Widely distributed in Quebec, balsam fir (Abies balsamea (L.) Mill.) is highly vulnerable to wind damage. Recently, there has been a trend in forest management to increase the use of partial cuttings in naturally regenerating stands, leaving the remnant trees at increased risk of wind damage. In order to limit wind damage after partial cuttings, it is therefore important to find silvicultural practices that minimize the risk of wind damage in these fir stands. Our main objective was to find balsam fir-specific values of parameters to integrate into the wind risk model ForestGALES, in order to simulate the impact of different types of commercial thinning on wind damage risk, and to determine which practice potentially minimizes the risk in a naturally regenerated stand. An anemometer placed at canopy height and strain gauges attached to the trunks of balsam firs allowed us to measure the wind-induced bending moments experienced by a sample of balsam fir trees. This enabled the calculation of the turning moment coefficients specific to each of the trees in order to compare them with the ForestGALES model predictions and to adapt the model for balsam fir stands. The model was tested first with only tree diameter and height as input variables to calculate the turning moment coefficient, then with the addition of a competition index, and finally with the addition of crown dimensions. Wind climate parameters for prediction of the probability of damage were calculated using the Wind Atlas Analysis and Application Program airflow model. The model with the highest accuracy was then used to simulate two types of thinning and determine the impact on wind damage risk for each tree in the stand. According to the model’s predictions, thinning from below has a reduced risk of wind damage compared with thinning from above.

中文翻译：

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在自然再生的苦瓜冷杉林中测试单个树风损害风险模型：间伐对风险水平的潜在影响

广泛分布在魁北克的苦瓜冷杉（Abies balsamea（L.）Mill。）非常容易受到风的损害。近来，森林管理中存在一种趋势，即在自然更新的林分中增加部分采伐的使用，使残余树木遭受风害的风险增加。为了限制部分cutting割后的风害，因此重要的是找到造林实践，以使这些冷杉林中风害的风险最小化。我们的主要目标是找到香脂冷杉的特定参数值，以将其集成到风灾风险模型ForestGALES中，以模拟不同类型的商业间伐对风灾风险的影响，并确定哪种做法可能将风蚀风险最小化。自然再生的立场。放置在冠层高度的风速计和附在香脂冷杉树干上的应变仪使我们能够测量香脂杉树样品遭受的风致弯矩。这样就可以计算特定于每棵树的转弯力矩系数，以便将它们与ForestGALES模型预测进行比较，并使该模型适用于香脂冷杉林。首先仅以树木直径和高度作为输入变量对模型进行测试，以计算转弯力矩系数，然后添加竞争指数，最后添加树冠尺寸。使用“风图集分析和应用程序”气流模型计算了用于预测损坏可能性的风气候参数。然后使用精度最高的模型来模拟两种间伐类型，并确定对林分中每棵树的风害风险的影响。根据模型的预测，与从上方稀疏相比，从下方稀疏具有降低的风害风险。