Shelter screens of 63 % permeability, erected at right angles to the prevailing wind, gave increases in growth and yield of raspberries (Rubus idaeus). In the year of establishment the total length of cane produced in the region extending from the screens to a distance 3 times their height (0-3 h) was 30% higher than that in the exposed plots. In the following fruiting year yields at the same point were increased by almost 40 % by shelter. Corresponding figures for the next year’s cane growth and the second fruiting year were 23 % and 16 % respectively. Mean wind speeds during the period of the experiment were 1.7 m/sec and 1.2 m/sec for the exposed and sheltered plots respectively, measured at a point 45 cm above the top of the crop, at a distance of 2 h from the screens.
The yield responses appeared to reflect differences in size of the fruiting frame work resulting from differences in vegetative growth. There was no evidence of direct physical damage due to exposure.