Oh thanks and sorry- this one was a bit random but i couldn't resist picking those leaves. The leave are now soaking and are giving off a yellow colour dye.
I can't say from the photos which species; probably not a local Eucalyptus. Decades ago several Eucalyptus species that are not local were planted around the Hackett water tank, I think in order to test which one is suitable to re-timber Mt Majura which has been cleared for sheep and cattle farming and timber collection. At that time it seems that there wasn't a concern whether species was local or not. The branch could have been fallen / blown from any of those planted not local trees. To see Mt Majura's local trees visit https://www.flickr.com/photos/61627737@N03/albums/72157627244893256/
abread111 the records of the euc trees I presented on CNM are all from young trees in the < 2m category in an area of about 20m2. Wikipedia on E. aggregata: "The leaves on young plants vary but are mostly elliptic to egg-shaped or broadly lance-shaped, 40–70 mm (2–3 in) long, 15–30 mm (0.6–1 in) wide and a slightly lighter shade of green on the lower side." See for instance my record Eucalyptus (genus) (A Gum Tree) with the 3rd photo of lower side. The group of 4 young possibly E aggregata trees occur about 100m south of mature (planted) and young (recruits) E aggregata trees, see for instance Eucalyptus aggregata (Black Gum) and https://canberra.naturemapr.org/sightings/4506260.