In any of these circumstances, if possible, pruning should be postponed until the tree recovers or the environmental conditions are suitable. If pruning is conducted in unfit conditions, the reasons for the work and the possible consequences must be communicated to the tree owner. All work performed on trees and in their surroundings should take into account the possible presence of accompanying organisms, in particular protected species.1 Their occurrence will be very likely on veteran trees and other trees showing increased natural value (due to the presence of hollows, decay, etc.). Due diligence must be exercised in order to prevent damage and destruction of the habitats of valuable and protected species, both during access to the tree (e.g. damage to protected lichens while climbing, knocking down a bird‘s nests, removing fungal fruit bodies etc.).
hollows inhabited by birds, bats etc.)