Land cover class descriptions for the Upper San Pedro Watershed. Land cover class descriptions for the Upper San Pedro Watershed. Forest Vegetative communities comprised principally of trees potentially over 10m in height and typically characterized by closed or multi-layered canopies.
Tree canopy is usually open or interrupted and singularly layered.
This cover type often grades into forests at its upper boundary and into semi-arid grassland below. Winter deciduous and generally found at elevations below 1,200m. Semi-arid grasslands are generally positioned in elevation between evergreen woodland above and desertscrub below. Within the San Pedro river basin this community is often dominated by one of at least three species, i.e. creosotebush, tarbush, and whitethorn acacia. Many desertscrub species are drought-deciduous.