Impacts of climate change on forest management and implications for Swedish forestry

摘要

While climate change is expected to increase the growth rates of most tree species in Sweden in the future, during this period, there are also increased risks of tree damage due to various risk factors associated with climate change. Therefore, it is necessary to develop adaptive management measures in order to exploit the benefits of climate change and minimize the damage resulting from these risk factors. In this thesis, the interactive effects of future climate change and various risk factors associated with the future climate such as storms, environmental pollutants, pests and pathogens such as root rot and bark beetle on growth and yield of important tree species in Swedish forestry such as Norway spruce (Picea abies (L.) Karst.), Scots pine (Pinus sylvestnis L.) and birch (Betula spp) are investigated and possible adaptive management measures are proposed. Simulations of a representative Norway spruce stand in southern Sweden performed using the empirical Heureka-Standwise model (Paper I) showed that forest management practices such as changing the thinning regime, shortening rotation periods, and switching to exotic tree species like hybrid aspen and hybrid larch could effectively reduce damage caused by risk factors and be financially rewarding. Standlevel simulations of six representative stands across Sweden using the ozone parameterized process-based model 3-PG showed that future growth and biomass production could be adversely affected by increasing tropospheric ozone concentrations (Paper II). However, the reduction in growth and biomass production was much lower than the increase due to climate change in all parts of Sweden other than the south. A new landscape-level hybrid model 3PG-Heureka was developed, parameterised and evaluated for Kronoberg county, Sweden (Paper III). The overall performance of the model was satisfactory with highest average error content of 1.5%. The hybrid model’s predictions under the future climate scenarios indicated that the storm events could drastically affect the growth and economy of forest landscape in Kronoberg county if the current forest management remains unchanged (Paper IV). Adaptive management regimes featuring shorter rotation periods were predicted to improve annual volume increments and net revenue while reducing storm-felling under two future climate scenarios (RCP4.5 and RCP8.5) but replacing Norway spruce with Scots pine was found to be less effective than reducing the rotation period.