NEWS ARTICLES / NOVEMBER 2025

The first multi-model benchmarking study identifies growth and mortality rates as critical variables in VDM development 

Wed 4 November 2025,  NGC Communication Team

NEW NEXTGENCARBON PUBLICATION A newly published study has highlighted the need to refine post-disturbance establishment conditions, such as after fire or storm, for the development of vegetation demographic models.  This includes using specific benchmarking variables to improve predictions of how forests will respond to environmental change.

The third scientific paper from NextGenCarbon was published in New Phytologist - International Journal of Plant Science on 23 October. “Demography, dynamics and data: building confidence for simulating changes in the world's forests”discusses how identifying critical variables, such as growth and mortality rates, have improved our understanding of vegetation demographic models (VDMs). NGC colleagues Peter M. Cox (University of Exeter), Rosie A. Fisher (CICERO - Center for International Climate Research), Aleksi Lehtonen (LUKE - Natural Resources Institute Finland), Sebastiaan Luyssaert (Vrije Universiteit Amsterdam), Guillaume Marie (Science Partners), Jessica F. Needham (CICERO - Center for International Climate Research), Mikko Peltoniemi (LUKE - Natural Resources Institute Finland), and Stephen Sitch (University of Exeter) are among the authors of the paper. 

The article discusses the recent advancements in vegetation demographic models (VDMs), which are advanced tools used to simulate how forests respond to climate and land-use changes. They are also important for projecting carbon cycling and large-scale forest management strategies. Furthermore, the article explains how benchmarking nine VDMs against observational data from boreal, temperate and tropical sites enabled researchers to identify specific issues for each model, and to make improvements. This was carried out by simulating models under consistent climate conditions to monitor the post-disturbance recovery process over a period of at least 420 years.

NextGenCarbon makes use of vegetation demographic models such as RED, CLM-FATES and ORCHIDEE to help improve our understanding of Europe's greenhouse gas (GHG) budget. The vegetation demography model that the University of Exeter is using within NextGenCarbon, ‘RED’, was one of the models tested in this study, with runs carried out by Terrestrial Carbon Cycle Scientist Arthur Argles at the UK Met Office. 

“This allowed us to test some of the underlying assumptions of RED against real world data for forests that are not in a demographic equilibrium. This sort of evaluation work is vital as we endeavour to develop better predictive models of global forests. We hope to take model evaluation to the next level using the new data sources being made available through NextGenCarbon”, says Peter Cox, who is Professor of Climate System Dynamics in Mathematics and Director of the Global Systems Institute at the University of Exeter.

The study revealed the diversity in approaches to simulate forest demography currently implemented by the different modelling teams, and the need to advance the monitoring of mortality and recruitment - Sebastiaan Luyssaert

Another model, The CLM-FATES, was run as part of this study by Jessica Needham, who was formerly with the Lawrence Berkeley National Lab and has recently joined CICERO and NextGenCarbon as Senior Researcher.

“Many upgrades to reporting of mass and individual fluxes and pools in FATES were facilitate by this study, and these will provide a very solid basis for intercomparison of demographic models and data within NextGenCarbon”, comments Research Professor Rosie Fisher from CICERO. 

Lastly, the ORCHIDEE team contributed to the study with simulations carried out by with the trunk of the ORCHIDEE model (v4). The ORCHIDEE simulations were done by Guillaume Marie, an expert in multi-scale ecosystem modelling at Science Partners and Sebastiaan Luyssaert, Associate Professor in Systems Ecology at Vrije Universiteit Amsterdam.

“The study revealed the diversity in approaches to simulate forest demography currently implemented by the different modelling teams, and the need to advance the monitoring of mortality and recruitment”, summarises Sebastiaan Luyssaert.

The team at the first D-BEN meeting in Amsterdam. Photo: Rosie Fisher 

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Read the open access paper from New Phytologist: 

Eckes-Shephard, A.H., Argles, A.P.K., Brzeziecki, B., Cox, P.M., De Kauwe, M.G., Esquivel-Muelbert, A., Fisher, R.A., Hurtt, G.C., Knauer, J., Koven, C.D., Lehtonen, A., Luyssaert, S., Marqués, L., Ma, L., Marie, G., Moore, J.R., Needham, J.F., Olin, S., Peltoniemi, M., Piltz, K., Sato, H., Sitch, S., Stocker, B.D., Weng, E., Zuleta, D. and Pugh, T.A.M. (2025), Demography, dynamics and data: building confidence for simulating changes in the world's forests. New Phytol. https://doi.org/10.1111/nph.70643