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华南植物园在亚热带森林马尾松木质部形成及其驱动因子方面研究取得重要进展

【PDF原文: Intra-annual wood formation of subtropical Chinese red pine shows better growth in dry season than wet season

 近年来的研究发现我国亚热带森林生态系统正在持续固碳,在全球碳循环中起着至关重要的作用。树干是碳的主要储存器官,而该区域森林生态系统中树木树干木质部如何形成且什么因子驱动其形成至今无文献报道。 

  中科院华南植物园森林生态与模拟研究组黄建国研究员等利用微采样技术连续监测广东鼎湖山和石门台国家级自然保护区马尾松(Pinus massoniana Lamb.)的形成层活动和木质部(增大期、增厚期和成熟期)的形成过程,通过线性混合模型定量分析发现:马尾松的树干木质部生长开始于2月中下旬,结束于12月末,1月份形成层不活跃,极有可能处于半休眠状态,首次精确定量了马尾松生长季的长度,更新了普遍认为亚热带树木全年生长的传统观点。同时表明我国亚热带马尾松林树干生长季长度比温带和北寒带树木的生长季长4-6个月,从其他角度支持了我国亚热带森林是个净碳汇的观点;此外,与传统观念不同,马尾松林树木在干季(集中在9-11月)的生长明显比湿季旺盛,说明在水热充足的亚热带,马尾松的生长更多的受到净光合能量的影响,而不是环境因子(如温度和降水),表明马尾松生态系统是一个能量限制的生态系统,而不是一个环境因子限制的生态系统。在未来气候变化的背景下,我国亚热带马尾松林可能将受益于更长的干季而长的好,从而有利于持续固碳。此研究是国际上首次报道亚热带树木木质部发育过程及其驱动因子,对于进一步明确中国亚热带森林生态系统固碳机制有重要意义。 

  该研究得到中国科学院百人计划项目、国家自然科学基金面上项目、国际合作项目,以及中国科学院国际合作重点项目等的资助。相关研究成果已近期发表在领域顶级SCI期刊Tree Physiology(2017影响因子3.653)上。 

Abstract

China's subtropical forests play a vital role in sequestering global carbon; therefore, it is critical to conduct a precise investigation of intra-annual wood formation in these ecosystems to clarify the mechanisms behind this. Two field experiments were established in Chinese subtropical forests to monitor weekly the intra-annual xylem formation of Pinus massoniana Lamb. from January to December 2015, using the recently developed micro-sampling approach. The effects of climate on wood formation were also assessed using linear or mixed models. Results indicate that there is an inactive period that might be semi-dormancy in subtropical pine ecosystems in January compared with the complete dormancy in temperate and boreal ecosystems and the fully active or short-term dormancy in tropical ecosystems. The duration of xylem formation of Chinese red pine in subtropical China in 2015 was 4–6 months longer than temperate and boreal forests. Moreover, trees were found to grow better during the dry season than the wet season, indicating that the Chinese red pine ecosystem is more strongly regulated by net energy than by environmental factors. Our findings indicate that China's subtropical pine forests may benefit from the expected longer dry seasons, possibly leading to better forest growth and improved carbon sequestration under continued climate warming.



 

【PDF原文: Intra-annual wood formation of subtropical Chinese red pine shows better growth in dry season than wet season

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