Meet the London Planetree. You'll find lines and valleys of them all throughout Brooklyn. I've come to find out it's because they're a very hearty breed that can withstand the smog and pollution of an urban environment.
For some time I've noticed that they drop their leaves not only in winter but in summer as well. It's so strange to go crunching down the block in 90+ degree weather! After doing some research, I've found that that high temperature is actually why they've fallen. The trees are undergoing heat stress!
I patted this one reassuringly, telling it this too shall pass :)