Quantifying the Impact of Climate Change and Forest Management on Swedish Forest Ecosystems Using the Dynamic Vegetation Model LPJ-GUESS

Abstract

Boreal and temperate forests are undergoing structural, compositional and functional changes in response to increasing temperatures, changes in precipitation, and rising CO₂, but the extent of the changes in forests will also depend on current and future forest management. This study utilized the dynamic vegetation model LPJ-GUESS enabled with forest management (version 4.1.2, rev11016) to simulate changes in forest ecosystem functioning and supply of ecosystem services in Sweden. We compared three alternative forest policy scenarios: Business As Usual, with no change in the proportion of forest types within landscapes; Adaptation and Resistance, with an increased area of mixed stands; and EU-Policy, with a focus on conservation and reduced management intensity. LPJ-GUESS was forced with climate data derived from an ensemble of three earth system models to study long-term implications of a low (SSP1-2.6), a high (SSP3-7.0), and a very high (SSP5-8.5) emissions scenario. Increases in net primary production varied between 4% and 8% in SSP1-2.6, 21%–25% in SSP3-7.0 and 25%–29% in SSP5-8.5 across all three forest policy scenarios, when comparing 2081–2100 to 2001–2020. Increased net primary production was mediated by a higher soil nitrogen availability and increased water use efficiency in the higher emission scenarios SSP3-7.0 and SSP5-8.5. Soil carbon storage showed small but significant decreases in SSP3-7.0 and in SSP5-8.5. Our results highlight differences in the predisposition to storm damage among forest policy scenarios, which were most pronounced in southern Sweden, with increases of 61%–76% in Business-As-Usual, 4%–11% in Adaptation and Resistance, and decreases of 7%–12% in EU-Policy when comparing 2081–2100 to 2001–2020.