Reforestation

This Protocol provides the requirements and procedures for the calculation of net carbon dioxide equivalent (CO₂e) removal from the atmosphere via reforestation. Reforestation refers to activities that lead to an increase in forest cover on land that was previously covered by forest, restoring the native forest ecosystem¹.

Earth’s forests store approximately 861 gigatonnes of carbon². Forests can act as a source or sink of carbon, and are estimated to absorb a net 7.6 gigatonnes of CO₂ per year³ by converting atmospheric CO₂ into biomass through photosynthesis. Carbon is also steadily released from forest biomass through respiration and oxidation, or as a result of disturbances such as timber harvesting, fires, and deforestation.

Reforestation activities include planting tree seedlings, facilitating natural regeneration, and ongoing management of the forest to maximize and preserve the carbon removed from the atmosphere that is stored in tree biomass. Restoration of forested lands globally could represent an additional storage of 200 gigatonnes of carbon at forest maturity⁴, making it a useful tool in reaching the projected IPCC Carbon Dioxide Removal (CDR) storage needs of the mid-century. In addition to carbon sequestration potential, reforestation has several co-benefits such as restoration of forest habitat, creation of wildlife corridors, and enhancement of biodiversity on previously degraded lands.

This Protocol accounts for the quantification of the gross amount of CO₂ removed via growth and regeneration of forest vegetation, as well as all cradle-to-grave life-cycle Greenhouse Gas (GHG) emissions associated with the process. This Protocol is developed to adhere to the requirements of ISO 14064-2: 2019 – Greenhouse Gasses – Part 2: Specification with guidance at the Project level for quantification, monitoring, and reporting of greenhouse gas emission reductions or removal enhancements.

The Protocol ensures:

• Consistent, accurate procedures are used to measure and monitor all aspects of the reforestation process required to enable accurate accounting of net CO₂e removals;
• Consistent system boundaries and calculations are utilized to quantify net CO₂e removal for reforestation projects;
• All net CO₂e removal claims are verified by a third party;
• Forests that are planted are biodiverse, suitable for the region, and resilient to climate change;
• Removals are additional through the use of dynamic baselines and other guardrails set forth in the Isometric Standard;
• Comprehensive guidance on project design and monitoring mechanisms to confirm Durability and protect against Reversals, ensuring transparent Credit delivery; and
• Market leakage impacts are quantified.

Throughout this Protocol, the use of “must” indicates a requirement, whereas “should” indicates a recommendation.

This Protocol relies on and is intended to be compliant with the following standards and protocols:

• The Isometric Standard
• ISO 14064-2: 2019 - Greenhouse Gases - Part 2: Specification with guidance at the project level for quantification, monitoring, and reporting of greenhouse gas emission reductions or removal enhancements

Additional reference standards that inform the requirements and overall practices incorporated in this Protocol include:

• ISO 14064-3: 2019 - Greenhouse Gases - Part 3: Specification with Guidance for the verification and validation of greenhouse gas statements
• ISO 14040: 2006 - Environmental Management - Lifecycle Assessment - Principles & Framework
• ISO 14044: 2006 - Environmental Management - Lifecycle Assessment - Requirements & Guidelines

Additional principles that were considered in the development of this Protocol and aligned with, where feasible, include:

• The Core Carbon Principles of The Integrity Council for the Voluntary Carbon Market, v1.1, ICVCM, 2024
• Criteria for High-Quality Carbon Dioxide Removal, Carbon Direct & Microsoft, 2023
• Ten golden rules for reforestation to optimize carbon sequestration, biodiversity recovery and livelihood benefits, Global Change Biology, 2021
• Quality criteria for afforestation, reforestation, & revegetation projects, Symbiosis, 2024
• ABACUS Label Guidelines, v1.0, Verra, 2024

Protocols and Methodologies that were assessed as part of a literature review during the development of this Protocol include:

• VM0047 Afforestation, Reforestation, and Revegetation, v1.0, Verra, 2023
• Climate, Community & Biodiversity Standards, v3.1, Verra, 2017
• Afforestation - Reforestation GHG Emissions Reductions & Sequestration Methodology, v2.1, Gold Standard
• Quantification Methodology for Terrestrial Forest Restoration, v1.1, Ecosystem Restoration Standard, 2024
• Afforestation/Reforestation/Revegetation (ARR) Carbon Whitepaper, v1.1, Open Forest Protocol, 2024

This Protocol was developed based on the current state of the art, publicly available science regarding reforestation activities and long-term monitoring of forest carbon projects. This Protocol aims to be scientifically stringent and robust. We recognize that some requirements may exceed the status quo in the market and that there are numerous opportunities to improve the rigor of this Protocol. Key future improvements to the Protocol are outlined in Appendix E.

Additionally, this Protocol will be reviewed when there is an update to published scientific literature which would affect net CO₂e removal quantification or the monitoring guidelines outlined in this Protocol, or at a minimum of every 2 years.

This Protocol aims to guide Projects that restore inland forests to a state of ecological integrity⁵ in areas where they have historically existed and are resilient to future climate scenarios. Projects should emphasize protection and restoration of ecosystem function, biodiversity, and social livelihoods. Projects should not resemble commercial forestry, and the fate of forests restored in accordance with this Protocol must not be clear-cutting for timber sale, even beyond the Monitoring Period.

• Project activities must include reforestation and/or assisted natural regeneration on degraded lands, or lands that do not meet the definition of a forest⁶, which are ecologically intended to hold forests.
• Project activities must reforest lands that have historically supported forest ecosystems, and where reforestation would restore landscape-level ecological integrity. This historical forest presence and ecological suitability must be evidenced by at least one of the following:
  • Land cover classification, in accordance with Section 4.1.1: Land Cover Classification Requirements
  • Historical documentation or imagery showing forest presence
  • Scientific analysis of soil composition, pollen records, or other ecological indicators
  • Established scientific consensus regarding the project area's natural forest biome
  • Traditional ecological knowledge documenting historical forest presence
• Project activities must not reforest lands classified as forests for the 10 years prior to project initiation (see Section 4.1.1). Exceptions are permitted when land clearing at < 10-year intervals is the result of a documented natural disaster or is demonstrated common practice in the region, evidenced by management logs, traditional ecological knowledge, remote sensing data, or photography.
• Project activities must not occur on terrestrial or tidal wetlands (e.g., peatlands, marshes, mangroves), evidenced by soil maps or land cover classification (see Section 4.1.1).
• Projects must not be located in regions where albedo changes lead to a net warming effect based on the map in Fig. 1 of Hasler et al., 2024⁷. While the restoration of nature is an important project benefit, the primary objective of reforestation projects funded by Carbon Finance is to store carbon and mitigate the worst effects of anthropogenic climate change.

Land cover data sources derived from remote sensing and used for land cover classification in Section 4.1 should meet the following criteria:

• Be a peer-reviewed product with publicly available data and code;
• Have a minimum classification accuracy > 90%, with reported uncertainty values;
• Have a spatial resolution ≤ 30 m; and
• Have annual data for at least the 10 years prior to project initiation.

• Projects must not occur in regions where significant reforestation activities are driven by market demand, local and/or national incentives, or forestry policies that would lead to forest restoration without Carbon Finance.
  • Throughout this Protocol, region is defined by the RESOLVE terrestrial ecoregion⁸ within the same country as The Project (e.g., Southwest Amazon moist forests in Brazil).
  • To determine eligibility, the Project Proponent must provide evidence that the land would not be reforested under baseline conditions, as required by Section 7.4: Additionality and the dynamic baseline approach described in Section 9.4.
• Projects should not resemble commercial plantation forestry.
  • Violation of this principle would include monoculture plantations, or plantations limited to several high-value timber species whose composition does not resemble native community assemblages, planted in regions where timber is common practice and thus the infrastructure exists to support wood harvesting.
    • In the rare cases where a species naturally grows in monoculture within the project region, Project Proponents may proceed with monoculture planting of this species in consultation with Isometric as outlined in Section 6.4: Safeguarding of Biodiversity.
  • Note that selective harvesting and harvesting of non-timber forest products is permissible under this Protocol, in consultation with Isometric.

• The Project must not disproportionately harm Indigenous People and local, underserved, or marginalized communities, in compliance with Section 3.7 of the Isometric Standard and Section 6 of this Protocol.
• Projects should aim to improve ecosystem function and biodiversity through increasing wildlife corridors, increasing forest habitat, and avoiding negative impacts on existing ecological functions.

Additionally, this Protocol applies to projects and associated operations that meet all of the following project conditions:

• The Project must provide a net-negative CO₂e impact (net CO₂e removal) as calculated in the GHG Statement, in compliance with Section 9.
• The Project must be considered additional, in accordance with the requirements of Section 7.4.
• The Project should strive to limit soil inversion to 25 cm during project establishment.
• The Project must provide 40+ years of CO₂ storage in the project area, as defined by the length of the Project Commitment Period (see Section 5.1).
• The Project Proponent must provide evidence that the area to be reforested can be conserved throughout the Project Commitment Period. Failure to maintain land tenure of the project location may result in the cancelation of Credits.
• The Project must meet the transparency requirements of this Protocol, outlined in Section 7.6: Data Sharing.

• Definition. The Project Commitment Period encompasses two distinct periods, the Crediting Period plus a minimum 40-year Ongoing Monitoring Period after the end of the Crediting Period.
• Requirements. Projects must provide the following to evidence the length of the Project Commitment Period (see Section 11: Pre-deployment Requirements).
  • Land tenure and contractual obligation. The Project Proponent must have legal, documented land tenure for the duration of the Project Commitment Period and contractual obligations to maintain forest carbon stocks throughout the Project Commitment Period. If the Project Proponent is contracting on smallholder land, smallholders must be contractually obligated to maintain forest carbon stocks.
    • In the event of land ownership transfer, including inheritance, sale, or other forms of succession, the Project Proponent must ensure that the new owner(s) or heir(s) are contractually obligated to uphold the commitments outlined in the Project Design Document (PDD). This includes maintaining forest carbon stocks and any other project requirements for the duration of the Project Commitment Period. Such obligations must be legally binding and explicitly detailed in the PDD to mitigate risks of tenure disputes or non-compliance.
  • Financial plan. Credit issuances will decrease over time, and continued financial payments are needed to incentivize maintenance of carbon stocks. To evidence the continued financial viability of The Project over the full Project Commitment Period, Project Proponents must provide a financial model and cash flow statement which demonstrates a clear payment structure for the duration of the Ongoing Monitoring Period. Methods to maintain continued financial incentives may include:
    • Investing a portion of revenue into a trust which shifts payments over the full Project Commitment Period; and/or
    • Transitioning to alternative income streams which promote the maintenance of forest carbon stocks.
  • Ex-ante duration estimate. The duration of the Crediting Period is determined by an ex-ante estimate of forest growth rates to reach forest maturity. Due to the variability of forest growth factors and tree biology, the Crediting Period may vary by project.
• Project Termination. Abandonment or failure to perform project activities at any point in the Project Commitment Period will result in project failure. All Credits issued under The Project will be canceled.

• Definition. The Crediting Period is the interval between project initiation (first activity on site associated with The Project) and the end of the last Reporting Period. The Crediting Period is made up of successive Reporting Periods.
• Credit Issuance. Credit issuances occur throughout the Crediting Period. Credits are issued upon Verification of a Reporting Period.

