Acacia burkei/Black Monkey Thorn progression.

The tree August 2010:

 I got the tree from a bonsai friend in July 2009. The left hand branch was still a twig and the initial idea was to use it as a sacrifice branch to thicken the trunk lower down.

The defoliated tree January 2011:

 The defoliation was an experiment because there was not much information on defoliation of Acacia. The tree responded well by a lot of back budding and smaller leaves.

The tree October 2011:

 In the last picture I am growing a new lower right branch.

Here is the tree March 2012:

The new branch have thickened very quickly. I will probably cut it back in spring to get the taper of the branch right.

The tree 19 July 2012:

 I also cut it back because the buds were swelling. Here is a picture from above showing where I planned to cut and a few branches I have to move a bit:

The Black Monkey Thorn normally bud out on the last bud on a twig. Cutting it back heavily normally wakes up buds lower down. Here is a virt showing you the potential buds when you cut back:

When you cut back at the yellow line the yellow arrows indicate where you may get buds going. Cutting back at the purple line(that twig was the primary bud), there are two secondary buds latent that may start growing.

The latest pic, October 2012:

The tree was cut back once this season. As soon as the buds swell I am going to defoliate the tree. After this the canopy will be left alone except for regular pinching. There are two twigs growing lower down that will be left to grow freely to thicken up the base and create a little more taper.

November 2012- defoliated and some twigs rearranged:

 For the rest of the season I will only pinch the growth and enjoy the tree.

March 2013-just as autumn is starting:

I have only pinched back the new twigs to two leaves the last few months. In winter I will probably compress the crown a bit to prevent it from looking top heavy.