Built with the bottomless labor of the Civilian Conservation Corps, is sought to segregate permanently the lower-elevation chaparral from the higher-level conifers, a Maginot Line of fire protection (and a weird counterpoint to the New Deal's Shelterbelt tree-planting scheme on the Plains). In place of either walking away from fire or attempting to beat it into submission, the readers reclaim our heritage as keeper of the flame and see that the right kind of fire gets to the right places at the right times. About 10% of the introduced plants adapt their new habitat and spread (naturalize) while about 1% of the introduced species become ecosystem transformers. After World War II, commercial saw timber operations increased on the Gila and Apache National Forests, as they did throughout the National Forest System. Current overstocking of forests was created purposely by the USFS and industry to maximize tree growth for fiber production.