S2In a recent study of the solar radiation reflected by a red pine canopy, one of the first problems we had to solve was how to position measuring devices above the tree canopy. We considered two alternatives. Should we erect a number of towers or masts at various locations to hold radiation-measuring devices above the stand? Or should we erect a few towers and run a system of tramways among them so that the instruments cound be moved around to different positions above the tree canopy? The tramway system appeared to be less expensive; so we devised a system consisting of three 70-foot towers and two 100-foot tramways. This system, constructed at a cost of about $1,000 for materials, has been operated successfully for more than a year (fig. 1). Because of the ease of construction and the relatively low cost, other research workers, might be interested in such a system.S3.