The mulga tree is a member of the acacia family. Wattle trees are also acacias. Although most people would say that the eucalypt (or gum) is the most common tree in Australia, I’ve heard it claimed that it is in fact the acacia. Certainly mulga trees and shrubs are common in many Outback areas.
Reader Raylene, who lives in the Outback, writes:
“The mulga is a beautiful tree synonymous with the bush. We love mulgas. They grow slowly and live a very long time. Mulgas are often the only tree/grove of trees for miles in the sandhill country. When mustering and you want a break from the sun in summer, they provide the shade for us and every other creature around… birds, bugs, native animals, cattle, horses, etc.
They also provide homes for many birds including wedge-tailed eagles and zebra finches. I have seen both living in the same huge nest, the eagle babies on top, the zebra finches and their babies living in a nest inside the big nest… obviously not a big enough snack…
As much as mulga is a wonderful tree, its wood has a dark side. A run-in with mulga-wood will cause a serious infection without question. Locals tend to run into mulga while mustering on motorbikes (leg/arm, sometimes head injuries), while both locals and tourists tend to have a run-in while gathering wood for camp-fires or just walking around and tripping over… leg, arm, head (due to standing up quickly below a branch and knocking the head).
Mulga wood is poisonous and a wound will become infected and needs antibiotic treatment. Without treatment, the wound can become serious very quickly. I have seen a number of people flown out with the RFDS for further treatment involving a hospital stay for a few days and intravenous antibiotics. [Editor’s note: Apparently aborigines often used a sharpened piece of mulga wood on their spear heads.]
Take care when gathering wood or even just walking around. Seek help if needed. We all have accidents occasionally.
One of the big differences I notice when I go to the city is when people are walking. In town, people watch ahead. Out bush, we watch the ground.”
Bobby Dazzler's Blog 
I did not know this, nor did I even suspect Mulga was poisonous. Very pleased that you’ve started a blog, I’ve been a newsletter reader for a few months now. Cheers, Jon.
I should have mentioned that for those people who are already scared to set foot in Australia because of the poisonous snakes, the sharks, the dingoes, the spiders, the crocodiles, the box jellyfish, etc, here’s another one for your list: the trees!
Thanks for the info. I was about to put some in my aquarium. Glad I researched first.