Narrow Leaved Ironbark Trees ( Eucalyptus crebra )line both sides of this Bush track in the Pilliga Forest , near Narrabri in North Western NSW, Australia.Eucalyptus. This native tree is a large spreading tree that grows up to 35 metres high. It is prized by beekeepers for it's blossoms which produce great honey. The wood is very hard and is used for construction. It was also used for railway sleepers years ago before concrete sleepers replaced the timber.