Tree cover loss estimate (GFW-based)

The baseline forest extent is calculated using the Hansen Global Forest Watch (GFW) Tree Cover dataset. First, all tropical and subtropical broadleaf moist forest areas within the 74 TFFF-specified countries are identified using the Ecoregion-Based Approach from Dinerstein et al., (2017)Within these zones, the tree cover from the year 2000 is considered the forest baseline. This baseline is then updated annually by subtracting the cumulative area of tree cover loss and adding areas of forest gain observed from 2000 to 2012. The result is a dynamically evolving baseline that reflects changes in forest extent over time.

Annual deforestation is assessed by identifying the total area of tree cover loss that occurs within the defined forest baseline during the reporting year. In this estimate, all tree cover loss not associated with fire is classified as deforestation. These values are aggregated at the country level to quantify area lost annually and evaluate performance against TFFF criteria.

Forest degradation is assessed using the Global Forest Watch fire-related forest loss dataset developed by Tyukavina et al. Fire-related loss is extracted and overlaid onto the forest baseline to determine areas where degradation (defined as fire damage within standing forests) has occurred. Only fire-induced tree cover loss is included in the degradation category, aligning with TFFF definitions, while all other causes of loss are assigned to deforestation.

Standard estimate (JRC + GFW-based)

The baseline is generated using two complementary datasets. Tropical areas that fall within the spatial coverage of the JRC Tropical Moist Forest (TMF) dataset (Vancutsem et al., 2021 ) are analyzed using TMF classifications. In these zones, forest cover is defined as a combination of undisturbed and non-fire-related degraded forest. Non-fire degradation is not considered a loss under TFFF rules; therefore, these areas are classified as remaining forest.

Subtropical regions located outside the TMF dataset extent are analyzed using the Hansen Tree Cover dataset using the same process as in the Tree Cover Loss Estimate. The combination of TMF-derived tropical baselines and Hansen-derived subtropical baselines ensures full geographic coverage across all TFFF countries.

Annual deforestation in tropical regions is calculated by comparing total forest area (undisturbed plus non-fire degraded forest) between the current year and the previous year using TMF data. A reduction in forest area is classified as deforestation. In subtropical regions, deforestation is calculated identically to the GFW-based method, as these areas rely on the Hansen dataset.

Degradation is identified in tropical regions by intersecting the TMF degraded forest class with the MODIS burned area product. Only areas confirmed by both datasets as burned and classified as degraded are included in the degradation category, in accordance with TFFF definitions that consider only fire-related degradation. In subtropical regions, fire-related degradation is assessed using the Hansen-based fire loss data in the same manner as the Tree Cover Loss Estimate.

We are continuing to refine our methodology and would welcome any feedback at tushar.bharadwaj@plant-for-the-planet.org.