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首页> 外文期刊>Wood and Fiber Science >Assessment of white spruce and jack pine stem curvature from a nelder spacing experiment.
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Assessment of white spruce and jack pine stem curvature from a nelder spacing experiment.

机译：通过纳尔德间距实验评估白云杉和杰克松树茎的曲率。

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This study presents a method for calculating stem curvature for trees with multiple deviations. Generally, tree curvature is assessed using the maximum deflection method. It consists of measuring the farthest point from a straight line drawn between the large and small ends of a stem. It works fairly well for a single deviation but gives poorer results for stems with several deviations. The stems used for developing this method were harvested from a 32-yr-old Nelder spacing experiment established near Woodstock, New Brunswick, Canada. A total of 96 trees were selected for this study from the white spruce (Picea glauca [Moench] Voss) and jack pine (Pinus banksiana Lamb.) that were planted on the same Nelder circle. This particular plantation design offered a gradient of initial spacings ranging from 640 to 12,000 stems/ha. Results of analysis revealed that initial spacing had an impact on tree curvature. Stem curvature increased with wider initial spacing. However, this influence varied between species and differed according to the method used to calculate curvature. The vector length calculation method showed that stem curvature in jack pine was more pronounced and more often encountered at lower densities than in white spruce. It was also observed that tree shape was influenced by the cardinal points with white spruce growing more in westerly and southerly directions.
机译：这项研究提出了一种计算具有多个偏差的树木的茎曲率的方法。通常，使用最大偏转方法评估树木曲率。它包括从杆的大头和小头之间绘制的直线测量最远的点。对于单个偏差，它的效果很好，但是对于具有多个偏差的茎，结果却较差。用于开发此方法的茎是从加拿大新不伦瑞克省伍德斯托克附近建立的32岁Nelder间隔实验中收获的。从白云杉（Picea glauca [Moench] Voss）和杰克松（Pinus bankiana Lamb。）种植在同一Nelder圆上，总共选择了96棵树进行此项研究。这种特殊的人工林设计提供了从640到12,000茎/公顷的初始间距梯度。分析结果表明，初始间距对树的曲率有影响。杆曲率随着初始间距的增大而增加。但是，这种影响在物种之间有所不同，并且根据用于计算曲率的方法而有所不同。向量长度计算方法显示，与白色云杉相比，千斤顶松中的茎弯曲更明显，在较低密度下更常见。还观察到树的形状受基点的影响，白云杉在西风和南风的方向上生长得更多。

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