Soil/Landform Unit 63

On cleared areas, weeds such as blackberries and ragwort become a problem

Area:

14 257 ha

1.07% of CMA region

From Upper Gellibrand to Peters Hill, steep spurs and ridges with long straight slopes and narrow valleys form the rugged northern margin of the Otway Range. The climate is significantly drier than in other parts of the range, with most areas receiving an annual rainfall of about 900 mm. The separation of these drier spurs and ridges from the rest of the range is well reflected by changes in the structure and composition of the native vegetation. In particular,

Eucalyptus radiata

becomes a prominent member the dominant stratum and the understorey changes from mesophytic species to drier sclerophyllous species such as

Acacia mucronata

A. verticillata

Cassini longifolia

and

Epacris impressa

. Most of this unit remains forested and is selectively logged for millable timber. Some parts of the eastern areas have been cleared for grazing, but management is difficult due to the rugged terrain. Softwood plantations have also been established. Landslips and sheet erosion have been severe in some areas, and rapid runoff from these hills creates problems of gully erosion on the plains of the Barwon River.

Deeply dissected hills with rounded crests
	Pine plantation along the plateau of deeply dissected hills

Component	1	2	3	4	5
Proportion of soil-landform unit	10%	50%	4%	35%	1%
CLIMATE Rainfall (mm)	Annual: 900-1100, lowest January (45), highest August (130)
Temperature (^oC)	Annual: 12, lowest July (7), highest February (17)
Seasonal growth limitations	Precipitation: less than potential evapotranspiration mid Nomver - mid March
GEOLOGY Age and lithology	Cretaceous fluvio-volcanic sandstone and conglomerate
Geomorphology	3.1.2 Deeply dissected upland ranges of the Southern Uplands
LANDUSE	Uncleared areas: Hardwood forestry for sawlogs, posts and poles; softwood forestry; nature conservation; active and passive recreation; water supply Minor cleared areas: Beef cattle grazing on mainly unimproved pastures
TOPOGRAPHY Landscape	Deeply dissected hills of the Otway Range
Elevation range (m)	150-400
Local relief (m)	150
Drainage pattern	Dendritic
Drainage density (km/km²)	2.7
Landform	Hills
Landform element	Steep slope	North and west facing slopes	Crest and upper slope	South and east facing slopes	Lower slope and drainage lines
Slope and range (%)	60 (20-70)	45 (25-65)	20 (5-3)	45 (25-65)	20 (1-35)
Slope shape	Linear	Linear	Convex	Linear	Concave
NATIVE VEGETATION Structure	Woodland	Open forest	Open forest	Tall open forest	Tall open forest
Dominant species	E. radiata, E. cypellocarpa	E. obliqua, E. radiata, E. cypellocarpa	E. obliqua, E. radiata, E. cypellocarpa	E. cypellocarpa, E. obliqua	E. cypellocarpa, E. obliqua, E. ovata, Acacia melanoxylong
SOIL Parent material	Colluvium	In situ weathered sandstone on conglomerate	In situ weathered sandstone on conglomerate	In situ weathered sandstone on conglomerate	Alluvium colluvium
Description (Corangamite Soil Group)	Stony brown gradational soils (7)	Brown texture contrast soils (6)	Brown texture contrast soils (6)	Brown gradational soils (7)	Brown gradational soils, weak structure (7)
Soil type sites	OTR732	OTR424, OTR735, SW71	OTR424, OTR735, SW71	COF01, OTR414, OTR736	COF01, OTR414, OTR607
Surface texture	Fine sandy loam	Loam	Loam	Loam	Silty loam
Permeability	Very high	Moderate	Moderate	High	High
Depth (m)	0.5	0.9	0.9	0.9	>2
LAND CHARACTERISTICS, POTENTIAL AND LIMITATIONS	Stony shallow soils with weak structure and low waterholding capacity on steep slopes are prone to sheet erosion and landslips.	Dry aspect, steep slopes and weakly structured surfaces lead to sheet erosion. Clay subsoils on steep slopes subject to periodic saturation are prone to landslips.	Steeper slopes are prone to sheet erosion.	Steep slopes are prone to sheet erosion. Clay subsoils on steep slopes subject to periodic saturation are prone to landslips.	Weakly structured soils receiving runoff are prone to scour gullying siltation and flooding.

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