• Definition. The Reporting Period is the interval of time over which removals are calculated. The first Reporting Period starts at project Validation. Subsequent Reporting Periods begin at the end of the previous Reporting Period.
• Duration. The minimum duration of a Reporting Period is one year. The maximum duration of a Reporting Period is five years. Project Proponents may request an extension for a longer Reporting Period provided they submit suitable justification for the delay (e.g., slower forest growth than expected).
• Verification. Verification of project activities by a third-party VVB is conducted for each Reporting Period (see Section 7.2: Verification and Validation).
• First Reporting Period. Due to higher levels of error in biomass in stands of younger trees^{9, 10}, the first Reporting Period may be longer than 5 years to allow for tree growth. Project Proponents should perform project surveys at 6-month intervals before the first Reporting Period to document and mitigate early tree mortality.
• Last Reporting Period. Project Proponents must indicate the last Reporting Period to be submitted for Verification. Failure to initiate a Verification within 5 years of the previous Reporting Period or request an extension will conclude the Crediting Period and shift The Project into the Ongoing Monitoring Period.

• Definition. The Ongoing Monitoring Period is the interval between the end of the Crediting Period through the end of the Project Commitment Period.
• Duration. The minimum duration of the Ongoing Monitoring Period is 40 years.
• Durability. The durability of Credits are determined by the duration of the Ongoing Monitoring Period (see Section 10.1: Durability).
• Monitoring. Monitoring for Reversals is conducted by Isometric throughout the Ongoing Monitoring Period, as described in Section 10.5. Reversals are compensated by a Buffer Pool (see Section 10.4: Buffer Pool).

• Definition. The indefinite period of time after the Project Commitment Period has ended.
• Long-term durability plan. Projects must have a plan for long-term maintenance of forest carbon stocks after the Project Commitment Period to prevent timber harvest or Reversals after The Project ends.

Figure 1 Summary of project periods. Colors represent actions owned by different stakeholders. Blue = Project Proponent. Green = VVB. Pink = Isometric.

A project starting in 2025 has a Project Commitment Period of 100 years composed of a 40 year Crediting Period followed by 60 year Ongoing Monitoring Period. Credits issued have a 60+ year durability. Monitoring for quantification is conducted by the Project Proponent through the Crediting Period, and the reported activities are verified by a Validation and Verification Body (VVB) for each Reporting Period. At the end of the Crediting Period, maintenance of carbon stocks and monitoring for Reversals occurs for the remaining 60 years of the Project Commitment Period.

The Project must consider environmental and social impacts at all project locations. Appropriate measures must be implemented to identify and eliminate potential risks to terrestrial and aquatic ecosystems and biodiversity. Where risks cannot be eliminated, the Project Proponent must identify measures to monitor ecosystem health and mitigate adverse effects through a site-specific mitigation plan. Mitigation plans must be prepared by subject matter experts, in consultation with Isometric, the VVB, and relevant local authorities, if applicable. Refer to Section 3.7 of the Isometric Standard for further guidelines on environmental and social impacts.

Following the Isometric Standard, Credits issued under this Protocol are contingent on the implementation, transparent reporting, and independent Verification of comprehensive safeguards. These safeguards encompass a wide range of considerations, including environmental protection, social equity, community engagement, and respect for cultural values. The process mandates that safeguard plans be incorporated into all major project phases, with detailed reports made accessible to stakeholders. Adherence to and verification of environmental and social safeguards is a condition for all Crediting Projects.

An environmental and social risk assessment in adherence with Section 3.7 of the Isometric Standard must be completed to identify potential risks, followed by the development of tailored mitigation plans. These plans must encompass specific actions to avoid, minimize or rectify identified impacts. Effective implementation of these measures must also be accompanied by a robust monitoring plan to detect adverse effects and pause project activities if necessary, using the principles of adaptive management described below.

Environmental and social risk identification, assessment, avoidance, and mitigation planning will be unique to the technical, environmental, and social contexts of The Project. To accommodate this variation, the requirements outlined in this section serve as a minimum to which the Project Proponent and Isometric can add risks on a case by case basis, to be included in the PDD, if applicable.

Project Proponents must comply with all national and local laws, regulations and policies, and receive any necessary permits for project activities, if applicable. Where relevant, projects must comply with international conventions and standards governing human rights and uses of the environment.

Project Proponents must document activities that trigger environmental permitting requirements.

Adaptive management incorporates learnings and takeaways from project monitoring into project development¹¹. Regular data collection and sharing is necessary to implement adaptive management. Results from data collection at the end of each Reporting Period must be shared with local stakeholders, as described in Section 6.5.1 of this Protocol, and be used to inform future iterations of project management and development.

Project Proponents are required to predict and plan for potential unintended outcomes of project activities and construct mitigation plans for such instances. Foreseeable risks identified during the preparation of the environmental and social risk assessment must be included in the PDD and the following must be detailed for each potential risk:

• A region specific mitigation plan
• The measured or observed outcome that will trigger the mitigation plan
• Plan for information sharing
• Emergency response plan, if applicable

The Project should not hinder the ability of the community or local ecosystem to adapt to climate change as a result of the CDR activity.

The High Conservation Values (HCV) Approach, developed by the HCV Network, identifies regionally specific facets of local communities and ecologies that must be considered during project developments resulting in land use change. The HCV Network has identified six values that may be at risk as a result of land use change projects. The values, along with corresponding requirements for Project Proponents to uphold them, are listed below:

• Species Diversity: Rare, threatened, endangered, or endemic species, at populations significant to regional, national, or global levels.
  • Requirements. Population density of these species in the project area must not decrease as a result of project activities (see Section 6.3.1). It is recommended that Project Proponents strive to increase the populations of these species during project activities to improve the climate adaptation potential of the local ecosystem, which in turn increases the durability of carbon stored in aboveground biomass.
    • In cases where reforestation will lead to a decrease in the population of rare, threatened, or endangered species which occupy non-forested or degraded lands, The Project may proceed if permitted by law and after a mitigation plan is developed in consultation with Isometric and included in the PDD. Mitigation plans must ensure no decrease in population density and should include activties such as:
      • Relocation of population to areas within the same region as the project area, which can support and maintain the species' population;
      • Maintenance of population in the project area through the development of ecologically appropriate reserves and wildlife corridors;
      • Active monitoring plans.
    • In some instances, endemic species may be overpopulated prior to project initiation and decrease as a result of project activities. These or similar situations may be allowable under this Protocol, in consultation with Isometric. Project Proponents must demonstrate that a population decrease in the project area will not adversely impact the species' metapopulation and that an endemic species was overpopulated in the project area through one of the following:
      • Peer-reviewed scientific literature;
      • Authoritative national- or regional-body publications; or
      • A population census conducted by an independent third party in consultation with Isometric.
• Landscape-level ecosystems, ecosystem mosaics and intact forest landscapes: Broad-scale regions of interacting ecosystems which contain species in their natural patterns or distributions at populations significant on regional, national, or global scales.
  • Requirements. Ecological integrity in the project area must be maintained throughout project activities.
• Ecosystems and habitats: Rare, threatened, or endangered ecosystems or habitats.
  • Requirements. Rare, threatened, and endangered ecosystems and habitats in the project area must be maintained and protected throughout project activities.
    • These ecosystems and habitats within the project area must be excluded from reforestation activities. Total area degraded by project activities should not exceed 10% and must not exceed 30% in these ecosystems and habitats^{12, 13}.
• Ecosystem services: Fundamental ecosystem functions critical to ecological integrity and life, e.g., oxygen production, water filtration and protection of catchments, soil formation and erosion prevention, temperature regulation, nutrient cycling, habitat formation, provisioning of food and forage for fauna, etc.
  • Requirements. Ecosystem services should be restored to those rendered by forests within the project area region and maintained throughout project activities.
• Community needs: Commodities, resources, and community functions that are necessary for the livelihoods of local communities and Indigenous Peoples. This may include food, water, and infrastructure sources.
  • Requirements. Community needs must be identified in consultation with local stakeholder groups. Community needs must not be damaged as a result of project activities. Access to community resources must not be limited as a result of project activities.
• Cultural values: Sites, landscapes, and habitats of significant cultural, historical, religious, economic, or archaeological value to local communities, Indigenous Peoples, or other groups identified to engage in those locations.
  • Requirements. Cultural values must be identified in consultation with local stakeholder groups. Cultural values must not be damaged as a result of project activities.

For each value above, the Project Proponent must identify in the PDD if the value is present or absent in the project area. This list must be constructed in consultation with relevant stakeholder groups, as identified in Section 6.5.1 and carried out in accordance with Section 3.5 of the Isometric Standard . The Stakeholder Engagement Plan for HCV identification must also be included in the PDD.

If a value is absent from the project area, the Project Proponent must provide an explanation or justification such as survey results or recent publications. If a value is present in the project area, the Project Proponent must include a plan to monitor and protect it throughout the Project Commitment Period in the PDD. We encourage Project Proponents to review the Common Guidance for the Management and Monitoring of HCV in developing this plan. If protection is not feasible during the project activities and an HCV is damaged as a result of project activities, the Project Proponent must provide a restoration plan to return the area to its prior condition and quality.

If an HCV is threatened or damaged by forces or parties outside of the Project Proponent’s jurisdiction and not as a result of or response to project activities, the Project Proponent must report such instances to Isometric, but may not be responsible for enacting a restoration plan. Failure to properly identify, monitor, and protect an HCV may result in the cessation of Credits.

The Project Proponent must provide due diligence to ensure that the population density of rare, threatened, and endangered species in the project area does not decrease, nor are new species added to this list, as a result of project activities. If either of these adverse impacts do occur, the Project Proponent must work with Isometric and the VVB to identify sources and explanations for these impacts in order to rule out project activities as the primary cause.

It is recommended that Project Proponents strive to increase the population of rare, threatened, and endangered species. Endangered species are defined as species under threat of extinction from all or a significant amount of their natural habitat. Threatened species are defined as those that are at risk of becoming endangered. Rare species are defined as those uncommon and found in isolated geographical locations. Project Proponents must consult local authorities for further regulations on these or similar groups. If local regulations exist, the Project Proponent must state them in the PDD.

The Project Proponent must consult reputable and current sources on rare, threatened, and endangered species to develop a list of these species, in the following order of priority:

1. Local and/or regional registries;
2. National registries;
3. Peer-reviewed publications; and
4. The International Union for Conservation of Nature (IUCN) Red List of Threatened Species¹⁴.
   • For the purposes of this Protocol, the IUCN Red List designation of Vulnerable (VU) shall be considered Threatened, and Near Threatened (NT) shall be considered Rare.

The results of the rare, threatened, and endangered species list review must be included and referenced in the PDD.

For each rare, threatened, or endangered species identified, the Project Proponent must list the following in the PDD:

• Ecosystem services vital to the ecology and population stability of the rare, threatened, or endangered species found in the project area.
• How The Project will maintain or enhance these ecosystem services so as to promote the survival of the rare, threatened, or endangered species.
• A population monitoring plan. We encourage Project Proponents to consult Isometric, external subject matter experts, and/or authoritative resources in developing their plan.

The Project Proponent must handle data and information related to rare, threatened, and endangered species with discretion for the protection of these species, especially regarding species and/or regions that have histories of poaching, over-harvesting, or other elevated threats to population density and livelihoods.

As stated in Section 4.1, reforestation projects must occur on degraded land to be eligible for crediting under this Protocol. Because of this applicability requirement and the nature of reforestation projects to plant and maintain species in the project area, reforestation projects are well placed to increase biodiversity in the region. To benchmark increased biodiversity, Project Proponents must include more than five species from two or more genera in their planting plan and should prioritize the planting of endemic, rare, threatened, and endangered native species. Species should be planted at ecologically appropriate richness and evenness¹⁵. There may be some regions that naturally support a limited number of species that fulfill ecosystem services and other functions or indicators of healthy ecosystems. Project Proponents in these regions may deviate from the minimum required species and genera included in planting plans, in consultation with Isometric. Such deviations must be accompanied by appropriate documentation, based in scientific literature and/or ongoing field studies, in the PDD.

