Transpiration of Festuca arundinacea Schreb, strain S170, was measured at two different wind speeds in a controlled-environment wind tunnel. As a result of a wind increase from 1 m s⁻¹ to 3.5 m s⁻¹ above the sward, transpiration gradually increased, especially at night-time. Similar effects were noted in three other grass species. The transpiration increase could be attributed to decreases in stomatal and cuticular resistances, as a result of leaf buffeting.