粤北马尾松人工林坡向效应分析

马尾松 Pinus massoniana 是粤北主要造林树种之一，研究以韶关地区 20 a 生马尾松人工林为研究对象，重点研究坡向对其人工林生长的影响，并探讨其可行的调整经营措施。结果表明，南坡马尾松的胸径和树高均显著高于北坡，坡顶胸径与北坡近似，树高大于北坡，且径高比最高；北坡的冠幅、冠长和冠体积均高于南坡和坡顶，反映马尾松喜光特性。南坡单株材积高于北坡和坡顶，坡顶中小径级个体 (DBH 10~25 cm) 比例高于南坡和北坡，但大径级个体 (DBH 25~30 cm) 比例明显下降，大径级个体单株材积和比例对林分蓄积影响最大，蓄积以南坡最高，其次为北坡，坡顶最低。根据不同径级单株材积和蓄积的坡向间差异及形成原因分析，探讨了不同坡向马尾松间伐强度、改造树种选择和培育模式，对于促进马尾松人工纯林的林分改造和森林质量精准提升具有指导作用。

Effect of Slope Aspect on Pinus massoniana Plantation in Northern Guangdong province

Pinus massoniana is one of the main afforestation species in northern Guangdong province.The 20-year-old P. massoniana plantation in Shaoguan city was taken as the research object. The effects of slope aspect on the growth of the plantation were analyzed, and the feasible adjustment and management measures were discussed further. The results showed that the DBH and tree height of P. massoniana on the south slope were significantly higher than those on the north slope. The DBH on the top of the slope was similar to that on the north slope, and the tree height was higher than that on the north slope, and the ratio of diameter and height was the highest on the top of the slope. The crown width, crown length and crown volume on the north slope were higher than those on the south slope and the top of the slope, reflecting the light-loving characteristics of P. massoniana. The volume on the south slope was higher than that on the north slope and the top of the slope, and the proportionof small and medium-size individuals (DBH 10~25 cm) on the top of the slope was higher than that on the south slope and the north slope, but the proportion of large-size individuals (DBH 25~30 cm) was significantly decreased. The volume and proportion of large-diameter individuals have the greatest impact on the volume, with the south slope being the highest, followed by the north slope and the top of the slope. According to the response of P. massoniana growth toward slope aspect, individual proportion of different diameter classes, individual volume and stock difference, the thinning intensity, tree species selection and cultivation mode on different slope aspect in plantations were discussed. The results could be applied in promoting the transformation of pure P. massoniana plantation stand and accurate improvement of the forest quality.