The tree species used for reforestation must follow the principles outlined below.

The Project Proponent must list the species planted and/or maintained in the project area via project activities in the PDD. These species may include native, naturalized, or non-native range-expanding species. Project Proponents must not introduce species invasive to the region or similar climates, geographies, or ecosystems of the project area^{16, 17}. The definition of 'invasive species' in this Protocol is consistent with the Convention on Biological Diversity's definition of Invasive Alien Species, being a "species whose introduction and/or spread threaten[s] biological diversity"¹⁸. Projects that plant invasive species will not be eligible for crediting under this Protocol. Additionally, Project Proponents must not introduce any species that harm rare, threatened, or endangered species as defined in Section 6.3.1 or adversely impact the integrity of rare, threatened, or endangered ecosystems and habitats (see Section 6.3). Project Proponents are highly encouraged to consult with Isometric, the VVB, and/or external subject matter experts to ensure that species included in the reforestation plan meet these requirements and the criteria described below.

For the purposes of this Protocol, native species are defined as:

• Species indigenous to the project area that would be found naturally (not planted or introduced anthropogenically via assisted migration) in the project area prior to deforestation or degradation, and/or species that are indigenous to and found naturally in land adjacent to the project area; or
• Species indigenous to the region that have not grown in the project region for the past 100+ years due to displacement via anthropogenic factors or competition from invasive species, but are still well suited to the climate of the project area, as demonstrated by scientific literature, presence of these species in similar climates, and/or evidence of displacement via one of these two forces.
  • Indigenous species that have not existed in the project region for the past 100+ years due to failure to adapt to changing climatic conditions may not be suitable for reintroduction for the purposes of GHG removal, but may be suitable for other ecosystem benefits. Reintroduction of such species should be done in consultation with Isometric.

Naturalized species are defined as:

• Species which occur in the project region at the time of project initiation, have existed in the project region for 100+ years, and have not threatened biodiversity in the region during that time frame, regardless of indigeneity.

Reforestation with native species should be the first course of action. If reforestation with only native and naturalized species is not feasible, non-native range-expanding species may be included in the reforestation planting plan. Any non-native species not considered range-expanding for the purposes of this Protocol must not be planted. Non-native range-expanding species are defined as:

• Species whose natural boundaries are expected to overlap with the project area by the end of the project lifetime and would naturally migrate to and occur within the project boundaries without human-intervention; or
• Species that currently exists in the same RESOLVE terrestrial biome⁸ as the project area, and where peer-reviewed literature or government agency documentation supports the species assisted migration as an adaptation response to climate change, and where such migration is projected to occur naturally over time due to climate change.

In such instances, the majority of species planted must be native and/or naturalized, and the plurality must be native species. Additionally, the following due diligence must be taken when planting non-native range-expanding species for a project to be eligible for crediting. The Project Proponent must demonstrate:

• Reforestation with native species will hinder the Project Proponent’s ability to meet project objectives:
  • Introduction of native species will lead to negative ecosystem impacts.
  • Native species will fail to thrive and contribute significantly to the carbon stock over the course of the Reporting Period. This may occur if the species lack climate resilience, marked by increased vulnerability to temperature fluctuations, changes in water availability, competition from invasive species, disease, etc.
• Reforestation via non-native range-expanding species will bring net positive ecosystem or community impacts that could not otherwise be achieved.
• Non-native range-expanding species are expected to serve as pioneer species for successional planting of native species, as demonstrated in scientific, peer-reviewed literature and/or in other reforestation projects in the same or similar regions.

Alternative burdens of proof may be sufficient, in consultation with Isometric.

The following due diligence must be conducted and included in the PDD if non-native range-expanding species are to be planted during project activities. The Project Proponent must demonstrate:

• The species are able to adapt to climate-induced changes expected to take place in the region over the project lifetime.
• The species will serve similar ecological niches as native and/or naturalized species present in the region at the time of project initiation (e.g., as a suitable food source for local fauna).
• The species do not have the potential to be invasive. This must be demonstrated through recent peer-reviewed literature and observational studies of the species in the same region and/or other regions with similar climates, geographies, and ecologies.

A robust seedling and germplasm pipeline is central to the ecological, socioeconomic, and cultural success of a reforestation project. A diverse, local, and sustainable pipeline ensures that project activities contribute to the restoration of ecosystem function and integrity, restore and protect biodiversity, safeguard community livelihoods, and uphold cultural values.

Project Proponents must procure and maintain their seedling and germplasm pipeline in alignment with the environmental and social safeguards outlined in Section 6 of this Protocol and Section 3.7 of the Isometric Standard.

The pipeline must be described in the PDD and the Project Proponent should:

• Procure genetically diverse seedlings and germplasms, sourced from within or near the project region. This conserves locally adapted traits and strengthens resilience to climate change, pests, and diseases.
• Prioritize sourcing from nurseries that employ local community members and align with the requirements and suggestions of Section 6.5: Safeguarding of Community Livelihoods, thereby generating equitable economic opportunities and fostering long-term community investment in project success.
• Stock and maintain sufficient germplasm resources to support not only forest regeneration, but also essential non-reproductive ecological functions such as nutrient cycling and faunal sustenance.

In accordance with Section 3.5 of the Isometric Standard, Project Proponents must demonstrate active stakeholder engagement throughout project planning and operation, ensuring that all risk mitigation strategies contribute to sustainable project outcomes. Local stakeholders may contribute an in-depth understanding of the project area and operations, and provide invaluable insights and recommendations on potential risks, necessary safeguards and specific monitoring needs. Engaging local stakeholders in reforestation projects creates community buy-in, providing long term commitment and investment in the success of reforestation projects^{19, 11}. Furthermore, lack of community support, stakeholder engagement, and perceived community benefits has been identified as a primary source of project failure in previous forestry projects²⁰.

The Project Proponent must develop a Stakeholder Engagement Plan in accordance with the requirements outlined in Section 3.5 of the Isometric Standard. The plan and supporting documentation, including evidence of meetings or other forms of engagement, must be submitted in the PDD.

Prior to the commencement of project activities, Project Proponents are required to assess if Indigenous Peoples will be impacted by project activities, in consultation with Isometric. Impacts may include, but are not limited to:

• Project activities that occur on land or territories that is owned, occupied, or utilized by Indigenous Peoples, regardless of whether or not this claim is recognized by the local governing body or held by rights to self-determination, as recognized by the United Nations;
• Project activities that will affect natural resources necessary for the livelihoods or cultural rights of Indigenous Peoples.

Project Proponents must consult a reputable third party or subject matter expert to assess if Indigenous Peoples will be impacted by project activities. The results of this report must be included in the PDD. If the report identifies potential impacts to Indigenous Peoples, the Project Proponent must enact a Stakeholder Engagement Plan consistent with the principles of Free, Prior, and Informed Consent (FPIC) as outlined by the United Nations (UN) Declaration on the Rights of Indigenous Peoples²¹ in 2007 and expanded upon by the Food and Agriculture Organization of the United Nations in 2016²².

• Free: Stakeholders are not subject to intimidation, coercion or manipulation during the decision making process.
• Prior: Engagement is sought in the early stages of project development before commencement of project activities. Consent must be sought as part of project development, regardless of local requirements. The timeline for the decision making and deliberation periods is set in consultation with all stakeholder groups and is informed by customary, local, and/or traditional practices.
• Informed: Information is presented in a manner that is accessible to all stakeholder groups. Accessible content may differ across stakeholder groups. The Project Proponent must consider in the information sharing process the language and medium of communication. For example, if information is presented electronically, stakeholders must have access to and familiarity with the necessary technology to review the information. If information is presented during in-person meetings, the meetings must be held at a time and in a location that is conducive to stakeholder attendance. Information presented to stakeholders must be objective and present trade-offs fairly and accurately. Finally, information must be provided on an ongoing basis. The following due diligence is strongly recommended to ensure stakeholder groups are well informed of project development and outcomes:
  • Stakeholders should be made aware of the value of the Credits, and anticipated revenue of The Project at-large. The Project’s anticipated growth and issuance should be modeled, and simulations describing the value of Credits at current market prices should be made clear to proponents.
  • Stakeholders should have full access to the project’s finances, budget, and forecasted returns.
  • Stakeholders should be aware of alternative land-use scenarios.
  • Stakeholders should be aware of the value of the timber on The Project once the Crediting Period nears an end, so that they can better commit to conservation and upholding the contract.
  • Stakeholders should have a clear understanding of the breakdowns in project income expenditure, and a clear understanding of the precise percentage of revenue that they are entitled to.
• Consent: Must be freely given and may be withdrawn. Consent may be conditional upon milestones in project development or the emergence of new information. Stakeholder consent is not guaranteed as a result of the Stakeholder Input Process. Consent must be reached by 75% of adults belonging to the stakeholder group.

The Project Proponent is encouraged to prepare alternatives for the withdrawal or denial of consent to project activities by stakeholder groups.

If required, the stakeholder engagement process must be enacted early in the project development process, prior to the initiation of project activities. The stakeholder engagement schedule must be circulated prior to project initiation, and with enough notice to engage stakeholders in the planning processes. In some instances, Project Proponents that initiated project activities prior to engaging with Isometric and did not engage Indigenous Peoples stakeholders under the principles of FPIC may still be eligible for crediting under this Protocol, in consultation with Isometric, by demonstrating how stakeholder engagement will be incorporated into future project planning.

The following may serve as burdens of proof that the Stakeholder Input Process conforms with the principles of FPIC. The Project Proponent must indicate how these steps in the stakeholder engagement process were or will be carried out during the project lifetime. Multiple rounds of stakeholder engagement may take place during a project lifetime, as needed. The Project Proponent may identify other burdens of proof demonstrating that the principles of FPIC have been observed and submit them in the PDD in addition to, or instead of, those below, in consultation with Isometric.

• Measures taken to effectively reach (i.e., identify and locate) all stakeholder groups. If the Project Proponent is not able to reach all adult community members, the percentage of adults in the community reached must be included in the PDD, as well as proof of the attempt to reach the remaining community members. The majority of adult community members must be successfully reached to be eligible for crediting under this Protocol.
• The manner in which information was presented to stakeholders, including the medium and language.
• How stakeholder input was obtained, including the medium and language.
• How stakeholder input was incorporated into the project design.

The VVB may conduct random surveys or interviews with stakeholder groups, and/or witness some or all of the processes described above.

Project Proponents that do not identify Indigenous Peoples that will be affected by project activities are encouraged to consider if other relevant stakeholders rely on land or resources located within the project area, and engage them following the principles of FPIC described above. All stakeholder groups and local communities have valuable and unique perspectives on developments in the project area, which can contribute to project success.

The following information from the stakeholder engagement process must be made publicly available, with personal information anonymized or redacted to protect stakeholders, project personnel, and project outcomes. This may include:

• Due diligence that the FPIC processes were carried out (e.g., meeting recordings or copies of information shared with stakeholders)
• Budget reports, including revenue sharing agreements

The Project Proponent must identify and develop processes for the protection and promotion of community well-being in the PDD, as follows:

• Protection of human rights:
  • Policies and practices upholding anti-discrimination on the basis of gender, sexual orientation, etc.
• Grievances, feedback, and complaints:
  • The process by which the Project Proponent accepts grievances, feedback, and complaints. Project Proponents must consult a third party to address grievances. The grievance redress process must be outlined in the PDD.
  • Mediation and resolution process for grievances and complaints.
• Employment Opportunities:
  • Hiring practices and policies, including the number of short-, medium-, and long-term employment opportunities that were recruited for in the local community relative to total new jobs created.

