保留密度对油松飞播林生长的影响

以丹凤县流岭林场的标准地调查资料为依据，采用测树学方法，研究了不同保留密度和不同坡向对油松飞播林生长的影响。结果表明，保留密度的变化对树高生长影响不大，对林分胸径和单株材积的生长影响显著。在阳坡，当保留密度为2800—6300株／hm2时，胸径年均生长量为0．36-0．28cm，单株材积生长量为0．00124-0．00062m3；在阴坡，当保留密度为l125-5306株／hm2时，胸径年均生长量为0．54-0．33cm，单株材积生长量为0．0036-0．00098m3，呈现出随保留密度增加而减小的趋势；在相同立地条件下，阴坡较阳坡生长好。

Effect of Reserve Density on Growth of Aerial Seeding of Pinus tabulaeformis

The effect of reserve density and exposure on the aerial seeding forests of Pinus tabalaeformis were studied according to the investigating data of standard site of Liuling forestry centre in Danfeng-county. The results showed that the effect of the reserve density on the diameter and volume of individual tree were obvious. When the reserve density were 2 800 - 6 300 tree/hm2, the annual average growth of diameter and volume of individual tree were 0.36 ~0. 28 cm and 0. 001 24 ~0.000 62m3 respectively at south - facing slope. When reserve density were 1 125-5 306 tree/hm2, the annual average growth of diameter and volume of individual tree were 0.54 ~0.33 cm and 0.003 6 ~0.000 98 m3 respectively at north-facing slope. Meanwhile, the growth at north-facing slope was better than that of south-facing slope.