The effect of shelter on the yield of grasses in southern Scotland.
The growth of Festuca arundinacea and Lolium perenne at a moderately exposed site in SE Scotland was compared with that in a sheltered enclosure in 1975, 1976 and 1977. The wind speed was reduced by 27% in the sheltered enclosure. There was no effect of shelter on DM production in spring. However, during the subsequent regrowth period, shelter increased the DM by up to 28%. The greater yield could not be attributed to differences in leaf water potential, the temp. of the apical meristem or the rate of phytosynthesis/unit leaf area, though leaf extension rates were significantly greater in the sheltered enclosure. It was suggested that the effect of shelter on yield was due to mechanical stimulation of the plants and changes in the distribution of assimilates.