Available free online, some cities have detailed interactive maps of all trees. Well, maybe not ALL trees. Most maps have some errors or missing data, perhaps because the data is not perpetually verified and maintained. Some maps are specifically “street trees”, meaning it may not include trees in parks or on privately-owned land.
Sometimes a map may show the genus, but the exact species of a tree is not known.
You might use one of these maps to identify the species for a particular tree. Or you might use it to locate unknown instances of a specific species you are seeking.
Here are some links to online tree maps that I have found helpful.
Philadelphia PA – Tree Map (2023)
New Haven CT – Street Tree Inventory Map