Douglas-fir树木生长模型分析及建模(英文)

Modeling the growth of Douglas-fir

主要对一棵24岁的Douglas-fir(花旗松,北美西北部的主要树种之一)的生长情况进行详细的测量和描述,其目的是创建出一个准确的计算机三维模型.同样的研究由Mark Goebel在2002年对同一试验地砍伐的另一棵Douglas-fir的地下部分作过.把两次研究的结果结合起来制作出一个可以用于教学演示的Douglas-fir生长模型.使用G.H.Duff和Noran J.Nolan首创的分析法对测量结果进行了分析.主干年轮的直径生长,主干平均年轮面积,主干垂直生长,枝干长度增长和年平均枝干直径的数值都进行了构图分析.生长曲线同理想生长曲线表现出了一定的差异,同时显示了各年间的细微变化.过去24年间好的生长年份可以因此被确定出来.测量分析结果和Goebel的研究结果相吻合,因此重建一棵Douglas-fir的目的能够被实现.但是研究结果表示我们砍伐的Douglas-fir并不是完全没有受到生长压力的绝对优势物种,要进一步创建三维模型还需要一些计算才能实现.

Extensive study and description have been done on the root growth morphology of a dominant Douglas-fir tree. This work was used to create a 3-D model of root growth. The goal of our project was to do an extensive study and description of growth morphology for the aboveground portion of the tree, i.e. stem and branches. The study will be used to further the transition from 2-D to 3-D portrayals of tree growth. We used the Duff & Nolan tree and crown dissection technique, in which the tree stem is divided into sections of yearly growth increments. We measured the extension (length) of horizontal branch growth and vertical stem growth, the girth (diameter) of the stem at yearly increments and the branches at the point of emergence from the stem, as well as the direction (angle and azimuth) of branch extension. Using this method we have been able to reconstruct the tree in terms of the measured increments. Analysis of variation in extension, direction and girth shows regular patterns that can be accounted for based on location relative to the top of the tree, and due to the growth year or age of the tree. Additional analysis shows patterns of 'good' growth and 'poor' growth years due to variation in climate. These patterns will be compared with observed variation in annual root growth to see if a 'good' or 'poor' year of root growth corresponds to a 'good' or 'poor' year of aboveground growth.