California has environmental diversity and richness unparalleled anywhere in the world. The state's geographic undulations encompass the lowest and the highest points in the coterminous United States. Spanning more than ten degrees of latitude and extending over one hundred million acres, California is a bridge between cool-temperate, foggy, dimly lit rainforests and open, parched, hot sun-bathed subtropical deserts. California vegetation might appear continuous and healthy and relatively unchanged from 1848. However, only isolated areas of pre-European vegetation types in oak woodland, desert scrub, montane forests, chaparral, woodland, and grassland still exist. Except for small areas that are rare examples of prior landscapes, the vegetation types that remain are not the same as the ones that Native Californians lived in 150 years ago. The decline of natural systems in the state is intimately tied with the diminishment of the native cultural heritage. Among public lands agencies, there is increasing interest in Native American traditional ecological knowledge and past land management practices-indigenous burning, for example. Simulating some native practices in a series of long-term field experiments will give scientists and managers a more accurate sense of the impact of aboriginal activities on vegetation in different regions. These practices may be used to restore endangered ecosystems as well as enhance the productivity and biodiversity of wildlands.