六盘山南侧华山松树干直径生长及其对气象因子的响应

2010年5—10月份,在宁夏六盘山南侧的香水河小流域,应用带状树木径向变化记录仪研究了华山松(Pinus armandii)树干的直径生长变化及其对气象因子的响应。结果表明:①华山松树干直径呈现出由收缩期、膨胀恢复期和生长期组成的日周期性变化,其最大值出现在6:00—9:00,最小值则在16:00左右。②华山松各样木树干直径日生长量的季节变化趋势一致,即:5-6月份为匀速生长期,其日均生长量在17.65～98.11μm之间;7-8月份为快速生长期,其日均生长量在27.15～112.33μm之间;8月底—10月份为缓慢生长期,其日均生长量在10μm以下。然而,华山松树干在匀速生长期、快速生长期内的直径日生长量幅度存在明显的个体差异,其中优势木的生长速度明显大于亚优势木和中等木。整个观测期内,华山松树干直径的累积生长过程符合幂函数曲线(R2=0.75～0.93,P<0.01)。③主成分分析和偏相关分析表明,日最低温、日降水量、日平均辐射是影响树干直径生长的主要气象因子,而日平均温度、日最高温、日平均饱和水汽压差等对树干径向生长的影响作用则表现出较大的变异性。

Stem diameter growth of Pinus armandii and its response to meteorological factors in the south of Liupan mountain

From May to October in 2010,the growth in stem diameter of three sample trees of Pinus armandii were measured by using band dendrometer,and its response to the meteorological factors was also determined in the south of Liupan mountain,Ningxia,China.The results showed that ① A daily course of stem change could be divided into three phases,i.e.,shrinking phase,expansion phase and growth phase.The maximum of stem diameter reached from 6:00 to 9:00 and the minimum value occurred about 16:00.② The seasonal pattern in the growth of daily stem diameter was consistent.Uniform growth period was from May to June,and the daily stem growth was ranged from 17.65 μm to 98.11 μm;and rapid growth period was from July to August,with the values ranged from 27.15 μm to 112.33 μm;but slow growth period was from August to October,with the values below 10 μm.Furthermore,the daily stem growth varied greatly among individual trees in the different social position in the stand.The rate of the stem growth for dominant trees was significantly higher than that of others.And the seasonal pattern of cumulative stem diameter growth could be satisfactorily described by the power function(R2=0.75-0.93,P<0.01).3) principle component analysis and partial correlation analysis indicated that the minimum daily temperature,daily precipitation and solar radiation were three main meteorological factors to influence daily stem growth in these trees,but other factors including the average daily temperature,the maximum daily temperature and the daily vapor pressure deficit showed a great variability in the influence to tree growth.