以福建天宝岩国家级自然保护区内长苞铁杉〔Nothotsuga longibracteata (W. C. Cheng) Hu ex C. N. Page〕纯林、长苞铁杉-青冈（Quercus glauca Thunb.）混交林、长苞铁杉-猴头杜鹃（Rhododendron simiarum Hance）混交林和长苞铁杉-毛竹〔Phyllostachys edulis （Carriere) J. Houzeau〕混交林为研究对象，分析了不同林型林窗内的土壤微生物生物量碳（MBC）含量差异及其与土壤含水量的相关性。结果显示：4种长苞铁杉林林窗和非林窗内的土壤MBC含量的季节差异总体达到了显著水平，季节动态变化特征总体表现为春季和冬季高于夏季和秋季；林窗的形成可明显提高土壤MBC含量，林窗与非林窗间的土壤MBC含量差异总体达到了显著水平，大部分林窗内的土壤MBC含量高于非林窗，而林窗间的土壤MBC含量总体差异不显著。各林窗内土壤MBC含量在不同林型间存在显著差异；与长苞铁杉纯林相比，长苞铁杉-青冈混交林春季和秋季的大、中林窗内土壤MBC含量较高，长苞铁杉-猴头杜鹃混交林春季和夏季的大、小林窗内土壤MBC含量较高。总体上看，长苞铁杉-青冈混交林和长苞铁杉-猴头杜鹃混交林林窗内的土壤含水量明显高于长苞铁杉纯林和长苞铁杉-毛竹混交林。相关性分析结果显示：长苞铁杉-猴头杜鹃混交林和长苞铁杉-毛竹混交林林窗内的土壤MBC含量与土壤含水量分别呈极显著和显著负相关，相关系数分别为-0.788和-0.638。综上所述，相较于长苞铁杉纯林和长苞铁杉-毛竹混交林，长苞铁杉-青冈混交林和长苞铁杉-猴头杜鹃混交林林窗内的土壤MBC含量和土壤含水量较高，这2种混交林以及林窗的形成均能较好地改善林内小气候，增强土壤肥力，促进保护区内长苞铁杉林的土壤碳循环过程。

Taking Nothotsuga longibracteata (W. C. Cheng) Hu ex C. N. Page pure forest, N. longibracteataQuercus glauca Thunb. mixed forest, N. longibracteata-Rhododendron simiarum Hance mixed forest, and N. longibracteata-Phyllostachys edulis （Carriere) J. Houzeau mixed forest as research objects, the differences in soil microbial biomass carbon (MBC) content of gaps of different forest types and its correlation with soil water content were analyzed. The results show that the seasonal differences in soil MBC content of gaps and non-gaps of four N. longibracteata forests reach significant level in general, and the seasonal dynamic variations are generally higher in spring and winter than in summer and autumn; the formation of gaps can elevate the soil MBC content evidently, the differences in soil MBC content between gaps and non-gaps reach significant level in general, soil MBC contents in most gaps are higher than those in non-gaps, while the differences in soil MBC content among gaps are not significant in general. There are significant differences in soil MBC content of each gap among different forest types; compared with N. longibracteata pure forest, soil MBC contents in large and medium gaps in spring and autumn of N. longibracteata-C. glauca mixed forest are relatively high, and soil MBC contents in large and small gaps in spring and summer of N. longibracteataR. simiarum mixed forest are relatively high. Overall, soil water contents in gaps of N. longibracteata-C. glauca mixed forest and N. longibracteataR. simiarum mixed forest are obviously higher than those of N. longibracteata pure forest and N. longibracteata-P. edulis mixed forest. The correlation analysis result shows that soil MBC contents show extremely significant and significant negative correlations with soil water contents in gaps of N. longibracteata-R. simiarum mixed forest and N. longibracteataP. edulis mixed forest, respectively, their correlation confficient are -0.788 and -0.638, respectively. In conclusion, compared with N. longibracteata pure forest and N. longibracteata-P. edulis mixed forest, soil MBC contents and soil water contents in gaps of N. longibracteata-C. glauca mixed forest and N. longibracteata-R. simiarum mixed forest are relatively high, the formation of these two mixed forests and gaps can evidently improve forest microclimate, enhance soil fertility, and promote the soil carbon cycling process in N. longibracteata forests of the nature reserve.