Silty Backslope

Description

These ecological sites on located on well drained loess uplands throughout LRU 115XA. Sites have slopes 18% or higher. Historic reference sites were a mature oak-hickory forest with a high level of diversity in the shrub and herbaceous understory. Common canopy species included white oak, shagbark hickory, southern red oak, scarlet oak, and black oak. The driest sites may include post oak, chestnut oak, and red hickory. Sub-canopy trees included flowering dogwood, wild black cherry, sassafras, hophornbeam, and red maple.

Density and composition of understory species would be noticeably influenced by slope and aspect. Common species on these sites would includeVirginia creeper (Parthenocissus quinquefolia), pointedleaf ticktrefoil (Desmodium glutinosum), clustered blacksnakeroot (Sanicula odorata), spotted geranium (Geranium maculatum), roundleaf greenbrier (Smilax rotundifolia), and shining bedstraw (Galium concinnum).

Natural impacts such as drought, wind damage, ice storms, and wildfires influenced these communities over centuries. Periodic fire was one of the disturbances that helped to maintain the oak dominance. Often these fires were of low-severity and helped to clear the litter from the forest floor, reduced shrub, and encourage oak regeneration. Lightening was the usual ignition source; although native Americans did use fire to reduce understory brush, increase forage, and improve hunting. Long-term periods of drought did occur and would have influenced the fire severity thereby altering species composition, shrub density, plant mortality, and tree growth rates.

Cleared sites are often grazed; however, management is limited by slope. Landowners should be aware of potential overgrazing impacts such as soil erosion, soil compaction, water quality impacts, and noxious weeds. Invasive non-native vegetation is a serious concern in many remaining wooded areas as bush honeysuckle, euonymus, Japanese honeysuckle, privet, and other non-native plants have been introduced and are increasing without management controls.

Long-term fire suppression has resulted in many sites transitioning to an oak-maple-hickory forest with a dense understory of sugar maple, red maple, and white ash saplings. In Indiana, tulip poplar has become co-dominant on some sites. Without management inputs such as prescribed fire or timber stand improvement work, oak regeneration is often limited and species composition on these sites will continue to transition toward shade-tolerant, fast-growing tree species.

Submodel

Description

Most remaining Silty Backslope sites have been ecologically altered due to a long-term absence of fire, grazing, clearing, or selective harvest (i.e. oak removal). Trees on site, will depending on the type, length and severity of disturbances. However, sites that have had a long-term absence of fire will display the following characteristics: an increase in fire -intolerant species, an increase in shrub density, an increase in leaf-litter buildup, and an increase in shade-tolerant understory species. Diversity of species may also be reduced, especially if there has been an introduction of non-native species such as bush honeysuckle (Lonicera maackii).

Submodel

Description

A portion of these sites have been converted to pastureland or forage production. Slopes will be limiting on many sites; thereby not appropriate for clearing or grazing.

For sites that are appropriate for conversion, species selection will depend upon the objectives and goals of the landowner; however, commonly planted grasses include tall fescue (Schedonorus arundinaceus), brome (Bromus spp.), white clover (Trifolium repens) and red clover (Trifolium pratense). Species health and productivity are determined by the management and long-term overgrazing on some sites has caused soil erosion and compaction.

Submodel