Key Message A model describing species composition, density and diameter distribution of saplings was developed from operational inventory data. It could be used as an input into growth models calibrated exclusively with merchantable trees to correct some recruitment bias. Important differences in distributions were found between plantations and naturally regenerated stands. Longer-term monitoring would be required to observe the effects of thinning treatments on saplings. Context Saplings play important ecological and structural roles in forest stands. They also constitute the pool of candidate trees that are responsible for recruitment of merchantable sized trees. However, sapling information is often absent from regular inventory measurements (e.g. where no saplings are measured) even though they could be used as inputs in predicting recruitment in merchantable trees. Aims The objectives were to develop models describing density and diameter distribution of saplings from operational inventories, e.g. having only merchantable tree inventory, and to evaluate how stand type (naturally regenerated stands and plantations) and various thinning treatments influence these distributions. Methods Using data from both white spruce ( Picea glauca [Moench] Voss) plantations and naturally regenerated balsam fir ( Abies balsamea (L.) Mill.) stands having been commercially thinned, a zero-inflated poisson regression was used to model the stand density and a gamma regression to predict the two parameters of the Weibull used to characterize the diameter distribution. Results Despite the fact that the operational inventory data is often limited (e.g. species, dbh, height), the accuracy of the models was good and unbiased. It could be integrated into growth models to complete missing sapling distributions and help to correct some recruitment bias. Important differences in species composition, density and diameter distribution were found between plantations and naturally regenerated stands, but only a moderate response in diameter distribution was observed with thinning treatments. Conclusion These models will enable managers to estimate saplings in intermediate aged softwood forests of eastern Quebec using harvesting inventories or National Forest Inventory. Characterization of differences between plantations and naturally regenerated stands will be useful for integrating intensive plantation silviculture with ecosystem-based management. Longer-term follow-up would be needed to better evaluate the effects of thinning treatments.

中文翻译：

---

在采用各种商业间伐方法后，魁北克自然再生和种植的针叶林中树苗的密度和直径分布

关键信息 描述树苗的物种组成、密度和直径分布的模型是根据操作清单数据开发的。它可以用作专门用可销售树木校准的增长模型的输入，以纠正一些招聘偏见。在人工林和自然再生林之间发现了重要的分布差异。需要长期监测以观察间伐处理对树苗的影响。背景 树苗在林分中发挥着重要的生态和结构作用。它们还构成负责招募适销型树木的候选树木库。然而，常规库存测量中通常缺少树苗信息（例如 在没有测量树苗的情况下）即使它们可以用作预测可销售树木的补充量的输入。目标 目标是开发描述操作库存中树苗密度和直径分布的模型，例如只有可销售的树木库存，并评估林分类型（自然再生林分和人工林）和各种间伐处理如何影响这些分布。方法 使用来自白云杉 ( Picea glauca [Moench] Voss) 种植园和已进行商业间伐的自然再生香脂冷杉 (Abies balsamea (L.) Mill.) 林分的数据，使用零膨胀泊松回归对林分密度进行建模和 gamma 回归来预测用于表征直径分布的 Weibull 的两个参数。结果 尽管操作清单数据通常是有限的（例如物种、dbh、高度），但模型的准确性良好且无偏差。它可以集成到增长模型中以完成缺失的树苗分布并有助于纠正一些招聘偏差。在人工林和自然再生林之间发现了物种组成、密度和直径分布的重要差异，但在间伐处理中仅观察到直径分布的适度响应。结论 这些模型将使管理人员能够使用采伐清单或国家森林清单估算魁北克东部中龄针叶林中的树苗。表征人工林和自然再生林分之间的差异将有助于将集约化人工林造林与基于生态系统的管理相结合。需要更长期的随访以更好地评估细化治疗的效果。