GeoLINK Ecologists trial the Hollowhog technique for creating tree hollows.
Natural tree hollows are valuable and often essential for many wildlife species. They provide refuge from the weather and predators, as well as providing a safe site for roosting and breeding.
The destruction of natural tree hollows in Australia continues to be an issue. When land is cleared, tree hollows that can take decades to form, are lost. An intense fire or an area that has been subject to repeated burns can also lead to a shortage of hollows for native wildlife. Because it takes so long for hollows to form, we’re losing them faster than we’re gaining them.
Features of natural tree hollows
Valuable hollows for wildlife are generally found in mature and dead trees. As trees age over time, they are subject to various natural forces such as wind, heat, fire, lightning, rain or attack from termites, beetles and fungi. This causes decay and allows a hollow to slowly form. Small hollows can take approximately 70 years to form and large hollows take more than 100 years.
Alternatives for natural tree hollows
Nest boxes are one solution for providing “replacement” tree hollows for native fauna. They mimic natural hollows and provides wildlife with a comfortable and safe place to rest in and raise their young. GeoLINK has recommended the use of nest boxes for projects where natural hollows have been cleared or damaged.
Another alternative is chainsaw-carved cavities (also known as chainsaw hollows) which are an innovative approach for creating additional habitat opportunities for arboreal hollow-dependent species. Creating chainsaw hollows needs to be done by a highly skilled arborist who will first decide if hollows can be created without causing damage to a live tree.
Both options have their limitations. Nest boxes are not a long-term substitute for natural hollows. They typically last around ten years compared to a natural tree hollow that may exist for over 100 years. Chainsaw hollows don’t replicate a natural tree hollow which provides a much smaller entry than the hollow itself. This results in it being less protective from predators.
A more recent approach to creating tree hollows is a technique called ‘Hollowhog’.
What is the Hollowhog technique?
The Hollowhog is a unique wood carving tool that has been specifically designed to create habitat for hollow dependent wildlife. The Hollowhog efficiently and safely creates large internal cavities through small entry holes in both living and dead wood.
The Hollowhog technique provides improvements from the chainsaw technique as it creates a small entry providing a safe haven from larger predators.
GeoLINK and new techniques
GeoLINK likes to consider and use new tools and techniques that will provide benefits to clients in appropriate settings. Especially if they provide added benefits to the environments we work within.
Favourable characteristics of the Hollowhog technique:
- variations to the size and shapes of hollows that can be achieved
- efficient at making salvaged log hollows and habitat for ground dwelling fauna
- provide small entry for the many fauna that prefer to squeeze through the smallest entry possible
- remain cooler on hot days and warmer on cool ones than thin-walled nest boxes.
- creates a 50 mm entry hole and then progressively carves a larger and larger hollow of any dimensions up to about 600mm
GeoLINK have gained a reputation as industry leaders. That involves adapting to industry changes and trialling new approaches we think will be beneficial to clients and environmental outcomes. For example, we recently trialled the Hollowhog tool for a client using 50% drilled hollows (new technology) and 50% nest boxes (existing technology) and monitored for effectiveness. This project was appropriate to trial the drilled hollows on because it involved the replacement of some damaged nest boxes. We have been monitoring the progress of this project over time and already seeing positive results with utilisation of drilled hollows by native fauna.
While Hollowhogs are proving to be beneficial, they can be ‘pushed out’ by the tree as it scars over time. Monitoring remains an important aspect to providing alternative habitation to ensure it continues to provide the benefits that it’s intended to.
Trialling and considering new innovations are important for the industries and the environments we work in. While we look for efficiencies and improvements for clients, the most important aspect is ensuring new innovations also bring improvements for the flora, fauna and environment. Our approach is to assess each scenario on a case-by-case basis.
Get in touch with our team to discuss your next project.
