Wooden nest boxes can be a short term solution to the lack of hollow trees in our environment. When you place a nest box, try to get it in a place where there is some shading from the rest of the tree canopy. Also, plant smaller trees and shrubs around the nestbox site so that fledglings have plenty of perches and some protection when they emerge.
Also think about food sources. Not hand feeding birds but planting appropriate food trees and grasses so that they can obtain …natural food sources. If you live in the city of Knox then you can obtain some free advice on this from the Gardens for Wildlife – G4W . Food plants are available at indigenous nurseries such as the KES Knox Environment Society (KES).
We have found that carved hollows in tree limbs have a longer life expectancy than some of the cheaper plywood boxes. But a carved hollow requires an arborist to make the installation. Both have their purpose.
Of course the best habitat boxes of all are the ones that develop naturally in old growth trees. If you are not sure about the safety of a tree with a natural hollow then ask a qualified arborist to inspect the tree. Many hollow bearing trees can still be quite stable. There are other several options to consider rather than just tree removal.