不同林龄、树种落叶松人工林径向生长与气候变化的关系

研究人工林径向生长与气候变化的关系对全球气候变暖背景下人工林合理经营有着重要的意义。该文对在辽东山区广泛栽培的黄花落叶松(Larix olgensis)和日本落叶松(Larix kaempferi)人工林, 运用树木年轮气候学方法建立了辽宁草河口和湾甸子林场落叶松人工林年表, 分析了落叶松径向生长对气候变化的响应以及气候条件、树种、立地条件和林分因子(林龄、密度、蓄积量等)的相对影响程度。结果发现在影响年轮-气候关系的因素中, 气象因子的潜在蒸发散(PET)的影响力最大; 林龄、密度和蓄积量同时也具有重要的影响作用。中龄落叶松人工林径向生长主要与气温呈正相关关系, 成熟落叶松人工林径向生长主要与气温呈负相关关系; 而其他因素, 如树种、立地条件等的影响作用不大。这表明在气候变暖背景下随着林龄增加, 林分会逐渐受到气温升高导致的水分亏缺的限制, 导致明显的生长下降趋势, 因而气候变暖对成熟落叶松人工林威胁更为严重, 所以要注重对成熟林的优先保护, 同时可以预测, 随着东北地区今后气候进一步变暖, 可能将逐步影响到林龄更小的林分的生长, 因此需要进一步研究如何在落叶松人工林经营中采取科学的措施来更好地应对未来气候变化。

Relationships of radial growth with climate change in larch plantations of different stand ages and species

Aims This study examined how climatic conditions, tree species and stand factors (i.e. stand age, stem density, and wood volume, etc.) affected the tree growth-climate relationships in larch plantations.Methods The dendroecological method was used to determine the relative effects of climatic condition, tree species, site quality and stand factors on tree growth in larch plantations in response to climate change in Caohekou and Wandianzi of Liaoning Province, China.Important findings The effects of potential evapotranspiration (PET) were strongest among all the variables in explaining the tree growth-climate relationships. Stand age, tree density and wood volume were also important factors influencing growth-climate relationships. Climate warming had differential effects on radial growth in plantations of different stand ages: while the growth of mid-age stands were positively correlated with temperature, the growth of mature stands had a negative response to warming, possibly due to increased susceptibility to warming-induced water stress with stand age. Tree species and site quality were weak modulators of growth- climate relationships in this study. Our finding of the negative impact of climate warming on mature larch plantations highlights the need to explore management methods in larch plantations for better adaptation to future climate change.