立地土壤水分对脂松人工幼林生长的影响1）

在帽儿山地区引种栽培的12年生脂松试验林中，设立上、中、下坡位3种常规尺度立地类型及设立凹地、凸地、伐桩附近、平缓坡地（对照）4种微立地类型，研究立地、微立地土壤水分物理性质变化对脂松林木生长的影响。结果表明：①立地、微立地对土壤水分物理性质有显著影响（ p＜0．05），土壤含水量从大到小依次为：下坡位、中坡位、上坡位；凹地、伐桩、对照、凸地。②上坡位脂松生长最好，胸径（5．7 cm）分别比中、下坡位高11．8％（p＜0．05）和29．6％（p＜0．05）；树高（4．3 m）分别比中、下坡位高3．1％（p＞0．05）和14．5％（p＜0．05）。③与对照相比，凸地有利于脂松生长，凹地和伐桩对脂松生长产生负影响。凸型微立地上，脂松胸径、树高略高于对照（ p＞0．05）；而凹型微立地上胸径、树高分别比对照低40．5％（ p＜0．05）和24．9％（ p＜0．05）；伐桩附近微立地上，脂松胸径、树高略低于对照（ p＞0．05）。含水量过高不利于脂松的生长，脂松造林应选择排水良好的上、中坡位；种植点的配置上，应避开容易产生季节性积水的凹地。

Effect of Soil Moisture under Different Site/microsite Conditions on Growth of Young Pinus resinosa Plantation Stand

We set downhill , middle solpe and upperhill sites , and concave , convex , close to stump microsites and reference within middle slope site in a 12-year-old red pine plantation stand at Maoershan Experimental Forest Farm .We detected the Variation in soil moisture and physical properties between different sites and microsites .The moisture content of soil on dif-ferent slope positions was in an descending order of downhill , middle slope, and upperhill.The ranking of moisture content of soil within microsites was in an descending order of concave , close to stump , reference , and convex .The greatest growth of red pine trees was with trees on the upperhill site , with DBH (5.7 cm) of 11.8%(p<0.05) and 29.6%(p<0.05) grea-ter, and height (4.3 m) of 3.1%(p>0.05) and 14.5%(p<0.05) greater than those on middle slope and downhill sites , respectively .Compared with reference microsite , the convex microsite had greater tree growth , while concave and close to stump microsite had a negative effect .Tree DBH and height on convex microsites were slightly greater ( p>0.05) than those on reference microsites , while compared with concave microsites they were significantly lower .The tree growth on close to stump microsite was also lower than that on reference microsites ( p>0.05) .The relatively high soil moisture content retard-ed the red pine growth in this area .The upperhill and the middle-slope site with good drainage are suitable site for the es-tablishment of red pine plantation in this area .Avoiding concave microsite which would produce timely waterlogging will benefit tree growth .