Regional risks of wind damage in boreal forests under changing management and climate projections

We employed simulations by forest ecosystem (SIMA) and mechanistic wind damage (HWIND) models in upland boreal forests throughout Finland to study regional risks of wind damage under changing management preferences and climates (current and RCP4.5 and RCP8.5 scenarios) over 2010-2099. We used a critical wind speed for the uprooting of trees as a measure of vulnerability, which together with the probability of such wind speed defined a level of risk. Based on that, we also predicted the stem volume of growing stock at risk and the amount of damage. In this work, medium fertility sites were planted to one of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.), or silver birch (Betula pendula Roth) or to the tree species that was dominant before the final clear-felling. The vulnerability to wind damage, the volume of growing stock at risk, and the amount of damage all increased, increasing the most in the south when the proportion of Norway spruce (with shallow rooting) of the growing stock increased. Under a severe climate warming, the proportion of Norway spruce decreased the most in the south, opposite to that of birch. This decreased the risk of damage in autumn (when birch is leafless), unlike in summer. The low risk of damage in the north was due to the large proportion of Scots pine.