We examine portage sites in the U.S. South, Mid-Atlantic, and Midwest, including those on the fall line, a geomorphologic feature in the southeastern U.S. marking the final rapids on rivers before the ocean. Historically, waterborne transport of goods required portage around the falls at these...

Regional trade in South America since independence has long been much smaller than would be expected if geography were the only constraint on trade. Several potential explanations exist: low technological and demand complementarities; low productivity; high natural and policy barriers to trade....

Forestation is viewed as an important means of removing CO₂ from the atmosphere and thereby reducing net CO₂ emissions. But how much CO₂ can be removed, and at what cost? Focusing on forested and forestable areas in South America, and using spatially disaggregated data, we estimate a...