THE EFFECTS OF CLEARFELLING A SITKA SPRUCE STAND ON THE WATER-BALANCE OF A PEATY GLEY SOIL AT KERSHOPE FOREST, CUMBRIA

From 1981 to 1985 the water balance of four 2 ha plots of a ploughed and drained Sitka spruce plantation was monitored. During 1983, three plots were clearfelled and a fourth was left standing as a control.A ground level raingauge over-collected during snow, but otherwise collected 3 per cent more water than standard raingauges. Annual precipitation (1259-1688 mm) averaged 1439 mm.The forest canopy intercepted 38 per cent and transpired 12 per cent of gross precipitation. Fifty per cent of gross precipitation was evaporated while the other 50 per cent left the site as runoff. Throughfall and stemfiow fractions of net precipitation were 0.87 and 0.13 respectively.After clearfelling, annual runoff increased to 68 per cent of gross precipitation. After adjustment using the before and after comparison in the control plot, the decrease in annual evaporative loss resulting from clearfelling was 290 mm. © 1990 Oxford University Press.