trees were muturally independent, and the former had convincingness to the latter.With forest competitive situation, individual tree growth models were classified and fitted, then the single tree models were divided into2communities, respectively competition advantage forest(neighbourhood comparison>0.5)and competition disadvantage forest(neighbourhood comparison<0.5),thus growth situation of actual crop was expressed more precisely.In the terms of single tree models,comphrehensively considering fitting of the available data,complexiy of models and prediction effects about future.the single tree model, Gompertz model is the best in Choerospondias axillaris, Gauss model and Logistic model are the best in Castanopsis sclerophylla, Logistic model and Schumacher model are the best in Sassafras tzumu, Schumacher model and Logistic model are the best in Pinus massoniana, Gauss model and Gompertz model are the best in Cunninghamia lanceolata, Gompertz model is the best in Liquidambar formosana.In the terms of stand growth simulating aspect,with continuous growth of stand mean age from overall perspective of procession.avaerage of current annual growth was basically first increased and then decreased,the inflection point basically occurred in about50years. Among middle-age forest(Choerospondias axillaris forest and Sassafras tzumu forest), excluding the effection of stand mean age,there was a extremely significant negative correlation between shape parameters and average of current annual growth.Among matural forest(Castanopsis sclerophylla forest),there appeared a extremely positive correlation between shape parameters and average of current annual growth.On the constructure of whole stand models,the growth model of2parameters(stand mean age and shape parameters)had superior to that of1parameter(stand mean age).Although there was a positive correlation between stand mean age and stand current annual growth in moddle-age forest,contribution weight was smaller,whereas there appeared a negative correlation in the whole shape parameters,contribution weight was larger.There was a ngative correlation between stand mean age and stand current annual growth among mature forest,but contribution weight was smaller,while it appeared a negative correlation in the whole shape parameters,contribution weight was larger;the manifestation was more obvious in mixed forest.The main innovations of this study had following3aspects:1.The space structure of3kinds typical stand types of southern collective forest zone were researched by using influence circle,defining subject tree and constructing space analysis methods on the basis of non-fixing subject tree.2.The single tree growth models were classified by using competition situation,which accorded with standing growth of forest.Meanwhile.on the basis of fitting effects of existing data,models would be the optimal selection combined with future prediction results.3. The whole stand growth models of6seed types of3kinds typical stand types in southern collective forest zone were consturcted on the basis of shape parameters and stand mean age of stand diameter structure,what realized the goals that stand density of stand production practice was adjusted forward step by step and develped to the adjustment of stand diameter grade.更多还原