Vertical Profiles of Windspeed in a Pine Stand

Abstract

Abstract Simultaneous measurements of windspeed were made at six heights extending to the top of a lodgepole pine stand. These profiles were measured in simultaneous pairs, using movable masts at a number of points between trees. Associated windspeeds and air temperatures were measured at threelevels above the canopy at a fixed location, together with above-canopy wind direction. The data indicate that, for a given wind direction and position in the stand, the windspeed profile expressed as a fraction of the friction velocity above the stand is invariant for a relatively wide rangeof windspeeds above the canopy. These scaled profiles are combined to form an average local maximum speed profile for the stand. Both point profiles and the combined profile show a minimum in the live crown and a subcanopy maximum. Average differences between simultaneous profiles were about10 percent below the live canopy and 20 percent in the low-speed canopy region. Forest Sci. 17:314-321.