承德市木兰围场不同强度间伐对油松人工林生长的影响

Effect of Various Intensities on the Growth of Pinus tabuliformis Plantation in Mulan Enclosure of Chengde City

以河北省承德市木兰围场北沟阳坡中龄油松人工林为研究对象,研究不同间伐强度下油松林的生长.结果表明随间伐强度增加,胸径和冠幅均呈现逐渐变大的趋势,但超强度间伐的胸径和冠幅均小于强度间伐.树高生长在强度间伐时最小.间伐有助于人工油松林的林分生长,且随着间伐强度的加大林分生长较好,但超强度的间伐并不一定是最合适的.调查地原密度1815株hm^-2的油松人工林,在保留密度900-1000株hm^-2时林分生长情况最好,这说明原密度1815株hm^-2的油松人工林最适宜中度到强度间伐,间伐最适强度为40%-50%.

Taking middle-aged Pinus tabuliformis plantation in sunny slope of north ditch in Mulan Enclosure of Chengde City in Hebei Province as research objects,growth of Pinus tabuliformis under different thinning intensities were studied.Result shows that:diameter and crown show a progressively larger trend with the increase of thinning intensity,but DBH and crown with super thinning are less than that with thinning.Height growth is the minimum during great thinning.Thinning helps the growth of Pinus tabuliformis plantation;the growth of stand is optimal with the increase of thinning intensity.Super-strength thinning is not necessarily the most appropriate.Speaking for the investigation,the growth of Pinus tabuliformis plantation with original density (1 81 5 trees hm-2 )is the opti-mal under the reserved density being 900-1 000 plants hm-2 ;it is the most suitable for the original density(1 81 5 trees hm-2 )of Pinus tabuliformis to be conduct moderate thinning and great-intensity thinning,the optimal intensi-ty of thinning is from 40% to 50%.