But deputy mayor for environment Shirley Rodrigues told London Assembly members earlier this month that Khan would not be held to the vow because it "was not in his printed manifesto" - although the pledge still stands on his campaign website - and that instead the administration would increase London's tree coverage by five per cent by 2025.
London Tree Officers Association (LTOA) chairman John Parker told HW: "The pre-election aspiration of planting two million trees always seemed like an unlikely target and the LTOA was not surprised that it did not make it into the mayor's manifesto.
"We welcome the renewed commitment to increasing canopy cover, an ambition only likely to be delivered through a combination of new planting on both public and private land, retention of existing trees and a strong community of tree officers. The LTOA will continue to work with our membership, local and national government and other stakeholders to help achieve this objective."
Khan earlier said of his plans to pedestrianise Oxford Street that he wanted to "create the world's greatest public space" and that this was a higher priority than the city's Garden Bridge project, for which he has since given conditional support.