马尾松人工林近自然化改造对林分生长的影响

【目的】研究和阐明马尾松（Pinus massoniana Lamb.）人工林近自然化改造对林分保留木、套种树种和自然更新树种生长的影响。【方法】2005年1月,采用随机区组设计对中国林业科学研究院热带林业实验中心12年生马尾松人工林进行5种不同强度（0%,20%,30%,40%和50%）间伐后,套种米老排（Mytilaria laosensis）、红锥（Castanopsis hystrix）和润楠（Machilus pingii）3个乡土阔叶树种,每种强度设3次重复,每个套种树种密度均为120株/hm^2,2013年8月对所有样地（共15个,每个样地面积为600m^2）的马尾松保留木、套种树种和自然更新至乔木层的树种进行每木调查,记录种名、胸径和树高等。【结果】间伐处理8年后,不同间伐处理间林分保留木的平均胸径、树高和蓄积量均存在极显著差异（胸径：P〈0.001,树高：P=0.001,蓄积量：P=0.008）;林分平均胸径和树高随着间伐强度的增加而增加,林分蓄积量随间伐强度的增大而减少。间伐促进了3个套种树种幼树的生长,但不同树种间存在差异;米老排在50%间伐林分下生长最优,而红锥和润楠以40%间伐林分较优,前者的生长速率明显高于后者。间伐显著的提高了自然更新至乔木层的林木株数,与对照处理（100±25株/hm^2）相比,20%,30%,40%和50%间伐林分分别是对照处理的8.72倍、11.22倍、11.06倍和13.78倍;间伐显著提高了自然更新林木的树高生长,而胸径生长差异不显著。【结论】从人工林木材生产、套种树种生长和自然更新树种生长情况分析,采用30%或40%的间伐强度和套种优质乡土阔叶树是马尾松纯林近自然化改造的最佳选择。

Effects of Close-to-Nature Management on the Stand Growth in a Masson Pine (Pinus massoniana) Plantation in Southern China

【Objective】The effects of close-to-nature management on the growth of masson pine reserved tree,interplanted species and natural regeneration species in masson pine（Pinus massoniana Lamb.）plantation were researched and evaluated.【Methods】In January 2005,a thinning experiment was conducted in a 12-year-old masson pine plantation in Experiment Center of Tropical Forestry,Chinese Academy of Forestry,with five different levels of thinning intensity（i.e.0%,20%,30%,40%and 50%）,of which each treatment had three replicates,by the method of randomized blocks.Then,three native broad-leaved tree species,i.e.Mytilaria laosensis,Castanopsis hystrixand Machilus pingii,were interplanted with a density of 120 trees/hm^2 in the thinned masson pine plantation.In August 2013,we investigated the masson pine reserved tree,interplanted species and natural regeneration species in all plots（total 15 plots,each 30m×20m）,with recording species name,dbh and height of individuals.【Results】Eight years late,a re-investigation of the plots showed that：There were extremely significant differences in the growth of average dbh,average height and stand volume of masson pine reserved trees in different thinning treatment stands（DBH：P〈0.001;height：P =0.001;volume：P =0.008）;The average dbh and height of masson pine reserved tree in the stands increased with increasing thinning intensity,whereas the stand volume decreased with increasing thinning intensity.The saplings of broad-leaved tree species benefited greatly from thinning management,but there were significant difference between tree species.The growth of M.laosensis was optimal in the 50%thinninge intensity stand,while C.hystrixand M.pingii were optimal in the 40% thinning intensity stand.The growth rate of M.laosensis was significat higher than that of both C.hystrixand M.pingii.The individual number of tree layer species were significant increased with thinning treatment,compared with unthinned stand（100±25trees/hm^2）.The individual number of tree l