The Forest Carbon Tool

Teagasc, in conjunction with the Department of Agriculture, Food and the Marine (DAFM) and Forest Environmental Research and Services (FERS) Limited, have developed an indicative online Forest Carbon Tool. Tom Houlihan, Teagasc Forestry Specialist has more details

This useful tool was launched on January 13 by Minister of State with responsibility for forestry, Senator Pippa Hackett.

We know that forests play an important role in the capture and removal of carbon dioxide (CO₂) from the atmosphere in a process called sequestration. The Forest Carbon Tool provides a user-friendly way to get an indication of how much carbon can potentially be removed in various forest scenarios and through important pathways that help address our climate change challenges. These include net carbon removals at forest level, removals through harvested wood products (e.g. construction timber and furniture) and emission avoidance through the substitution of appropriate timber assortments for fossil fuel energy. The tool provides indicative values only and is not intended to provide definitive or absolute data on any particular forest or for processes related to forest carbon valuation or potential trading platforms.

Functions of the Forest Carbon Tool

Users of the tool can select from a dropdown list of current planting options under the Forestry Programme (called Grant and Premium Categories or GPCs) or otherwise from selected forest species or species groups. They can then select an appropriate soil type and, upon hitting the calculate button, will get indicative values for mean yearly CO₂ sequestration (t/CO₂-eq/ha/yr) and mean cumulative sequestration values (t/CO₂-eq/ha), the latter being an estimate of the maximum potential sequestration. Both of these metrics are derived over 2 forest cycles or rotations. As we know that the sequestration levels do not stay constant but change significantly over time, the tool also graphically displays the annual sequestration trends over the two forest cycles. While growing forests capture and store CO₂ during active growth, activities such as forest thinning and harvesting give rise to emissions which are also taken into account.

Forest Carbon Tool Outputs

Outputs from the tool indicate that mean annual sequestration rates (under the current assumptions described) can range from 1-9 tonnes of CO₂ per hectare and are influenced by the tree species, forest age and soil types entered. They highlight that all forest types can have an important role to play in helping address climate change. Figures 1-3 provide summary examples of mean annual and mean cumulative sequestration for GPC 3, GPC 8 and GPC 11 planting categories. Productive conifer species (e.g. GPC 3, figure 1) such as spruce can return high sequestration 

rates, especially when their harvested wood products are taken in account. Broadleaf forests (e.g. alder, birch), while having a lower mean annual rate of carbon capture, can also cumulatively remove large amounts of CO₂ over their lifetime (figure 2). Agroforestry, which combines trees and continued agricultural activity on the same land, can provide sequestration capacity while also offsetting emissions from livestock such as sheep, as indicated in figure 3.

 Worked Examples

Figure 1: GPC 3 – 70% spruce (by area), 15% broadleaf species, 15% area retained for biodiversity enhancement (ABE - open space, hedgerows and retained habitat) on a mineral soil

• Mean annual CO₂ sequestration - 6.8 t/CO₂-eq/ha/yr
• Mean cumulative CO₂ sequestration - 357 t/CO₂-eq/ha

Figure 2 - GPC 8 – Fast growing broadleaves e.g. alder and birch with 15% area retained for biodiversity enhancement on a suitable mineral soil

• Mean annual CO₂ sequestration – 3.46 t/CO₂-eq/ha/yr
• Mean cumulative CO₂ sequestration - 471 tCO₂-eq/ha

Figure 3: GPC 11 Agroforestry – Fast growing broadleaves e.g. sycamore on a mineral soil combined with grazing for sheep between rows of trees (7 ewes per hectare)

• Mean annual sequestration – 1.68 t/CO₂-eq/ha/yr
• Agricultural emissions offset – 1.18 t/CO₂-eq/ha/yr
• Mean cumulative sequestration - 251 tCO₂-eq/ha

Current use and Future potential

Users of the Forest Carbon Tool are requested to become familiar with the range of assumptions involved as well as current limitations as outlined. The objective of this first iteration is to provide high level indicative information on the capacity of forests to sequester carbon and particularly provide some insights for users on the comparative merits of different forest planting options.

The Forest Carbon Tool also provides useful awareness raising and decision support functions, providing indicative data on the role of different planting options and their capacity to contribute to farm level carbon mitigation. There is also an ongoing need to further develop our knowledge on the impact of a range of factors such as forest types, species choices, rotation lengths and management approaches on sequestration potential. To this end, it is anticipated that updates and enhancements can be incorporated into future iterations of the tool as new data and research becomes available.

Benefits of sustainably managed forests

Finally, it is also important to consider that carbon sequestration is one of a range of important services provided by sustainably managed forests. These include timber production, water quality protection, landscape and biodiversity enhancement. Factors such as landowner’s objectives, tree species choices and forest management approaches are central to determining the specific mix of services that farm forests can provide.

The Forest Carbon Tool and the potential of forests to sequester carbon will be the subjects of a future Teagasc webinar, details to follow.

The online Forest Carbon Tool can be found here www.teagasc.ie/forestcarbontool.