森林转化对乔木地上部分与土壤的碳氮储量及分配格局的影响

Effects of forest conversion on carbon and nitrogen storage and distribution of the aboveground part of trees and soil

森林变化影响其碳氮储量，准确评估碳氮储量是森林碳汇管理的重要理论依据。本研究以福建南平天然常绿阔叶林、闽楠人工林、樟树人工林、杉木人工林为对象，采用野外调查研究方法，比较了福建省重要森林生态系统地上生物量和土壤碳库和氮库储量。结果表明：天然林、闽楠人工林、樟树人工林、杉木人工林生态系统碳储量分别为215．68、207．50、120．14、207．53t·hm^-2，氮储量分别为7．73、11．50、9．20、9．05t-hm^-2；地上部分碳、氮储量最高的为天然林，而土壤碳、氮储量最高的为杉木林；杉木林叶片与表层土壤的C：N最高；从空间上看，天然林向人工林的转换改变了碳、氮的分配格局，天然林植被部分具有较高的碳、氮储量，应在后期的经营措施中加以保护。

Forest conversion affects ecosystem carbon（ C） and nitrogen（ N） storage. The accurate assessment of forest C and N storage is an important theoretical basis for forest C sink management. In this study,we measured C and N storage in broad-leaved evergreen natural forest（ BE）,Phoebe bournei plantation（ PB）,Cinnamomum bodinieri plantation（ CB）,and Cunninghamia lanceolata plantation（ CL） at Nanping in Fujian Province. The C and N storage in aboveground biomass and soil was compared. The results showed that ecosystem C storage of AF,PB,NS,and PA was 215. 68,207. 50,120. 14,207. 53 t · hm^-2,and N storage was 7.73,11.50,9.20,9.05 t·hm^-2,respectively. The C and N storage in aboveground biomass was the highest in BE,while CL had the highest soil C and N storage. C ∶ N ratios in both leaf and surface soil were highest in CL. Spatially,the conversion of natural forest to plantation forest altered C and N distribution patterns. The natural forest ecosystems had higher C and N storage,which should be protected in future management.