石梓幼林生长与立地因子的关系

THE INVESTIGATION AND ANALYSIS ON SITE CONDITION AND GROWTH OF GMELINA ARBOREA

试验和调查研究表明:北纬23°30′以南为石梓适生地区,其年平均气温20.5—24.5℃,极端最低温>-1.5℃,年降水量1200—2200mm。适宜的生境为地形开阔、阳光充足的静风环境(旬平均风速<<2m/s)。要求土壤疏松、表层有机质>2％,全氮>0.1％,速效磷>0.25mg/100 g土,pH值4.5—6.9,土壤含水率10—24％。不同植被类型和不同坡位上的石梓幼林生长差异达显著水平。经相关分析,在一定范围内,石梓的生长与土壤pH值、水分、养分(N、P)的关系分别成显著和极显著的直线、幂函数、指数函数和S型曲线正相关。其中与速效磷的关系更密切。

The result of investigation and analysis showed that, the tropical and the south-subtropical below 23.5°N in China, the annual mean temperature is 20.5-24.5℃ the extreme minimum temperature>-1.5℃, the mean annual rainfall 1200-2200mm, is the most suitable region for growth of Gmelina arborea. It demands the habitat with topography wide, sunshine abundance, gentle breeze (the ten days average wind speed<2 m/second), loose soil structure, humus content>2%, total nitrogen>0.l%, available phosphate >0.25mg/100g soil, pH 4.5-6.9, moisture content 10-24% of the surface layer soil. The growth effect of young plantation is significantly different in different kinds of vegetation types and slop position. The results of correlation analysis showed, in a certain range, that the growth of Gmelina arborea has respectively extremely significant positive correlation of linearity, power function, exponential function and S curve with pH value, moisture content, nutrient(N,P), but the available phosphate is a more important factor for the tree growth than the others.