This circle is closest to the Resource Centre. It was discovered in early summer 2012 during a DSV weeding bee and was so unusual that it prompted us to look for other holes. Although it's difficult to illustrate clearly in photos, this is definitely a peculiar phenomenon. The DSV-free zone is almost a perfect circle with a clear outline of small DSV plants that become wilted in summer. It's right next to the Bill Holland Trail about halfway between the centre and the kiosk at the parking lot. This whole area was originally grass, but slowly became covered in sumac, which is now starting to die back.