亚热带次生常绿阔叶林目标树经营效果分析

Effect of Target Tree Management in Subtropical Secondary Evergreen Broad-leaved Forest

为了探讨亚热带萌生性次生常绿阔叶林目标树经营后的初期效果,选取分布在浙江省遂昌县3个不同发育阶段的次生常绿阔叶林样地(样地1,林分年龄20~30年;样地2,林分年龄>30~40年;样地3,林分年龄50~60年)为研究对象,分别实施封禁(对照)、传统经营和目标树经营,通过2017年(试验前)和2020年(试验3年)的调查,比较分析了目标树经营后早期的植物群落结构、物种多样性和土壤理化性质的动态变化。结果表明,目标树经营提高了林木的混交程度,降低了林木聚集度;目标树经营林分乔木层林木胸径断面积和的年均生长率最高,传统经营的次之,对照的最低,并且目标树经营林分中林木的年均生长率显著高于样地1和样地2的(P<0.05);传统经营林分的下木层幼树密度、下木层和草本层的多样性指数均显著低于目标树经营和对照林分的(P<0.05);3个样地的各样方中的土壤容重、总孔隙度、pH值、有机碳含量、全N含量、全P含量、全K含量、速效K含量均没有明显差异,只有速效P含量在目标树经营3年后有明显下降(P<0.05)。以上结果说明,目标树经营有效地改善了林分的空间结构,提高了目标树的生长量,有助于加快林木的分化和分层,同时减少了对林下植被的干扰,土壤理化性质未有明显改变,缓解了作业初期对水土流失的影响,在林分发育初期(20~40年),目标树经营是针对亚热带次生常绿阔叶林较为有效的森林经营措施。

In October 2017,subtropical secondary evergreen broad-leaved forest in Suichang county,Zhejiang province was sampled with age group of 20-30-year,30-40-year and 50-60-year.3 quadrats with area of 50 m×50 m were established for traditional and target tree management treatment in each sample area,with no management as control.In October 2020,investigations were carried out on species composition,stand structure,growth,undergrowth vegetation and soil physio-chemical properties,and comparison was made on the result in 2020 and that in 2017.The results showed that target tree management could improve mingling and reduce contagion of the forest.The basal area of DBH and annual growth rate in quadrat with target management was the highest,that with traditional management the second,that in the control stand the lowest.The density of young trees,the diversity index of understory and herb layer in quadrats with traditional management was significantly lower than in those with target management and control.There were no significant differences in soil bulk density,total porosity,pH,organic carbon content,total N,total P,total K and available K content among different sample areas,except available P,which reduced in quadrat with target tree management.