As previously mentioned, community buy-in is critical to the success of a reforestation project ^{19 , 11 , 20}. Community buy-in may be established when stakeholders are properly informed about the benefits they can expect from the reforestation project. Equally important in maintaining buy-in is for the positive impacts resulting from the project to match the (perception of) potential benefits presented to community stakeholders at the project onset. A mismatch in benefits expected and benefits realized may similarly hinder project success.

While this Protocol will not prescribe requirements for community impacts, the Project Proponent is strongly encouraged to consider establishing the following programs and activities:

• Employment opportunity programs favoring local community members, especially in the creation of long-term jobs;
• Establishment of community benefit-sharing arrangements;
• Construction of infrastructure, such as roads, that are accessible to the community;
• Development of site specific mitigation plans for potential negative community impacts.

Positive impacts should be felt by all stakeholder groups identified in Section 6.5.1. Project Proponents should consider which groups may face the brunt of negative community impacts, and how positive community benefits may be shared equitably with these and other marginalized groups.

It is recommended that the Project Proponent provide support to the local communities and ecosystems to establish region specific mitigation strategies to adapt to changing climates.

The following topics are covered briefly in this Protocol due to their inclusion in the Isometric Standard, which governs all Isometric Protocols. See in-text references to the Isometric Standard for further guidance.

For each specific project to be evaluated under this Protocol, the Project Proponent must document project characteristics in a Project Design Document (PDD) as outlined in Section 3.2 of the Isometric Standard. The PDD will form the basis for project Validation and evaluation in accordance with this Protocol.

Projects must be validated and net CO₂e removals verified by an independent third party, consistent with the requirements described in this Protocol, as well as in Section 4 of the Isometric Standard.

The Validation and Verification Body (VVB) must consider the following requisite components:

• Verify that The Project meets the Applicability conditions described in Section 4
• Verify that the Environmental & Social Safeguards outlined in Section 6 are met
• Verify that the System Boundary & Leakage assessment adheres to the requirements of Section 8
• Verify that the quantification approach and monitoring plan adheres to requirements of Section 9
• Verify that the conditions for ensuring durability and monitoring for Reversals in Section 10 are met
• Verify that The Project is compliant with requirements outlined in the Isometric Standard

The threshold for Materiality, considering the totality of all omissions, errors and misstatements, is 5%, in accordance with Section 4.3 of the Isometric Standard.

Verifiers should also verify the documentation of uncertainty of the GHG Statement as required by Section 2.5.7 of the Isometric Standard. Qualitative Materiality issues may also be identified and documented, such as:

• Control issues that erode the verifier’s confidence in the reported data;
• Poor management documented information;
• Difficulty in locating requested information; and
• Noncompliance with regulations indirectly related to GHG emissions, removals or storage

Project Validation and Verification must incorporate site visits to project facilities, namely in situ field plots, in accordance with the requirements of ISO 14064-3, 6.1.4.2. This is to include, at a minimum, site visits to the project site during Validation and initial Verification. Validators should, whenever possible, observe project operations to ensure full documentation of process inputs and outputs through visual observation (see Section 4 of the Isometric Standard).

Additional site visits may be required if there are substantial changes to field operations over the course of Validation, or if deemed necessary by Isometric or the VVB. Site visit plans are to be determined according to the VVB’s internal assessment, in consultation with Isometric.

Verifiers and Validators must comply with the requirements defined in Section 4 of the Isometric Standard. In addition, verification teams must maintain and demonstrate expertise associated with the specific technologies of reforestation and forest management, including both forest field measurements and Earth System remote sensing data processing and analysis.

CDR via reforestation is a result of a multi-step process (e.g., seed planting, forest maintenance, monitoring), with activities in each step potentially managed by a different operator, company, or owner. A single Project Proponent must be specified contractually as the sole owner of the Credits when there are multiple parties involved in the process, and to avoid Double Counting of net CO₂e removals. Contracts must comply with all requirements defined in Section 3.1 of the Isometric Standard.

The Project Proponent must be able to demonstrate additionality through compliance with Section 2.5.3 of the Isometric Standard. The Baseline scenario and Counterfactual utilized to assess additionality must be project-specific and comply with Section 9.4 of this Protocol.

Government subsidies or civil contractual obligations for reforestation, such as organization bylaws, inhibit additionality and fall under the Regulatory criteria in Section 2.5.3 of the Isometric Standard. Environmental additionality is assessed each Reporting Period using dynamic baselining as outlined in Section 9.4.

Additionality determinations should be reviewed and completed at every Verification at a minimum, or whenever project operating conditions change significantly, such as the following:

• Regulatory requirements or other legal obligations for project implementation change or new requirements are implemented;
• Project financials indicate Carbon Finance is no longer required to operate the Project, potentially due to, for example:
  • sale of non-timber co-products that make the business viable without Carbon Finance; or
  • reduced rates for capital access.

If a review indicates The Project has become non-additional, The Project will be ineligible for future Credits. Current or past Crediting Periods will not be affected.

The uncertainty in the overall estimate of the net CO₂e removal as a result of The Project must be accounted for. The total net CO₂e removed for a specific Reporting Period, $RP$, ${CO}_{2}^{}e_{Removal, RP}^{}$, must be conservatively determined in accordance with the requirements outlined in Section 2.5.7 of the Isometric Standard.

Projects must report a list of all key variables used in the net CO₂e removal calculation and their uncertainties, as well as a description of the uncertainty analysis approach, including:

• field measurements used for the net CO₂e removal calculation
• parameters that impact the estimation of the total aboveground woody biomass, such as allometric equation parameters, canopy height, etc.
• parameters used for calculating carbon stocks, including root-to-shoot ratios and carbon fractions
• quantification of aboveground biomass (AGB) model strength through comparison with independent datasets
• emission factors utilized, as published in public and other databases used

The uncertainty information should at least include the minimum and maximum values of a variable. More detailed uncertainty information should be provided if available, as outlined in Section 2.5.7 of the Isometric Standard.

In addition, a sensitivity analysis that demonstrates the impact of each input parameter’s uncertainty on the final net CO₂e uncertainty must be provided. Details of the sensitivity analysis method must be provided such that a third party can reproduce the results. Input variables may be omitted from an uncertainty analysis if they contribute to a < 1% change in the net CO₂e removal. For all other parameters, information about uncertainty must be specified.

In accordance with the Isometric Standard, all evidence and data related to the underlying quantification of CO₂e removal and environmental and social safeguards monitoring will be available to the public through the Isometric platform. That includes:

• Project Design Document
  • See Section 11 for a list of pre-deployment requirements that must be included in the PDD
• GHG Statement
• Measurements taken, with supporting documentation (e.g., calibration certificates)
• Emission factors used
• Scientific literature used
• Proof of approval for necessary permits
• Remote sensing and field plot data collected by The Project
• All maps generated for calculating carbon stocks in the project area
• All maps generated for calculating carbon stocks in control areas (geospatial reference data can be removed for privacy reasons)
• Model specifications and output

The Project Proponent can request certain information to be restricted (only available to authorized Buyers, the Registry, and VVB) where it is subject to confidentiality. This includes emission factors, specific data, and/or proprietary models from licensed databases. However, all other numerical data produced or used as part of the quantification of net CO₂e removal will be made available.

The scope of this Protocol includes GHG sources, sinks and reservoirs (SSRs) associated with a reforestation project. A cradle-to-grave GHG Statement must be prepared encompassing the GHG emissions relating to the activities outlined within the system boundary.

Any emissions from sub-processes or process changes that would not have taken place without The Project, and any activity that ultimately leads to the issuance of Credits, must be considered in the system boundary. This allows for accurate consideration of additional, incremental emissions induced by The Project.

The system boundary must include all SSRs controlled by, and related to, The Project, including but not limited to the SSRs in Table 1. If any GHG SSRs within Table 1 are deemed not appropriate to include in the system boundary, they may be excluded, provided that robust justification and appropriate evidence is included in the PDD. Materiality considerations for exclusions are set out in Section 8.1.1.1.

Table 1. Scope of activities and GHG SSRs to be included in the system boundary.

The Project Proponent must consider all GHGs associated with SSRs, in alignment with the United States Environmental Protection Agency’s definition of GHGs, which includes: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O) and fluorinated gasses such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆) and nitrogen trifluoride (NF₃). For CO₂ stored, only CO₂ will be included as part of the quantification and for Fertilizer use (Direct), only N₂O shall be included as part of the quantification. For all other activities, all GHGs must be considered. For example, the release of CO₂, CH₄, and N₂O is expected during diesel combustion.

All GHGs must be quantified and converted to CO₂e in the GHG Statement using the 100-year Global Warming Potential (GWP) for the GHG of interest, based on the most recent volume of the IPCC Assessment Report (currently the Sixth Assessment Report²⁴).

Miscellaneous GHG emissions are those that cannot be categorized by the GHG SSR categories provided in Table 1. The Project Proponent is responsible for identifying all sources of emissions directly or indirectly related to project activities and must report any outside of the SSR categories identified as miscellaneous emissions.

Emissions associated with The Project's impact on activities that fall outside of the system boundary of The Project must also be considered. This is covered under Leakage in Section 8.3.

Some studies^{25, 26} have identified reforestation projects to have high removal efficiency, with lower emissions on average when compared to removal capacity, than other CDR pathways. These studies also indicate that emissions associated with reforestation projects still make up a material fraction of net CDR for these projects. Studies²⁷ also highlight that other existing methodologies vastly underestimate emissions associated with reforestation projects, therefore leading to a risk of over-crediting.

At the time of Protocol development, a lack of suitable benchmark data exists to exclude categories of SSRs from GHG accounting requirements. When a suitable range of appropriate project data is available, this will be revisited. In the meantime, a Materiality threshold has been set at 1% of total removals. If emissions for an SSR are expected to be < 1% of total removals, they may be excluded from the GHG systems boundary. A sensitivity analysis must be used to demonstrate that excluded GHG SSRs are likely to contribute to < 1% of total project removals. The sensitivity analysis may be based on high level information and indicative values, but the decision making and logic followed must be appropriately and transparently evidenced. All exclusions must cumulatively make up < 1% of total removals. This threshold will be revised in light of new information or literature becoming available.

Ancillary activities (such as supplementary research and development activities and corporate administrative activities) that are associated with The Project, but are not directly or indirectly related to the issuance of Credits, can be excluded from the system boundary.

Reforestation may have additional impacts on GHG emissions beyond the scope of this Protocol. For example, positive leakage may occur where reforestation practices lead to positive ecological impacts outside of the project boundary. These potential secondary climate effects are not considered in this Protocol.

The Baseline scenario for reforestation assumes that the activities associated with The Project do not take place and that any infrastructure associated with The Project is not built.

The Counterfactual is the CO₂ stored that would have occurred due to natural regeneration over the Crediting Period in the absence of The Project. This Protocol uses a dynamic baseline approach to quantify the Counterfactual. This is detailed in Section 9.4.4.

