Artificial and Natural Hollows Cannot Withstand Negligence

This is not a protest but indeed a call-up

Brush-tailed possum’s eyes / Credit: the author

Where Arborists at Within Habitat Creation and Maintenance

Apart from big timber, high climbs and adrenaline, arborists also have different skills under their sleeves. Although it is easy to associate arboriculture with a few traditional tree services, most ordinary people rarely consider arborists as environmentalists.

The term may sound inappropriate or antiquated, but it is a crucial role to fill in. The creation and maintenance of hollow habitats aren’t new concepts yet are poorly discussed among our peers. We usually think that only conservation biologists, zoologists and wildlife experts promote habitat restoration, ecosystem rehabilitation and public awareness. They are indeed indispensable, but arborists aren’t far away from the scene.

The creation and maintenance of hollow habitats have never been so important. New paths of study and practice in arboriculture have improved a lot in the last five years in Australia, with changes in the Cert III in Arb, allocating a path called “environmental arboriculture”.

The subject isn’t new, with many experts, including arborists, who have promoted ecosystem restoration by creating boxes and artificial hollows habitat in the last two decades.

Credit: the author

Hollow is a Home and Where Humans Stand Amongst It

There is an incredible amount of fauna reliant on nesting holes, and it is indispensable to think about the habitat fragmentation that compromises the life of many birds, mammals, reptiles and frogs. Australia has one of the highest rates of wildlife dependency on tree hollows globally. Our action of mimicking nature by creating nesting boxes and artificial cavities is, not to say the least, a work of art on understanding nature.

As deep as it gets, especially with this passionate tone of mine, I cannot deny that birds and mammals lack accommodation at this stage. Due to deforestation, increased property development, habitat fragmentation, agricultural land development, and utterly unchained footprints, we cannot wait any longer to encourage biodiversity.

And creating artificial hollows and nesting boxes is more than essential to solving problems locally that affect globally, thus understanding that each geographic location has its ecological requirements.

Brush-tailed possum resting inside / Credit: the author

Here Comes That Word Again

People still don’t understand why biodiversity is so important to our lives. We preserve at max our social wellbeing as a glorified stage of peace and love. Yet, we forget that we aren’t the only players responsible for ecosystem services in many cases. We rely on keystone species to drive forward our well-claimed way of life. Trees are one of them. I don’t need to babble about trees here, as I presume you are tired of hearing the benefits of this much-loved living organism.

Trees provide a habitat for many mammals, reptiles, birds, insects, and microorganisms and sustain a life grid that is self-functioning. Like any human society, civilisation has an integrated system that provides enough resources for individuals. We are still animals. Even with our highly evolved brains, we still depend on food to survive, which equals reliance on animals and plants.

Credit: the author

If I have to define the word “life” briefly, I would say it is a self-sustainable chemical system dependent on three main things: surface, resources and energy — go figure!

So, long story short, biodiversity means that the preservation of specific keystone species and their intermediaries must be amended. Or at least considered as an asset. Because without it, we wouldn’t be here in the first place.

Hence, humans being one of the primary consumers must realise that now our actions may determine the future of many species, whether plants or animals. We destroy, fragment kilometres of land and consecutively play against the ecosystem services and the ‘natural way’ of living on behalf of other living organisms.

By ‘natural way’, I mean the consistency that nature has done for millions of years — not understanding how we should behave towards natural resources will leave a big rock on the way for humankind’s progression (whatever that means). Perhaps then we should re-evaluate what progression means, adding different concepts to the only socioeconomic we’ve had in the last two hundred years or so.

What About the Creation and Maintenance of Hollow Habitats?

Coming back to the natural hollows in Australia, they may take several years to form. I am talking about hundreds of years.

Trees can develop cavities in different ways, and the one we know of depends on fungi to decompose wood before attracting borers and other cavity creators. Those saprophytes fungi are responsible for recycling and maintaining our planet alive, allowing the nutrient cycle to feed us and other living organisms.

Specific fungi develop heart rots (consumption of the heartwood of trees), aka wood-decaying fungi. During this process, trees fight to contain diseases and intrusions in the wood’s vascular tissue.

By plugging xylem cells (water carriers forming the wood integrity), resisting inward decay spread, inhibiting lateral decay spread, and creating the next layer of wood to contain other pathogens, these responsible parts may develop that beautiful, cave-like appearance of hollows with almost unique shapes, like a modern house.

Natural hollows cannot fit all purposes for inhabitants. Different shapes, dimensions and directions must suit a specific species. Birds, mammals and micro-bats have distinct behaviours allowing them to choose particular sites for roosting and nesting or just temporary housing.

They are very similar to us when we want to choose our perfect spot to live. The good thing about hollows in the correct position/aspect is that it allows them to be facing the right direction, preferably south-easterly for birds and mammals and north-westerly for micro-bats here in South Australia (it changes depending on geographic location).

Placing the hollows at a specific height also contributes to the correct species’ preference and avoids common predators and disturbances like cats, foxes and dogs. Entrance holes are crucial, where different dimensions will attract distinctive species. Not always you might expect to have the selected species to the specific following hole’s size, for instance.

The other beauty of natural hollows is that everything is there. Natural cavities can provide the essential home for animals to survive the weather extremes with the right temperature and air pressure conditions. Trees transpire more during hot days, accelerating the evaporation rate through their leaves. While this happens, cool air may be transported by xylem vessels inside the wood. This process might help cool down the hollow extremities, providing the best self-sustainable air conditioning system.

Credit: the author

Tree cavities can contain temperature during winter, keeping moisture away and maintaining ideal conditions to protect against prevailing winds within the right direction and position.

Natural hollows are no doubt of essential significance. Now that arborists may contribute to a small but significant piece of the climate change puzzle, we should develop better techniques. New technologies will help identify knowledge sources and provide better practices — not a wrong way to explore new areas, I believe.

Wrapping up…

What we can only expect from now is a change in behaviour toward our environment. For many reasons we are here in the first place, I cannot think otherwise about any other unless our survival capability and unquestionable ability to extract resources to provide energy.

If for one second we could bring back the idea of natural law, not just we could see ourselves learning more from each other, but also a lack of dependency on concepts that only humans seem to appreciate may emerge, which not necessarily play a fair game with nature.

Perhaps if principles and truth, inherent to creation, could rule over dogmatic beliefs (constructs of mind), knowledge and understanding could diminish the fear of punishment and universal laws that exist and apply anywhere in the Universe, regardless of location, discard moral relativism, we would be better of worry about what sustains us: the earth we stand on and the air we breathe in!

Thank you for reading!



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Tiago Miranda

Tiago Miranda

Naturalist | Arborist | Lecturer | Climber