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樟子松人工林树冠动态三维图形模拟技术的研究

The Three Dimensional Computer Graphics Simulation Technique of Tree Grown Dynamic for Mongolian Scots Pine in Plantation

【作者】 刘兆刚

【导师】 李凤日;

【作者基本信息】 东北林业大学 , 森林经理, 2007, 博士

【摘要】 本文以东北林业大学帽儿山实验林场樟子松人工林为研究对象,采用树干解析、枝解析的方法,分别于2002年和2003年在老山施业区选择不同年龄、不同立地和不同密度的樟子松人工林有代表性的林分设置固定标准地15块(其中,2002年设置7块,2003年设置8块),共获取解析样木53株(其中生物量样木36株),实测了2298个一级枝活枝条变量因子(包括总着枝深度(DINC)、方位角(φ)、着枝角度(θ)、基径(BD)、枝长(BL)、弦长(BCL)、弓高(BAH))数据资料。基于理论或经验生长方程,建立了樟子松人工林树冠结构静态模型及树冠动态生长模型。采用VC++6.0语言为开发平台,结合OpenGL开放式图形库,将生长模型与形态结构模型结合,建立了樟子松人工林树冠动态三维图形可视化模拟系统。实现了基于实测数据和生长模型的静态、动态单木和林分的可视化模拟。因此,基于生长模型的林分可视化三维树冠动态模拟主要核心问题从两个方面进行研究,一是基于野外实测数据构建树冠结构静态和动态模型。另一方面是利用编程语言实现模拟的过程。本文详细研究工作包括以下内容:1樟子松人工林树冠结构静态模型的建立。主要从树冠形状模型和结构模型两方面进行了研究。采用野外实测樟子松一级枝条数据,利用总着枝深度枝条变量因子和林木胸径和树高变量建立了最优的反映树冠形状模型的枝条基径模型和枝长模型;着枝角度总体上是随着总着枝深度的增加而增大,但构建的模型精度过低,因此本文从着枝角度的总体分布方面对其进行了描述。树冠结构模型的研究包括一级枝条数量预估模型的构建以及枝叶的空间分布模型规律。结果表明:一级枝条个数在树冠有效冠内垂直方向上呈现一“多”一“少”的趋势,在有效冠以下,随着着枝深度的增加,枝条个数呈现直线下降趋势;枝条的水平分布可以用均匀圆形分布进行很好的拟合,也表明圆形分布统计量是用来分析枝条方位水平分布非常有用的工具。文中通过对树冠内一级枝条的空间分布规律的研究,可以为樟子松人工林树冠结构的动态模拟提供基础。基于实测各树冠变量,同时建立了基于林木和林分测定因子的全树冠叶量和单个枝条着叶量的预估模型,并对树冠内叶量的空间垂直分布规律进行了研究。结果表明:胸径(DBH)和冠长(CL)作为合适的树木变量,可以用来构建樟子松单木全树冠叶量的预估模型;单个枝条叶量与枝条基径、枝长和枝条在树冠内相对高度(BRH)相关紧密,其对数变换形式构建的单个枝条叶量模型有很好的预估效果;树冠叶量的空间垂直分布可以用二参数Weibull分布函数进行描述。尺度参数b变化范围为0.47-0.72之间,形状参数c变化范围在2.01-4.52之间,所有样木均通过t检验,相关指数r~2(0.958-0.997)均大于0.95。36株样木中有26株样木形状参数c的95%置信区间包含3.6,表明这些样木的叶量在树冠上的垂直分布符合正态分布,即大多数样木树冠叶量集中在中部,较小级别的样木表现出树冠叶量向上部倾斜,这是处于林冠下层的被压木,为了获取更多光能以维持自身生命活动导致的结果。2樟子松人工林树冠结构动态模型的建立。在树冠静态模型的基础上,为了反映树冠结构的动态变化,根据实测样木一级枝条枝解析基径、枝条生长数据,引入年龄因子作为自变量,建立了树冠内一级枝条基径、枝条的动态生长模型。由于树冠内的枝长和基径生长主要与树木的胸径、树高相关,因此在研究树冠动态变化规律时有必要建立反映树高、胸径动态变化的生长模型。通过树干解析和查数轮枝高度获取了樟子松胸径和树高生长动态数据,优选利用Richards理论生长方程建立了樟子松树高和胸径动态生长模型。检验结果表明:所有样木的相关指数均在99%以上,所以应用构建的Richards生长模型非常适合预估樟子松人工林树高、胸径生长。为了掌握樟子松人工林树冠枝下高和冠长动态变化情况,本文引用现有的樟子松人工林枝下高和冠长动态生长模型用来预估枝下高和冠长动态生长模型。并对引进的模型进行了精度验证。3基于实测数据和生长模型的樟子松人工林树冠动态三维可视化图形模拟。本文利用基于少数几个参数和读取数据文件的方式(由实测数据组成的Excel文件以及由生长模型生成),采用简单几何建模方法,利用Opengl 1.4的可编程图形功能及VC++6.0开发语言建立了樟子松人工林树冠动态三维可视化模拟系统软件(3DTree 1.0v),实现了基于实测数据单木、林分三维图形静态重建以及基于生长模型的单木、林分静态和动态三维图形可视化模拟,为实现虚拟间伐、整枝等三维可视化经营措施及景观设计等提供依据。

