This document discusses the development and application of forest carbon models in UK greenhouse gas inventories. It notes that the UK recognized early the important role of forests and developed the first analytical model of carbon sequestration and losses in forests in 1988. This model, eventually named CARBINE, and other similar models are now used to estimate how much carbon UK forests are storing. CARBINE is applied in GHG inventories to better represent detailed forest composition and management. The document outlines the components and assumptions of CARBINE, including relying on long-term forest data and yield tables to estimate carbon stock changes, and notes the importance of transparency in documentation.

1. Paul Henshall
Forest Research
Alice Holt Research Station
Farnham
GU10 4LH
UNITED KINGDOM
paul.henshall@forestresearch.gov.uk
Tier 3 forest model development and
application in UK GHG inventories
COP25, Madrid
IPCC Side Event
3rd December 2019

2. 2 05/12/2019
Where it all began …
• First meeting of the IPCC held in November 1988
• Before this, World Conference on Changing Atmosphere (June 1988)
• UK recognized early the important role of forests:
Motivation
• Analytical model of carbon sequestration and losses in forests
• Not the only model, probably the first (1988)
• First UK Information Note published in Spring 1989
• Other similar models followed in UK (CFLOW) and abroad
• Forest Research model eventually named “CARBINE”
• “Basics” of ECOSSE soil carbon model now added into CARBINE.
Model development
“How much carbon are the UK’s forests storing?”…
GHG inventories
• CFLOW applied in GHG inventories until 2012 (simpler to apply)
• CARBINE used since then – push to better represent detailed
forest composition and management, soil carbon ...

3. 3 05/12/2019
Example: Impacts of afforestation
-20
-15
-10
-5
0
5
10NetGHGemissionsincrease/decrease
(+/-)(tCO2-eqha-1yr-1)
“Savings”
“Emissions”
Forest
machinery
etc. Soil
Trees
Dead and litter
Wood products
Bioenergy
Materials etc.
2030 2050 2100
“A multi-purpose
forest stand in UK”
planted in 2020

4. 4 05/12/2019
What’s involved
• Carbon stock changes can be estimated using tables of volume
production, biomass expansion factors and turnover rates
• Reliance on forest yield tables/models dating back to 1960s
• (Currently) growth not influenced by changing CO2 or climate.
Main assumptions
• Framework for systematically integrating and reconciling
different country-specific data sources at different scales (e.g.
tree allometry, turnover rates, forest areas, age classes,
management, wood production)
• Easy to update parameters and activity data when available
• Projections for policy/scenario assessment are relatively easy
• Projections consistent with GHG inventories
• Wider applications (e.g. LCA of wood supply chains, economics).
Advantages
Be aware
• No turning back!

5. 5 05/12/2019
Verification and transparency
• Growth models/yield tables calibrated/verified against long-term
data from permanent research sample plots (not NFI)
• Litter and soil parameters derived from literature reviews
• Smaller network of intensive forest monitoring sites provide data
for verification of litter and soil
• Basic checks against Tier 1 values
• High level in inventories: managed forest area consistent with
wood production given forest production potentials (yield models)
• Forest areas consistent with National Forest Inventory.
Verification of model outputs and GHGI results
• Documentation needs to be systematic, thorough and
understandable to those using model results – can be challenging
• Example calculations (simple and complex) to help explain how
inputs relate to relate to results
• Tier 2 calculations are simpler – easier to check, but still complex
to estimate activity data and does not match well UK forests.
Transparency of assumptions and calculations

6. 6 05/12/2019
IPCC Expert Meeting Report
• Elements consistent with UK QA processes, with some extensions
• Where to find IPCC elements:
Basis and type of model NIR/CARBINE documentation
Application and adaptation of model NIR/QA documentation
Main equations and processes NIR/CARBINE documentation
Key assumptions QA documentation
Domain of application QA documentation
Estimation of model parameters
CARBINE documentation
Other reports (e.g. growth
models)
Key inputs and outputs
NIR/CARBINE documentation
Separate “RECONCILE” report
Model calibration and evaluation CARBINE report
Uncertainty and sensitivity analysis Separate report (in progress)
QA/QC procedures
Internal Forest Research
procedures
References to literature CARBINE documentation
• Has needed sustained effort (development, documentation, data).

7. Thank you
Tier 3 forest model development and
application in UK GHG inventories
Paul Henshall
Forest Research
paul.henshall@forestresearch.gov.uk