This study showed that regeneration success (presence of oaks ≥ 150 cm in total height) in artificial canopy openings of a mature mixed sessile oak stand was mainly driven by initial oak seedling density. Small-scale harvesting methods as practiced in close-to-nature forestry may disadvantage the regeneration of more light-demanding tree species including sessile oak (Quercus petraea [Mattuschka] Liebl.) and thus cause regeneration failure. However, owing to the short-term nature of many previous studies, regeneration success of sessile oak could not be properly ascertained. This study examined oak seedling development over a time period of ten growing seasons in canopy openings of 0.05 to 0.2 ha in size created through group selection harvesting in a mature mixed sessile oak forest in southwestern Germany. We tried to answer the following research questions: (i) how do initial stand conditions relate to and interact with oak seedling density and seedling height growth, and (ii) what are the driving factors of regeneration success under the encountered site conditions. We evaluated the influence of solar radiation, Rubus spp. cover, initial oak seedling density, and competition from other tree species on change in density and height of oak seedlings, as well as overall regeneration success (oak seedlings ≥ 150 cm in height). Regeneration success increased with initial oak seedling density and solar radiation levels and decreased with early Rubus spp. cover. Density and maximum height of oak seedlings was negatively related with competition of other woody species. Results of our longer-term study demonstrate that forest management activities to regenerate sessile oak naturally are only successful in stands (i) without advance regeneration of other woody species and without established, recalcitrant ground vegetation, (ii) with a sufficiently high initial oak seedling density in larger patches following mast years, and (iii) where periodic monitoring and control of competing woody individuals can be ensured. Our findings further corroborate the view that natural regeneration of sessile oak in small-scale canopy openings is possible in principle.

中文翻译：

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在无柄橡树 (Quercus petraea [Mattuschka] Liebl.) 林分群选收获 10 年后，幼苗发育和再生成功

该研究表明，成熟混合无柄橡木林分人工树冠开口的再生成功（橡树总高度≥150 厘米）主要是由初始橡树幼苗密度驱动的。在近自然林业中采用的小规模采伐方法可能不利于包括无柄橡树（Quercus petraea [Mattuschka] Liebl.）在内的对光照要求更高的树种的再生，从而导致再生失败。然而，由于许多先前研究的短期性质，无法正确确定无柄橡木的再生成功。本研究调查了橡树幼苗在 0.05 到 0.2 公顷大小的树冠开口的十个生长季节的发育情况，这些树冠开口是通过在德国西南部成熟的混合无柄橡树林中进行群体选择收获而形成的。我们试图回答以下研究问题：（i）初始林分条件如何与橡树苗密度和苗高生长相关并相互作用，以及（ii）在遇到的立地条件下再生成功的驱动因素是什么。我们评估了太阳辐射的影响，Rubus spp。覆盖率、初始橡树苗密度以及其他树种对橡树苗密度和高度变化的竞争以及整体更新成功率（橡树苗高度 ≥ 150 厘米）。再生成功率随着初始橡树幼苗密度和太阳辐射水平的增加而增加，而随着早期的悬钩子属种而降低。覆盖。橡树苗的密度和最大高度与其他木本物种的竞争呈负相关。我们长期研究的结果表明，自然再生无柄橡树的森林管理活动仅在 (i) 没有提前更新其他木本物种和没有建立的顽固地面植被，(ii) 具有足够高的初始橡树幼苗的林分中取得成功肥大年之后较大斑块中的密度，以及 (iii) 可以确保对竞争木本个体进行定期监测和控制。我们的研究结果进一步证实了小规模树冠开口中无柄橡木的自然再生原则上是可能的观点。(iii) 可以确保对竞争木本个体进行定期监测和控制。我们的研究结果进一步证实了小规模树冠开口中无柄橡木的自然再生原则上是可能的观点。(iii) 可以确保对竞争木本个体进行定期监测和控制。我们的研究结果进一步证实了小规模树冠开口中无柄橡木的自然再生原则上是可能的观点。