丹凤县油松飞播林间伐后胸径结构和蓄积变化初探

本文以丹凤县1975年飞播的油松林为对象,研究不同间伐强度(4个梯度)间伐前及间伐6年后,油松蓄积量和直径结构的变化规律,结果表明:(1)与对照相比,间伐后的油松飞播林生长状况、林分内部竞争等都有显著的改善;(2)在株数间伐强度为50%时,林分内的竞争及生长状况达到最优;(3)当以50%的强度开展森林抚育时,抚育间隔期应控制在5年以上;(4)初始林分密度对经营效果有显著影响,因此,在确定抚育间伐强度时,应充分考虑林分初始密度。

The Volume and DBH Variation after Thinning in Aerial Seeded Forest of Pinus tabulaeformis in Danfeng County of Shaanxi

Aerial seeded forest in 1975 at Danfeng was the research subject and their growing before thinning and 6 years after thinning(four thinning intensities applied)were observed.The result showed that 1)the stands after thinning performe better in growth and inter-stand competition in comparison with stands before thinning;2)the stands after thinning intensity at 50%performe extremely well in inter-stand competition and growth;3)when thinning intensity is at 50%,the interval period for tending is expected to be 5years or above;4)initial density of stand has an impact on the management effect,indicating that the initial density should be considered in the calculation of thinning intensity.