大兴安岭南段华北落叶松人工林径向生长对气候变化的响应

Response of Radial Growth of Larix principis-rupprechtii Plantation to Climate Change in Southern Part of Great Xing’an Mountains

【目的】华北落叶松是内蒙古大兴安岭南段主要的人工林树种,分析华北落叶松年轮宽度指数的变化以及与气象因子的相关性,以此判断华北落叶松人工林在大兴安岭南段地区的适应性,为可持续经营管理提供理论依据。【方法】赛罕乌拉是大兴安岭南段次生林的典型地段,并且是内蒙古最大的次生林区。在1986年种植的华北落叶松人工林区域内,按国际树木年轮库(ITRDB)的要求,2013年随机采集54棵华北落叶松108根树芯,其中死树14棵。运用树木年轮气候学方法,建立华北落叶松年轮宽度年表,利用相关函数分析1986-2013年的气温和降水气象因子与年表的相关性,揭示华北落叶松径向生长对气候响应规律。【结果】(1)华北落叶松径向生长与上一年5、7月的平均最高温和平均气温呈显著性负相关(P <0.05),与当年冬季11月的降水量具有显著性正相关(P <0.05),和其它月份也均成正相关但显著性不明显,表明华北落叶松主要受到冬季降水量的影响。(2)通过年轮与气象因子的响应分析得出,华北落叶松对气候的响应具有明显的"滞后性",具体表现为,干旱胁迫对当年树木的径向生长量影响不显著,对第2年树木的径向生长量影响显著。2006年发生极端干旱年,发生后的4年内华北落叶松发生死亡现象。【结论】大兴安岭南段华北落叶松人工林的径向生长主要受到当年冬季11月降水量的显著性影响。华北落叶松受到干旱胁迫时有明显的"滞后性",影响体现在第2年即形成窄轮。这可能意味着,随着未来干旱的加剧,冬季降水对华北落叶松的生长变得更加重要。

【Objective】Larix principis-rupprechtii is the main plantation species in the southern section of Great Xing’an Mountains of Inner Mongolia. By analyzing the change of ring width index of Larix principis-rupprechtii and its correlation with meteorological factors,to judge the adaptability of Larix principis-rupprechtii plantation in the southern section of Great Xing’an Mountains,and to provide theoretical basis for sustainable management.【Method】Saihanwula is a typical area of secondary forest in the southern section of Great Xing’an Mountains and is the largest secondary forest area in Inner Mongolia.According to the requirements of ITRDB,108 cores of 54 Larix principis-rupprechtii plantations were randomly collected in Larix principis-rupprechtii plantation area planted in 1986,which including 14 dead trees in 2013. The tree ring climatology method was used to establish the annual ring width chronology of Larix principis-rupprechtii. Use correlation function to analyze the correlation between meteorological factors of temperature and precipitation and the chronology from 1986 to 2013,which revealing the response of radial growth of Larix principis-rupprechtii to Climate.【Result】(1)The radial growth of Larix principis-rupprechtii was negatively correlated with the average maximum temperature and average temperature in May and July of the previous year(P < 0.05),and it was positively correlated with the precipitation in November of that year(P< 0.05). It was also positively correlated with other months,but not significantly,which indicated that Larix principisrupprechtii was mainly affected by winter precipitation.(2)Through the analysis of ring and meteorological,Larix principisrupprechtii for climate had obvious "hysteresis" characteristic. The effect of drought stress on the radial growth of trees was not significant in the first year and in the second year was significant. The death of Larix principis-rupprechtii occurred especially during the extremely drought year of 2006 to 2010.【Conclusion】The radial growth of Larix principis-rupprechtii plantation in the southern part of Great Xing’an Mountains was mainly affected by the precipitation in November. Larix principis-rupprechtii had obvious "hysteresis" under extremely drought stress,which was reflected in the second year formation of narrow rings.This may mean that winter precipitation will become more important for the growth of Larix principis-rupprechtii as drought intensifies in the future.