Woodland Uplands Transition 16-35

Description

This state represents the most ecologically stable conditions in terms of resistance to erosion. Moreover, this state has the highest potential for productivity and plant diversity.
Tree canopy cover ranges from 25 to 35 percent.

Dominant plant species

1. twoneedle pinyon (Pinus edulis), tree

2. alligator juniper (Juniperus deppeana), tree

3. ponderosa pine (Pinus ponderosa), tree

4. Rocky Mountain juniper (Juniperus scopulorum), tree

5. alderleaf mountain mahogany (Cercocarpus montanus), shrub

6. winterfat (Krascheninnikovia lanata), shrub

7. skunkbush sumac (Rhus trilobata), shrub

8. spike muhly (Muhlenbergia wrightii), grass

9. James' galleta (Pleuraphis jamesii), grass

Submodel

Description

This state occurs where the understory has been diminished in diversity.
This state has evolved from long-term heavy grazing and the reduction of fine fuels that has contributed to the disruption in the natural fire cycle. Progression toward HCPC from State #2 requires elimination of grazing, with extensive land treatments (thinning, reseeding, and burning) to restore the plant community structure and function. The site appears aridic due to the lack of ground cover which benefits the establishment of drought tolerant species, such as Rocky Mountain and oneseed junipers.

Plant Community 2 (PC2) is prevalent in this state and appears to be self-sustaining, almost a static state. Pinyon is the dominant tree species with Rocky Mountain and oneseed junipers as subdominant.

Alligator juniper and ponderosa pine occur on the site but only as remnants due to lack of fire necessary to suppress the growth of other junipers. Natural fires (ground or crown) are essentially non-existent. Incidental fires may occur as individual tree fires caused by lightning strikes or small area (patch-size) crown burns aided by ladder fuels and strong wind events. Gambel and wavy-leaf oak can be encountered on this site but as a minor component in the plant community. Rubber rabbitbrush and horsebrush are the most common shrubs. The age structure is comprised of about 14% very old trees, which are widely scattered throughout the site. The mid-aged and young age-class trees comprise about 71% of the site, with the remainder comprised of saplings taller than 4.5 feet but less than 3 inches in diameter at the root collar.

In State #2, the trees per acre (t/a) can range from a low of 81-135 t/a in some sites to a high of 130-218 t/a in other sites. Canopy cover ranges from 55 to 65% overall, with canopy cover expected to be slightly lower in basalt-derived soils. The canopy cover is expected to be greater on north aspects than on south aspects. The herbaceous component is dominated by blue grama with minor occurrences of spike muhly, squirreltail, prairie junegrass, littleseed ricegrass, pine dropseed, and red threeawn. Ground cover and forage production values are both very low. Shrubs are dominated by rabbitbrush or horsebrush with substantial densities of snakeweed. Desirable shrubs, such as hairy mountain mahogany and skunkbush sumac, are heavily browsed and decadent from overuse.

Submodel