Kirchubel (Kl)

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Kirchubel- geo

Area: 287 sq. km (1.4%)

In the west of the uplands precipitous mountain slopes with a high rainfall and vigorous vegetative growth are mapped in Kirchubel land system. These slopes flank the major plateaux on granodiorite, for example Mount Baw Baw and the Toorongo Plateau, and result from differential erosion, although faulting may be involved in places.

A cool climate, high rainfall and a parent rock that weathers relatively easily have produced deep soils, even on steep slopes. Active weathering of iron-bearing minerals, combined with leaching and a high production of organic matter have resulted in well-aggregated soils with a crumb or fine blocky structure in the upper horizons; subsoils are usually apedal with an earthy fabric. The soils are moderately acidic and permeable. Mica and feldspar are often abundant in the deep subsoil and hence soils are relatively fertile despite leaching. Steep slopes are susceptible to sheet erosion once disturbed but vertical slopes, such as road batters, do not slump due to the excellent soil drainage. The well-structured topsoils are sensitive to compaction.

The vegetation is mainly layered open forest III or IV, with open forest II on more exposed slopes.

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Kirchubel- image

A long, steep slope, typical of Kirchubel land system, on the southern side of Mount Toorongo.

CLIMATE Rainfall, mean (mm) Temperature, mean (°C) Seasonal growth limitations	Annual 900 - 1600; lowest January or February (60 - 90), highest August or October (120 - 150) Annual 8 - 12; lowest July (3 - 7), highest February (16 - 20) Temperature <10°C (av.): April - October Rainfall < potential evapotranspiration: February; frequent winter snow
GEOLOGY Age, lithology	Devonian; Baw Baw and Toorongo Granodiorites, Tynong Granite and associated metamorphics
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Long, precipitous mountain slopes with very high relief and ridge-and-ravine topography 240 - 1180 200 - 720 Dendritic 0.5
PRESENT LAND USE	Mostly uncleared: hardwood forestry (mainly ash timber); apiculture; small areas in Baw Baw National Park

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Kirchubel- cs

A study of the land in the Catchment of Gippsland Lakes - Vol 2 - land system Kirchubel- graph

LAND COMPONENT Percentage of land system Diagnostic features	1 55 Long, very steep sheltered slopes	2 40 Long, steep, more-exposed slopes	3 5 Drainage corridors
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	40 - 50, (30 - 70) Straight	30 - 50, (15 - 70) Straight	-, (0 - 5) Straight
SOIL
Parent material	Granodiorite, granite and associated metamorphic rock		Alluvium
Description	Black sandy loam to sandy clay loam merging into red or brown sandy clay loam to sandy clay; deep; subsoils often fine blocky structured, sometimes apedal	Very dark to black sandy loam to sandy clay loam merging into red or brown sandy clay loam to sandy clay; mainly deep. Maybe somewhat stony; subsoil structure as in component 1	Limited observations — probably variable; fine to coarse textured, sometimes gravelly
Classification	Red and Brown Earths/Krasnozems, Lithosols Gn2.21, Gn2.11, Gn3.11, Gn4.11, Gn4.10, Um5.52, Um6.12, Um7.11	Red and Brown Earths/Krasnozems, minor Lithosols Gn4.11, Gn4.31, Gn2.11, Um5.51	Alluvial Soils Uc5.21, Uf1.41
Surface texture	Sandy loam to sandy clay loam	Sandy loam to sandy clay loam	Sandy loam to sandy clay
Surface consistence	Soft	Soft	Soft
Depth (m)	>2.0	>1.5	Variable
Nutrient status	Low to moderate		Low to moderate
Available soil water capacity	Moderate		Moderate
Perviousness to water	Rapid		Rapid
Drainage	Good		Often waterlogged
Exposed stone (%)	<10		0
Sampled profile number	-	35	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Layered open forest II, IV: E. regnans+ with or without E. obliqua and E. cypellocarpa; E. nitens occasionally predominant. Nothofagus cunninghamii associated in higher rainfall areas	Open forest II, often shrubby: Pure or mixed stands of E. obliqua, E. sieberi, E. cypellocarpa, E. baxteri	Layered open forest III, IV: E. regnans+; E. viminalis+ (at lower elevations)

Disturbance	Affected process and trend	Primary resultant deterioration			Casual activities	Primary off-site process
Disturbance	Affected process and trend	Form	Susceptibility of components	Incidence with components	Casual activities	Primary off-site process
Alteration of vegetation: — reduction in leaf area, rooting depth and/or perenniality — reduction in density of tree roots	Reduced transpiration, resulting in: a) increased deep percolation b) increased regolith wetness Decreased root-binding	Nutrient loss Landslip and soil creep Soil creep	Not determined 1,2; moderate 12; moderate	Not determined Not determined Not determined	Removal of trees Usually after the removal of native vegetation Usually after the removal of native vegetation	Increased movement of water to groundwater; increased base-flow of streams Increased sediment load Increased sediment load
Increased exposure of surface soil	Increased overland flow and soil detachment	Sheet and rill erosion	1,2; high	Not determined	Clearing, logging, burning, road building and other earth-moving activities	Increased flash flows and sediment load.
Increased physical pressure on soil	Increased compaction With Reduced infiltration	Structure decline Sheet and rill erosion	1,2,3; moderate - high 1,2; high	Not determined Not determined	Increased trafficking, export of organic matter As for sheet and rill erosion above	- Increased flash flows
Increased soil disruption	Increased soil break-up	Gully erosion	1,2; high 3; low	Not determined	As for sheet and rill erosion above	Increased sediment load.
Comments: Regeneration of vegetative cover is quite rapid because of good growing conditions

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