杉木不同地理种源树轮对气候变化的响应

Provenance selection for afforestation has already become an important approach for the reply of mankind to climate change. The discussion of the response of different provenance of main tree species to climate change and the evaluation of the impact of climate change on different provenance has become principal scientifical question to be solved. The maturity of tree provenance trails and dendroclimatology method have provided a credible approach to solve this problem. The project will view mature chinese fir provenance trial stands as objective, adopting dendroclimatology method to build the tree ring width, timber density and stable-carbon isotope series, and through correlation analysis and regression analysis, discuss the relationship between tree ring radial growth, timber density and stable-carbon isotope and climate factors such as temperature, precipitation and comprehensive factors. The aims of this study are to find the response difference of different chinese fir provenances to climate change and the impacts of climate change on chinese fir growth in view of different tree ring indices. The studies of impact of climate change on tree growth based on tree ring data of different provenances still have no reports in China, and the research on responses of different tree provenances to climate change in view of different tree ring indices have obvious creation in this project. The research results can provide important direction for provenance-level forest resource cultivation under future climate change, and provide theoretical and practical evidences for drawing up forest countermeasure to replying climate change.

造林树种种源选择已成为人类应对气候变化的重要途径。探讨主要造林树种不同地理种源对气候变化的响应及评价未来气候变化对树木种源生长的影响已成为亟需探讨的重要科学问题。种源试验林及树轮气候学方法的成熟为这一问题的探讨提供了可靠依据。项目拟以成熟龄杉木种源试验林为对象，采用年轮气候学研究方法，构建杉木不同地理种源树轮宽度、木材密度及稳定碳同位素序列，通过相关分析和回归分析，探讨杉木地理种源树轮径向生长、木材密度及稳定碳同位素与气候因子温度及降水量等指标的关系，从不同树轮指标层次，揭示杉木不同地理种源生长对气候变化的响应差异，揭示气候变化对杉木生长的影响。以不同种源树轮资料研究气候变化对树木生长的影响在国内尚无报道，而结合探讨不同种源树轮多层次指标对气候变化的响应在国内外亦属首创。项目成果将可为我国未来气候变化条件下种源层面上森林资源的培育起到重要指导作用，并为林业应对气候变化制定对策提供依据。

造林树种种源选择已成为人类应对气候变化的重要途径。项目运用树木年轮气候学分析方法，基于设置于南亚热带广西柳州33年生杉木全国种源试验林，研究了52个杉木地理种源整轮宽度、早材宽度、晚材宽度、早材密度、晚材密度、最小早材密度和最大晚材密度等7个树轮指标对温度和降水量月值与年值数据的响应，进而揭示了30个杉木地理种源树轮α纤维素中δ13C对温度及湿度等气候因子月值的响应差异，发现：(a) 不同树轮指标对气候敏感程度不同，树轮宽度年表相对于树轮密度年表敏感度更大；整轮宽度及最大晚材密度与气候因子相关最紧密；上年7月和当年8月温度、年平均温和年最高温是影响整轮宽度生长的关键气候因子，而当年4月的降水量是影响最大晚材密度生长的关键气候因子；(b) 基于上年7月和当年8月温度构建的整轮宽度的双因素响应函数具有最高的模拟精度，可解释树轮宽度生长变异的38.3%；(c) 大部分种源树轮α纤维素中δ13C受到8月平均相对湿度及上一年7月最低气温的影响达显著，贡献量为15.2%- 59.1%；(d) 不同种源整轮宽度随温度的升高呈差异化的下降趋势，如未来温度升高1℃，杉木不同种源树轮宽度生长量将平均下降18.5%，且中亚热带中心产区生长量较高的种源受温度升高的影响相对更大；(e)筛选出江西遂川、湖南双牌、广东广宁等15个未来气候变化下南亚热带可供选择的高或较高生产力种源。项目共发表项目标注相关国内科技论文7篇，其中SCI 5篇。主要成果为首次我国主要造林树种种源层面气候变化响应研究的展示，对杉木未来气候变化条件下重要分布区南亚热带杉木造林种源选择具有重要指示依据，可我国为林业应对气候变化制定对策提供可靠数据依据。