Background to the development of CARBINE

The CARBINE model was first developed in 1988 by the Research Division of the Forestry Commission, now Forest Research. The development of CARBINE represented one of the first attempts to systematically model the exchanges of carbon between the atmosphere, various types of forests and other long-term reservoirs of carbon such as harvested wood products. The stimulus for its development was the first meeting of the IPCC held in November 1988 and the preceding World Conference on Changing Atmosphere (June 1988). Since then, several forest carbon accounting models have been developed worldwide with some level of influence from CARBINE.

Since 2014, the CARBINE model has been applied in the estimation of the contribution of forest land, harvested wood products and deforestation to removals and emissions of greenhouse gases (GHGs) in the United Kingdom, as reported in national greenhouse gas inventories under the United Nations Framework Convention on Climate Change.

CARBINE model scope

CARBINE includes the detailed representation of:

• A diverse range of tree species, growth rates and forest management practices
• Complex changes or trends in forest composition and management over time
• Forest carbon reservoirs (tree stems, branches, foliage, roots, litter, deadwood and soil carbon) and associated carbon fluxes for a range of climate and soil conditions, including peat soils
• The utilisation of harvested wood and the retention and loss of carbon from a variety of semi-finished or finished wood products
• GHG emissions associated with the use of machinery, fuel and other resources (e.g. pesticides, fertilisers) in carrying out forest management operations.

Applications of the CARBINE model

The purpose of the CARBINE model is to address questions about the carbon and greenhouse gas balances of forestry systems. This helps to inform the development of forest policy and practice, particularly related to climate change mitigation, and to track progress towards meeting climate targets. CARBINE is applied to a wide range of research questions, with examples including:

• What are the carbon stocks in a defined area of forest?
• How much carbon is stored by creating new forests?
• What impacts do different approaches to forest management such as planting techniques and tree harvesting have on carbon stocks in forests?
• What contribution can forests make to meeting climate change goals, by removing carbon dioxide from the atmosphere?

Implementation of CARBINE

CARBINE has been continually developed since its inception in the 1980s, leading to a complicated and monolithic implementation in a programming language (Fortran) that has a limited pool of available developers. FR is currently working on a project to modernise the design of CARBINE and enable implementation in the widely used R language.

The project delivering the upgraded version of CARBINE is also reviewing how the model might be made more widely available once initial development and testing is complete.

Recent examples of research projects and policy reports using CARBINE outputs

United Kingdom 2023 National Inventory Document (NID), see Sections 6.2, 6.8 and Annex 3.4, UK Greenhouse Gas Inventory, 1990 to 2022: Annual Report for submission under the Framework Convention on Climate Change | National Atmospheric Emissions Inventory (energysecurity.gov.uk)

Greenhouse Gas Inventories for England, Scotland, Wales & Northern Ireland: 1990-2022 | National Atmospheric Emissions Inventory (energysecurity.gov.uk)

Projections of Emissions and Removals from the LULUCF Sector to 2050/2100 (consistent with the GHG inventory 1990-2017) | National Atmospheric Emissions Inventory (energysecurity.gov.uk)

Quantifying the sustainable forestry carbon cycle. Summary Report prepared for Scottish Forestry, 2022. Forest Research: Farnham, Quantifying the sustainable forestry carbon cycle: Report download page – Forest Research

National Forestry Accounting Plan of the United Kingdom. Forest Reference Level for the Period 2021-2025. BEIS Research Paper Number 050/1819, 2020, UK National Forestry Accounting Plan 2021-2025

Environment and Rural Affairs Monitoring & Modelling Programme (ERAMMP). Report-36 National Forest in Wales – Evidence Review Annex-4: Climate Change Mitigation. Report to Welsh Government (Contract C210/2016/2017), 2020. 36 ERAMMP Rpt-36 NF Annex-4 Climate Change v1.0_en.pdf