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首页> 外文期刊>Schweizerische Zeitschrift fur Forstwesen >Short time window for natural regeneration of spruce in coniferous mountain forests
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Short time window for natural regeneration of spruce in coniferous mountain forests

机译：针叶山地云杉自然更新的短时间窗口

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© 2021, Schweizerischer Forstverein. All rights reserved.Over the past 30 years, in a few places, Swiss coniferous mountain forests have been regenerated with clear-felling and not with small openings, as it is common with group selection management in mountain forests. The development of such openings after 13 to 29 years was examined in ten clear-cuts in south-eastern Switzerland and Ticino with aerial photo analysis and sampling inventories. Historical aerial photographs were used to assess stand history and crown cover before the harvest. The density of regeneration and the local site conditions including the cover of ground vegetation were recorded using sampling inventories. The density of the regeneration (trees between 10 cm tall and 12 cm diameter at breast height [dbh]) averaged 5450 stems/ha, of which 71% were Norway spruce. This high mean value came about through plots with very dense regeneration. Most of the spruce regeneration originated from post-harvest establishment, but 30% of the regeneration in the size class 130 cm to 12 cm dbh had established before harvesting. The pre-harvest regeneration was denser in plots in which the pre-existing stand had been thinned already. The highest densities of regeneration occurred in stands with medium to high crown cover before the harvest. Competing vegetation reduced the density of pre-and post-harvest regeneration. The presence of rotting wood and tree stumps was associated with a higher regeneration density, while browsing by ungulates was associated with a lower one. If there is little competing vegetation, the creation of a large opening is followed by a phase of favourable regeneration conditions during which regeneration is often successful. In contrast, on sites that tend to develop dense competing vegetation, regeneration establishes only slowly, and is dependent on rotting wood and tree stumps.
机译：© 2021 年，Schweizerischer Forstverein。保留所有权利。在过去的30年里，在一些地方，瑞士针叶山林已经通过砍伐进行再生，而不是像山地森林中的群体选择管理那样用小开口进行再生。在瑞士东南部和提契诺州的10个明确地带，通过航空照片分析和取样清单，对13至29年后这种开口的发展进行了检查。历史航空照片用于评估采伐前的林分历史和树冠覆盖率。使用采样清单记录了再生密度和当地场地条件，包括地面植被的覆盖情况。再生密度（胸高10厘米至直径12厘米的树木[dbh]）平均为5450茎/公顷，其中71%是挪威云杉。这种高平均值是通过再生非常密集的地块实现的。大多数云杉再生起源于收获后的建立，但30%的130厘米至12厘米胸径等级的再生是在收获前建立的。在已经疏伐的地块中，收获前的再生更密集。在收获前，树冠覆盖率中到高的林分的更新密度最高。竞争性植被降低了收获前和收获后再生的密度。腐烂的木材和树桩的存在与较高的再生密度有关，而有蹄类动物的浏览与较低的再生密度有关。如果竞争植被很少，那么在创造一个大开口之后，就会进入一个有利的再生条件阶段，在此期间，再生通常是成功的。相比之下，在倾向于发展茂密竞争植被的地方，再生只能缓慢建立，并且依赖于腐烂的木材和树桩。

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