Vegetation Classification and Mapping Project Report - USGS

Vegetation Classification and Distribution Mapping Report: Petrified Forest National Park
C.5 Sparse
C.5.2. Ephedra torreyana - Artemisia bigelovii Sparse Vegetation
Base map class
NatureServe common name
NatureServe code
Torrey’s.Jointfir.–.Bigelow’s.Sagebrush.Sparse.Vegetation
Torrey’s.Joint-fir.-.Bigelow.Sagebrush.Sparse.Vegetation
CEGL002350
Summary:
This Colorado Plateau association has been described from Petrified Forest National Park in northern
Arizona and Capitol Reef National Park in southeastern Utah, where it is widespread. Stands occur on
plateaus, mesas, ridges, hills, cliffs, rocky colluvial slopes, benches, terraces, and near drainage channels
that are gently sloping to steep (3-50%) between 1402 and 1915 m elevation on all aspects. The
unvegetated surface has moderate to high cover of gravel and low to moderate cover of large rocks
and litter. Cryptogams are typically absent, but one stand has 75% cover. Parent materials include
sandstones and shale. Soils are rapidly drained and variable in texture, including loams, sands, and
clays, but are unified by a coating of fine to coarse gravels composed of sandstone, shale, basalt, or
petrified wood. The vegetation is typically sparse (