Modelling Soil Organic Carbon Stocks in Forest Soils

Forest ecosystems store large amounts of carbon, in aboveground, below ground biomass, dead organic matter, and in the soil, through primary production. Climate change affects plant photosynthesis as well as soil carbon mineralization creating uncertainties about the forest carbon budgets. Especially in the context of climate change, terrestrial carbon stocks and their changes need to be measured and monitored. European Union members are required to register greenhouse gas emissions from the land use, land use change and forestry sector (LULUCF), starting with tier 1, and then transitioning to higher tiers. The present work investigated changes in soil organic carbon stocks in forest soils. Carbon turnover model RothC was used to model soil organic carbon stocks in forest soils in Xanthi regional unit, Northeastern Greece. The effects of soil type, soil cover, plant cover and climate on carbon turnover are included in the model. It has a monthly time step and is a decomposition model, it does not include a plant growth model. Sampling in the field was conducted, and soils were analyzed in the lab. Soil organic carbon, bulk density, soil texture and soil nutrients were measured. Soils were assumed to be in equilibrium for modelling. The model was initialized with a spin up phase and then run in forward mode for 20 years. A climate model was used to simulate the effects of climate change. To assess measured versus modelled values, root mean square error, mean absolute error and modelling efficiency were calculated. Two different datasets, from different points in time were used (soil data from 1995 and 2023). Then, spatiotemporal soil organic sequestration potential was calculated. Abstract submitted to the 1st Open-Air Cities International Conference: Local and Regional Sustainable Development & Urban Reconstruction.