Leakage emissions, $CO_2e_{Leakage}$, occur when project activities lead to emissions that occur outside the system boundary of reforestation projects. They include increases in GHG emissions as a result of reforestation projects displacing emissions or causing a secondary effect that increases emissions elsewhere. Three key types of leakage can occur for reforestation projects:

• Activity-shifting leakage. Reforestation projects may displace activities in their project areas, leading to an increase in those activities outside of the project area, which may result in potential land conversion. Examples are where the local community can no longer use the project site for subsistence, or where farmers are displaced as a result of project activities. This type of leakage is known as “Direct” leakage as the relevant stakeholders can be identified and the activity-shifting is traceable.
• Market leakage. Reforestation projects may displace activities, which results in a reduction in supply of a commodity. Changes to the supply and demand equilibrium causes other market actors to shift their activities, leading to potential land conversion. This type of leakage is known as “Indirect” leakage because its effects cannot be isolated and measured directly. Quantifying the likelihood and potential magnitude of market leakage is complex and relies heavily on modeling and available literature.
• Ecological leakage. Project activities may lead to emissions in areas outside of the project site as a result of ecological interactions, for example unintended hydrological impacts, introduction of disease, or secondary impacts of faunal influx.

Project activities that adversely alter the water table, harming ecological integrity within the project area and surrounding landscape and watershed, are not permitted under this Protocol. Furthermore, this Protocol limits reforestation to landscapes that were historically forests. Therefore, it is unlikely that surrounding landscapes sensitive to hydrological dynamics that were not present at the time the site was historically forested would have been established since deforestation. Assessing wider ecological leakage impacts is complex. For this version of the Protocol ecological leakage is assumed to be zero. This will be revisited in future updates to the Protocol.

Activity-shifting and market leakage are addressed in this Protocol. The overall process for addressing activity-shifting and market leakage is set out in the flowchart in Figure 2.

Figure 2 Flowchart of process for addressing activity-shifting and market leakage.

The flowchart is based on the following principles:

• If the commodity was used for subsistence this presents a risk of activity-shifting leakage.
• Activity-shifting leakage risk can be directly identified and mitigated.
• If the commodity was commercial, there is always a risk of market leakage.
• If the commodity was commercial, there might also be a risk of activity-shifting leakage.
• Where Direct Actors have been identified as impacted, activity-shifting leakage mitigation activities will address both activity-shifting leakage and market leakage. However, if only market leakage mitigation is implemented, this will not satisfy the activity-shifting leakage risk. For this reason, if only market leakage mitigation is undertaken, additional activity-shifting leakage monitoring must take place. If only partial or no leakage mitigation is in place, then the market leakage deduction must be applied, as well as a requirement for activity-shifting leakage monitoring.
• Where the commodity was used for subsistence and is not mitigated in full, The Project is not eligible. This is on the grounds of a very high risk of activity-shifting leakage due to dependencies on the land, but also because the project area was an area fundamental for the livelihoods of communities.
• Leakage mitigation has different requirements depending on whether it is addressing activity-shifting leakage or market leakage.

Implementation of the flowchart in Figure 2 requires an understanding of Pre-Project Productivity, $PPP$, including pre-project information about Direct Actors and how the commodity was used. Direct Actors are defined as site owners, tenants or other users that engaged with the project site in a way that produced commodities before the project activities commenced.

The information required is set out below:

• $PPP$ including the type of commodity and yield; and
• Whether the commodity was used for subsistence or commercial production.
  • For the purposes of this assessment, commodities that are commercial, but primarily sold to the local community, are considered subsistence.

$PPP$ is defined as the annual productivity of a commodity type at the project site in relevant units (e.g., tonnes/ yr). This should be an average of the three years prior to the project activities starting. For crops, this should be reflective of the last three complete annual crop cycles. For livestock, this should be reflective of the maximum cattle inventory over the last three years of production. For all other commodities, this should be reflective of production over the last three years of production.

The data hierarchy for obtaining information for $PPP$ is set out below:

1. Farm records, including physical production records and accounts for crops, livestock, poultry and timber, and financial logs including income and expense records and receipts. Farm records may include traditional activity log data, or data from technology like smart tractors and GPS tags on cattle;
2. Land registry data which details previous land holdings at the project site and production information related to land holdings;
3. Remote sensing data which can be used to inform commodity production on land.

The hierarchy must be followed and data choices evidenced. For example, if land registry data is used, sufficient evidence of no available farm records will be required.

As part of determination of $PPP$, the Project Proponent must confirm the following:

• The type of commodity, $c$, that existed at the project site pre-project
• The productivity of commodity production, $Y_c$

The following considerations and assumptions should be made when determining the type of commodity, $c$:

• Where land registry data is used to determine commodity type and commodities produced by one land holding are not quantified separately, or spatially separated, the most conservative assumption on commodity type for the site as a whole must be made. The most conservative assumption should be determined by running the calculations for $ha_{LC}$ (see Equation 5) assuming 100% of the production for each commodity and zero mitigation. The commodity that contributes to the highest value for $ha_{LC}$ should be assumed as full commodity production at the site.
• Where remote sensing data is used:
  • Conservative assumptions on commodity type must be made in any areas of uncertainty. Any assumptions made must be transparently documented and justified.
  • If the land use changed within the five years prior to the project start date, for example from arable use to pasture, the most recent commodity type should be used if it was in use for at least one year or one full crop rotation cycle.
  • If more than one commodity type is identified, they must both be assessed as part of the leakage assessment provided that the spatial extent of each commodity type is clear.

Productivity must be reflective of an average of the three years prior to the project activities starting.

The following considerations and assumptions should be made when determining productivity:

• Farm records must reflect the most recent relevant commodity or ownership class where estimates have been disaggregated by those attributes, and must be substantiated with a signed attestation from the farmer or landowner.
• Any assumptions made to interpret productivity data from farm records or land registry data must be of a conservative nature and be transparently reported.
• Methodologies that determine productivity data from remote sensing may be reviewed on a case by case basis. Models must be regionally- and commodity-appropriate and should have a minimum observation frequency of twice per year over a three-year period. Any inferences of productivity made using remote sensing data must be clearly referenced and justified. These must be of a conservative nature and be transparently reported. Future revisions of this Protocol will consider appropriate requirements for using remote sensing data to determine productivity as standard methodology.
• Where productivity related information is not available, average yield for the region may be used as a proxy for productivity. For example, annual yield data per state or region for the commodity type from the United States Department for Agriculture. An average over the last five years must be taken to account for anomalies.
• Where region-specific data is not available, average yield data at a national level may be used as a proxy for yield. For example, annual yield data for the commodity type from the Food and Agriculture Organization of the United Nations. An average over the last five years must be taken to account for anomalies.
• Where regional or national averages are not available for fuelwood production, average above-ground biomass growth rates published by the IPCC that are applicable to the region should be used.

The Project Proponent must determine the previous use of the commodity and whether it was:

• A commercial commodity: a commodity that is destined for regional, national, or global commercial markets; or
• A subsistence commodity: a commodity that is not destined for regional, national, or global commercial markets and is consumed by the local community.

The Project Proponent must determine this using the following information:

• An affidavit from the identified Direct Actors confirming the end-users of the commodity, or the majority buyer(s) the commodity was sold to. Direct Actors must include the previous site owners, tenants, or other users that engaged with the project site in a way that produced commodities.
• An affidavit from the local authority claiming that the project area was publicly owned and used for subsistence.
• An affidavit from members of the local community confirming that the project area was used for subsistence.
• An affidavit or records from local intermediaries such as wholesalers, distributors, food processors, grain elevators, or livestock auctions, confirming that they purchased commodities from the project site in the past.

If it is not possible to determine whether the commodity was for subsistence or commercial use, then the Project Proponent must assume it was subsistence.

If The Project determines that $PPP$ is zero, this must be evidenced appropriately. This includes:

• Evidence of no farm records on open source sites;
• Land registry data which details no previous agricultural land holdings at the project site;
• Self-assessment from Direct Actors regarding prior use of the site, including photo evidence;
• Written confirmation from project site neighbors regarding the prior use of the site, including photo evidence. This may be land owners or managers from adjacent areas. Where possible this must include a diverse range of stakeholders.

Evidence must be provided for three years preceding the Project Proponent’s purchase of the site for reforestation, or the project start date, whichever is earlier.

In addition, Isometric will undertake remote sensing analysis on project sites which claim that $PPP$ is zero. Remote sensing mapping will be transparently displayed on the registry. Only where remote sensing analysis indicates there are no signs of agricultural production, pasture, or timber harvesting will The Project be eligible for claiming zero $PPP$.

$CO_2e_{Leakage}$ is part of the calculation of $CO_2e_{Emissions}$, as set out in Equation 21 in Section 9.5.

$CO_2e_{Leakage}$ is quantified with the following equation:

$$CO_2e_{Leakage}\; =\; CO_2e_{Market\; Leakage}\;   +\;   CO_2e_{Activity-shifting\;Leakage\:Adjustment}\; +\; CO_2e_{Leakage\; Mitigation\; Emissions}$$

(Equation 1)

Where:

• $CO_2e_{Leakage}$ is the total emissions associated with leakage during the first Reporting Period, RP, in tonnes CO₂e.
• $CO_2e_{Market\: Leakage}$ is the total emissions associated with market leakage for a Reporting Period, RP, in tonnes of CO₂e, see Section 8.3.5.
• $CO_2e_{Activity-shifting\;Leakage\:Adjustment}$ is the adjustment to leakage emissions as a result of activity-shifting leakage being identified via monitoring for a Reporting Period, RP, in tonnes of CO₂e, see Section 8.3.6.2.
• $CO_2e_{Leakage\: Mitigation\: Emissions}$ is total emissions associated with leakage mitigation activities for a Reporting Period, RP, in tonnes of CO₂e, see Section 8.3.4.

$CO_2e_{Leakage}$ is quantified for every Reporting Period, however the following should be noted:

• $CO_2e_{Market Leakage}$ is only estimated once during the first Reporting Period. The emissions associated with market leakage must be allocated to the first Reporting Period.
• $CO_2e_{Activity-shifting \:Leakage\:Adjustment}$ is based on ongoing monitoring and therefore must be reported at every Verification. It is not reported during the first Reporting Period. For the first Reporting Period, and any preceding Reporting Periods where no activity-shifting leakage is identified, $CO_2e_{Activity-shifting \:Leakage\:Adjustment}$ is zero. Activity-shifting leakage adjustments identified (up to a maximum of total possible leakage) should be allocated to the Reporting Period in which they are identified.
• $CO_2e_{Leakage\: Mitigation\: Emissions}$ must be allocated to the Reporting Period in which they occur. For example, emissions that occur as a result of establishment should be allocated to the first Reporting Period. Ongoing emissions, such as fuel use must be allocated to the Reporting Period in which they occur.

The aim of leakage mitigation activities is to reduce the amount of leakage by increasing production of the commodity elsewhere. Leakage mitigation must take place in areas called Leakage Mitigation Sites. These must be separate to the project site, but may be directly adjacent.

The following equation is used to calculate the effectiveness of leakage mitigation:

$$uPPP_c = PPP_c - MAP_c$$

(Equation 2)

Where:

• $uPPP$ is unmitigated Pre-Project Productivity, in appropriate units (e.g., tonnes per year).
• $PPP$ is Pre-Project Productivity - average annual production of commodity that would have been produced in the absence of The Project, in appropriate units (e.g., tonnes per year).
• $MAP$ = Mitigation area productivity, in appropriate units (e.g., tonnes per year).

When $PPP$ is 0, The Project had zero productivity.

When $PPP$ is > 0 and $uPPP$ is 0, The Project has achieved full leakage mitigation and does not take a market leakage emissions deduction.

When $PPP$ is > 0 and $uPPP$ is > 0, The Project takes a market leakage emissions deduction.

