摘要
以祁连山北坡海拔2 700m(分布下限)、3 000m(中部)和3 300m(分布上限)的青海云杉为研究对象,采用长短两种不同步长的样条函数去趋势对1952～1980年和1981～2009年两个时段青海云杉径向生长与气候的关系进行对比分析,以揭示青海云杉年轮中包含的不同频率生长趋势与气候之间的关系及其在海拔梯度上的差异,探讨海拔梯度上气候变化对树木径向生长的影响。结果显示:(1)随着海拔升高,限制青海云杉径向生长的气候因子从降水转变为温度,不同时期的限制因子也发生变化。(2)在海拔2 700m处,上一年12月份平均温度与青海云杉生长的关系发生了分异,小步长的样条函数得到的年表中保留了较多降水信号;海拔3 000m处青海云杉径向生长与上年9月份降水量、平均温度表现出显著正相关关系;海拔3 300m处青海云杉生长与当年夏季降水量呈显著正相关关系,而在后一时段相关关系不显著,与当年春季、夏季的平均温度相关关系不稳定,大步长的样条函数得到的年表中表现出温度与生长关系的分异,且不同海拔青海云杉径向生长的降水量制约趋势变得明显。研究表明,祁连山北坡青海云杉与气候的关系在海拔梯度上存在差异,其对气候变化的响应也存在差异,水分的限制作用随着温度的逐年升高逐渐突出;采用不同步长的样条函数去趋势可以在年表中保留不同的气候信息,从而对分异现象分析结果产生影响,选择合理步长的样条函数进行去趋势才能得到合理准确的分析结果。
Climate change not only affect the growth of trees but also lead the relationship changing between the growth and climate, many studies had focus on the growth-climate relationship divergence phenomena, while standardization methods also effect this relationship. So to understand the influence of standardization methods on the divergence phenomena in different distributed altitudes, we tested the relationship stability of growth-climate by comparing relationship between the climate and the tree-ring width chronologies in two paired of Picea crassifolia in different elevations by different bootstrap cubic spline detrending meth-ods. （1）With the raising elevation,limited climate factor of P. crassiiJozza raalat growm bm^L~ ~, ture to thermals. （2）At the altitude of 2 700 m, relationship between the radial growth and mean tempera- ture of last December had undergone differentiation, standard chronology fitted by short bootstrap spline retained more precipitation signals;at altitude of 3 000 m, positive correlation of radial growth with mean temperature and precipitation in September of previous year was becoming more significant;at the altitude of 3 300 m,positive correlation between radial growth and precipitation of current Summer in the latter pe- riod was no longer significantly,while positive correlation between radial growth and temperature of cur- rent Spring and Summer was obviously changed. The short bootstrap spline detreding method highlighted the precipitation signal in 2 700 m,while the long bootstrap highlighted the temperature signals in 3 300 m. All the results indicated that divergence phenomena were effect by the climate signals in the chronologies which was heavily depending on the detrending methods. That suggested it was necessary to choose a suit- able spline bootstrap in growth divergence phenomenon studies.
出处
《西北植物学报》
CAS
CSCD
北大核心
2012年第12期2518-2529,共12页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家科技支撑计划(2011BAD38B00)
国家林业局林业公益性行业科研专项(200804001)
关键词
气候变化
海拔
去趋势
分异问题
青海云杉
年轮
climate change
elevation gradient
detrending methods
divergence problem
Picea crassifolia tree-ring
