Abstract
Eucalyptus gomphocephala (Tuart) is an iconic woodland canopy tree, endemic to the Swan Coastal Plain of Western Australia, and one of few eucalypts able to dominate on calcareous soils. Unfortunately, less than one third of the original E. gomphocephala woodland ecosystem remains today (Government of Western Australia 2003), largely as a result of clearing for urbanisation, agriculture and industry. Equally disturbing is a decline of complex and unknown cause(s) within the Yalgorup region, south of Mandurah, 50 km south of the capital city of Perth. The decline and death of mature trees has been occurring within Yalgorup for approximately 15 years with the majority of the region affected and up to 1 00% mortality of E. gomphocephala in some locations.