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首页> 外文期刊>Forestry >Long-term effects of single-tree selection cutting on structure and composition in upland mixed-hardwood forests of the southern Appalachian Mountains.
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Long-term effects of single-tree selection cutting on structure and composition in upland mixed-hardwood forests of the southern Appalachian Mountains.

机译：单树选择砍伐对阿巴拉契亚山脉南部山地混合硬木森林的结构和组成的长期影响。

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In 1946, this study was initiated to examine the efficacy of single-tree selection cutting in submesic to mesic mixed-hardwood forests of the southern Appalachian Mountains. Seven stands comprising 40 ha of mixed-hardwood forests plus three unmanaged stands were utilized. Species composition of the overstorey prior to treatment was dominated by species intolerant and mid-tolerant of shade, including oak (Quercus L.) species and yellow-poplar (Liriodendron tulipifera L.). After 10 years of improvement cuttings, the BDq method of regulating stocking was employed. Selective cuttings occurred in 1956-1957, 1962, 1970, 1984 and 2006. Early observations suggested that control of shade-tolerant midstory species might be required to regenerate the mid-tolerant overstory species. In 1972, shade-tolerant species between the 5 and 20 cm d.b.h. classes present in small openings created during the 1970 entry were injected with herbicide in all seven managed stands. In 1986, another treatment which included the complete removal of the shade-tolerant midstory occurred in two of those seven stands. After 60 years, the majority of managed stands have diameter distributions other than the traditional reverse-J shape, including concave and rotated sigmoid shapes. Even after the treatment of shade-tolerant competitors, results suggest that single-tree selection has thus far been ineffective at recruiting the desirable tree species that are intolerant or mid-tolerant of shade. In fact, the density of mid-tolerant oak-hickory and shade-intolerant species in the sapling and pole size classes in the managed stands did not differ from that in unmanaged stands. As applied in this study, the BDq approach to single-tree selection cutting has led to the sapling and pole size classes being increasingly dominated by shade-tolerant species and is not likely to be sustainable, in terms of both desirable species composition and structure, in the long-term.
机译：1946年，这项研究开始了，以检验单树选择砍伐在阿巴拉契亚山脉南部亚中度至中度混合硬木森林中的功效。使用了包括40公顷混合硬木林的七个林分加上三个未经管理的林分。在处理之前，高层建筑的物种组成主要由不耐荫和中耐荫的物种主导，包括橡树（Quercus L.）和黄杨树（Liriodendron tulipifera L.）。经过10年的改良后，采用了BDq调节放养量的方法。选择性cutting插发生在1956-1957年，1962年，1970年，1984年和2006年。早期的观察表明，可能需要控制耐荫的中层树种才能再生耐中层的中层树种。 1972年，d.b.h在5至20 cm之间的耐荫树种。在所有七个管理的展位中，对在1970年进入时创建的小开口中出现的类进行了除草剂注射。 1986年，在这七个摊位中的两个摊位上进行了另一种处理，其中包括完全去除耐荫中间层。 60年后，大多数受管理的架子都具有除传统的反向J形以外的其他直径分布，包括凹形和旋转的S形。即使经过耐荫的竞争者的治疗，结果也表明，单树选择迄今在招募不耐荫或中耐荫的理想树种方面仍然无效。实际上，在管理林分的幼树和极尺寸等级中，中容忍的橡木山胡桃和不耐荫的树种的密度与未管理林分的密度没有区别。正如本研究中所应用的那样，BDq方法用于单棵树选择砍伐已导致树苗和树杆尺寸类别越来越多地由耐荫树种主导，就理想的树种组成和结构而言，这不太可能是可持续的，在长期。

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