Thanks for the interesting feedback.
No intention to start tree culling for it own sake.
Imagine a highway with two 9 feet wide traffic lanes, kerbs, grass verges and footways each side.
A highway authority plants Hornbean trees with the centre 2 feet from the kerb edge: 11 feet from the centre of the made-up carriageway
Over time the outer edge of the trunk will get increasingly closer to carriageway.
If the highway authority maintains clearances, as some do, the tree will be almost "bald" on one side because the branches will be cut back almost to the trunk.
Some authorities such as National Highways specify 500mm side clearance from the edge of the carriageway to take account of lorry wing mirrors, etc. If that were done in this exampe there would be no place for the tree.
I have nothing against trees, bird nesting, bees, bats, berries or other forms of wild life.
Some believe that trees near roads are good for the environment because they absorb carbon dioxide. But if we considered all the pollution from internal combustion engines when trees have to be cut back it tips the balance. Lorries, cherry pickers, chain saws, shredders, return trips to the dumping ground, cuttings emitting carbon dioxide as the die, etc.
If someone drew up a chemical equation considering the rate of oxygen consumption of internal combustion engines, the emission from the engines versus the rate of gas exchange through trees it may not compute the way they would prefer. Then there is the matter of consumption of dwindling fossil fuel reserves.
As electric vehicles become more the norm the harmful emissions will be local to the power station rather than the roads. It would make sense to have trees growing to their full size close to the power station. Is that the case?
The highways exist primarily for the benefit of humans.
If humans want to enjoy the benefit that trees provide surely it would be better to place them where they do not need to be cut back and are allowed to grow to full capacity.
Attached is an image showing examples of clearances published by some authorities.