Abrasive damage by wind to the needle surfaces of Picea sitchensis (Bong.) Carr. and Pinus sylvestris L.

After a period of one week at 11m s −1 in a wind tunnel, the leaf surface of Picea sitchensis and Pinus sylvestris had undergone structural modification. Low‐temperature scanning electron microscopy was used to examine these changes. Picea showed flattening and smearing of wax crystals, as well as cracks in some of the wax structures filling the stomatal antechambers. In Pinus , most damage was on the cells surrounding the stomatal antechamber or on needle ridges. Artificially abraded surfaces were of similar appearance. Minimum epidermal conductance to water vapour ( g e MIN ) was determined gravimetrically. In Picea g c MIN was more than doubled by wind treatment and increased eightfold by rubbing. Similar but less extreme increases occurred in Pinus. Neither species showed recovery of g e MIN after 1 week at low windspeed.