Liability of Saplings to Browsing on a Red Deer Range in the Scottish Highlands

Abstract

(1) The amount and seasonality of browsing on experimentally planted saplings (<30 cm tall) of Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth), rowan (Sorbus aucuparia L.) and juniper (Juniperus communes L.) were observed on rangeland where red deer (Cervus elaphus L.) was the main herbivore. The effects of clipping on the survival of saplings grown outdoors in pots was also studied. (2) The extent to which saplings were browsed varied according to their location and species. In general, deer spent most time on the lower slopes of hills and so there was an inverse correlation between altitude and the frequency of browsing on saplings. (3) Tall, conspicuous saplings were more liable to browsing than small, partially obscured plants. (4) Overall, pine was the species most liable to browsing. Juniper and birch were browsed least. Deciduous species were browsed most often in summer, when they were leafy. There was much less seasonal variation in the browsing of pine and juniper. (5) Pine was easily killed by clipping. Rowan was most tolerant of damage. (6) Pine seems least able to regenerate where deer stocks are large because of its high liability to browsing and consequent heavy mortality. In general, the regeneration of tall woody species could be increased, especially at 600-700 m above sea level, if deer numbers were to be reduced substantially.