Modelling managed forest ecosystems in Sweden : An evaluation from the stand to the regional scale

• Published in: Ecological Modelling
• Main Authors: Bergkvist, John, Lagergren, Fredrik, Finnander Linderson, Maj-Lena, Miller, Paul, Lindeskog, Mats, Jönsson, Anna Maria
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2023
• Subjects: Physical Geography; Forest ecosystems; Forest management; Norway spruce; Standing volume; Vegetation dynamics; Norway; Northern Sweden
• Online Access: https://lup.lub.lu.se/record/3bd0a97d-284d-404a-a739-c2e280f52ae9; https://doi.org/10.1016/j.ecolmodel.2022.110253

Incorporation of a forest management module in the dynamic vegetation model LPJ-GUESS has allowed the study and predictions of management treatment effects on the carbon cycle and on forest ecosystem structure. In this study, LPJ-GUESS is evaluated at the regional scale against observational data from the Swedish National Forest Inventory. Simulated standing volume is compared against observations for the four most common forest types in the country. Furthermore, eddy-covariance flux measurements from the Integrated Carbon Observation System (ICOS) are used to evaluate model predictions of net ecosystem exchange (NEE), gross primary productivity (GPP) and ecosystem respiration (Reco) at the site scale. The model results suggest an adequate representation of standing volume in monocultures of Norway spruce and Scots pine for regional simulations in southern and central Sweden, after an updated parameterization of the species. For northern Sweden, the standing volume in Norway spruce monocultures was overestimated with the updated parameter values. At the stand scale, the model produced mixed results for carbon fluxes when evaluated against eddy-covariance data for two sites, one in central and one in southern Sweden. The interannual variation of GPP was well captured for the central Swedish site, but the modelled average GPP for the period 2015–2019 was overestimated by 9%. For the southern Swedish site, GPP was underestimated by 15% for the corresponding period and the simulated interannual variation was half of the observed. The seasonal estimates of modelled net ecosystem exchange (NEE) deviated from observations and the simulated standing volume was underestimated by 25% for both sites. The results highlight further potential to perform species-specific calibration to capture latitudinal gradients in key ecosystem properties, and to incorporate additional characteristics of site quality which could benefit model accuracy at the scale of individual forest stands, both regarding simulated carbon fluxes and ...