Building Better Baselines: A New Verra Methodology for Forest Carbon Projects Using Co-Located Control Plots

If you’ve ever done research on the effectiveness of a medication, supplement, or diet, you’re probably familiar with the concept of control groups. When researchers seek to understand how well a given treatment works, they administer it to some trial participants, while other participants who don’t receive the treatment are otherwise kept under the same conditions.

Similar to these human trials, nature-based interventions can be assessed using control groups to observe outcomes in treated vs. untreated plots of trees, agricultural crops and more. As part of our own approach to ensure integrity of measured project outcomes, Funga establishes control plots everywhere we work. This allows us to measure the efficacy of our soil restoration technology with a high degree of certainty. In the realm of forest-based carbon projects, using a treatment to create carbon additionality (carbon that would not have been stored if not for the existence of the project) in an existing forest is relatively new. Of the established methodologies for quantifying and monitoring carbon additionality in forests, tracking progress with controls was not an option. Funga had a choice: use these control plots for internal monitoring purposes only and work with an existing methodology, or lead the charge in writing a new methodology with a novel approach to baselining that enables future innovative solutions.

Funga, in collaboration with Conservation International, CTrees and The Nature Conservancy, has developed a brand new methodology with Verra that will utilize a series of rigorous control plots for precise measurement of additional carbon removals, encouraging innovation and versatility in the forest carbon space. This methodology (M0274) is currently undergoing its public comment period, and is expected to be approved later in 2026.

What Is a Methodology?

A key component of establishing a carbon project is determining which registry a project proponent will issue credits through, and which methodology they will use. A methodology is a standardized set of procedures and guidelines used in carbon crediting projects to quantify, monitor, report on, and verify the reduction or removal of greenhouse gas (GHG) emissions.

Since there are many different approaches to creating additional carbon storage or reducing carbon emissions, there is no one-size-fits-all method for measuring this additional carbon and monitoring the project over time. Verra's Verified Carbon Standard (VCS) Program offers dozens of methodologies for documenting carbon additionality that results from interventions ranging from reducing food waste to utilization of biochar to more efficient cook stoves. The best measurement approach for one project might produce inaccurate results for another. This is the situation Funga’s team faced when determining that the best existing methodology was VM0045, “Improved Forest Management Using Dynamic Matched Baselines from National Forest Inventories”.

The Need for Something New

VM0045 was developed for forest-based carbon projects that create additional carbon storage through a variety of interventions. To track the effectiveness of a given project, a group of forests comparable to the project site is identified through national forest inventories, and used to create the “baseline scenario”. Over time, carbon additionality is measured by comparing the project to its baseline scenario. This methodology is considered a massive leap forward by establishing dynamic baselines grounded in observed, real-world data and represents important progress in integrity of additionality measurement. However, this innovative leap in measurement is also currently limited in application to geographies that have robust national forest inventories, and is particularly suited to post-planting interventions, rather than pre-planting treatments. Both of these realities result in a missed opportunity to capture the true carbon storage created by Funga’s intervention.

At the same time, Conservation International (with project partner CTrees) faced challenges when establishing carbon projects in the tropics with VM0045. While the nature of the project was a good fit for this methodology, without the robust forestry databases we have in North America, there was insufficient information to assign an external baseline for measurement. Utilizing control plots for measurement would mean that projects would not have to rely on data documented outside of their project site, allowing Conservation International to have baselines that accurately represent the project area and detect subtle differences in additional carbon storage.

The Nature Conservancy was very involved in developing VM0045 and has seen it successfully implemented in many projects. However, they remained interested in expanding the applicability of VM0045 and other tools to provide robust, dynamic accounting for natural climate solutions in landscapes that lack the data VM0045 currently requires. They also recognize that improvements in forest management and new climate-positive interventions emerge every day, and demand flexible methodologies. Wanting to enable more natural climate solutions to access funding through the Voluntary Carbon Market (VCM), they became interested in expanding the methodologies available to forest carbon projects.

Getting to Work

Starting in June 2023, Funga and Verra began detailed discussions around VM0045 and potential new tools and frontiers in carbon project design. These discussions uncovered the need and high-level applicability of the control plot approach. Verra was interested in supporting an approach that would improve the scientific rigor of Verra’s registered carbon projects while allowing new carbon-storing methods to emerge.

After connecting with Conservation International, CTrees, and The Nature Conservancy over our shared interest in a control plot baseline methodology, we began working out what this methodology would look like. Our initial concept was simple: set up the project like a scientific experiment, with treated plots and untreated control plots. Through the development process, we identified new complexities, and strengthened our approach through feedback and layers of accountability. From idea conception to a fully approved methodology later this year, this project will have taken around three years.

Paving the Way for Other Innovations

The methodology we are developing will be available for many other projects to utilize, and will hopefully encourage new project types that could not be effectively monitored before. Some possibilities are:

• Vine Cutting (also called Liana Removal): The strategic cutting of super-abundant woody vines in disturbed forests to improve tree growth is an emerging method for increasing the carbon sequestration of managed forests. The presence of vines reduces tree growth through competition. Research shows that when vines are removed, tree growth and carbon storage accelerate significantly. Reserving a control plot where vines are not actively managed can clearly demonstrate the difference in the managed plots.

• Soil Amendments: Funga improves tree growth by reintroducing microbial communities, but there are many other ways to improve soil and enhance the growth of aboveground vegetation in the process. As new techniques in soil restoration emerge, their efficacy can be tracked with control plots where soil is under “business as usual” conditions.

• Mixed Species Planting: Species diversity can create positive outcomes for reforestation, afforestation, and in forests grown for timber harvest. But standard approaches in any of these scenarios often still means monoculture planting. Monocultures are more vulnerable to disease and pests, impacting average tree survival. Projects planted with a diversity of species could compare biomass to a co-located control plot where a monoculture was established.

• Future Innovations: Perhaps most exciting is all the forest improvements that are yet to be developed. The versatility of this control-vs-treatment design will be applicable to a wide range of practices, and we hope that the existence of this methodology will incentivize investment in new solutions.

What’s Next

The methodology is on track to be finalized in late 2026. It is currently undergoing a 30-day public comment period hosted by Verra, after which comments and suggestions will be considered for further revisions. Finally, it will undergo an expert review by an accredited VVB and then final registry approval before it is available for use.

We are so grateful to collaborate with fellow carbon project developers who embrace opportunities for partnership and mutual uplift. By coming together to design this new methodology, Funga, Conservation International, The Nature Conservancy, CTrees, and Verra are creating new opportunities not just for our own organizations, but for new, high-integrity natural climate solutions to emerge and flourish.