In Australia a large proportion of our native fauna species utilise and rely on tree hollows and other tree habitat features. In particular, many of our threatened bird and mammal species are not only reliant on tree hollows but require a certain shape and size hollow. Hollows and other tree features provide protection from weather and predators and are safe sites for roosting and breeding. Natural hollows can take 100s of years to form and have been rapidly disappearing with the increased rate of land clearing and development.
In an attempt to mitigate the negative effects of hollow loss, artificial hollow structures such as nest boxes and carved hollows can be installed. There are positives and negatives to nest boxes; they are easy to install and can be easily tailored to suit a variety of different species, but they only last so long (often only 5-10 years) and some native fauna are less likely to use nest boxes. Carved hollows are another way to create artificial hollows. They can be used in conjunction with traditional nest boxes, or as an alternative if a site has suitable recipient trees. Carved hollows have traditionally been created using chainsaws until the recently developed Hollowhog tool. The Hollowhog allows efficient and safe creation of large internal cavities through small entry holes in both living trees and dead wood. No other damage to the tree’s cambium (living tissue) occurs through the carving process, and hollows can be tailor made for a target fauna species. Fauna have often been observed inspecting and utilising carved hollows within weeks of them being installed. Furthermore, carved hollows can last up to 70 years, which is around 10 times longer than a timber next box.
When nest boxes and carved hollows are installed in large quantities to offset land clearing, they are often required to be monitored over a few years. Artificial hollow monitoring allows us to assess the rate of uptake, ensure they are not being used by pest species, and determine any patterns in use. It also ensures the boxes and hollows are maintained and replaced if damage has occurred. This data is valuable and allows us to improve the way we prescribe and install nest boxes and hollows in the future.
In order to install and monitor artificial hollows a suitably qualified Tree Climber is required. With the increased demand for ecological tree climbing, we saw a gap between arborists and ecologists, with many jobs requiring both to be present. Additionally, tree climbing arborists were often difficult to engage due to their incredibly busy schedules and this would delay our jobs. That’s why we decided to train a small team of ecologists for ecological tree climbing. Our tree climbing ecologists have all completed their ‘Safe Tree Climbing for Science’ with Ironbark Environmental Arboriculture and have since been busy monitoring and installing nest boxes.
Our tree climbing ecologists can assist with many ecological tree services such as natural and artificial hollow monitoring, nest box and carved hollow installation, and pre-clearance surveys.
Check out our video to see the team in action installing Artificial Hollows!
