by Rob Waterworth, Bryan Adkins, Werner Kurz
To date, the forest Growth and Yield Community has had limited engagement with Greenhouse Gas (GHG) estimation and reporting, having focused largely on modelling timber volumes.
However, with the rapidly increasing need to act on climate change, assessing the potential Greenhouse Gas mitigation contribution of forests through both increased carbon storage and the provision of wood products, is more important than ever before.
To do this, the Greenhouse Gas community needs to improve the current methods for estimating Greenhouse Gas from forests and work closer with the forest yield community.
Compared to timber growth and yield estimations conducted by mensurationists (people who measure Forest Yield), estimating Greenhouse Gas emissions and removals from forests is a relatively new field.
While some countries began establishing systems for carbon (and Greenhouse Gases) reporting in the 1980s and now have advanced systems (in particular, Canada), most systems for estimating emissions from forests have been built in the past decade.
In many cases, these systems are completely absent, and this is particularly true in developing countries and emerging market economies. Even more so, many of those that are in place depend solely on the use of simple emissions factors that may or not be reflective of true emissions on the ground.
How are Emissions Measured
An Emissions Factor (EF) is a single value representing a defined class, such as a forest type (e.g. boreal, tropical wet). It is expressed as mass or rate per unit area.
Emissions Factors can be applied in multiple ways
- At a single point in time (such as to estimate emissions from deforestation) or
- Over time (e.g. representing carbon accumulation as a straight line with or without maximum carbon stock per hectare).
To obtain estimates of total emissions, the emissions factors are combined with activity data, which describe the area annually affected (e.g., harvested, deforested or reforested) within a set stratum.
Why is this Unsuitable for Forests
For those familiar with forest growth, it is immediately clear EFs do not properly represent growth over time.
Management of forests can have an effect on the EF through site preparation prior to planting, early competition removal, herbicide spraying after reforestation or thinning.
EFs also do not adequately estimate impacts of natural disturbances such as fire or insects and do not include estimates for sub-components of aboveground biomass, such as the stem mass and volume that are required for estimating timber yields.
They also do not provide information about mortality and turnover processes that contribute to dead organic matter accumulation.
How can this be Improved
The use of EFs reflects two main historical circumstances:
- limited data availability leading to a reliance on ad hoc, point in time measurement systems; and
- a focus on infrequent, national scale reporting with little consideration for strategic, tactical or operational use of forests, other than for timber.
However, these circumstances are rapidly changing.
Huge volumes of new data are becoming available from both field measurements and remote sensing (satellite and airborne). At the same time, policies are demanding more of these Greenhouse Gas estimation systems, especially in the land sector.
For example, most countries are looking to use their forests as sinks to increase their mitigation contributions in meeting national Greenhouse Gas reduction targets under the Paris Agreement (2015).
Many countries are also looking at large scale forest restoration activities under the New York Declaration on Forests (2014), which highlights the role forest restoration can play in global climate change mitigation efforts. This means countries now not only need to report more often on the status of forest carbon, but also use systems to develop projections, as well as to support emissions reduction policies and programs through both their regular reforestation activities and forest restoration/afforestation efforts.
Moving to more advanced and realistic representations of forest carbon fluxes that can underpin better decision making will take time, and time is limited if we are to meet the targets set out in both the Paris Agreement and New York Declaration on Forests.
How to Get Started for Accurate EF Measures
There are three obvious starting points:
The First is to start working on methods and processes for developing more realistic carbon growth curves using existing datasets from both natural and managed stand databases.
The second is to work with countries to design measurement systems that more efficiently collect the data required at scale to further develop and improve model estimations of forest growth and mortality alongside the current work on traditional forest inventories.
Thirdly, the Growth and Yield Community needs to take on the challenge of including the impacts of climate and other environmental changes on forest growth and mortality rates.
Finally, and most importantly, we need to build a community of growth and yield modellers with expertise in forest carbon estimation across the globe. Regional planning action is required to support national scale.
Meeting the Challenge
To meet the new challenges of moving from systems purely designed at the national-scale to those that can support regional mitigation planning action, close collaboration between the Carbon Community and Growth and Yield Community is required.
However, to date, this engagement has been limited and it is hard to adjust course after a decade of accepted, but siloed, practice.
This merging of communities presents a new opportunity for the Growth and Yield Community to advance and expand the science of growth and yield modelling into carbon reporting and to demonstrate how existing and new knowledge on forest growth dynamics can enhance current reporting systems.
Without increased understanding of climate change impacts, projection systems will become increasingly unreliable.
Increasing Collaboration for EF Accuracy
There are several ways to go about enhancing this collaboration. For example, the Growth and Yield Community could take the next step by signalling their openness to engage through writing a paper outlining how their support can complement and enhance current Greenhouse Gas estimation efforts.
Such a paper can refer to the success of countries or companies (such as large forestry groups) that have taken this approach and show how it is possible to start simple and build to more complex and comprehensive systems over time. Alternatively, other fora such as jointly hosting a dedicated side- event at a major conference, may be an obvious next step.
For example, the Global Forest Observation Initiative (GFOI), an informal group that aims to help developing countries with their Greenhouse Gas reporting systems, could provide an excellent conduit.
Similarly, a joint application for funding to host a joint workshop, to bilateral or multilateral funding organisations may prove to be a preferred avenue. From this paper, we, the authors, would willingly help with any of these proposed options. As time is of the essence, a proactive approach is recommended.
Climate change presents the most comprehensive suite of challenges we will face in the 21st century, and forests will play a key role, either positively or negatively in the outcomes. It will only be positive if we have the right systems and information available to support decision-makers as we seek to tackle the impacts across the globe.
So, to the Growth and Yield Community, please reach out to the Greenhouse Gas community in your area.
If you don’t know who, then reach out to us and we can assist (email below). Your knowledge is going to be crucial to help meet the mitigation and adaptation challenge.
Chief Executive Officer, The Mullion Group
Senior Consultant, The Mullion Group
Senior Research Scientist at the Canadian Forest Service