Management proposals for bilberry in Scots pine woodland

The abundance and height of three common shrubs (bilberry Vaccinium myrtillus, cowberry V. vitis-idaea and heather Calluna vulgaris) in Scots pine Pinus sylvestris woodland in Scotland were studied in relation to irradiance and browsing by herbivores (deer). In particular, we were interested in how these variables could be manipulated in order to increase the abundance of bilberry, a species that contributes substantially to pinewood biodiversity. Bilberry cover was greatest at intermediate irradiance, which coincided with high crown forest stands, and was least in the thicket stages of forest development. It was also less abundant where there was a high level of browsing. By contrast, heather cover and height increased with irradiance. In order to increase bilberry in Scots pine woodland, and thereby enhance woodland for wildlife, managers should aim to match stand densities to particular tree heights to provide the best light conditions for bilberry, allowing it to compete successfully against heather. This may mean reducing tree densities in plantations, but increasing them in the more open stands of native pinewoods. Because browsing by deer appears to reduce bilberry abundance, it may also be important to reduce numbers of deer to increase bilberry.