【摘要】 自养机制的形成是人工林可持续经营的目标之一.本研究通过混交模拟杉木人工林不同恢复阶段林分,观察比较发现从退化的杉木林阶段到地带性树种比例较低的混交林、地带性树种比例较高的混交林和地带性树种纯林阶段凋落量、N、P、K、Ca和Mg5种元素的归还量逐渐增加,特别是5种养分元素的循环速率也不断增大,其中N、Mg的循环速率由杉木纯林的0.1左右增大到火力楠纯林的0.5以上,与此同时林分土壤有机质含量和养分含量也不断增加,表明退化杉木人工林在恢复过程中随着林内地带性火力楠树种混交比例的增加,林分的自养机制逐渐获得重建.从杉木人工林可持续经营角度来看,杉阔混交比例的确定应以林分自养机制的形成和土壤养分状况的改善为标准更多还原

【Abstract】 The formation of self sustaining mechanism is one of the major objectives for the sustainable management of plantations.In this study,the incorporation of different proportions of native Michelia macclurei into Cunninghamia lanceolata plantation was practiced to restore the degraded C.lanceolata plantation,and the comparison of nutrient cycling characteristics and soil nutrient concentrations was made among four types of plantation stand with different mixed rate of native M.macclurei representing four different restoration stages of degraded C.lanceolata plantations.With the increase of the proportion of M.macclurei in the plantation,the litterfall and returned nutrients N,P,K,Ca and Mg increased.The nutrient cycling efficiency increased significantly, e.g.,that of N and Mg increased from about 0\^1 for the degraded pure C.lanceolata plantation to above 0\^5 for the pure M.macclurei plantation.Soil organic matter and nutrients also elevated.It is suggested that the self sustaining mechanism of the C.lanceolata plantation forest gradually reformed as the proportion of native M.macclurei mixed in the plantation increased. The criteria to determine the proportion of native broad leaved tree species mixed in C.lanceolata plantations for the purpose of sustainable management should be based on whether the self sustaining mechanism was reformed and whether the soil nutrient status was improved.更多还原