Modeling of carbon stocks in aboveground biomass and harvested wood products of Cupressus lusitanica plantations in Munessa forest district, Ethiopia

Climate change is a global challenge that is propelled by increasing atmospheric concentrations of greenhouse gases. Forest ecosystems and the Harvested Wood Products make a valuable contribution to mitigating climate change through carbon sequestration and storage. This study integrates field-based biomass measurements with CO₂FIX modeling to quantify aboveground biomass and harvested wood product carbon dynamics in Cupressus lusitanica plantations in Ethiopia. The combined approach provides the first locally calibrated assessment of long-term carbon retention across biomass and wood product pools for this plantation system. Biomass carbon changes were simulated over 120 years using a dynamic growth model (CO2FIX V. 3.2). Data were collected from 20 systematically laid plots, complemented by log recovery and lumber conversion efficiency analysis from sawmills. Results indicated that mean measured and simulated standing aboveground biomass carbon stocks were 122.87 ± 40.33 and 85.96 ± 37.82 Mg C ha⁻¹, respectively. Carbon stock in HWPs was estimated to be 7.46 ± 4.23 Mg C ha⁻¹. Log recovery rate was 49.99%, with high biomass loss during lumber processing. Management strategies that retain medium-sized trees and minimize stem losses through good silviculture are presented, together with increasing the share of long-lived wood products, as methods that can substantially improve total ecosystem and product carbon storage. The results highlight the importance of stand structure, log quality, and processing efficiency in maximizing carbon storage, with direct implications for climate-change mitigation strategies and sustainable plantation management in Ethiopia.