Wind reduction downwind from a savanna woodland edge

Abstract

A study was made in 1987-89 of the wind protection provided by a sparse tree canopy in a savanna woodland (mainly Acacia tortilis) edge in N. Tanzania. Wind speeds were measured at two heights (1.0 and 2.5 m) along transects perpendicular to the prevailing wind; tree density ranged from 60 to 150 stems/ha. A simple model was formulated for average wind reduction within such canopies. Average wind speeds decreased with increasing distance from the woodland edge, until they become almost constant (saturation reduction). Airflow around single trees was studied for more understanding of these results. It is suggested that preservation or regeneration of trees should be encouraged for wind protection in planning and developing crop land.