南方型杨树引种区划的研究

<正>应用逐步回归方法,通过电子计算机分析南方型杨树三个无性系的树高和胸径生长量与当地21个组合气象因子的相关性。结果表明,引起生长差异的主导生态因子为年平均温度(x_1),极端最低温度(x_3),寒冷指数(x_8),日均温≥10℃积温(x_9),年降水量(x_(10))和无霜期(x_(14))。经逐步回归组建的最佳方程如下: lnY_H=4.12201-0.37742x_1-0.12085x_3+0.08949x_8+0.00096x_9 +0.00729x_(20) (R_(y12m)=0.93,F=13.57,I-69/55) lnY_H=1.56430-0.17273x_3 + 0.01334x_6-0.02141x_7 + 0.054196x_8 +0.00103x_9+0.00075x_(10)-0.00453x_(14) (R_(y12m)=0.95,F=10.19,I-72/58) 以此为依据,运用模糊数学方法,计算46个站的六个气候要素与固定样本(湖南汉寿)之间的相似程度。最后按和数值“S”的大小,结合南方型杨树的生态学特性,划出3类适宜引种区和1个不适宜引种区。

THE DIVISION OF REGIONS FOR THE INTRODUCTION OF SOUTHERN TYPE PUPLARS

This paper studies the correlation between the growth in length and thickness of three puplar clones and the local climatic factor combinations. Results of tests showed that the leading ecological factors giving rise to the variation of growth are ths annual average temperature, minimum temperature, accumulated temperature (≥10°C), cold index, annual precipitation and frost-free period. By means of successive regression, the optimum equations worked out for growth of the clones are as followes: 1nYH=4.122007-0.374162X1-0.120849x3+0.08949lX8 + 0.000963X9+0.007288X20 (Ry12m=0.93, F=13.57, I-69/55) 1nYH=1.564302-0.172733X3+0.013341Xe-0.021414X7+ 0.054196X8+0.00103X9+0.000748X10-0.004527X14 (Ry12,=0.95, F=10.19, I-72/58)On the basis of these results, the similarity levels between the six climatic factors at each of the forty-six experimental sites and those of the fixed sample site in Hanshou, Hunan were compared by the method of Fuzzy Mathematics. According to the value"S", the regions for the introduction of the southern type popular, can bs divided into four types: optimum area, favourable area, suitable area and unsuitable area as is described in the discourse.