Homes for Wildlife - Tree Hollows and Bush Rock

How Do Tree Hollows Form?

Tree hollows form in the trunk or branches of live or dead trees, and usually are found in much older trees, typically 100-150 years old. 

They vary in shape and size, and form as a result of limbs being broken off in the wind, lightning strike, fire or after attack by termites, other insects or fungi.

Because they take so long to form, and are such important habitat for many of our native animal species, it is vital that they are retained wherever possible.


Tree Hollows

Why Are Hollows Important?

Hollows are an incredibly valuable resource for many native species. They  are used a refuge during weather events as well as protection from predators. they are also an essential roosting and breeding site for several species, including birds, bats, possums, reptiles and frogs. 

Examples of animals that use hollows in our shire include Glossy Black Cockatoos, Powerful Owls, Sugar Gliders, Squirrel Gliders, Kookaburras and the Eastern False Pipistrelle (microbat).


Tree Hollows 2

How Can We Help Keep Tree Hollows?

When undertaking developments or landscaping, efforts should be made  protect all trees with hollows including dead standing trees (stags) wherever possible. An arborist can assist to ensure these are kept in a safe condition. Additionally, young trees are needed to develop into trees that will form future hollows for animals.

Nest Boxes

In areas where natural tree hollows are scarce, nest boxes may be used as artificial hollows for many hollow-dependent fauna species. 

It is important to recognise that whilst nest boxes may increase habitat for many fauna species, they should not be considered a replacement for natural tree hollows. 

There are also several planning, installation and monitoring considerations that come with determining whether a nest box is a suitable option for assisting native wildlife.

To assist you or your group with deciding whether a nest box is suitable, please review this Nest Box Guide:

Nest Box Guide(PDF, 737KB)

Complementing the guide are two recording form templates:

Nest Box Installation - Recording Template

Nest Box Monitoring - Recording Template

Bush Rock

Bush rock is loose, fragile rock found on rocky or soil surfaces. Like hollows, it can take a long period of time to form and is critical habitat for many species. 

When available, many animals use the habitat created by bush rock as shelter to avoid extreme weather and bushfires, protection from predators and nest sites for reptiles. Plants such as mosses, lichens and liverworts also thrive in areas with bush rock.

In order to retain this valuable habitat, it is important to minimise disturbance to rocks while you are out bush walking or mountain biking. Bush rock should also not be taken from the bush for landscaping purposes. For more information, watch the below video. 

Department of Planning, Industry and Environment's Bush Rock Video

Further information

For more information about how to create or conserve habitat for wildlife in your backyards or properties, see the below websites: