Planning future forests for energy, environment and wildlife : Evaluation of forest management scenarios using a forest landscape model in Sweden

University essay from KTH/Hållbar utveckling, miljövetenskap och teknik

Abstract: Comparing the future state of natural capital and ecosystem services with quantitative scenarios  is essential in the decision-making process for a sustainable management of forest landscapes. In Sweden, an intensified forest management will likely be necessary to meet future demands of woody biomass as a source of bioenergy and building materials. At the same time an intensified forest harvest can cause conflicts with goals  for biodiversity conservation and reduce the amount of carbon being stored the forest. This study conducted a scenario analysis to evaluate how different types of forest management would affect changes in carbon stock between the above ground biomass in a Swedish forest and the biomass harvested from the forest. Potential conflicts between the harvesting scenarios and the in Sweden critically endangered White-backed Woodpecker (Dendrocopos leucotos) was also evaluated. The White-backed Woodpecker can be seen as an umbrella species, which means that there are about 200 other endangered plant and animal species that depend on the same kind of forest environments and could therefore be a measure of the state of the forest biodiversity in Sweden.  The forest landscape model LANDIS-II was used to simulate vegetation dynamics in species composition, age structure and biomass while considering disturbances only from harvesting. The simulation had a 100-year timeframe and used initial conditions gathered from a previous case study done in Sweden. The IPCC’s representative concentration pathway 4.5 was used to simulate impact from climate change. A business as usual scenario was simulated along with an intensified harvesting scenario and a conservation scenario to evaluate the impact on carbon sequestration in the aboveground  biomass  and the impact on the White-backed Woodpecker  habitat  between different forest management scenarios. The change in the stored and harvested carbon was calculated using the Carbon Stock Change Method and by comparing the initial biomass values with the values from the last ten years of the simulation. A habitat suitability score was made with respect to two key habitat requirements for the White-backed Woodpecker (1) the fraction of deciduous trees in the forest; and (2) the age structure of the forest.   From the result it was found that the carbon stock change in the forest was relatively stable for all the simulated scenarios during the 100-year period. The forest carbon stock for the intensified harvesting scenario was 1.04 of the initial carbon stock of the simulation while business as usual was 1.08 and the conservation scenario 1.10.  A conservation scenario would therefore be preferable if the forest landscape is to be used mainly as a carbon sink. If biomass extraction is to be increased to meet future demands for bioenergy and woody products, it should be noted that the intensified harvesting led to a 23.6 increase of the initial biomass harvest values while business as usual had a 4.2 increase and the conservation scenario a 3.1 increase. The result also suggests that increasing the proportions of deciduous and old forest to recreate  the White-backed Woodpecker’s preferred habitat require considerable time and effort and cannot likely be achieved with the current business as usual scenario nor with the intensified harvesting or conservation scenarios simulated in this study. Thus, a more ambitious and targeted restoration effort is needed if the species is to be preserved.   How the forest should be sustainably managed in the future depends on which interests takes priority in decision-making. However, a forest landscape model can provide valuable information throughout the management process so that more informed decisions can be made while also saving  time, money and resources better used elsewhere. 

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