I don't remember exactly but there may have been a small crab apple tree by the entrance. This was below and in front of Hamerschlag Hall that I believe is now filled in. The offices behind connected to the library floor of Wean Hall.
Yeah, the old parking lot around Hamerschlag became the new fab / nanotech lab when Scott Hall was built (finished 2016) -- they connected HH C-level to Wean 4, a major boon to winter-time indoor connectivity. Google Streetview has a pretty good view of it:
Likely some trash or debris. At 3:35, after the camera cuts to the machine turned around, you can see a couple more similar white objects underneath the front of the Walker that appear to be blown about.