FORMIT-M + EFDM + Yasso workflow for forest state modelling across Europe

This repository documents the models developed under the PathFinder project (WP3.2), specifically the subtask Forest Structure and Living Biomass Carbon, focusing on forest growth and management modelling for scenario analysis. A total of four pan-European scenarios based on RCP2.6 + SSP1 and RCP4.5 + SSP2 for the period 2020–2100 are provided to demonstrate the modelling workflow, which combines the process- and data-based hybrid forest simulator FORMIT-M, the European Forestry Dynamics Model (EFDM), and the soil carbon model Yasso.
FORMIT-M simulates forest development at the plot level, accounting for climate change impacts via the maximum annual gross primary productivity (maxGPP) parameter, with pre-calculated maxGPP values corresponding to RCP2.6 and RCP4.5 across Europe. EFDM is a transition matrix model that simulates forest area dynamics based on management activity probabilities and transition probabilities, parameterized using paired permanent National Forest Inventory (NFI) plot data and FORMIT-M outputs. EFDM activity probabilities at the 1 km² resolution were derived using present-day forest management intensity maps generated with the CLUMondo land-use model. Initial forest area distributions for 2020 were based on analysis of high-resolution (10 m²) satellite imagery and NFI data. Biodiversity indicator calculation, including species richness and the Shannon index, were incorporated into the EFDM simulations. Variation in forest structure and growth patterns across European continent is accounted for by using ten tree species groups and three sub-regions (i.e. North, Central, and South Europe). Regional soil fertility effects on growth are partially accounted using spatially explicit net annual increment (NAI) data from JRC covering time period of 2010-2020. EFDM activity and transition probabilities were calibrated against present-day regional harvest removals and NAI values. Yasso is soil carbon model, in which decomposition of various biomass carbon input components is modelled as a function of climate, chemical composition, and the size of woody litter elements. EFDM scenario outputs were processed into Yasso model inputs following the completion of a full EFDM simulation.
Pan-European EFDM scenarios for the period of 2020-2100 were created following four CLUMondo forest management storylines: (1) Biodiversity Focused (RCP2.6–SSP1), (2) Participatory Forest stewardship (RCP2.6–SSP1), (3) Multifunctional Forests (RCP4.5–SSP2), and (4) Competitive Forest Industry (RCP4.5–SSP2). Documentation and the complete FORMIT-M - EFDM - Yasso framework code is provided for modelling future forest structure and living biomass carbon at a resolution of 1 km² over Europe.