Well, London _is_ technically a forest, after all... https://www.timeout.com/london/things-to-do/did-you-know-tha...

You're absolutely right. I think this is of trees that need checking and maintenance to keep roads, cars, pedestrians safe. Hence the URL /street_trees/

Parks and woods would be maintained in a different process. Obviously it's acceptable and even desirable to have fallen down trees in woods and some parks.

Trees on private property are also missing — in front of people's houses/communal areas in front of blocks of flats. There's quite a few of those around me that I would consider to be "street trees".

Pretty cool site, though!