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近年来,国际上由于工资水平的提高和劳动力的缺乏,从而普遍采用低密度控制,即加大造林株行距,加大疏伐强度、减少疏伐次数,以提高林分质量,提前获得收益。杉木(Cunninghamia lanceolata Hook)是我国重要用材树种,生产中通常采用多次下层间伐方式。本文对杉木中幼林一次性间伐的合理保留密度即主伐密度以及深抚的有效性进行了研究。一、试验地概况试验是在江西大岗山山下林场陂元Ⅰ区杉木人工林中进行的。地理坐标为114°36’E、27°42’N,地处中亚热带东部罗霄山北端武功山余脉,海拔130-220m,属丘陵山地。土壤为页岩上发育起来的黄红壤,土层厚度为80-150cm,腐殖质层(A+AB)厚度约为25cm。土壤容重为1.2(g/cm~3)左右,pH值为4.4-4.8,有机质含量约为2.5％。气候属中亚热带湿润型,具有四季分明,气候温和,日照充足,雨量充沛的特点:年均降雨量1590.9mm,降雨量集中分布在4-6月,占全年降雨量的45％,年均蒸发量1503.8mm,相对湿度80％,1月平均最低温度-5.3℃,无霜期270天左右。主要林下植被为:杜茎
In recent years, due to the improvement of wages and the lack of labor force in the world, low-density control is generally adopted, that is, increasing the row spacing of silvicultural trees, increasing the thinning intensity and reducing the frequency of thinning in order to improve the quality of forest stands and obtain benefits in advance. Chinese fir (Cunninghamia lanceolata Hook) is an important timber species in our country. In this paper, the reasonable reserve density of primary thinning of young and middle-aged Chinese fir, that is, the primary densification density and the effectiveness of deep sowing were studied. First, the general situation of the test The experiment was carried out in the Chinese fir plantation of Yuan Ⅰ district in the forest farm, Dagangshan, Jiangxi Province. Geographic coordinates of 114 ° 36’E, 27 ° 42’N, is located in the northern subtropical eastern Mount Luosuoyu Wugongshan vein, 130-220m above sea level, is a hilly mountain. The soil is yellow-red soil developed on shale with a soil layer thickness of 80-150 cm and a humus layer (A + AB) of about 25 cm. Soil bulk density is about 1.2 (g / cm ~ 3), pH value of 4.4-4.8, organic matter content of about 2.5%. The climate is subtropical humid type, with four seasons, mild climate, adequate sunshine, abundant rainfall characteristics: the average annual rainfall of 1590.9mm, rainfall concentrated in April-June, accounting for 45% of the annual rainfall, the average annual Evaporation of 1503.8mm, relative humidity of 80%, January average minimum temperature of -5.3 ℃, frost-free period of 270 days. The main understory vegetation is: stems and tubers