珍贵乡土树种与桉树混交对生态系统生物量和碳储量的影响

阐明珍贵乡土树种与桉树混交对生态系统生物量和碳储量的影响是精准评估人工林碳源/汇性质和提升人工林质量的重要基础。本研究以6年生的桉树纯林(EP)、桉树×红锥混交林(MEC)、桉树×望天树混交林(MEP)为对象,探讨珍贵乡土树种与桉树混交对生态系统生物量和碳储量的影响及作用机制。结果表明,EP、MEC、MEP的生态系统生物量和碳储量分别是135.78,154.75,155.24t/hm~2和197.89,225.45,227.37t/hm~2。方差分析表明,珍贵乡土树种红锥和望天树与桉树混交显著提高了人工林生态系统的生物量和碳储量,混交林生态系统生物量比纯林提高13.97%—14.33%,而碳储量比纯林提高13.93%—14.89%。说明红锥和望天树与桉树混交属于促进(Facilitation)或竞争减弱(Competitive reduction)的种间相互作用关系,种间竞争小于种内竞争,资源的有效性和利用率提高,因而促进林分生态系统生物量和碳储量的提高。红锥和望天树与桉树混交可以实现桉树木材生产与其他生态服务的平衡,是一种较好的经营模式。

Effects of Mixing Precious Indigenous Tree Species and Eucalyptus on Ecosystem Biomass and Carbon Stocks

To elucidate the effects of precious indigenous tree species mixed with Eucalyptus on ecosystem biomass and carbon stocks is an important foundation for accurately evaluating the property of carbon source/sink and improving the quality of plantation. In this study,6-year-old pure Eucalyptus plantations (EP),mixed Eucalyptus and Castanopsis hystrix plantations (MEC),and mixed Eucalyptus and Parashorea chinensis plantations (MEP) were selected as the subjects to investigate the effects and mechanisms of mixture of precious tree species with Eucalyptus on ecosystem biomass and carbon stocks. The results showed that the ecosystem biomass and carbon stocks of EP,MEC and MEP were 135.78,154.75,155.24 t/hm² and 197.89,225.45,227.37 t/hm²,respectively.Variance analysis showed that mixture of precious indigenous tree species with Eucalyptus could significantly improve the biomass and carbon stocks of the artificial forest ecosystem.The biomass of mixed forest ecosystems increased by 13.97%-14.33% over pure forests,while the carbon stocks increased by 13.93%-14.89% over pure forests.These results suggested the mixture of C.hystrix and P.chinensis with Eucalyptus were inter-species interaction relationship of facilitation or competitive reduction.In the mixture plantations,inter-species competition was less than intra-species competition,and the availability and utilization of resources were improved,thus promoting the improvement of biomass and carbon stocks of stand ecosystem.Our results suggest that mixing C.hystrix or P.chinensis with Eucalyptus should be a better management model for the balance between eucalypts wood production and other ecological services.