Black she oak

[Beau]

About a year ago I was in the the big green shed for unrelated matters and I'm sure like a lot of people here, regardless of the usual quality, variety and price of the plants there, I find it hard not to at least have a quick look, this time it paid off for me, well I think so, I found this little black she oak, it has some nice rough bark, a bit of taper and it was $12, I couldn't help myself.
I tipped the top and designated a new leader which even stood up on its own without wire which i thought was pretty cool. I'll be honest i dunno what to do with it so for the time being I'm just going to enjoy it for what it is until I can draw a better picture, any ideas are more than welcome.
All is good but what i have noticed is where the branches meet the trunk and at the cut site it has swollen callouses like knuckles, i dunno what they are, is this typical? Is it just juvenile growth behaviour? Or it something else?
Cheers Beau

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[Raging Bull]

I have a few casuarinas and a couple of them have a similar growth around the base of new vigorous branches, but not nearly as pronounced as on yours. I would say and I'm no expert, that this is normal growth, but you should avoid having more than one branch grow from the same place on the trunk as they do thicken there and you'll get areas of reverse taper.

[Rory]

I would say and I'm no expert, that this is normal growth, but you should avoid having more than one branch grow from the same place on the trunk as they do thicken there and you'll get areas of reverse taper.

Raging Bull is on the money. Thats completely normal. Often Allocasuarina littoralis develops this bulging of growth. It strengthens the connection of the branch and is quite common. Even on branches that do not have bar branching, you will find this. Its also a very common trait on Banksias.
But as Raging Bull says, if you allow bar branching (2 or more branches from same junction) to develop, it can lead to significant bulging. This can actually work in your favour if you are trying to thicken certain areas, but detract if you aren't. Depends on the look you are going for.

For $12, thats a great buy. One of the great attributes of Allocasuarina littoralis is that the bark doesn't bulge significantly like Allocasuarina torulosa does. On bonsai, this often looks stupid as the tree gets older. But with littoralis it often ages and thickens in proportion to the entire tree, making it look very natural. Personally I don't wire branches to bend them down significantly if they are less than about 1/2 cm thick at the base. You can promote die-back.

The wonderful trait of this species is that over time you will find they shoot from everywhere and will give you a plethora of options to work with. I'd go for an upright lean look if it was mine, and allow multiple trunks to develop in time.

They love sun, and love a well draining mix. Don't allow the medium to get bone dry on a hot or slightly windy day.
Wind is the most dangerous thing for Casuarina bonsai. In the wild, Casuarina roots are usually very long and deep. But not so in a bonsai pot. They usually don't recover from drying out on a windy day.