近自然化改造对马尾松和杉木人工林生物量及其分配的影响

Effects of close-to-nature transformation on biomass and its allocation in Pinus massoniana and Cunninghamia lanceolata plantations

近自然化改造作为森林新增碳汇的最有希望的选择之一,将如何通过改变林分结构影响林分生物量和生产力进而影响林分固碳能力和潜力目前尚不清楚,因此,了解近自然化改造对人工林生物量及其分配的影响,对人工林生态系统碳管理具有重要意义。以马尾松近自然化改造林(P(CN))、马尾松未改造纯林(P(CK))、杉木近自然改造林(C(CN))和杉木未改造纯林(C(CK))4种人工林为研究对象,采用样方调查和生物量实测的方法,分析4种林分生物量差异,旨在揭示近自然化改造对马尾松和杉木人工林生物量及其分配的影响。结果表明:马尾松杉木人工林近自然化改造通过调整林分结构显著提升马尾松和杉木人工林生物量和生产力,8a后马尾松和杉木林分生物量分别增加46.71%和37.24%。乔木层生物量在林分生物量总量中占主导地位(95.48%-98.82%),并对林分生态系统总生物量变化起决定性作用。林分生物量和生产力的增加主要因为近自然化改造改变了林分群落结构,进而提高了乔木层生产力。研究结果表明,合理的经营措施不仅可以改善林分结构,提升林分生产力,并可为增强植被固碳能力创造有利条件。

Close-to-nature transformation is considered one of the most promising options for creating new forest carbon sinks, but the mechanism by which it influences the biomass by changing the forest structure and thereby influencing the ability and potential of the forest for carbon sequestration remains unclear. Therefore, there is an urgent need to understand these key effects of close-to-nature transformation on the biomass for carbon management in plantation ecosystems. Based on a close-to-nature forest of Pinus massoniana plantation （P（CN）） and an unimproved pure stand of P. massoniana （P（CK））, and a close-to-nature stand of Cunninghamia lanceolata （C（CN）） and an unimproved pure stand of C. lanceolata （C（CK）） as the research objects, the biomass and allocation difference of the four forest types were studied using the method of quadrat sampling combined with biomass measurement, aiming to reveal the influence of close-to-nature transformation on forest biomass and its allocation patterns in P. massoniana and C. lanceolata plantation. The results indicated that the biomass and productivity of P. massoniana and C. lanceolata plantations can be significantly increased by close-to-nature transformation, and the biomass of P. massoniana and C. lanceolata forest stands can be increased by 46.71% and 37.24%, respectively, after 8 years. The biomass of the arborous layer dominates the total biomass （95.48%-98.82%）, which plays a vital role in the overall change in forest stand ecosystem biomass. The increase in biomass and productivity in the forest is mainly due to the change in the forest stand community structure, which increases the productivity of the arborous layer. Taken together, the results indicate that reasonable management measures can not only improve stand structure and productivity, but also create favorable conditions that enhance vegetation carbon fixation capacity and potential.