红锥树干节疤分布及修枝对生长的影响

Distributions of knots in trunks and pruning effects on growth in Castanopsis hystrix

【目的】对红锥树干节疤分布规律进行调查并开展修枝试验,提出红锥修枝措施以促进其生长,以减少木材节疤形成,培育大径级无节良材。【方法】通过对30年生红锥自然生长形成的节疤分布情况进行调查,了解其节疤形成的时间和在树干中的分布规律。在6年生红锥人工林中设置不同的修枝强度,并对修枝后18个月林地中各单株的生长情况进行调查,分析修枝对树木生长的影响,选取最优修枝强度。选择3种常见建材用漆作为修枝锯口保护剂,通过对锯口愈合情况和锯口部位横切面的调查,判断不同锯口保护剂的保护效果及修枝后对锯口部位木材径向生长的影响。【结果】红锥节疤主要分布在心材中,死节数量占87%。修枝可以显著提升红锥单株的胸径生长,但不同修枝强度间暂未出现显著差异。使用锯口保护剂可有效促进节疤愈合并减缓木质部从锯口处向深处坏死,油性漆对锯口保护效果最好,直径3.5 cm以下锯口愈合率可达94.2%以上;直径大于3.5 cm锯口的愈合率可达84.1%;对直径3.5 cm以上锯口的坏死深度可降低61.2%。此外,修枝可以显著改善枝条下方径向生长受到抑制的情况。【结论】本研究总结的修枝方法操作性较强,成本较低,可提高单株的生长量和圆满度,减少木材节疤的形成,可应用于红锥人工林经营。

【Objective】 After investigating the distribution of knots in Castanopsis hystrix and performing a pruning experiment on them,a new pruning management method was developed to reduce the formation of knots in the trunk,promote plant growth and enable the cultivation of large-diameter-grade and knot-free wood.【Method】 The time and distribution of knot formation in the trunk were determined by investigating the scar distribution in six naturally grown 30-year-old individiuals.Different pruning intensities were then set for trees in a six-year plantation,and growth after 18 months of pruning was measured to select the best intensity.Three types of common paint were selected for pruning incision protection.The healing and transverse sections of incision were investigated to evaluate the protective effects of the radial growth after pruning.【Result】 The knots were mainly distributed in the core of the trunk,with 87% dead knots.The best pruning intensity demonstrated a 26.1% increase in the diameter at breast height(DBH) growth compared with the control,but no significant difference with the other pruning intensities.All the incision protection methods can increase the healing rate and protect the incision rot from extending into deeper areas.Oil paint exhibited the best protecting effect,and the healing rate of incision reached 94.2% and 84.1% for diameters under and greater than 3.5 cm,respectively.Post-incision necrosis deeper than 3.5 cm can be reduced by 61.2%,and pruning can significantly change the inhibition of the radial growth under the branch area.【Conclusion】 The pruning method summarized in this study is operable and can improve growth and roundness,reduce the formation of wood knots,and appropriate for the management of C.hystrix plantations.