Bald Hills Land System

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Inland from Anglesea is a deeply dissected landscape with very stunted native vegetation, referred to as the Bald Hills. The Tertiary sediments exposed here include both sands and clays and are characterized by soils of extremely low fertility.

Heaths and low woodlands are found on the upper parts of the landscape, where the sand soils tend to predominate. Xanthorrhoea australis is particularly common and tends to dominate on sites with hardpans developed in the soil profile. Lower down in the landscape, low forests or open forests of Eucalyptus nitida and E. obliqua tend to occur.

Productive land uses are limited to the mining of sand and gravel in numerous shallow extraction pits, and mining of coal near Anglesea. Nature conservation and recreation are other forms of land use.

A Study of land in the catchments of the Otway Range and adjacent plains - bald hills
Low open woodlands of E. nitida with Xanthorrhoea australis
in the understorey typify this land system, hardpan areas being
demarcated by the absence of the tree stratum.

A Study of land in the catchments of the Otway Range and adjacent plains - bald hills

Area: 92 km²	Component and its proportion of land system
Area: 92 km²	1 10%	2 25%	3 10%	4 40%	5 15%
CLIMATE Rainfall, mm	Annual: 700 – 1,000, lowest January (35), highest August (100)
Temperature, 0^oC	Annual: 13, lowest July (8), highest February (18)
	Temperature: less than 10^oC (av.) mid June – mid August
	Precipitation: less than potential evapotranspiration November - March
GEOLOGY Age, lithology	Palaeocene unconsolidated quartz sand, gravel and clayey silt.
TOPOGRAPHY Landscape
Elevation, m	0 – 210
Local relief, m	90
Drainage pattern	Dendritic
Drainage density, km/km²	2.1
Land form	Hill		Valley floor
Land form element	Upper slope, crest	Upper slope, crest	Broad, slightly depressed area of impeded drainage	Lower slop	-
Slope (and range), %	7 (3-15)	15 (2-35)	7 (3-12)	19 (10-35)	1 (10-3)
Slope shape	Convex	Convex	Concave	Linear	Concave
NATIVE VEGETATION Structure	Low woodland	Low open woodland	Closed heath	Open forest	Closed scrub
Dominant species	E. nitida	E. nitida	Xanthorrhoea australis, Casuarina pusilla, Platylobium obtusangulum, Leptospermum myrsinoides	E. obliqua E. nitida	E. ovata, Leptospermum juniperinum, Leptospermum lanigerum, Acacia verticillata
SOIL Parent material	Kaolinitic silty clay; surface layers of quarts sand	Quartz sand and gravel	Quartz sand and gravel	Sand, silt and clay	Plant remains; alluvial silt, sand and gravel
Description	Grey sand soils, kaolinitic clay underlay	Grey sand soils, uniform texture	Grey sand soils with hardpans, uniform texture	Yellow gradational sols, weak structure	Grey gradational soils
Surface texture	Sandy loam	Loamy sand	Loamy sand	Loamy sand	Silty loam
Permeability	Low	Very high	Low	High	Very low
Depth, m	>2	>2	0.6	>2	>2
LAND USE	Uncleared areas: Nature conservation; extraction of gravel an sand; active and passive recreation; some attempts at pine establishment. Minor cleared areas: Mining for coal.
SOIL DETERIORATION HAZARD Critical land features, processes, forms	Weakly structured surface soils and slowly permeable subsoils on moderate slopes are prone to sheet and rill erosion. Clay subsoils subject to periodic saturation are prone to landslips.	Very low inherent fertility and high permeability lead to nutrient decline. Steeper slopes with compacted soils are prone to sheet, rill and gully erosion (scouring).	Very low inherent fertility with some leaching of permeable surface soils leads to nutrient decline. Impermeable hardpans prevent vertical drainage leading to seasonal waterlogging.	Low inherent fertility and high permeability lead to nutrient decline. Steeper slopes with weak structured surface soils are prone to sheet erosion.	High seasonal water table leads to waterlogging and soil compaction. Rapid run-off from adjacent hills leads to flooding, siltation and gully erosion.

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