桉树人工林生态系统服务权衡的营林模式差异：土壤碳氮调节与物种多样性的协同演变

Differences in Silvicultural Modes for Addressing Trade-offs in Ecosystem Services of Eucalyptus Plantations: Synergistic Evolution of Soil Carbon and Nitrogen Regulation with Species Diversity

关键词:  机械化营林  桉树人工林  土壤有机碳  土壤全氮  物种多样性  权衡与协同

Key words:  mechanized silviculture  eucalyptus plantation  soil organic carbon  total nitrogen  species diversity  trade-offs and synergies

摘要:

通过生态系统服务权衡的研究，探索不同营林模式下桉树人工林多项生态系统服务间的协同演变，为桉树人工林的经营管理提供理论依据。按照不同林龄和营林模式共设置40个样地，对所选林分的2种调节服务[土壤有机碳（SOC）调节、全氮（TN）调节]及1种支持服务（物种多样性）进行测算，利用均方根偏差（RMSD）和广义线性混合效应模型（GLMM）分析不同生态系统服务权衡与协同关系及其影响因素。结果表明：随着林龄的增加，机械营林模式下的土壤SOC和TN含量逐渐趋于稳定，且与传统营林模式无显著差异。机械营林初期显著降低了林下物种多样性，但随林龄增长物种多样性逐步恢复。土壤 SOC 调节、TN调节与物种多样性之间具有明显的权衡关系，其中机械营林模式中物种多样性具有较高的相对收益，而随林龄增加，传统营林趋于土壤 SOC收益，机械营林趋于TN收益。林分平均胸径和林龄是影响生态系统服务权衡的关键因素，随林龄增加土壤因子、林分因子变化促进生态系统服务权衡关系之间的关系逐渐趋于平衡。因此，在机械经营和管理过程中应考虑生态系统服务权衡的空间特征和驱动因素的差异性，适当引入局部人工干预，以缓解权衡冲突，提升生态系统服务功能。

Abstract:

This study investigated the trade-off of ecosystem services, explored the co-evolution of multiple ecosystem services among eucalyptus plantations under different forest management models, and provided a theoretical basis for the operation and management of eucalyptus plantations. A total of 40 plots were set up according to different forest ages and afforestation models. The two regulation services [soil organic carbon (SOC) regulation, total nitrogen (TN) regulation] and one support service (species diversity) of the selected forest stands were calculated. The root mean square deviation (RMSD) and generalized linear mixed effects model (GLMM) were used to analyze the service trade-offs and synergies of different ecosystems and their influencing factors. The results show that with the increase of forest age, the contents of soil SOC and TN under the mechanized afforestation mode gradually tend to stabilize, and there is no significant difference from the traditional afforestation mode. Results showed that as stand age increased, SOC and TN contents under mechanized silvicultural modes gradually stabilized, showing no significant difference from traditional silvicultural modes. In the early stage of mechanized afforestation, the species diversity under the forest was significantly reduced, but it gradually recovered with the increase of forest age. Clear trade-offs were observed among SOC regulation, TN regulation, and species diversity. Specifically, species diversity exhibited higher relative gains in mechanized plantations, while traditional plantations tended to benefit more from SOC accumulation as stand age increased. In contrast, mechanized plantations showed greater TN benefits with age. Stand average diameter at breast height (DBH) and stand age were key factors influencing ecosystem service trade-offs. As stand age increased, changes in soil and stand factors promoted a gradual balance in ecosystem service trade-off relationships. Therefore, during mechanized silvicultural modes, spatial characteristics of ecosystem service trade-offs and differences in driving factors should be considered. Appropriate localized manual interventions should be introduced to mitigate trade-off conflicts and enhance ecosystem service functions.