Fire Blasting the Invasives

The majority of our time so far has been spent manually pulling out the barberry, using a rock bar to pry it out or wrapping a sling around the base and using a winch to rip it out. These methods are effective, but are a lot of work and very time consuming. We decided to look for other approaches and came up with torching. 

Torching is used sometimes in place of weed whacking. Since the stems of barberry are pretty thick, we start off by clipping the base of the bush before actually torching. In order to completely kill the bush, the torch must be held on the plant for about 30 seconds or more. We are not 100% certain this method works, so a test grid was set up. That way in a year we can come back to see if torching was effective. Overall I would say torching took about the same amount of time as using a rock bar, and it should not be done on a dry day. However, it was much less strenuous and would be a good manner for getting the isolated bushes that surround the dense thicket of barberry.

Where in the World: Mapping Stiltgrass Communities

Japanese stiltgrass tends to grow in homologous communities, covering large areas and choking out all other vegetation. The problem is especially obvious in sites cleared by humans—chiefly roads, crop fields, and drainage sites.

After we kill the stilgrass in one of these patches, there’s almost no remaining ground cover. These immediate landscape changes are obvious, but we’re really more interested in observing how the areas regrow, to assess whether our work is effective in the long-term. To gauge our baseline, we’ve begun using portable GPS units and GIS software to map areas currently dominated by Japanese stiltgrass. Basically, one of the project members walks the edge of a stiltgrass patch carrying a GPS unit.

The unit tracks the path, which we then import into a GIS program that superimposes the data points over a map of the area. Keeping tabs on annual changes in these borders will allow us to determine both whether we’ve successfully contained stiltgrass in areas where we’re working and whether stiltgrass communities we haven’t reached are continuing to expand.