Leakage mitigation requirements are different depending on whether mitigation is to address market leakage (see Section 8.3.3.2) or activity-shifting leakage (see Section 8.3.3.1). Activity-shifting leakage will also by nature address market leakage, however market leakage alone will not address activity-shifting leakage.

In addition to the leakage type specific requirements, all leakage mitigation activities must meet the following requirements:

• A written agreement must be in place stating that the landowner of the Leakage Mitigation Site allows the Project Proponent to uniquely claim the increases in productivity as leakage mitigation associated with The Project. This must be covered via legal agreements for a five year term.
• Leakage mitigation activities must provide support to landowners of the Leakage Mitigation Site for a minimum of five years. This is on the basis that the initial leakage mitigation activity leads to sustainable recurring revenue for landowners of the Leakage Mitigation Site.
• Leakage mitigation may lead to increased productivity via creating new production on lands that were not previously used for production, or via intensifying production on existing production lands.
• Land selected for leakage mitigation must not have any other productivity that is negatively impacted by mitigation.
• The mitigation activity must lead to an increase in productivity as a direct result of intentional action from the Project Proponent.
• The spatial extent of the Leakage Mitigation Site and full details of activity must be provided as part of the PDD.

For mitigation of activity-shifting leakage, the Project Proponent must have a full understanding of the information set out in Section 8.3.2.1: Determining Pre-Project Productivity. The mitigation must be informed by the Direct Actors and be undertaken in agreement with Direct Actors. Mitigation activities must lead to new productivity or productivity increases that directly benefit the Direct Actors. This likely means that the increase in production should be limited to the same commodity type, but this decision should be informed by the Direct Actors. This also likely means that the Leakage Mitigation Site should be in the same locality, but again this should be informed by the Direct Actors.

The Project Proponent should engage with Direct Actors associated with the site’s prior productivity to understand how the project activity impacted the previous users of the project site. Direct Actors include the previous site owners, tenants or other users that engaged with the project site in a way that produced commodities.

The Project Proponent must receive an affidavit from the identified Direct Actors confirming the following:

• Their occupation;
• How they previously used or engaged with the project site;
• How the project activities impacted their use of the project site; and
• How they designed mitigation activities with the Project Proponent.

Full records of correspondence, including meeting notes, and signed agreements must be made available as part of the PDD.

If information from Direct Actors is unavailable, the Project Proponent will be unable to undertake activity-shifting leakage mitigation.

For mitigation of market leakage, the following must be true in addition to the requirements set out in Section 8.3.3:

• The mitigation may increase productivity of a substitute crop that comes under the same commodity category, as this will result in a land sparing effect.
• The Leakage Mitigation Site should be in the same region. If this is not possible, the Leakage Mitigation Site must be in the same national boundary.

The emissions impact of leakage mitigation activities, $CO_2e_{Leakage\;Mitigation\;Emissions}$ must be considered. The same system boundaries set out in Table 1 must be considered, noting that it is likely only certain GHG SSRs will be included. At minimum, the following emissions sources must be considered:

• Embodied Emissions associated with any new construction (e.g., fencing or erection of shelters);
• Emissions associated with fertilizer use (e.g., if fertilizers are used to increase productivity);
• Emissions associated with farm operations (e.g., fuel use and water consumption); and
• Emissions associated with land clearance for mitigation activities.

Only activities that are additional as a result of the leakage mitigation activity should be considered as part of $CO_2e_{Leakage\;Mitigation\;Emissions}$. Activities that were already occurring and would continue to occur without the leakage mitigation activity may be omitted from the emissions accounting, if evidence that the activity was already occurring and would have continued to occur in the absence of the leakage mitigation activity is provided.

$CO_2e_{Market\;Leakage}$ considers emissions associated with land conversion as a result of market leakage. It is noted that other emissions may result from market leakage, such as fertilizer use as part of intensification to produce an increase in commodity supply. These emissions sources have been excluded at this time given a lack of globally appropriate data availability. These emissions are also expected to be negligible compared to land conversion emissions.

If $PPP$ includes multiple commodity types, $CO_2e_{Market\;Leakage}$ must be quantified for each commodity type.

Market leakage emissions are quantified using the following equations:

$CO_2e_{Market\;Leakage} = \sum\limits_{c=1}^n CO_2e_{Market\;Leakage, c}$

(Equation 3)

Where:

• $CO_2e_{Market\ Leakage}$ is total leakage emissions, in tonnes CO₂e.
• $c$ is commodity type c.

and:

$CO_2e_{Market\;Leakage, c} = ha_{LC, c} \times EF_{Carbon\;Stock}$

(Equation 4)

Where:

• $ha_{LC}$ is induced land conversion to bring new land into production, in hectares.
• $EF_{Carbon\;Stock}$ is the carbon stock factor for forested lands in tonnes CO₂ per hectare.
• $c$ is commodity type c.

Project Proponents are required to estimate the amount of new land brought into production, $ha_{LC}$. This estimate must be informed by:

• Pre-Project Productivity of a commodity type at the project site;
• the estimated proportion of this productivity that would be replaced with new production via an increase in supply of the commodity type;
• the increase in supply that would result in new land being brought into production; and
• the yield of new land being brought into production.

The new land brought into production must be calculated separately for each commodity type being displaced as a result of The Project.

Land conversion for production is quantified using the following equation:

$ha_{LC, c} = \frac{aPPP_{c} \ \times \:IS_{c}\ \times \:NL_{c}}{Y_{NL, c}}$

(Equation 5)

Where:

• $ha_{LC}$ is induced land conversion to bring new land into production, in hectares.
• $aPPP$ is adjusted unmitigated Pre-Project Productivity, in appropriate units (e.g., tonnes per year.)
• $IS$ is increased Supply - proportion of foregone $PPP$ that will be replaced by increased supply elsewhere, as a percentage.
• $NL$ is increased supply that will result in new land brought into production, as a percentage.
• $Y_{NL}$ is yield on new land brought into production, in appropriate production units (e.g., tonnes per year).
• $c$ is commodity type c.

Adjusted unmitigated Pre-Project Productivity, $aPPP$, must be calculated using the following equation:

$aPPP_c = uPPP_c \times GR_c$

(Equation 6)

Where:

• $aPPP$ is the adjusted unmitigated Pre-Project Productivity, in appropriate units (e.g., tonnes per year).
• $uPPP$ is the unmitigated Pre-Project Productivity, average annual production of commodity that would have been produced in the absence of The Project, in appropriate units (e.g., tonnes per year).
• $GR$ is the annual growth rate in productivity of the commodity type.

The annual growth rate in productivity of the commodity type and region must be assigned as part of Equation 6. This is a requirement to ensure that any likely future increases in productivity are accounted for as part of the assessment.

Growth rate must be calculated based on the following hierarchy:

1. Regional commodity specific data should be used to source yield values to determine growth rates, where available. For example from the United States Department for Agriculture for the commodity type and state;
2. National commodity specific data for agriculture from FAOSTAT may be used to source yield values to determine growth rates.

Growth rate must be calculated using the following equation:

$GR_c = \frac{yield_{c,t}}{yield_{c,t-x}}-1$

(Equation 7)

Where:

• $GR$ is the growth rate, as a percentage.
• $yield$ is the yield as sourced from regional or national datasets, in production unit per hectare per year.
• $c$ is the commodity type.
• $t$ is the most recent year of recorded yield data.
• $t-x$ is the historic year yield data.

Average growth rate is determined by taking the difference between yield in the most recent year of recorded data ($t$) and a historic year ($t-x$). Where possible $t-x$ should represent 25 years prior to $t$. Where this is not possible, a minimum of 10 years prior to $t$ is allowable.

If a recent negative shock leads to a negative growth estimate of yield growth, a value of zero should be used.

Increased Supply is the proportion of foregone productivity that will be replaced by increased supply elsewhere. This is underpinned by the premise that foregone production will not necessarily be replaced in totality by increased supply elsewhere as a result of elasticities of supply and demand. Global markets for commodities have been assumed for the purposes of the leakage assessment.

Estimates for $IS$ are determined using the following equation:

$IS = \frac{ε_{s,c}}{ε_{s,c} +\ ε_{d,c}}$

(Equation 8)

Where:

• $IS$ is increased supply, as a percentage.
• $ε_{s}$ is elasticity in supply, as a ratio.
• $ε_{d}$ is elasticity in demand, as a ratio.
• $c$ is commodity type c.

Isometric has carried out a literature review of $ε_s$ and $ε_d$ values for certain regions. Values for $ε_s$ and $ε_d$ for these regions are provided in Appendix A. Where The Project falls into these regions, the default values provided must be used. This is because understanding which values to use from literature is challenging as academic papers are typically not written with this purpose or audience in mind. Isometric has completed this work for certain regions to lessen this complexity and provide consistency across projects.

The default values also serve as an example of appropriate values to select from the literature for other regions; however, it should be noted that the quality of research differs across regions. For all other regions, values for $ε_s$ and $ε_d$ must be sourced from literature. The procedure and requirements for sourcing default values for $ε_s$ and $ε_d$ are set out in Appendix A.

$NL$ considers the percentage of increased supply that will result in new land brought into production for the commodity type. This is underpinned by the premise that not all increased supply will result in new lands being brought into production. Some increased supply may be made up of intensification of activities and increased yields on existing production lands.

Isometric have carried out a literature review of $NL$ values for certain regions. Values for $NL$ for these regions are provided in Appendix A. Where The Project falls into these regions, the default values provided must be used. The procedure and requirements for sourcing default values for $NL$ are set out in Appendix A.

The default values also serve as an example of appropriate values to select, however it should be noted that the quality of research differs across regions.

$Y_{NL}$ considers the yield on new land brought into production for commodity c. To determine yield on new land, follow the regional and national approach set out in the assessment of $Productivity$ (Section 8.3.5.1.2).

$EF_{Carbon\;Stock}$ must be derived from the IPCC average national aboveground biomass content of forests. Mean carbon stocks should be derived from aboveground biomass estimates in Table 3A.1.4 of the IPCC Good Practice Guidance for Land Use, Land Use Change and Forestry²⁸. Carbon stocks should be determined using the same ratio of mass of CO₂ to mass of C, and carbon fraction, $CF$, as set out in Section 9.3.1. Belowground biomass stocks should be estimated using the same process as set out in Section 9.3.3.

Where activity-shifting mitigation is in place, activity-shifting leakage monitoring is not required. Where only market leakage mitigation is in place, activity-shifting leakage monitoring must be undertaken for The Project. This is because market leakage mitigation does not necessarily mitigate activity-shifting leakage and Direct Actors may still be implicated. Where only partial or no leakage mitigation is in place, activity-shifting leakage monitoring must be undertaken in addition to a full or partial market leakage emissions deduction.

Activity-shifting leakage monitoring requires satellite imagery of a buffer or boundary zone along the project perimeter, called the Leakage Monitoring Zone. The Leakage Monitoring Zone will form a consistent buffer zone along the perimeter of the project site. The distance between the exterior perimeters of the project site and Leakage Monitoring Zone (i.e., the buffer width) will be determined by the smaller of the following:

• A five-kilometer buffer width extending outward from the project site exterior perimeter; or
• A uniform buffer width extending outward from the project site boundary such that the total area of the Leakage Monitoring Zone equals five times the project area.

The Leakage Monitoring Zone sizing is based on the likelihood that most of the displacements from the project area will not go beyond a five-kilometer radius, as well as to reflect the relative impact of variations in project size.

