As the planet warms, carbon markets are getting hot too. Forest landowners have been looking for ways to enter these markets, making money from their commercial timberland not just by selling logs—but also by demonstrating that their land is absorbing climate-warming carbon dioxide from the air. The more carbon an acre of trees holds, the more valuable it will be in these new carbon markets—whether in the California “cap and trade” market, international voluntary markets, or others that have been sprouting up across the US and Canada.