This report aims to illustrate the methodological improvements for estimating greenhouse gas (GHG) emissions and removals from forest management practices and disturbances implemented in the FAO's Environmental eXternalities ACcounting Tool (EX-ACT), an online accounting app that estimates and tracks the outcomes of agricultural interventions on environmental externalities, including GHG emissions. It highlights key updates from the previous tool's version, EX-ACT v.9, and shows the main limitations that have been overcome through a change in methodology. The revision follows the International Panel on Climate Change's Guidelines for National Greenhouse Gas Inventories (2006, 2019).The methodology update now better reflects the effects of various forest management interventions on yearly GHG emissions and reductions, as beforehand the tool only considered overall forest biomass changes over the entire accounting period. The updated EX-ACT online app now provides a more detailed approach, accounting for both positive and negative changes in forest-carbon stocks, as well as multiple drivers of changes in forest-carbon stocks, including forest management (thinning, logging, reduced impact logging, etc.) and use (timber, fuelwood), as well as disturbances (fire, forest pests and diseases, storms, drought, etc.).A major shift in methodology is the transition from the Stock-Difference approach to the Gain-Loss approach to capture annual changes of forest carbon stocks. The refined methodology improves estimates of GHG emissions and reductions, offering a valuable tool for assessing the climate change mitigation effects of forestry activities in agrifood investment activities, projects, programmes, and policies.