Isometric will undertake monitoring of the Leakage Monitoring Zone. The satellite imagery will be monitored at every Verification and will account for seasonal differences in vegetation cover. The satellite imagery will compare the deforestation rate of the Leakage Monitoring Zone with the average deforestation rate in the region. Whenever the deforestation rate in the Leakage Monitoring Zone is higher than the average for the region, the Project Proponent must provide additional information. The additional information must include:

• Identification of the actors responsible for deforestation and whether they are the same, or affiliated in any way to the Direct Actors; and
• Analysis of the motivations and contributing factors that resulted in the above-average rates of deforestation, to include the commodity type if the deforestation was motivated by commodity production.

If the Project Proponent is able to provide justification that the above-average rates of deforestation observed are unrelated to The Project and not as a result of actions relating to the Direct Actors, then no further action is required. If the Project Proponent is unable to provide sufficient justification, then the above-average area of deforestation must be considered as part of the leakage calculation.

Consider two forest conservation projects with different areas:

Example 1: Small Project

The small reforestation project has a project area of 1 km². Using the first approach, a 5 km buffer width would create a Leakage Monitoring Zone of 120 km² (calculated as an 11 km x 11 km total area minus the 1 km² project area). Using the second approach, the Leakage Monitoring Zone would only need to be 5 km² (five times the project area). In this case, the second approach would be used as it results in the smaller Leakage Monitoring Zone.

Example 2: Large Project

The large reforestation project has a project area of 100 km². Using the first approach, a 5 km buffer width would create a Leakage Monitoring Zone of 300 km² (calculated as a 20 km x 20 km total area minus the 100 km² project area). Using the second approach, the Leakage Monitoring Zone would need to be 500 km² (five times the Project Area). In this case, the first approach would be used as it results in the smaller Leakage Monitoring Zone.

The amount of above-average deforestation that should be attributed to The Project as activity-shifting leakage is determined by the total amount of possible activity-shifting leakage. The difference between market leakage and identified activity-shifting leakage is included in the calculation of $CO_2e_{Leakage}$ in Equation 9. $CO_2e_{Activity-shifting\;Leakage\:Adjustment}$ is calculated with the following equation:

$CO_2e_{Activity-shifting\;Leakage\:Adjustment} = max\;(ha_{ASL} \times EF_{Carbon\;Stock}-CO_2e_{Market\:Leakage}\:, 0)$

(Equation 9)

Where:

• $CO_2e_{Activity-shifting\;Leakage\:Adjustment}$ is the adjustment to market leakage emissions as a result of activity-shifting leakage as identified with monitoring for a Reporting Period, RP, in tonnes of CO₂e.
• $CO_2e_{Market\:Leakage}$ is the total market leakage emissions for The Project, in tonnes CO₂e (see Equation 3).
• $ha_{ASL}$ is the activity-shifting leakage attributed to The Project, in hectares
• $EF_{Carbon\;Stock}$ is the carbon stock factor for forested land.

The amount of above-average deforestation that should be attributed to The Project as activity-shifting leakage, $ha_{ASL}$, is determined by the total amount of possible activity-shifting leakage. This is represented in the following equation:

$ha_{ASL} = min\:(\frac{ha_{Monitored\:LC}}{ha_{Max \:LC}},1) \times ha_{Max\;LC}$

(Equation 10)

Where:

• $ha_{ASL}$ is the activity-shifting leakage attributed to The Project, in hectares.
• $ha_{Monitored\:LC}$ is the monitored land conversion area of above-average deforestation as identified from activity-shifting leakage monitoring, in hectares.
• $ha_{Max\:LC}$ is the maximum land conversion that can be attributed to leakage for The Project for all commodities combined, in hectares.

$ha_{Max\:LC}$ is calculated using the following calculation:

$ha_{Max\:LC} = \frac{aPPP}{Y_{NL}}$

(Equation 11)

Where:

• $aPPP$ is the adjusted unmitigated Pre-Project Productivity, in appropriate units, e.g., tonnes per year (see Section 8.3.5.1.1).
• $Y_{NL}$ is the yield on new land brought into production, in appropriate production units, e.g., tonnes per year (see Section 8.3.5.1.5).

The Reporting Period for reforestation projects represents an interval of time over which removals are calculated and reported for Verification. The minimum duration of a Reporting Period is one year and the maximum duration of a Reporting Period is five years (see Section 5.3).

Total net CO₂e removal is calculated for each Reporting Period and is written hereafter as $CO_2e_{Removal, RP}$. The net CO₂e removal quantification must be conservatively determined, giving high confidence that at a minimum, the credited amount of CO₂e was removed and stored.

GHG emission calculations must include all emissions related to the project activities that occur within the Reporting Period (see Table 1). This includes:

• any emissions associated with project establishment allocated to the Reporting Period;
• any operations emissions that occur within the Reporting Period;
• any end-of-life emissions that would occur after the Reporting Period that have been allocated to the Reporting Period; and
• market and activity-shifting leakage emissions that occur outside of the system boundary that are associated with the Reporting Period.

In line with the Isometric Standard, this Protocol requires that Removal Credits are issued ex-post. Credits may be issued once CO₂ has been removed from the atmosphere and is stored in living trees.

Net CO₂e removal for a reforestation project for each Reporting Period (RP), is calculated with the following equation:

$CO_2e_{Removal, RP} = CO_2e_{Stored, RP} - CO_2e_{Counterfactual, RP} - CO_2e_{Emissions, RP}$

(Equation 12)

Where:

• $CO_2e_{Removal, RP}$ is the total net CO₂e removal for the RP, in tonnes of CO₂e.
• $CO_2e_{Stored, RP}$ is the total CO₂ removed from the atmosphere and stored as organic carbon in living trees for the RP, in tonnes of CO₂e.
• $CO_2e_{Counterfactual, RP}$ is the total counterfactual CO₂ removed from the atmosphere and stored as organic carbon in living trees in the absence of The Project for the RP, in tonnes of CO₂e.
• $CO_2e_{Emissions, RP}$ is the total GHG emissions for the RP, in tonnes of CO₂e.

The total amount of CO₂ stored from a reforestation project is calculated as

$CO_2e_{Stored,RP}=CO_2e_{AGB, RP}+CO_2e_{BGB, RP}$

(Equation 13)

Where:

• $CO_2e_{AGB, RP}$ is the total carbon stored in living aboveground woody biomass (AGB) over the RP, in tonnes CO₂e.
• $CO_2e_{BGB, RP}$ is the total carbon stored in living belowground woody biomass (BGB) over the RP, in tonnes CO₂e.

The carbon pools within the scope of this Protocol are aboveground and belowground woody biomass (see Table 1), since they can be quantified with the highest level of accuracy and are able to be effectively monitored over time. Soil, deadwood, and litter carbon pools are excluded from the calculation of $CO_2e_{Stored, RP}$ due to large uncertainties in quantification approaches and/or relatively small contributions to the total forest carbon pool. For the remainder of the Protocol, the use of AGB and BGB refers to only the living aboveground and belowground woody biomass, respectively, unless otherwise noted. Details of how to calculate $CO_2e_{AGB, RP}$ and $CO_2e_{BGB, RP}$ are described below.

The total carbon stored in aboveground biomass over a Reporting Period is calculated by taking the difference between the start and end of the Reporting Period:

$CO_2e_{AGB, RP} = CO_2e_{AGB}(t_2) - CO_2e_{AGB}(t_1)$

(Equation 14)

Where:

• $CO_2e_{AGB}(t_1)$ and $CO_2e_{AGB}(t_2)$ are the total aboveground biomass carbon stock in the project area at times $t_1$ and $t_2$.
• $t_1$ and $t_2$ denote the start and end of the RP, respectively.

Reporting Periods are consecutive, so that $t_2$ then becomes the start of the next RP.

The aboveground biomass carbon stock at a point in time, $t$, is further calculated as:

$CO_2e_{AGB}(t) = \frac{44}{12} \times CF \times M_{AGB}(t)$

(Equation 15)

Where:

• $\frac{44}{12}$ is the ratio of mass of CO₂. to mass of C, used to convert to tonnes CO₂
• _$CF$ is the average fraction of carbon content for the tree species in the project area, in $\frac{tonne\ C}{tonne\ dry\ biomass}$.
• $M_{AGB}(t)$ is the total aboveground woody biomass over the project area at time $t$, in tonnes of dry biomass.

The carbon fraction, $CF$, must be chosen from the following hierarchy:

1. A regional and species-specific factor that is justified based on scientific literature (e.g., Doraisami et al., 2022²⁹). This is the preferred approach to have the most accurate estimate and avoid overestimation;
2. If the above is not available, then a genus-specific or national average factor that is justified based on scientific literature can be used;
3. As a last resort, if it is proven that the above two factors are not available, then a default factor of 47%, which is a mean across species, can be used^{30, 31}.

This Protocol currently supports the following three options for quantifying the total AGB over the project area at a point in time, $M_{AGB}(t)$:

1. Estimating the average AGB density using field plots;
2. Using a regional AGB map generated from an area-based LiDAR model; or
3. Using a global third-party AGB map.

Requirements for each approach is described in the sections below. Project Proponents must describe in the PDD which option is used, and adhere to the requirements of that approach. Note that Options 2 and 3 still require field plots as the source of truth for benchmarking the maps. This list of acceptable approaches may be expanded upon in future versions of the Protocol.

Project Proponents who wish to use an alternative approach must provide sufficient evidence to demonstrate that it meets or exceeds the accuracy of the workflows presented in this Protocol. Alternative approaches must be agreed upon ahead of time with Isometric and undergo an independent scientific review.

$M_{AGB}$ can be calculated by taking sufficient field plot measurements to obtain an estimate of the mean AGB density, which can then be multiplied by the project area to obtain a total AGB:

$M_{AGB}(t) = \bar{m}_{AGB}(t) \times A$

(Equation 16)

Where:

• $\bar{m}_{AGB}(t)$ is average AGB density, in tonnes/hectare.
• $A$ is the total project area, in hectares.

Estimation of $\bar{m}_{AGB}(t)$ is based on direct measurements of tree parameters (e.g., diameter at breast height (DBH) in field plots), and the use of allometric equations to convert tree parameters to biomass.

Allometric equations must be specific to the forest type and ecoregion in which The Project is located. Fixed size thresholds must be imposed on independent variables (e.g., DBH > 10 cm).

Project Proponents must use independently published allometric equations, from the following sources, in order of preference:

1. Local peer-reviewed equations;
2. Chave, et al., 2014³² for project areas in the Tropics;
3. National forest inventories;
4. IPCC generalized equations.

Field measurements must follow a prescribed field manual, such as the USFS field guide, the Climate Action Reserve’s field guide, or similar manuals produced for national forest inventories. Field measurements should occur during the leaf-off season when possible, to encourage alignment with potential LiDAR sampling (see Appendix B).

Field sampling must be conducted within a number of representative plots spanning the project area. Project Proponents should consider the following when establishing field plots and inventories:

• Fixed-radius permanent sample plots are recommended. Field plots must be determined a priori, and any changes in field plots during the Crediting Period must be justified.
• There should be a sufficient number of plots so as to ensure a +/-10% uncertainty at 90% confidence.
  • The number of field plots needed will vary based on the size of the project area, but at minimum should be greater than 30 (as the Central Limit Theorem suggests that the mean values from a population ≥ 30 will yield a normal distribution).
• Measurements must be made for each Verification.

Project Proponents must report the following information in the PDD for this option:

• Field measurements:
  • Field manual that was followed for sampling
  • Description of field plots, and how they were designed and selected
  • GPS coordinates, shape, size, and orientation of field plots
  • Description of measurement approaches and instruments used (e.g., diameter tape or calipers for DBH, clinometer or hypsometer for tree height)
• Allometric equations used and their sources

For each Verification, Project Proponents must submit a description of the measurements collected and report the full field inventory data.

