Igneous Exposed Backslope Woodland

Description

The historical reference state for this ecological site was old growth oak woodland. This state was dominated by white oak and black oak with occasional scarlet oak, and shortleaf pine. Periodic disturbances from fire, wind and ice maintained the reference structure and diverse ground flora species. Long disturbance-free periods allowed an increase in both the density of trees and the abundance of shade tolerant species. Two community phases are recognized in the reference state, with shifts between phases based on disturbance frequency. Reference sites are rare today.

Most of these sites have been subject to repeated, high-graded timber harvest (State 3). Fire suppression has resulted in increased canopy density, which has affected the abundance and diversity of ground flora (State 4). Relatively few igneous woodlands have been managed effectively for timber harvest (State 2), resulting in either even-age or uneven-age woodlands.

Submodel

Description

Periodic timber management, along with the absence of fire, will maintain this state. Continued exclusion of prescribed fire without a regular 15 to 20 year harvest re-entry into these stands, will slowly create an increase in more shade tolerant species. White oak will become less dominant and mid-story species such as sassafras, serviceberry and hickory will become more dominate and cause a transition to community phase 2.2.

Submodel

Description

This state is subjected to repeated, high-graded timber harvests resulting in a significant reduction in white oak densities. Fire cessation has also occurred. This state exhibits an over-abundance of black oak and hickory and other less desirable tree species, and weedy understory species such as coralberry, gooseberry, poison ivy and Virginia creeper. The canopy is somewhat open. Some intermittent uncontrolled domestic livestock grazing may also occur further degrading the site. Proper forest management techniques and cessation of grazing can cause a transition to State 2.

Submodel

Description

This state is dominated by black oak, scarlet oak and to a lesser extent white oak. They can form relatively even-age stands, dating to when fire suppression became the dominant management characteristic on the site. This stage can occur relatively quickly (20 to 25 years). Canopy closures can approach 80 to 90 percent with decreasing ground flora. Without active management or long term presence of fire, woody species will continue to encroach into these woodlands. Once established, these woody species can quickly fill the forest system.

Most occurrences of this state today are dense and shady with a greatly diminished ground flora. Some logging typically occurs. Removal of the younger understory, opening the upper canopy, and the application of periodic prescribed fire (5 to 10 years) has proven to be effective management tools in restoring the stage back to the reference state.

Submodel

Description

Conversion of wooded sites to planted, non-native grassland species such as tall fescue is a stage that is primarily associated with upper slope positions of this ecological site. If active grassland management is discontinued, the site will eventually transition to Phase 5.2 with an increase in broomsedge and oak sprouts and a loss of clover species. Return to the reference state from this state may be impossible requiring a very long term series of management options and stages. Many species may need to be eventually planted or reseeded to restore the system.

Studies on Ozark woodlands indicate that conversion to grassland may result in soil loss from the clearing process and from erosion before the grassland is well established. Long-term grassland management results in higher soil pH levels and higher levels of calcium and magnesium from pasture liming. These effects may extend a foot or more into the soil profile. The effects of liming are more evident in phase 5.1 (Tall fescue – red clover – birdsfoot trefoil).

Submodel