<正>以加拿大新布郎斯威克省自然资源与能源部1966年建立的天然林抚育间伐实验基地为研究对象，从3种疏伐强度（1.22m×1.22m，1.52m×1.52m，2.13m×2.13m）的样地和一块控制地中共采伐了154株树，胸径范围10～24cm，研究抚育间伐（PCT）对北美短叶松的生长及材质的影响。结果表明：随着疏伐强度从1.22m×1.22m增加到2.13m×2.13n1，北美短叶松的死亡率从67.6%下降到32.7%。随着疏伐强度的增加，树干胸径、商品材树干高度和材积、树干削度、树枝直径均显著增加.3种疏伐强度中，只有2.13m×2.13m的疏伐强度对树高和树冠的尺寸有显著影响。PcT能增加无节材的长度，但对木材的密度没有显著影响。

Community characteristics of natural secondary forest after selective cutting were investigated in Changbai Mountain area, and the dynamics of natu;al regeneration during the 28 years restoration period were analyzed and discussed in allusion to the saplings and seedlings. The results showed: (1) the appearance rate of regeneration species was very low in initial 10 years, but it was higher than 75% after 15 years and had little change later; (2) the distribution density of regeneration species increased gradually along with the restoration of secondary forest, it could reach 7 500 tree per hectare and had little change later; (3) most of saplings and seedlings were distributed 1.5～3.5 m from the nearest standing tree. With the restoration of the secondary forest, the distribution of saplings became near to the standing tree, but the distribution of seedling became far from the standing trees.