State or province

Arizona, United States of America: 6 ecoregions. Each with its climate now and toward 2050, and its conservation tier.

Six ecoregions reach Arizona, and four of them are desert. The Sonoran desert holds the south and west, the Mojave desert the northwest corner, the Colorado Plateau shrublands the north, and the Chihuahuan desert reaches in from the southeast. Against that dry majority sit two forest systems: the Arizona Mountains forests, a temperate conifer ecoregion in the Nature Imperiled tier, and a reach of the Sierra Madre Occidental pine-oak forests. Elevation is what separates them, and it is the whole story for a gardener here. The same state supports saguaro and agave on the low desert floor and ponderosa country a couple of hours uphill, so the ecoregion you are actually in matters more than the state on the map.