A rather whimsical drawing of a greater glider, fast asleep in a tree hollow.
Many beautiful beasties live in wet sclerophyll forest, including those that dwell or nest in the hollows of venerable old trees. Gliding possums that eat leaves, blossoms or trees sap; owls, tree-creepers and parrots; bats, snakes and antechinuses¹. As I started drawing my next forest portrait, the shape of the tree branches reminded me of these hollows, and the beasts that might be dozing within. I had decided to draw another ‘flavour’ of wet sclerophyll forest: one dominated by the blackbutt, Eucalyptus pilularis. Blackbutts, like many other eucalypts, develop ‘bayonet’ and ‘elbow’ -type branches, which often produce hollows as they age.
Hollow formation in blackbutt (Eucalyptus pilularis). Left: A branch forms from the main trunk of the tree. Centre: As the original branch grows longer its leafy tips sag down and become more shaded. This activates one or more epicormic buds on the upper side of the original branch, and these grow into ‘bayonet’ branches. Right: The original branch eventually dies and is shed, forming an ‘elbow’. Termites eat out the main trunk and original branch, forming hollows that are used by many different types of animals.
It’s hard to find large old trees in our forests, since so many places have either been logged over or burnt in the last 100 years or so. (And these blackbutts only start forming hollows well after their 100th birthday. A remarkable study by Mackowski² estimates that hollow formation only really gets going when these trees are 144 to 194 years old.) Often the only large, old trees that remain are those that were too gnarled and crooked to be useful for timber. Here’s one that the lovely Ray and I found when we went looking for big blackbutt trees in Bellthorpe State Forest. Can you spot the bayonet and elbow branches?
Old blackbutt tree at Bellthorpe
This forest portrait would be different from the first in a number of ways. Most obviously, it would feature blackbutts instead of flooded gums, but I also wanted to capture the misty atmosphere of a drizzly winter day – just like it was out in the forest when I was doing my preliminary sketches. It would also have a grassy understorey, which I find intriguing – since I’m more familiar with the dark, dense, shrubby understory of wet sclerophyll forests in Victoria. The wet sclerophyll forests here in south east Queensland can have either a grassy or a rainforesty/shrubby understorey. Both understorey types, and the ecotones they create, provide important habitat for threatened species such as the eastern bristlebird and Hastings River mouse.
As always, it was important to include people in the picture to provide scale. I was first introduced to these grassy-understoreyed forests by the Queensland Herbarium botanists – so who better to include in the picture? Here’s a couple of them hard at work:
Botanists at work, Bellthorpe State Forest
So once again, I took all my sketches, photos and mental images back home and started drawing. After many days, this is what emerged:
Blackbutts in the mist, a wet sclerophyll forest portrait. Pastel on paper, by Paula Peeters. Original size: 52 cm x 72 cm.
What do you think of this next forest portrait? The intense green of the grass is the actual colour we get up here, in subtropical Queensland – even (or maybe especially) on a cloudy day. The rainforest plants – including two different types of palm – are hanging in there, on the left-hand-side of the picture. These fire-sensitive plants will spread out to colonise the grassy area if there are no fires for a while. You can see evidence of a fairly recent fire in the black charcoal marks at the bases of the trees on the right. And there are a probably a number of hollows in these old, bumpy trees, including in their elbow branches. Who knows what creatures might be snug and fast asleep, high above those busy botanists way below?
This is the third post in a series on forest portraits. You can also read more about how and why I started to paint forests, and check out my previous and next forest portraits.
1. Small marsupials that look somewhat like rodents, but are fearsome predators.
2. Mackowski,C.M. (1984) The ontogeny of hollows in blackbutt (Eucalyptus pilularis) and its relevance to the management of forests for possums, gliders and timber. pp. 553-67 in A.P. Smith and I.D. Hume Possums and gliders, Australian Mammal Society, Sydney.
I love your finished artwork, with those unseen snoozing marsupials, and the way you’ve used people to show the huge size of the trees. Makes me want to visit Australia again soon!
Hi Sarah, thanks for your kind feedback. I hope you get to come back again, so you can continue to produce more fab Australian-inspired artwork! Cheers, Paula
Thank you I will post to our Family Nature Club page. I am in Bendigo the city in the Box Ironbark forest. I assume the “Elbow” growth pattern applies to Box , Ironbark forest. There are so few Old Ironbark and Box trees on Public Land. I will look more closely on the regrowth trees. The tree hollow formations are one of the arguments we are using to transfer State Forest to National Park. Any science we can muster would be helpful. Maybe we can count the “Elbows” and project what accommodation may be available in the future. Swifties , Phascogales , Tree goannas , Powerful Owls etc.
Hi Brenton, Good luck in your quest to conserve box-ironbark forest in Victoria. It’s been a while since I’ve been out and about in your part of the world, so I don’t remember if either box or ironbarks develop hollows in the same way. I think someone would have looked into the development of hollows in these species, but I don’t have a relevant scientific paper at my fingertips – perhaps another reader can help? But basically, as you’re probably well aware, older and bigger trees almost always support more wildlife – in terms of both species and individuals. And larger trees store much more carbon than small ones – another good reason to preserve them. Thanks for reading and commenting, cheers Paula
Hi Paula,
I love the whimsical drawing of the greater glider and the pastels do an excellent job of showing the soft light of a misty forest. Beautiful work! I think that the important of hollows in such old trees for wildlife is something that is not necessarily appreciated by enough people. When we plant new forests, it takes a long time before hollows are available for creatures to live in. Using old fallen logs for wood fires removes habitats for many creatures as well. Thanks for another interesting lesson, Paula. 🙂
Hey Jane, thanks again for your great comments. Yes I am sure many people aren’t aware that many of the trees our forests are relatively young, and don’t necessarily have the habitat values of the old ones that have been removed. Your message about leaving fallen wood alone is very important too. Often it’s better NOT to ‘tidy up’ Cheers, Paula
Just like the last, as I’ve scrolled up and seen your painting I’ve sucked in my breath and thought “Ahh! That’s IT!”
You’re nailing them, Paula.
Thanks Dayna, I’m glad the pictures are speaking to you, it means a lot to me
Your blackbutt portrait is stunning Paula. It’s a visual treat. Thank you!
Thankyou Gail for your encouragement!