Maybe others will contribute to this. We had a pretty bad wind storm last weekend, power out in many places. Many of the power problems were caused by trees that blew over. I happened to walk past what was my favourite Robinia Purple Robe (TM), on Willow north of 39th, and it's so gone. In this case, it wasn't the tree that fell over, but rather that it just shredded. It still had a few flowers. Here is the tree in 2012. And now. There are lots of sprouts from the roots, but these have spines and the cultivar, as far as I can see, does not. In Kitsilano, 3rd Avenue between Balsam and Larch, two private Fraxinus excelsior keeled over. My friend's blue car is between them, untouched (and it remains untouched because she can't move it). The Vancouver Trees app describes these trees as having shallow, fibrous roots (actually it seems it describes a lot of street trees that way).