内蒙古大青山前坡油松人工林生长特征研究

以内蒙古大青山前坡38 a生、17 a生油松人工林为研究对象,对林分生长特征、部分立地因子特征进行调查分析,研究造林立地因子对人工林生长的影响。结果表明:(1)38 a生油松人工林平均树高、胸径和冠幅分别为7.36 m、9.8 cm和261.1 cm;17 a生油松人工林平均树高、胸径和冠幅分别为2.86 m、8.1 cm和209.5 cm。(2)在林分密度相近时,38 a生油松人工林不同坡位平均树高、胸径、冠幅大小顺序均为:下坡位>上坡位;在不同坡向,上述指标大小顺序为:北坡>东坡>西坡>南坡,且相互之间差异显著(P<0.05)。(3)林地土层厚度和土壤砂砾含量通过改变水分和养分物质储量对油松生长产生影响。以南坡为代表的阳坡平均土层厚度83.9 cm,砂砾含量58.9%,以北坡为代表的阴坡平均土层厚度53.6 cm,砂砾含量为42.0%,不同坡向之间的差异极显著(P<0.01)。土壤含水率随砂砾含量的增加而降低,且相关性显著(P<0.05)。(4)38 a生油松林分密度在<2000株·hm-2或>2700株·hm-2时,平均树高、胸径均低于2300株·hm-2。因此,在今后林分经营过程中应对高密度林分加强抚育间伐,优化林分结构,提高林分生产力和生态功能。

Study on Growth Characteristics of Pinus tabuliformis Plantation in Forward Slope of Daqing Mountains in Inner Mongolia

In this paper,taking 38-year-old and 17-year-old Pinus tabuliformis plantation in Daqing Mountains in Inner Mongolia as research object,the influences of site factors on the plantation growth were studied through investigating the characteristics of stands growth and some site factors.The results show that:(1)For 38-year-old Pinus tabuliformis plantation,the average height,DBH and crown width were 7.36 m,9.8 cm and 261.1 cm,and for 17-year-old Pinus tabuliformis plantation,they were 2.86 m,8.1 cm and 209.5 cm.(2)For 38-year-old Pinus tabuliformis plantation,when the stand density was similar,the average height,DBH and crown width in lower slope were higher than that in upper slope.The order of average height,DBH and crown width in different slope aspects was north slope>east slope>west slope>south slope,with significant diffe-rence between each other(P<0.05).(3)Soil thickness and coarse sandstone content influenced the growth of Pinus tabuliformis through changing water and nutrient reserves.On sunny slope,the average soil thickness was 83.9 cm,the gravel content was 58.9%.On shady slope,the average soil thickness was 53.6 cm,the gravel content was 42.0%.There was extremely significant difference among different slope aspects(P<0.01).The soil moisture content decreased with the increase of gravel content,with significant correlation(P<0.05).(4)When the stand density of 38-year-old Pinus tabuliformis plantation was lower than 2000 plants·hm-2 or higher than 2700 plants·hm-2,the average tree height and DBH were lower than that with stand density at 2300 plants·hm-2.Therefore,in the high-density forest stand,it should strengthen tending thinning,optimize stand structure,improve stand productivity and ecological function during management in future.