Abstract
The equations of motion applying to the wind field in a forest canopy are simplified to a balance between the shearing stress gradient and either the form-drag of the leaves in the upper dense canopy, or the overall horizontal pressure gradient in the more open space beneath. The equations imply that, in descending through the forest, the stress and wind vectors turn through an angle which depends on the forest characteristics and on the stability and the speed of the airflow above the forest. The turning is roughly confirmed by an overall average measured on a very flat site near Thetford, Norfolk, covered by an extensive uniform pine forest.
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Smith, F.B., Carson, D.J. & Oliver, H.R. Mean wind-direction shear through a forest canopy. Boundary-Layer Meteorol 3, 178–190 (1972). https://doi.org/10.1007/BF02033917
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DOI: https://doi.org/10.1007/BF02033917