That is a neat little recycle program described in “New test traces underground forest carbon.” As fast as the CO2 comes out of the ground, the tree grabs the carbon by photosynthesis and leaves two oxygen atoms in the atmosphere. A portion of the carbon is stored until the wood rots or burns. Some carbon goes down into the soil and rejoins a couple of oxygen atoms. Of course, these scientists have upset the whole system by killing the trees yet not harvesting them for lumber or planting new trees. It’s amazing the lengths to which people will go to downplay the vast CO2 sink that a managed forest can be. Chuck Phegley
Baker City, Ore.