Sydney’s Cumberland Plain is often cited in anti development cases. So why is it so special?
Partly it’s the value of its underlying soil type.
The geology of the Sydney Basin commenced nearly 300 million years ago as a shallow seabed, followed by river and swamp environments. These marine sediments formed what we now call Hawkesbury Sandstone and the river and swamp environments resulted in shale soils plus the economically important coal deposits.
As a sweeping generalisation the two main soil types of the Sydney Basin are the sandstones and the shales.
Of the two, the shales are better suited to agriculture; consequently, following the initial European settlement, they were extensively cleared. The sandstone soils around the original Farm Cove, now part of the CBD, were a contributing factor in the crop failures of early European settlement.
When the European settlers arrived the Cumberland Plain Woodland was estimated to cover 30 per cent of the Sydney Basin. It did not take long for the settlers to correlate the Cumberland Plain Woodland species of Grey Box eucalyptus moluccanna, Forest Red Gum eucalyptus tereticornis, Narrow Leafed Ironbark eucalyptus crebra and Spotted Gum eucalyptus maculata with better quality farmland.
As a result, early settlement followed where Cumberland Plain Woodland was identified. The settlement in Parramatta commenced in 1788 with the establishment of a government farm which involved extensive clearing of the undulating plains of what is now “the Western Suburbs”. In Blacktown land grants in 1819 and 1823 resulted in the area becoming a patchwork of small farms, grazing land and orange groves.
Camden is synonymous with the Macarthur family and their original farm was approximately 200 ha (the cow pastures) on the fertile Nepean river flats. Further farms were developed in the area around Narellan, Cobbitty and Campbelltown (marking the south-eastern boundary of The Cumberland Plain) in the early 19th century.
The Cumberland Plain stretches further north along the Hawkesbury River including the localities of Castlereagh and Richmond.
The situation facing remnant Cumberland Plain Woodland is similar to that facing the white rhino in Africa; while poaching is impacting on the remaining population, the greatest reduction in rhino numbers occurred in the early 19th century when trophy hunters decimated the population.
In contrast the Hawkesbury Sandstone is associated with much poorer farming soils and is often found along ridges. Consequently the early settlers learned not to favour this as farming land, although Hawkesbury Sandstone itself is highly priced with many heritage buildings in the Sydney being constructed of this stone.
The few remaining pockets of remnant Cumberland Plain Woodland are found throughout the Western Suburbs. This puts developers and planners looking for infill sites on a direct collision course with those concerned with saving these few remaining pockets of the original woodlands.