Another approach for estimating $M_{AGB}$ is Area Based Modeling with airborne laser scanning (ALS) measurements, where LiDAR or stereo photogrammetry data is collected from the air using drones, helicopters, or airplanes. In this approach, a machine learning model is trained on ALS measurements as well as plot measurements in similar regions that are representative of the project area. The model is trained to predict AGB for every pixel on a map. Once a regional model is trained, the model can be applied to "wall-to-wall" ALS measurements taken over the entire project area to generate a map of AGB at a point in time.

Project Proponents taking this approach should follow established best practices, such as White et al., 2013: A best practices guide for generating forest inventory attributes from airborne laser scanning data using an area-based approach (Version 2.0)³³. See Appendix C for more details on this approach, including requirements for training data, ALS data acquisition, data processing, and statistical modeling.

Project Proponents must conduct field sampling to quantify aboveground biomass density (biomass over area) in field plots. The biomass density derived from field sampling must be reported as a benchmark against biomass density estimated from the regional AGB map over the same region. This benchmarking must be done at least once every 5 years during the Crediting Period.

Field plots for the purpose of validating an external map should adhere to the following requirements:

• Plot size should be a minimum of 0.5 ha in area, in order to
  • Support a normalized distribution in AGB³⁴; and
  • Reduce the impact of edge decisions by field staff (e.g., inclusion of trees on border of plot).

• Plot measurements should also be temporally aligned to the greatest possible extent with map products derived from remote sensing.

• The plot number should be sufficient to establish statistical equivalence using an equivalence test at 90% confidence with +/-10% allowable error.
  • This plot number can be calculated using a power analysis, or estimated at the start of The Project so as to obtain those accuracies.
• Spatial autocorrelation should be accounted for, e.g., setting a minimum distance between plots such as 100 m or based on the decorrelation scale.
• Field measurements for benchmarking should be collected temporally close (e.g., same year and season) to when ALS data is collected and regional AGB map is generated.

Project Proponents must report the following information in the PDD, to ensure transparency and with enough detail to allow for repeatability:

• Sampling plan and data collection:
  • Justification for the stratification method used and how spatial autocorrelation is accounted for. Failure to account for spatial autocorrelation can lead to erroneous errors³⁵.
  • LiDAR instrument and calibrations used, which must adhere to manufacturer's specifications.
  • Spatial coverage of laser scanning.
  • Flight altitude and velocity of drone/plane.
  • Acquisition parameters, e.g., beam divergence, scan angle, scan rate, pulse density, swath overlap.
• Processing methods and documentation, including software and specific procedures followed.
• Model accuracies and uncertainties, including r², RMSE (absolute and as a percent of mean), bias, a 1:1 plot of model performance, and uncertainty estimates for The Project itself, with and without the remote sensing model.
• Data and code used to train the model, including metrics extracted from LiDAR measurements.

The following information must be reported for Verification:

• Generated AGB maps over the project area for each Verification.
• Full field inventory data, at a minimum of every 5 years.

This final option for quantifying $M_{AGB}$ is to use independent third-party global AGB maps, which are typically generated from a combination of satellite remotely sensed data, ground data, and models. Third-party forest biomass data products must be assessed at a validation stage of 2 or higher under the CEOS validation hierarchy. Isometric will, in due time, publish acceptable third-party AGB resources based on region and forest type, updating the resource list as new products and vendors become available and are reviewed by Isometric.

The third party global AGB map must be benchmarked against field plot measurements, at least once every 5 years during the Crediting Period. Field plots for the purpose of validating an external map should adhere to the following requirements:

• Plot size should be similar to pixel-area of the global being validated.
• The plot number should be sufficient to establish statistical equivalence using an equivalence test at 90% confidence with +/-10% allowable error.

If the equivalence test is not passed, then the global map cannot be used directly for quantifying $M_{AGB}$ directly. In this case, the global map can be corrected and remapped with field plots to adjust for any local errors. This should be done using a simple linear regression relating field measurements to estimated carbon stock, which requires a sufficient number of field plots to obtain a model with reasonable accuracy (such as an R² ≥ 0.85). This corrective mapping should ideally either be done across many forest ages at once (i.e., a chrono-sequence), or should be remapped periodically.

Reporting requirements for global third-party AGB maps include:

• Data products and time periods used;
• Description of pre-processing of data for model input;
• Description of additional processing of satellite data (e.g., filtering out images with clouds);
• Field measurements; and
• Benchmarking results, including discussion and interpretation of results.

The total carbon stored in belowground biomass over a Reporting Period is calculated as:

$CO_2e_{BGB, RP} = RS \times CO_2e_{AGB, RP}$

(Equation 17)

Where:

• $CO_2e_{AGB,\ RP}$ is the total carbon stored in aboveground biomass over a Reporting Period, RP, as calculated in Section 9.3.1, in tonnes of CO₂e.
• $RS$ is the root-to-shoot ratio, which is a dimensionless belowground biomass to aboveground biomass ratio.

Appropriate root-to-shoot ratios should be selected by regional and species-specific factors that are justified based on scientific literature (e.g., USFS's Component Ratio Method or similar national-level species-specific ratios). This is the preferred approach to have the most accurate estimate and avoid overestimation. If sufficient evidence is provided to demonstrate that no suitable project-specific factor can be obtained, matching to the ecological zone and continent of the project area, based on the IPCC 2019 Table 4.4³⁰, must be used.

The uncertainty in selected $RS$ factors must be reported from the same source dataset. For example, the IPCC 2019 Chapter on Forest Land³⁰ provides an uncertainty in the root-to-shoot ratio.

This Protocol uses a dynamic baseline approach to quantify the counterfactual impact on forest carbon stocks if the project activity had not occurred. As a default, dynamic baselines will be independently determined and transparently reported by Isometric at each Verification to determine any deduction in Credit issuance based on the Baseline scenario. The following section outlines the workflow that Isometric will take–the Project Proponent is not responsible for carrying out the steps in this section. However, Project Proponents who wish to own the selection of control plots must follow a similar approach and provide a transparent and reproducible plan that is agreed upon ahead of time with Isometric.

Additionally, Isometric will make a pre-project estimation of the Baseline scenario at project initiation using historical data as described below.

The control plot zone must meet the following eligibility criteria:

• Located in the same country and ecoregion as the project area;
• Does not lie within protected areas, or within other carbon projects; and
• Control plots are also ineligible if they support active wood harvesting (e.g., commercial forestry.

If possible, other features should also be matched between the control plot zone and project area, such as:

• Species
• Productivity
• Stocking (i.e., tree size)
• Bioclimatic variables (e.g., temperature and precipitation)
• Topography
• Accessibility
• Wealth/Land value
• Millsheds

Initially, the zone for eligible control plots should be limited to a 100 km band around the project area. However, if suitable matches (see Section 9.4.3 for matching step) are not found in this zone, additional step-outs in 10 km increments may occur to find appropriate control plots, assuming they meet the criteria above. The final area determined for suitable control plots is hereafter referred to as the Donor Zone.

Once the boundaries of the Donor Zone are determined, Isometric will generate high-resolution (≤30 m) pixel maps representing forest carbon stocks or a suitable proxy for forest carbon stocks. These layers must cover the entire project area and Donor Zone at the same resolution for at least five historical time points relative to the start of The Project. Each historical time point must be separated by at least 1 year.

Isometric will select a suitable proxy that meets the following criteria:

• The proxy must be correlated with AGB throughout the Crediting Period.
• If the proxy saturates in the project area or Donor Zone during the Crediting Period and becomes insensitive to further carbon gain (e.g., as is the case for many simple optical indices), it will be excluded³⁶. Proxies such as canopy height from models which use datasets from multiple types of earth observation (particularly 2D satellite imagery, LiDAR and SAR) are preferred³⁷.
• The proxy map product should exclude cloud occlusion, saturation, and other contamination. This may lead to seasonal composite images.
• The proxy should be insensitive to seasonal variability, which may be addressed through taking an annual average to remove the seasonal cycle.
• The proxy should be stable, so that in the absence of carbon change, the proxy value stays the same.
• If an AGB map itself is used instead of a proxy map, then the AGB map product used to generate the dynamic baseline must meet the quality requirements in Section 9.3.2 (Calculation of M_AGB).

Project pixels are matched to control plot pixels based on the historical time series of the selected forest carbon proxy, $C_{proxy}$, of each pixel, using k-nearest neighbors with replacement (or an alternative justified algorithm). Each project pixel must be matched to a minimum of 10 different control pixels, and the mean forest carbon proxy over the group of control pixels is used. Multiple project pixels may be matched to the same control pixels.

The baseline correction is calculated using the equation below. The difference between forest carbon stock change is assessed per project-control pixel set. Then, the differences are summed across The Project to determine the cumulative baseline.

$CO_2e_{Counterfactual,RP}=\sum_{i=1}^n[CO_2e_{Stored,RP, i}\times(\frac{\Delta\ C_{proxy,control,i}}{\Delta\ C_{proxy,project,i}})]$

(Equation 18)

Where:

• $i$ denotes each project pixel.
• $CO_2e_{Stored,\ RP,\ i}$ is the CO₂e stored for the RP at project pixel $i$, as calculated in Section 9.3.
• $\Delta\ C_{proxy,\ control,\ i}$ is the average change in forest carbon proxy over the RP in the group of control pixels matched to project pixel $i$.
• $\Delta\ C_{proxy,\ project,\ i}$ is the change in forest carbon proxy over the RP in project pixel $i$.

The $\Delta$ represents the change over a Reporting Period, e.g.,

$\Delta C_{proxy} = C_{proxy}(t_2) - C_{proxy}(t_1)$,

(Equation 19)

where $t_1$ and $t_2$ are the start and end of the Reporting Period, respectively.

At each Verification, the control pixels are reviewed to determine continued eligibility within control plots as outlined in Section 9.4.1. In the event that control pixel matches are no longer suitable, replacements will be selected for the impacted project pixels. Example scenarios that should lead to control pixels being reviewed and reselected include:

• A sustained decreasing trend in control pixels. The control pixels for reforestation projects must not have a trend of decreasing forest carbon proxy over time, as that can lead to crediting more carbon than was removed in the project area.
• A value of $\frac{\Delta C_{proxy,\ control,\ i}}{\Delta C_{proxy,\ project,\ i}}$ > 1 would indicate that the reforestation project pixel is gaining less biomass than natural regeneration in the control pixels. This may be legitimate, but it is recommended that control pixels be reviewed to ensure they still meet the conditions set out in Section 9.4.1.

A performance benchmark for the project area, $PB_{RP}$ can be calculated by:

$PB_{RP} = \frac{CO_2e_{Removed,\ RP}}{CO_2e_{Counterfactual,\ RP}}$

(Equation 20)

The performance benchmark must be $PB_{RP} > 1$ to meet the environmental additionality requirement.

Isometric will account for uncertainty in the dynamic baseline to obtain a conservative estimate of $CO_{2}e_{Counterfactual,\ RP}$ in Equation 18. This will include an evaluation of at least the following sources of uncertainty:

• Uncertainty in the forest carbon proxy maps, due to the uncertainty in data and models used to generate the proxy map;
• Uncertainty in how well the forest carbon proxy represents relative changes in carbon stock between the control and project pixels; and
• Uncertainty in the control pixels matched and if they adequately represent the likely Counterfactual scenario.

$CO_2e_{Emissions, RP}$ is the total GHG emissions associated with a Reporting Period, RP. This can be calculated as: