AZ-NM Mountains
This ecoregion encompasses the largest contiguous ponderosa pine (Pinus ponderosa) forest in the US. lower in elevation than neighboring mountainous ecoregions and have vegetation indicative of drier, warmer climates. Semiarid grassland, chaparral, and pinyon-juniper (Pinus spp. and Juniperus spp.) and oak woodlands (Quercus spp.) grow in the lower elevations.
Melting snow and summer monsoonal rains feed the headwaters of several river systems within the ecoregion, including the Verde, Salt, Gila, and Little Colorado Rivers in Arizona and the Mimbres River in New Mexico. Average temperatures vary greatly by season and along elevation gradients but range from −18°C during the winter months in the highest elevations to more than 38°C during the summer months in the lowest elevations.
