Botanic Gardens Trust, Sydney, Australia

Geography and Vegetation

Geography of the Newnes Plateau

 

Location

The plateau is north of Lithgow and covers about 300-400 km2. Most of this is within Newnes State Forest which has extensive areas of pine plantations on the eastern side. Adjoining areas to the north and east are in Blue Mountains and Wollemi National Parks. The Newnes Plateau has a lot of natural vegetation as well as pine plantation.

Newnes location

 

 

Landforms

The Newnes Plateau is the highest area of the Triassic sandstones in the Blue Mountain and ranges from 1000 to 1200 m high, with limited areas above 1100 m. The areas are cold, cold enough for areas of Snow Gum Woodland. The Plateau is the headwaters for the main rivers of the Hawkesbury-Nepean system including the Coxs and Colo. Creeks drain to a number of catchments including Wolgan River, Carne, Wollangambe, ,Farmers Creek, and the Coxs River

   
Climate

Annual rainfall is about 1070 mm with highest rainfall at the Clarence end. Lithgow annual rainfall is 860 mm.

 

Newnes-Rainfall

Annual rainfall in the Newnes area recorded between 1939 and 1998. The red line shows the average.

Vegetation communities of the Newnes Plateau

General patterns and past paleo history

Vegetation on the Newnes Plateau is very diverse and includes structural formations of forest, woodland, heath and shrubswamp, as well as areas of  planted pine forest. Vegetation patterns are related to geology, topography, soils and hydrology. Forest is found on the deeper soils of the upper plateau with the highest rainfall, and in deep canyons on the edge of the Plateau. This grades into woodland on shallower soil. Very shallow areas of soil around the margins of the plateau and on high rocky tops have heath while the margins of the plateau terminate in characteristic sandstone pagoda formations. Long narrow low-slope valleys have accumulations of sediment and peat with permanently moist shrub swamp.

The imprint of past climatic factors is strong, and recent work has begun to probe some of their impacts over the last 20,000 years. The Newnes Plateau is the highest part (up to 1200 m) of the sandstone plateau systems that makes up the Blue Mountains and includes features not found elsewhere, including elongate plateau swamps, and soft sandy plateaus with some interesting remnant sand dunes. These dunes have only been recently recognised, despite the Newnes Plateau being an important site for botanical study since the early 20th century. A recent  geomorphological study  of the dunes by Hesse et al. 2003 provides strong evidence of the landscape and by implication the vegetation at the time of the last Glacial Maximum about 20,000 years bp. Hesse et al. conclude that the sand dunes found on the Newnes Plateau indicate sparse vegetation, presumably above the treeline, at the Last Glacial Maximum and that remnant stands of trees must have survived through the cold glacial interval, perhaps only in deep moist valleys. Elsewhere, above the treeline or in the greatly expanded steppe-like vegetation of lower areas, sand dunes demonstrate that vegetation was sparse and unlike the thick alpine meadows of today.

There have also been recent palynological studies for a sites on the Newnes Plateau, in Newnes State Forest (Chalson & Martin 2009) and Gooches Crater (Black & Mooney 2006) which provide pollen and charcoal records over the last 12,000 years.

Below are details of the main structural habitats, forest, heath, pagoda, swamps and vegetation communities on the Newnes Plateau with images showing different aspects of each community.

Vegetation communities on the Newnes Plateau have been included in the NSW Office of Envirnment and Heritage (formerly the Department of Environment and Conservation) study, The Vegetation of the Western Blue Mountains including the Capertee, Coxs, Jenolan & Gurnang Areas. It contains descriptions with structural information, diagnostic species and maps. This information is available here.

Links to individual communities on the Newnes Plateau area given below:

Forest

Heath

Pagodas

Swamp