The photographed specimen is an isolated tree growing uphill of a patch of introduced Eucalyptus trees along a gully that runs parallel and south of Valour park / Federal Highway. They are escapes from trees planted in Valour park. Some mature trees > 20 m. The trees spread like weeds. There are patches of thick bark and leaf litter on the ground; bark of mature trees peels in long ribbons that touch the litter.
I identified Eucalyptus globulus subsp. bicostata (http://canberranaturemap.org/Community/Sighting/3343056) along the gully from juvenile leaves and fruits.
A second species originally thought to be Eucalyptus viminalis (from juvenile leaves) turned out to be E. aggregata.
The map shows the approx. extend of the two species in the nature reserve.
The last 3 photos show details of buds (photo taken of material I found on the ground), leaves, and a fruit (taken of material I found on the ground). Fruits and flowers in umbels of three.
Michael Isobel Crawford and I have been there today; Isobel confirmed Blue gum for this specimen (see leaf size, fruits and buds). The specimen which grow in the same area and which I thought are E. viminalis turned out to be E. aggregata.