In praise of She Oaks
Why aren't Casuarinas more popular and widespread?
A bit like Red Cedar (Toona australis) they were victims of their own success (or quality). European settlers found the timber so valuable for building and the wood so useful as fuel, that the tree disappeared from many areas. Unlike Eucalyptus, the regrowth was palatable to their sheep and, later, to rabbits. Seedlings were mown down. People forgot that they had ever been around.
Rowan Reid, in his book “Heartwood”, Melbourne Books 2017, says “.....she-oaks were known as 'bakers fuel'. They were prized because they burnt fast and hot and produced coals that kept their heat, which allowed the early risers to get their ovens up and running quickly and maintain an even temperature during baking.”
With two bakers ovens running regularly at Millpost (see right), I am confident that the Casuarina fuel we grow will be similarly prized.
Greening Australia has sparked an interest in planting Casuarinas (technically known now as Allocasuarina) as a food source for the endangered Glossy Black Cockatoo. They feed almost exclusively on the large cones of Black or Drooping She-Oak (Casuarina littoralis or C.stricta).
There is a project to plant 50,000 trees at Tarago, Bungonia, Windellama, Marulan, Goulburn and Sutton. Bungendore is included in a new proposed project extension.
We have never seen a Glossy Black here, but we have plenty of the Yellow-tailed Black Cockatoos. Over the past few months I have been collecting and sowing River Oak (Casuarina cunninghamiana) and Black She-oak (C. littoralis) seed. Casuarina is one of my favourite plants. It wasn't always. Back in the early 1980s when Judith and I and started planting trees “en masse”, Casuarinas often succumbed to frost. The winter of 1982 was especially cold, even killing naturally-occurring Silver Wattle on lower slopes.
After many failures, we tried growing them on in the nursery for 2 or 3 years. We then planted them out in November with a pencil-thick stem. We now have some fine stands established this way.
In 2008 the Murrumbidgee Catchment Management Authority planted thousands of trees here along Millpost Creek in 4 or 5 hours, and they included hundreds of Casuarinas that were so small you could hardly see them. Most of these trees grew! Perhaps because the site had best-practice site preparation, including ripping and mounding and several herbicidings. But a warmer climate was surely a contributing factor. 2008 was not as frosty as 1982. 2020 is warmer still.
So why have Casuarinas become a favourite? Have you experienced the beautiful soughing of the wind as it passes through a grove of She-oaks? It is so soothing, I consider Casuarinas soul builders. Pictured right is a grove with such great atmosphere we visit it often just to hear its sough.
But they are also soil builders. They fix nitrogen in the soil by forming symbiotic relationships with various soil/root micro-organisms, including Frankia and mycorrhizal fungi. This capacity helps Casuarina to thrive on poor soils and improve soil fertility. In addition, Casuarinas are nowhere near as flammable as Eucalyptus. And their evergreen canopy makes them the perfect shelter tree, filtering rather than blocking the wind.
What’s not to like?
David Watson 9/5/2019