Catalpa or Catawba, which I have a vague memory of from my child hood in Illinois, and the Chestnut. I thought it might be, having once seen some amazing chocolate candies in the window of a shop in Paris that were all spiky and being told they were chocolate replicas of chestnuts. The third tree, might be a box elder, as suggested by one person, but the seeds look a bit different. I'll have to take a look at the downed tree again to see what the leaves look like. In any case, thanks for the answers, the research, the fun, the prizes are on their way.
Here are another from the series of minimal pieces with Washi tape and Maths titles (thanks Richard.) This is #276 "Minimal Cycle Base"
The papers are from old magazines, which has a color quality that I like.