【Abstract】 This study was performed in Mongolian scots pine(Pinus sylvestris L.var.mongolica Litvin)plantations in Maoershan experiment forest centre of Northeast forestry university. Based on stem and branch analysis,data were collected from 53 sample trees in 15 plots with different age,site condition and density in 2002 and 2003.The variables of 2298 branches were measured in this paper,which included depth into crown,branch azimuth,branch angle, branch diameter,branch length,branch chord and height of branch bow.Based on theory and experience growth model,the crown static models and dynamic growth models of Mongolian scots pine plantations were developed in this study.The crown three-dimensional visualization dynamic graphics simulation system of Mongolian scots pine was established on the developing platform of VC++6.0 language and OpenGL through the combination of growth model and configuration structure model.The visualization simulation of static and dynamic single tree and stand based on actual measurement data and growth model was realized in this paper.The study of crown three-dimensional visualization simulation based on growth model was performed from two aspects in this paper.One is to develop the crown static and dynamic models based on field actual measurement data;the other is to realize the simulation process using programming language.The contents of this paper were as flows:1 The establishment of crown static models of Mongolian scots pine,which were performed from the aspects of crown form model and structure model.The best models for predicting branch diameter and length of Mongolian scots pine were established based on the actual measurement data using the variables of depth into crown of the branch(DINC),tree diameter at breast height(DBH)ant tree height(HT).The precision of the models for predicting branch angle was too low but branch angle increased with the increasing of DINC. The general distribution of branch angle was described in this paper.The study of crown structure model includes the establishment of the models of predicting branch number and the space distribution.The results showed that the branch number in a whorl decreased along with the increasing number of adjacent whorls in effective crown.The branch number had a linearly decreasing with the increasing of DINC below the effective crown.The branch horizontal distribution can be fitted by circle proportional distribution and the circle distribution statistic was useful for analyzing the branch azimuth.The study of the space distribution of branch can provide base for the dynamic simulation for the crown structure of Mongolian scots pine plantation.The models of whole leaf biomass of a tree and single branch based on stand and forest factors were established and the vertical distribution of leaf biomass in the crown was studied in this paper.The result shows that diameter at breast height(DBH) and crown length(CL) were best variables for establish the model of total leaf biomass;the leaf biomass of single branch was relation with branch diameter(BD),branch length(BL) and branch relative height in crown(BRH) and their log transformation were the best predictors;the vertical distribution of leaf biomass can be described use Weibull distribution function with 2 parameters.The scale parameters b ranged from 0.47 to 0.72 and the shape parameters c ranged from 2.01 to 4.52;all the sample trees past through t test and the correlation index were all over 0.95(ranged from 0.958 to 0.997);the shape parameter c of 26 sample trees in all the 36 sample trees contains 3.6 at the confidence interval of 95%,which shows that the leaf biomass of these sample trees obey normal distribution.i.e.the leaf biomass of most sample trees centered at the middle of crown and the leaf biomass of suppressed trees were often at the upper part of crown to obtaining more light to maintain tree activity.2 The establishment of crown structure dynamic models of Mongolian scots pine plantation.Based on the crown static models,the dynamic growth models of branch diameter and length were established by inducting branch age into theory growth model according to the branch analysis data of branch diameter and length growth data to reflect the crown structure dynamic.The branch diameter and length growth were mainly related with DBH and HT.It was necessary to establish the dynamic growth models of DBH and HT to study the crown dynamic. The Richards theory growth model was selected according to dynamic data of DBH and HT obtained by stem analysis and checking whorl height.The correlation index of all the sample trees were above 99%,which showed that the selected models were suitable for predicting the growth of DBH and HT.The dynamic of height of the first alive branch and crown length was predicted using the dynamic growth model provided in existing dissertation.The precision of the referenced models was tested.3 The crown three-dimensional visualization dynamic graphics simulation of Mongolian scots pine based on the measurement data and growth model.The simulation software (3DTree 1.0v) was developed based on the software of OpenGL 1.4 and VC++6.0 adopting simple geometry modeling method.The software can be operated by inputting few parameters and reading data files,which were the Excel file of measurement data and the files created by the growth model.It can rebuild the static three-dimensional graphic of single tree and stand based on measurement data.It also can simulate the static and dynamic three-dimensional graphic of single tree and stand based on the growth mode to provide reference for the visualization management and landscape design,such as suppositional cutting and training.The study in this paper can provide theory base and management method for the development and application of Mongolian scots pine plantations so as to get more ecology and economy benefit and improve the management level of Mongolian scots pine plantations in our country.

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