The study presents the application of a numerical model to analyze conditions under which tree stands may lose wind firmness. Using the ArcView software and a Rismo two-dimensional flow pattern model an application software was created to calculate critical holding moment values of trees. Riparian forests of the Vistula River valley near the town of Puławy were selected to verify the numerical model of tree stand wind resistance. Those forests were destroyed on August 4th, 2001 during a violent storm. The storm in the area of Puławy coincided with the passage of a flood wave on the Vistula River. On the selected stretch of the Vistula detailed measurements of tree and subsoil parameters were taken. Using hydrological and meteorological data it was possible to simulate conditions, under which wind falling occurred.

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