Not far from the house is the edge of the "Big Woods", several hundred thousand contiguous acres of publicly-owned woodland. Although almost all of the Big Woods has always been forested, there is a scattering of former farmland - some has been planted with tree seedlings but most has been allowed to revert to woodland naturally.
Yesterday I walked through some of the reverting fields that haven't been farmed in almost 100 years. Trees were slow to seed into those acres where the soil was depleted of both nutrients and organic matter, so many of the trees are small in diameter and widely scattered. Because trees still don't fully occupy the site, many exotic plants have invaded the fields: the Asiatic honeysuckles, multiflora rose, autumn olive and Japanese stiltgrass are the common invaders. The most abundant and pernicious of these exotic plants is Japanese stiltgrass.
Stiltgrass is an annual plant that appears to prefer moist, fertile soils but will grow in many situations, especially sites that have been disturbed. Because it creates thick mats of stems and leaves and totally dominates the site's herbaceous layer, stiltgrass easily suppresses native plants - and the fact that white-tailed deer won't eat the stuff compounds the problem. Stiltgrass is gradually (in some areas not so gradually) spreading in the Big Woods and so threatens to reduce or eliminate desirable native plants and adversely impact wildlife as food sources are eliminated.
Any type of soil disturbance increases the likelihood of stiltgrass spreading through the forest. The miles of logging roads that have been built in the Big Woods in the last 40 years have certainly helped spread stiltgrass. The thousands of miles of access roads and pipelines that many expect to be constructed to extract natural gas from the Marcellus shale beneath northern and western Pennsylvania will probably hasten the spread of stiltgrass.
Controlling the spread of stiltgrass is difficult, but possible given enough time, effort and funds. Responsible forest managers will take steps to control or eliminate stiltgrass -- unfortunately, others will not.