The Forest Carbon Sink Optimization Model (FOX), developed by REKK, is a bio-economic model that integrates biological growth functions with economic decision-making to maximize profits. FOX incorporates the benefits of wood products and introduces the concept of carbon payments for delayed harvesting, while also considering carbon release costs during final cuts.

This dynamic, linear mathematical optimization model determines the optimal forest harvest based on exogenous growth functions, timber prices, and carbon prices and it accommodates multiple species and age classes. FOX was developed in 2021 to analyze forest management and carbon policies in Hungary and Romania. It has since been also applied to Bulgaria and most recently to Bosnia and Herzegovina (BiH).

BiH forests differ from the other countries, as they feature abundant uneven-aged, mixed-species forests with much stock of old ages, known as "high forests". The FOX Model structure was developed to effectively model these high forests, along with coppice and plantation forests. The results were presented to representatives from the BiH government, academia, civil organizations, and practitioners during a workshop held on June 13, 2023.

The REKK project, focused on implementing FOX for BiH, was funded by the European Climate Foundation, with Prof. Dr. Marijana Kapovic-Solomun, Dean of Forestry Faculty at the University of Banja Luka providing local expertise.

The final report as well as the workshop materials (presentations, the agenda, and a video recording) are accessible below.