Loamy Sand 23-31" PZ

Description

The interpretive or reference plant community for this site is a Tallgrass Prairie Community (1.1). This community is believed to have been a relatively open prairie with scattered motts of oak and an abundance of forbs. Little bluestem contributed from 20 to 25 percent of the herbage production. Indiangrass, switchgrass, sand bluestem, giant dropseed and purple tridens contributed 30 to 40 percent. Woody species included post oak, Havard oak, sand sagebrush, skunkbush, prickly-ash, bumelia and net-leaf hackberry. Woody plants are thought to have represented five to ten percent of the composition. The woody species were apparently kept at low levels because of frequent wildfires and occasional long droughts. Forbs such as Engelmann’s daisy, prairie clover, and dotted gayfeather thrived. It is estimated that the Tallgrass Prairie Community (1.1) produced as much as 5000 to 6000 pounds herbage in years with good moisture and as little as 3000 pounds to 4000 pounds in unfavorable years.

The Mixed-Grass Plant Community (1.2) still have most reference species present but the dominant tallgrasses are being displaced by increases in silver bluestem, Arizona cottontop, sideoats grama, sand lovegrass and weeds. Of the tallgrasses, little bluestem is most persistent, often increasing initially under continued overgrazing before declining. Havard oak, sand sagebrush, skunkbush sumac, yucca, elbowbush and post oak increase in density and cover, varying from 15 to 25 percent canopy cover in this phase. Most climax forbs such as gaura, heath aster, dotted gayfeather, and verbena persist in the Mixed-grass Community. Annual yields range from 2500 to 5500 pounds.

Submodel

Description

The Shortgrass/Mixed-brush Community (2.1) has a 25 to 45 percent woody plant canopy of Mixed-brush species. Post oak and/or mesquite are often becoming the dominant overstory and sand sagebrush or shin oak are the most common shrubs.

The Mixed-brush/Shortgrass/Annuals Community on the Loamy Sand Prairie site is a woodland state. Sand sagebrush, yucca, and skunkbush sumac are common. Mesquite and sometimes post oak often become the dominant overstory. Sand sagebrush will often form dense stands. With continued heavy grazing and no brush control, the trees and shrubs can approach 75 percent or more ground cover. Shortgrasses and low seral stage annual and perennial forbs occupy the woody plant interspaces.

Submodel

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