[Noah930]

I looked up the city records. The neighbors' pool was built (permitted, at least) in 1977. My parents' rental house was also built in 1977; they bought it new, and that was the transaction date. Presumably the three now-removed trees have been there since the house was purchased. There aren't too many renters who are going to go to the expense/effort of planting trees.

Then, I looked at the satellite images of the two houses, and while my parents' backyard is fairly barren, the neighbors with the pool have all sorts of landscaping with multiple mature trees throughout their oasis-style backyard.