Strata committee members have a huge amount of leeway to make mistakes provided they do so in good faith. What “in good faith” means is open to debate and interpretation but if they were ever told they couldn’t or shouldn’t do something, then that might be considered lacking the good faith required.
As an owner, you could pursue the strata scheme and strata manager to reinstate the trees and shrubs, and the current regime might consider pursuing the former committee members to cover the cost. Or you could report your OC to the council and hope the trickle-down effect works on the miscreants.
But there is no direct method that I can think of that would see the plants reinstated and the people responsible forced to pay.