Decarbonizing the economy requires a large-scale transition from fossil carbon-containing feedstocks to minerals and biomass, notably wood in buildings. Increasing harvesting is under discussion to meet the supply of wood for ‘timber cities’, with potentially negative impacts on forests and biodiversity. Here we investigate pathways to timber cities, including their impacts on land use, energy use and greenhouse gas emissions by quantifying global and regional wood cycles using Bayesian material flow analysis. We show that shifting wood fuel to industrial use and maximizing circular use of wood can make timber cities possible with the current harvest volume. Our results reveal that these pathways have better environmental performance than increased harvesting, reducing total CO2 equivalent emissions by 2100 by 40.8 Gt compared to business as usual. To achieve the wood transition, regional and cross-sectoral governance and planning are needed, addressing national-level pathways and inter-regional wood transport.