Despite being named for their leaves resemblance to the feathers of the Cassowary Casuarinas are unlikely to attempt to disembowel you should you startle one while out bushwalking, unlikely, but no guarantees.
While they may look like pine trees, Casuarinas (and Allocasuarinas) are flowering plants and belong with the Angiosperms. Within the Casuarinaceae family there are 4 genera and 97 species of which 3 genera and 67 species are found in Australia. The Hunter region has 10* species of Casuarina and Allocasuarina though there are a couple of extra that may just enter into the lower North Coast area.
They are separated into Casuarina and Allocasuarina by the number of teeth on their needles and by the colour of their seeds. The timber has a lovely “oak” grain (hence the common name “sheoak”), burn very hot, wear out saw blades and are an important food source for Black Cockatoos.
For identification purposes a small hand lens is useful, though the zoom function on your phone’s camera will work just as well.
You will need one of the Casuarina “needles” and a cone, grip the needle firmly on both ends and pull apart, the bottom “article” will have a number of small teeth, count the teeth and start from there.
(*and maybe another species if I can get another sample)
1 Leaves (needles) with 6-20 teeth, seed dull, grey or yellow brown (Casuarina) 2
Casuarina cunninghamiana seed
1* Leaves with 4-14 teeth, seed shiny red brown to black (Allocasuarina) 4
Allocasuarina torulosa seed
2 Teeth 12-20, cone 7-10mm diameter. Tree to 20m, frequently suckering, branchlets drooping generally grows in saline conditions.
Casuarina glauca Swamp Oak
2* Teeth 8-12 3
3 Teeth 8-10, cone, barrel shaped, 7-14mm long, 4-6mm diameter. Tree generally to 35m (sometimes 50m+), generally along freshwater creeks and rivers
Casuarina cunninghamiana River Oak