Silvicultural methods and landscape features affect tree browsing by deer: Scots pine as a model tree species

Browsing pressure by deer is one of the most important factors impeding forest regeneration and leading to simplified forest structure. There is a growing awareness that silvicultural methods can reduce the browsing impact; however, the knowledge on their application and efficiency is limited and requires further research. We present the data on an experiment conducted in north-east Poland (inhabited by red and roe deer, as well as by moose), based on 30 sites regenerated naturally (on prepared and unprepared soil) and artificially (using container and bare-root seedlings). We also checked how the habitat composition in the direct vicinity (at three spatial scales within 100, 300, and 500 m around site boundaries) of the regeneration sites affects browsing pressure. Artificially regenerated sites were browsed more intensively than the naturally regenerated sites. The former are characterized not only by lower tree density but also by a more uniform distribution of the trees (all of them grow in one line and are equidistant) and their comparable height. This leads to a more predictable browsing process for deer. Moreover, the container seedlings were damaged more often than the bare-root ones (in early age they usually grow faster, reach higher shoot biomass, and are of higher nutritional value). Concerning the effects of the site neighbourhoods, the forest developmental stages affected browsing intensity at all three scales considered in the study. Browsing incidence was positively affected by the share of cover offering phases, while negative impact was exerted by pole-sized and mature stands. Concerning distance to human-related areas, the negative impact on the browsing incidence was recorded in the case of villages, while agricultural areas and roads had no influence on the deer pressure. The above information can be obtained from the forest maps and used to indicate sites predisposed to browsing and possible site protection.