Multi-cohort forest management in northern hardwood stands may well be the best way to successfully regenerate tree species of intermediate shade tolerance, such as yellow birch (Betula alleghaniensis Britt.). The creation of large enough gaps in the canopy favors increased light availability within the opening, while soil scarification provides suitable germination seedbeds. Evidence of these methods’ success nonetheless remains mostly the purview of experimental studies rather than operational tests. In Quebec, Canada, the multi-cohort methods promoted include group selection cutting and patch cutting. The present study tested their implementation at an operational scale and over a large territory in both hardwood-dominated and mixedwood stands. We assessed their efficacy in promoting natural regeneration of commercial hardwood trees, notably yellow birch and sugar maple (Acer saccharum Marsh.). We conducted regeneration surveys at 2, 5, 10, and 15 years after harvest. Overall, group selection and patch cuttings were successful in regenerating the target species. Yellow birch, for instance, showed a mean stocking around 60% and a mean sapling density around 3400 stems ha⁻¹ after 15 years. We compared several variables for measuring regeneration in early years, and found that the relative abundance, the stocking based on one stem per sampling unit, and the mean maximum height were good predictors of the relative presence of yellow birch and sugar maple in 15-year-old canopy openings. Using smaller sampling units (6.25 m² rather than 25 m²) and waiting until year 5 may be more useful for making such predictions. In addition, there was an important turnover in vertical dominance in these openings. Non-commercial woody competitors were frequently dominant in early years but were often replaced by commercial hardwoods, notably yellow birch. We propose certain thresholds for assessing the success of post-harvest regeneration and for evaluating the need for a cleaning treatment.

中文翻译：

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评估北部阔叶林和混交林林分的采后更新：15年种群选择和斑块切割中物种组成和优势的演变

北部硬木林分的多队列森林管理很可能是成功再生中等耐荫性树种的最佳方法，例如黄桦（Betula alleghaniensis）布里特。）。在冠层中形成足够大的间隙有利于增加开口内的光利用率，而土壤稀疏化则提供了合适的发芽苗床。这些方法成功的证据仍然主要是实验研究而不是操作测试。在加拿大魁北克，推广的多队列方法包括群体选择切割和斑块切割。本研究测试了在硬木为主和混合木林分中的操作规模和大范围的实施情况。我们评估了它们在促进商品阔叶树（尤其是黄桦树和枫木树）（Acer saccharum）自然再生方面的功效。沼泽。）。我们在收获后的2、5、10和15年进行了再生调查。总体而言，群体选择和patch插插枝成功地再生了目标物种。例如，黄桦在15年后的平均放养量约为60％，平均树苗密度约为3400公顷ha ^{- 1}。我们比较了早期测量再生的几个变量，发现相对丰度，基于每个采样单位一个茎的放养量和平均最大高度是15年黄桦和糖枫相对存在的良好预测指标老树冠开口。使用较小的采样单位（6.25 m ²而不是25 m ²），直到5年级可能对做出此类预测更为有用。此外，这些空缺在垂直优势方面有重要的转变。早年，非商业性的木本竞争者通常占主导地位，但通常被商业硬木（尤其是白桦树）取代。我们提出了一些阈值，用于评估收获后再生的成功和评估清洁处理的必要性。