The Australian city has put in decks around ancient urban trees to avoid compaction and ramps over street trees' root zones. "We are claiming back some of the road for trees," said Foster.
"We don't allow trenching under the trees' canopy. You have to work round it," he added, while overhead cables are accommodated in hollows in trees' crowns.
The council will also go to some trouble to preserve mature trees in the wrong place. Foster once transplanted a 140-tonne veteran tree 150m to make way for a development, a task that cost AU$160,000 (£85,000).