Many scroungers here think - if the town cut the wood at the side of the road, it belongs to the city and I can have it if the city left it. That's simply not true. Above is a property I am the owner of. On the top of the photo is a public road that cuts through my property. The city has the legal right to pave and use the right of way as it so pleases, there is usually a legal document filed somewhere in the court house that gives them that right in Pennsylvania. However, I clearly own the right of way and my neighbor across the streets road frontage.
While the city can pretty much do what it wants on the 40' ROW, they are MY trees as they are on MY property. The city did not buy the property they bought the right to have a street on the property and do any necessary maintenance. Often, this is at a reduced price. I am going through this right now with an electric utility that wants to buy an electric line ROW. I can still build parking lots or retention ponds, etc... on the ROW, I just can't impede the electric lines or their poles.
Think about a farmer - how often do they plant corn or soybeans right up to 5' or so of the edge of pave, all the time right? Often the ROW is pretty far into his corn or soybeans. What do you think the farmer would do if you came and took all the corn out of the ROW? How are trees any different? Maybe I planted them and now they block vehicle's vision so the city cut them down. They are still MY trees.
Perhaps there is a lawyer here who can explain this better than I can, but I own a lot of property and have some experience with this kind of thing.
I think you guys confuse the fact that many of these circumstances the owner is a large corporate owner of 1,000 acres or it's state game lands or forest or similar, and lots of times that is true. Many of them don't enforce ownership because they don't mind that you took the wood. The problem is when the guy owns an acre and lives two miles away (or on top of the hill).