Tony's inadvertently demonstrating why there are regulations for public tree plantings, why guerilla gardening is illegal in many places. While he knows a LOT about botany, he's a little casual about the possible property damage/damage to lives, IMO.
By contrast, many governments now in the US are too cautious about it, taking advice from lawyers who don't know horticulture, which results in policy that is actually bad for trees and good for urban heat island worsening.
I advocate a middle way