Effect Of Planting Spacing In Production And Permeability Of Heartwood And Sapwood Of Eucalyptus Wood

ABSTRACT The objective of this work was to evaluate the influence of different useful areas provided by the planting spacings (3 × 1, 3 × 2, 3 × 3, 3 × 4 m) on the production and permeability of heartwood and sapwood of Eucalyptus grandis and Eucalyptus grandis × Eucalyptus urophylla clones at 4 years old. Regardless of the clone, there was no effect of planting spacing on the heartwood/sapwood relation and wood permeability. All clones showed a heartwood decrease with increased height, regardless of planting spacing, and E. grandis (B) was the only one that had its heartwood percentage positively and significantly correlated with the dendrometric variables (DBH and commercial height). The use of the dymethil yellow compound was indispensable in defining the heartwood and sapwood regions in the samples from 50% of the stem height. The heartwood permeability was low in all evaluated clones, suggesting vessel obstruction by tyloses or other deposits, while sapwood permeability reached 405.4 cm3/cm.atm.s.摘要 本研究旨在探究种植间距（3×1、3×2、3×3、3×4 m）所对应的不同有效种植面积，对4年生巨桉（Eucalyptus grandis）以及巨桉×尾叶桉（Eucalyptus grandis × Eucalyptus urophylla）无性系的心材（heartwood）、边材（sapwood）产量与渗透性的影响。无论无性系类型如何，种植间距对心材/边材比值与木材渗透性均无显著影响。所有无性系的心材占比均随树高增加而降低，且不受种植间距影响；其中仅巨桉（B）的心材占比与测树学指标（胸径（DBH）、商品材高度）呈显著正相关。在截取茎高50%处的样本中，需使用二甲基黄（dymethil yellow）试剂才能准确区分心材与边材区域。所有供试无性系的心材渗透性均较低，这表明导管可能被侵填体（tyloses）或其他沉积物堵塞；而边材渗透性可达405.4 cm³/(cm·atm·s)。