Modelling the effects of management intensification on multiple forest services : a

17 The study presents a method to evaluate the response of forest ecosystems to increased biomass 18 extraction based on the integrated ecosystem model ForSAFE. It evaluates the effects of residue 19 removal, intensification of thinnings and a shorter rotation period on a forest site in Southern 20 Sweden. The evaluation includes multiple ecosystem indicators for productivity, carbon storage, 21 wood production, water use and water quality. Such integrated assessments can contribute to 22 identify negative or positive impacts affecting ecosystem services provided by forests. Results 23 show that increased biomass extraction reduces the carbon stored in the forests, but at the same 24 time reduces the loss of nitrogen and carbon through leaching. Within one rotation, residue 25 removal affects the carbon stock in the soil, but it does not affect forest productivity and therefore 26 tree carbon stock. Contrarily, the intensification of thinnings and shorter rotation periods reduce 27 carbon stored in trees. In all cases, the amount of wood available for products increases, but the 28 additional harvest from increased thinnings and earlier clear cutting does not compensate for the 29 loss of carbon in trees. A positive consequence of removing the decomposing material from the 30 site is the reduced amount of nutrients lost with runoff. Both leached nitrogen and dissolved 31 organic carbon decrease with intensification. In addition, a positive effect of increased thinnings 32 and a shorter rotation period is a reduced evapotranspiration, i.e. reduced water use. The effect on 33 acidification differed depending on the time frame considered and the applied management 34 scenario, due to different dominating processes regulating acidity. To avoid acidification, 35 management intensification should include measures to prevent loss of base cations in the soil. 36 Overall, under the studied conditions, the risk for negative effects seems to be smaller for residue 37 extraction than for management changes including additional tree harvest. 38