The growing season ranges from less than 50 to 110 days, and winters are cold. Surface Water Characteristics. This Section is the primary watershed for much of Arizona and western New Mexico. Several large streams are perennial. Much of the water is stored in reservoirs, and small artificial lakes are common.
Ground water is limited and usually occurs at great depths.
Natural fires occurred in ponderosa pine about every 3 to 10 years, but have been prevented recently. This has led to a higher canopy cover and increased fuel loads, resulting in a less resilient ecosystem and increased hazard of wildfire. Much of this area is covered with timber, with rangeland and recreation being secondary uses. This diverse Section encompasses primarily the mountainous ponderosa pine and transition zones of central Arizona and western New Mexico. Human groups have utilized this Section's well-watered upland valleys and meadows, high mesas, and more sparsely forested basins and ranges for the full extent of human prehistory in the Southwest.