Post-Soviet farmland abandonment, forest recovery, and carbon sequestration in western Ukraine

Land use is a critical factor in the global carbon cycle, but land-use effects on carbon fluxes are poorly understood in many regions. One such region is Eastern Europe and the former Soviet Union, where land-use intensity decreased substantially after the collapse of socialism, and farmland abandonment and forest expansion have been widespread. Our goal was to examine how land-use trends affected net carbon fluxes in western Ukraine (57 000 km 2 ) and to assess the region’s future carbon sequestration potential. Using satellite-based forest disturbance and farmland abandonment rates from 1988 to 2007, historic forest resource statistics, and a carbon bookkeeping model, we reconstructed carbon fluxes from land use in the 20th century and assessed potential future carbon fluxes until 2100 for a range of forest expansion and logging scenarios. Our results suggested that the low-point in forest cover occurred in the 1920s. Forest expansion between 1930 and 1970 turned the region from a carbon source to a sink, despite intensive logging during socialism. The collapse of the Soviet Union created a vast, but currently largely untapped carbon sequestration potential (up to � 150 Tg C in our study region). Future forest expansion will likely maintain or even increase the region’s current sink strength of 1.48 Tg C yr � 1 . This may offer substantial opportunities for offsetting industrial