Till Upland Woodland

Description

The reference state for this ecological site was old growth oak woodland. The woodland was dominated by white oak and black oak. Maximum tree age was likely 150-300 years. Periodic disturbances from fire, wind and ice as well as grazing by native large herbivores maintained the woodland structure and diverse ground flora species. Long disturbance-free periods allowed an increase in both the density of trees and an increase in abundance of shade tolerant species. Two community phases are recognized in the Reference State, with shifts between phases based on disturbance frequency. Reference states are very rare today. Fire suppression has resulted in increased canopy density, which has affected the abundance and diversity of ground flora. Most Reference States are currently altered because of timber harvesting, domestic grazing or clearing and conversion to grassland or cropland.

Submodel

Description

Composition is altered from the Reference State depending on tree selections during harvesting. This state will slowly increase with more shade tolerant species and white oak will become less dominant and is also dense because of fire suppression. Without periodic canopy disturbance, stem density and fire intolerant species, like hickory, will increase in abundance. Uncontrolled grazing if present will also have an impact on community composition and understory quality diminishing the diversity of native plants and introducing species that are tolerant of grazing, such as buckbrush, gooseberry, and Virginia creeper and will transition the site to a High-Graded/Grazed Woodland.

Submodel

Description

States that were subjected to repeated, high-grading timber harvests and uncontrolled domestic grazing will transition to a High-Graded, Grazed Woodland State. This state exhibits an over-abundance of hickory and other less desirable tree species, and weedy understory species such as buckbrush, gooseberry, poison ivy and Virginia creeper. The existing vegetation offers little nutritional value for cattle, and excessive cattle stocking damages tree boles, degrades understory species composition and results in soil compaction and accelerated erosion and runoff. Two common transitions from this state are woody clearing and conversion to State 4, Grassland or removing livestock, limited harvesting, and allowing long term succession to occur to some other woodland or forest state.

Submodel

Description

Conversion of woodlands to planted, non-native cool season grassland species such as tall fescue and red clover is common for this region. Two community phases are recognized in the Grassland State, with shifts between phases based on types and levels of management. Poor management will result in a shift to Community 4.2 that shows an increase in oak sprouting and increases in broomsedge densities. If grazing and active pasture management is discontinued, the site will eventually transition to State 2 or if grazing is continued will transition to State 3.

Submodel

Description

This State exists currently with intensive cropping of corn, soybeans, and wheat occurring especially when commodity prices are high. Some conversion to cool season grassland occurs for a limited period of time before transitioning back to cropland. Limited acres are sometimes converted to native warm season grassland.

Submodel