Forest ecosystems provide many things which people value. Exactly what things are provided change as forests grow and are impacted by natural disturbances and human activities. Each change provides some values, but precludes others (Oliver et al. 1997). For example, a large clearcut or fire provides timber as well as habitat for species needing large openings (Hunter 1990, Oliver et al. 1998) but precludes future timber and habitat for species needing closed forests until the forest regrows. Selective harvesting provides timber and habitat for species needing closed forests, but does not provide large openings for species which need this habitat. Manipulating one forest also affects activities and values in nearby or distant forests. Stopping harvest in one forest leads to more harvesting in other forests (Perez-Garcia 1993), resulting in too little habitat for open forest species in the first area and too much open habitat in the second. Forest activities can also affect non-forest values. For example, too little forest harvesting will lead to high timber prices and cause people to use steel, aluminum, concrete, and brick products instead. Because these non-wood products consume so much more fossil fuel in their manufacturing, they add much more carbon dioxide pollution to the atmosphere than if wood products had been used instead (Koch 1991, Kershaw et al. 1993).