The increasing loss of habitat for our local and native wildlife is a real concern and, whilst development in a major city like Sydney is inevitable, there are things that can be done to try and alleviate the problem. Recently we ran an article about the innovative 3D printing of nesting boxes to highlight the out-of-the-box thinking that can lead the way in replacing this type of habitat loss for our local wildlife. Another innovative solution being adopted by some councils around the country is the creation of nesting boxes and hollows by way of some skilled carving… with a chainsaw.
Rather artistic in nature, these chainsaw hollows are carved out of both living and dead trees by skilled arborists to help replace hollows that can take up to 100 years to form naturally. Natural hollows form in the trunks and branches of mature trees and provide essential shelter for hundreds of species of vertebrates such as birds, possums, sugar gliders, frogs and microbats to name just a few, not to mention the enormous number of invertebrates such as insects. Roughly in excess of 300 different species in Australia rely on hollows for refuge and breeding.
However, once these naturally formed hollows are lost with the removal of old growth trees, an alternative needs to be found. The chainsaw-carved hollows as they are known are a great way to create additional habitat opportunities for local wildlife in the unfortunate event that trees must be cleared. The best option of course is always to leave the aged tree specimens where they are, but as this is not always practicable, the ability to carve a new hollow or nest box into a tree that has not formed its own natural hollow is a viable alternative for our hollow-dependent species.
Chainsaw hollows are created by skilled arborists who will carefully assess whether a tree is suitable for such a procedure. Often when a large branch is removed or a branch reduction is performed it provides an ideal opportunity for such a hollow to be created. Given the hollow can last for the lifetime of the tree, compared to a nesting box which has an average lifespan of 10 years, then it’s a process that should be considered by everyone in the role of caretaker for a large tree specimen.
To carve a hollow into a living tree requires a good deal of skill, but if done correctly the tree will heal over the cut section creating a callus with no long term damage to the tree. The chainsaw hollow is achieved by cutting a cavity on the side of the tree that is then covered with a pre-cut timber faceplate with an access hole provided. Research suggests that once carved, the chainsaw hollows have much better insulating properties than regular nesting boxes.
Successful examples of chainsaw hollows can be found at Jerry’s Downfall Reserve and Wearing Park at Munruben in South East Queensland where around 20 carved hollows were installed in early 2021 by Logan City Council. Returning to the sites a year or so later revealed they were being used by brush-tailed possums, little corellas, rainbow lorikeets, scaly-breasted lorikeets and squirrel gliders. Other examples around the country include Banyule City Council in Victoria where artificial hollows were created due to a lack of old hollow-bearing trees. The newly created chainsaw hollows were eventually inhabited by musk and little lorikeets, pardalotes and even sugar gliders.
While naturally formed hollows are always best, these artificially created alternatives are proving to be a good substitute. Chainsaw hollows are designed to replicate the external physical characteristics of natural hollows and the evidence suggests a good uptake with the local wildlife. In addition, there are very few reports of lasting damage, if any, to the trees that have had hollows carved into them. As such, it should be viewed as a fantastic option for councils in particular to adopt as an increasing amount of development results in the unfortunate loss of habitat for many species that rely on tree hollows to survive.
To learn more about chainsaw hollows visit Land for Wildlife and Sustainable Macleod.
