Vegetation Classification and Mapping Project Report - USGS

Appendix C: Global and local plant community descriptions
Petrified Forest National Park. The one relevé classified as Pinus edulis - (Juniperus osteosperma)
/ Bouteloua gracilis Woodland may need to be reassessed with additional data
collected at Petrified Forest National Park and the Navajo Nation. This relevé was separated
from Juniperus monosperma / Artemisia bigelovii Woodland (CEGL000705) based on codominance
of Pinus edulis in the tree layer. However, the Juniperus monosperma / Artemisia
bigelovii Woodland association does have similar characteristics to the relevé described
here: it lacks cover of Bouteloua gracilis in the herbaceous layer and has a dominance of
Artemisia bigelovii in the shrub layer.
Vegetation hierarchy:
Physiognomic class I Woodland
Physiognomic subclass I.A Evergreen.woodland
Physiognomic group I.A.4 Temperate.or.subpolar.needle-leaved.evergreen.woodland
Physiognomic subgroup I.A.8.N Natural/Semi-natural.temperate.or.subpolar.needle-leaved.
evergreen.woodland
Formation name I.A.4.N.a Natural/Semi-natural.temperate.or.subpolar.needle-leaved.
evergreen.woodland
Alliance name
Pinus edulis - (Juniperus spp.) Woodland.Alliance.(A.516),.
Two-needle.Pinyon.-.(Juniper.species).Woodland.Alliance
Ecological systems placement:
Ecological system unique ID
CES304.767
Ecological system name
Colorado.Plateau.Pinyon-Juniper.Woodland
NatureServe conservation status:
Global rank. G5 (23-Feb-1994).
Distribution:
Globally. This woodland association is known from mountains and mesas in the southern
Colorado Plateau and Mogollon Rim of northern Arizona and extends into southern Utah
and probably into western Colorado and possibly into western New Mexico.
Petrified Forest National Park. Pinus edulis - (Juniperus osteosperma) / Bouteloua gracilis
Woodland occurred on one relevé. It was located on a terrace north of Petrified National Forest
on the Navajo Nation.
Environmental summary:
Globally. This woodland association is known from mountains and mesas in the southern
Colorado Plateau, from the Mogollon Rim, extending north into southern Utah and
probably western Colorado. Elevations normally range from 1700-2400 m (5575-7875 ft).
Sites are variable but generally are relatively dry and rocky. Stands occur on flat to moderate
slopes along drainages and on mesatops, on gentle to moderate (10-40%) rocky slopes
of foothills, and at the bases of cinder cones. The substrates are variable and range from to
deep, coarse-textured soils derived from cinder, to sandy loams derived from sandstone or
fine-textured soils derived from limestone or shale.
Petrified Forest National Park. This association occurs at an elevation of 1840 m (6030 ft)
with a moderate slope of 7%. The relevé has mudstone surface rocks.
USFWS wetland system: Not applicable.
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