Factors affecting damage to Scots pine in a multiple ungulate species system

Abstract: Managing browsing impacts on commercial forestry is one of the main aims of ungulate management in Sweden, with Scots Pine being one of the major forestry species. Moose is the ungulate species with the greatest management focus, although in parts of Sweden it is forms a multiple ungulate species system, along with red deer, roe deer and fallow deer. Land use is also thought to be a significant factor on ungulate behaviour and resulting feeding impacts. But which species, and which land uses, result in increased economic damage to pine trees? By monitoring ungulate density, land use and browsing damages across multiple years and at locations across Sweden, these relationships were modelled using generalised linear mixed effect models. The results indicate that moose densities are a significant factor in levels of browsing damage, with roe deer having some impact, but that increases in red deer densities produced possibly the biggest impacts of all. Increased use of land for agriculture also leads to greater browsing damages. Although much of the physical browsing may be conducted by moose, competition from the other ungulates may be leading to increased browsing on pine. While increased disturbance from agricultural land, and the restrictions to daytime movement that result, may also be driving increased browsing damages. Further studies are needed to confirm the drivers behind the browsing damages, but these results will provide a better framework for landscape scale management that considers both the presence of multiple species, and the use of the surrounding landscape.