樟子松和落叶松径向生长对气候变化的响应

Responses of radial growth of Pinus sylvestris var.mongolica and Larix gmelinii to climate change

在全球变暖的背景下,升温可能会影响树木的生长,导致森林生态系统的平衡受到干扰。本研究利用树轮年代学方法中的生长-气候响应函数、滑动相关分析,探讨大兴安岭漠河地区樟子松和落叶松径向生长的限制因子,以及二者径向生长对快速升温的响应。结果表明:樟子松和落叶松的径向生长受温度和降水的共同作用,樟子松对气候变化的响应比落叶松更为敏感,对气候因子的敏感性比落叶松更稳定。樟子松径向生长与当年生长季月均温及月均最低温呈显著正相关,而落叶松与冬季月均温及月均最高温呈显著正相关。冬季降水促进樟子松生长,前一年生长季后期降水抑制落叶松的径向生长。1990年快速升温后,降水对樟子松的限制作用由升温前的负相关转变为升温后的显著正相关,高温对樟子松的抑制作用大于促进作用;高温对落叶松的抑制作用增强,降水对落叶松的限制作用也在升温后增强,生长速率显著下降,二者生长速率与温度和降水的相关性变化存在明显差异。本研究可为大兴安岭森林生态系统管理与保护提供科学依据。

In the context of global warming,the increases of temperature may affect tree growth and thus disturb ecosystem balance.In this study,we explored the main limiting factors for radial growth of Pinus sylvestris var.mongolica and Larix gmelinii in the Mohe area of Greater Khingan Mountains by using growth-climate response function analysis and moving correlation analysis,as well as the interspecific difference of the responses of radial growth to rapid warming.The results showed that the radial growth of P.sylvestris var.mongolica and L.gmelinii was affected by both temperature and precipitation.P.sylvestris var.mongolica was more sensitive to climate change than L.gmelinii,and its sensitivity to climate factors was more stable than L.gmelinii.The radial growth of P.sylvestris var.mongolica was significantly positively correlated with the monthly mean temperature and the monthly mean minimum temperature of the growing season,while that of L.gmelinii was significantly positively correlated with the monthly mean temperature and the monthly mean maximum temperature of winter.Precipitation in winter promoted the growth of P.sylvestris var.mongolica,whereas precipitation in the late growing season of the previous year inhibited the radial growth of L.gmelinii.After the rapid warming in 1990,the limiting effect of precipitation on P.sylvestris var.mongolica changed from negative to significantly positive,with the inhibition effect of high temperature being greater than the promotion effect.The inhibitory effect of high temperature on L.gmelinii was enhanced,and the limiting effect of precipitation on L.gmelinii was also enhanced after heating up.The growth rate decreased significantly,with obvious difference being observed in the correlations between the growth rate of two species with temperature and precipitation.Our results could provide scientific basis for forest ecosystem management and protection in Greater Khingan Mountains.