This study has quantified basic wood density and various types of wood shrinkage in relation to initial spacing (or initial planting density) and tree growth based on a 48-year-old black spruce (Picea mariana) spacing trial in eastern Canada. A total of 139 sample trees were collected from four initial spacings (3086, 2500, 2066, 1372 trees/ha) for this study. Analyses of variance (ANOVA) show that initial spacing is the most important parameter affecting wood density significantly, followed by tree diameter at breast height (DBH) class. With increasing spacing, wood density, radial and volumetric shrinkage tend to decrease, whereas longitudinal shrinkage tends to increase gradually. The largest spacing has the lowest wood density, the smallest transverse shrinkage and the largest longitudinal shrinkage. Path analysis indicates that wood density is the most important parameter affecting transverse shrinkage, followed by the distance from the pith. Furthermore, much of the variation of the transverse shrinkage with wood density may be due to the initial spacing and tree DBH class. Path analysis also reveals that longitudinal shrinkage is mainly related to log height and tree DBH class. With increasing log height, longitudinal shrinkage tends to increase, and transverse shrinkage tends to decrease. With increasing DBH class, the trees tend to have an increasing longitudinal shrinkage and a decreasing transverse shrinkage. Overall, this study suggests that a large increase in the initial spacing (e.g., 1372 trees/ha) might lead to a significant reduction in both wood density and transverse shrinkage, and a significant increase in longitudinal shrinkage in black spruce.

中文翻译：

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黑云杉（Picea mariana）的木材密度和木材收缩率与初始间距和树木生长的关系

这项研究基于加拿大东部48年的黑云杉（Picea mariana）间隔试验，量化了与初始间距（或初始种植密度）和树木生长相关的基本木材密度和各种类型的木材收缩。本研究从四个初始间距（3086、2500、2066、1372棵树/公顷）中收集了总共139棵样本树。方差分析（ANOVA）表明，初始间距是显着影响木材密度的最重要参数，其次是胸高（DBH）级的树木直径。随着间距的增加，木材密度，径向和体积收缩率趋于降低，而纵向收缩率则趋于逐渐增加。最大间距具有最低的木材密度，最小的横向收缩率和最大的纵向收缩率。路径分析表明，木材密度是影响横向收缩率的最重要参数，其次是距木髓的距离。此外，横向收缩随木材密度的大部分变化可能归因于初始间距和树木的DBH等级。路径分析还表明，纵向收缩率主要与原木高度和树木的DBH等级有关。随着原木高度的增加，纵向收缩趋于增加，而横向收缩趋于减小。随着DBH等级的增加，树木倾向于具有增加的纵向收缩率和减少的横向收缩率。总体而言，这项研究表明，初始间距的大幅增加（例如1372棵树/公顷）可能会导致木材密度和横向收缩率显着降低，