Green gains from connectivity: highway expansion and forest quality

Roads are often linked to deforestation in frontier settings, but their effects in managed forests are less well understood. We investigate the intensive-margin response of forest outcomes to roads using China's 2000-2010 expressway rollout as the setting. We construct a unique panel from the National Forest Inventory covering over 18,000 geo-located plots with ground-based measures of standing timber volume, which capture tree-level outcomes that satellite-based measures typically miss. Using long differences and standard instrumental variables, we find that moving 10 km closer to an expressway increases timber volume by approximately 2%, with gains concentrated within 1-20 km of new roads. The implied biomass increase equals 217-552 million tons of CO2, comparable to Canada's annual emissions at the upper bound. Mechanism evidence and a spatial equilibrium model show that improved downstream market access strengthens incentives for investment and specialization in forestry under strict forest land-use controls, highlighting a role for transport infrastructure in promoting sustainable growth.