Geophysics Conditions: Landscapes and Land Use

It also bears mentioning that a prominent landscape feature dominates the remains of the former plantation [Figure Natural 8]. A line of trees and dense shrubs cuts southwest-northeast across the breadth of the historic property in a line parallel to the river [Figure Natural 6]. At the south end of the property, in Grid 1, the line of foliage curves south, where it ends. At the center of the feature are the remnants of a barbed wire fence [Figure Natural 7]. Some of it is standing, still clinging to poorly preserved cedar posts, and some of it is buried beneath leaf cover. The fence and associated brush line date to at least the mid-1960s, when the current owners purchased the property, although they suspect it is of 1940s vintage.

This fenceline is significant both in terms of conditions affecting geophysical survey and in terms of understanding the impact of land use patterns on archaeological preservation. Relative to geophysics, the most obvious consideration for geophysics is the influence of significant quantities of iron on magnetism-based techniques. Relative to preservation, several aspects of the fenceline and its history suggest it may have protected shallow archaeological features:

1. The ground elevation is higher in its vicinity, either because the vegetation has captured soil (flood or farming turn row deposits) or because it has escaped mechanized plowing, which did not arrive in this region until the 1960s.
2. The fence in the 1960s separated cultivated fields on its southeastern side from the pasturage on its northwestern side. When the current owners purchased the property they converted the pasturage to hay production, which means the field northwest of the fence probably was never impacted by mechanical farming techniques.
3. The extent of the vegetation, especially along the southern end of the fence, has expanded and contracted over the years, which may have reduced the amount of plowing impact on the areas at the treeline’s edges.