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首页> 外文期刊>Allgemeine Forst und Jagdzeitung >Stand dynamics after variable-retention harvesting in mature Douglas-Fir forests of Western North America
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Stand dynamics after variable-retention harvesting in mature Douglas-Fir forests of Western North America

机译：在北美西部成熟的道格拉斯冷杉森林中保留保留量后的林分动态

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The Demonstration of Ecosystem Management Options (DEMO) study was established in mature Douglas-fir (Pseudot-suga menziesii (Mirb.) Franco) forests to test the effects of varying levels and patterns of residual trees on various forest taxa and standdynamics. Six treatments were implemented in 1997 or 1998 on 13-ha treatment units at each of six blocks in western Oregon and Washington, USA. Treatments were specified by the following levels and patterns of retained basal area: 100% retention, 75% aggregated retention, 40% dispersed retention, 40% aggregated retention, 15 % dispersed retention, and 15 % aggregated retention. By summer of 2003, annualized cumulative mortality of retained trees was significantly higher in 15% vs. 40% and in 15% dispersed vs. 15 % aggregated retention. Retained trees failed to show any acceleration of growth in stem volume 4 or 5 yr after harvest. Four- and five-year mortality of planted seedlings was significantly greater under 40% than 15% retention for ponderosa pine (Pinus ponderosa Dougl. ex. Laws), but did not differ among treatments for Douglas-fir. In 2002, height growth of planted seedlings was generally least under 40% dispersed retention and was greater under aggregated than dispersed retention. In 2002, height growth of advance regeneration of white fir (Abies concolor (Gord. & Glend.) Lindl. ex. Hildebr) and Pacific silver fir (Abies amabilis Dougl. ex Forbes) was greatest under 15 % retention. Continuing wind damage in 15 % dispersed retention and suppression effects of overstory trees in 40% dispersed retention may complicate attainment of vigorous two-layered stands.
机译：在成熟的道格拉斯冷杉（Pseudot-suga menziesii（Mirb。）佛朗哥）森林中建立了生态系统管理选择论（DEMO）研究，以测试残留树的不同水平和样式对各种森林分类和林分动态的影响。 1997年或1998年在俄勒冈州西部和美国华盛顿的六个区块中的每个区块的13公顷处理单元上实施了六种处理方法。通过以下保留基底面积的水平和模式来指定治疗：100％保留，75％聚集保留，40％分散保留，40％聚集保留，15％分散保留和15％聚集保留。到2003年夏季，保留树木的年累积累积死亡率显着提高，分别为15％对40％和15％分散对15％的总保留。保留后的树木在收获后4年或5年未能显示出茎体积的任何加速增长。在40％以下，种植的幼苗的4年和5年死亡率比黄松的保持力（15％的黄松）更显着高于15％，但道格拉斯冷杉的处理方法之间没有差异。在2002年，种植的幼苗的高度增长通常在40％的分散保持力下最少，而在聚集的条件下要大于分散的保持力。在2002年，白杉（Abies concolor（Gord。＆Glend。）Lindl。ex。Hildebr）和太平洋银杉（Abies amabilis Dougl。ex Forbes）提前再生的高度增长在15％的保留下最大。风在15％的分散保留中持续受到损害，而过高的树木在40％的分散保留中的抑制作用可能会使获得旺盛的两层林分变得困难。

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