Managing an invasive tree species - Silvicultural recommendations for Black cherry (Prunus serotina Ehrh.)

Black cherry (Prunus serotina Ehrh.) is considered to be an invasive species in different European ecosystems, like open land habitats and woodlands. In the study area, the 'Valle del Ticino' biosphere reserve (northern Italy), the species has established, since it reproduces and spreads. Its ability to dominate the understory of forests hampers the regeneration of native species. This can cause a shift in species composition, possibly lead to a loss of biodiversity, and modify ecological key processes. After being felled, P. serotina resprouts intensively, which makes it complicated to get rid of the species. The resprouting ability, however, is also an indication for the species' biomass potential. This potential could be used, without surrendering to the objective of reducing the abundance of the species in the long run. The aim of this paper was to analyse different management options to derive recommendations for the future management of the species. The options were evaluated in terms of economic profitability and environmental compatibility. For this purpose, a stand development model was applied to simulate the P. serotina growth over a time period of 50 years. The results show that there are promising strategies, which are effective in reducing the abundance of P. serotina and could result in positive revenues for the land owners. The findings suggest only felling trees of larger diameter at breast height and not treating thinner trees. However, intensive harvesting approaches are to be avoided. They are not only quite laborious, but could also lead to a substantial nutrient depletion of the soils in the study area, which might affect the sustainable productivity of the forest. Furthermore, it can also be assumed that the resulting intensive disturbances and canopy openings would be conducive for the pioneer characteristics of P. serotina, which would indirectly again promote the species.