A logyard at the Orcutt Road site is extensively invaded by Japanese stiltgrass in the year following creation of the log yard.
All of the harvested sites in this study were in Morgan Monroe State Forest in Monroe County, Indiana. All sites were selectively harvested following Indiana Division of Forestry Best Mangement Practices.
All of these sites are within 10 miles of each other and the rapid spread site is approximately one mile from the minimal spread site. All sites have similar soil types and topography.
Differences in spread rates of Japanese stiltgrass appear to be due to the presence of existing patches of stiltgrass around log yards and along skid trails. Areas that were invaded prior harvest had dramatic spread. Areas that were not previously invaded had very minimal spread.
These data suggest the best way to limit spread of Japanese stiltgrass into timber harvest areas is to treat existing patches of stiltgrass in the summer or fall prior to harvest. This would significanly reduce the seeds that could be spread through the site.
We also observed that when an annual grass seed mix was added after site disturbance to log yards and skidder trails, there tended to be much less invasion by Japanese stiltgrass. Adding seeds that can quickly occupy the site can greatly reduce the ability of stiltgrass to invade the disturbed areas. We have confirmed this in a greenhouse experiment testing the compet