Tanjil (Tj)

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

Area: 210 sq. km (1.0%)

Tanjil land system occurs on hilly terrain with plutonic and gneissic rocks, mainly in the south-west of the East Victorian Uplands. Ridge-and-ravine topography prevails but there is some rounding of ridge crests. Slopes are steep and moderately long. Areas are similar in geology and topography to Timbarra land system but they are much more humid.

High rainfall acting on granodiorites, granites and gneisses has produced deep soils. Profiles are generally well aggregated, particularly in the upper horizons, and are moderately acidic.

Layered open forest III is most common, with some open forest II on slopes at lower elevations.

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

Protected steep slopes with a humid Eucalyptus regnans (mountain ash) forest

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	Palaeozoic granodiorites, granites and coarsely crystalline gneisses
PHYSIOGRAPHY Landscape Elevation range (m) Relative relief (m) Drainage pattern Drainage density (km/km²)	Steep hills with a subdued ridge-and-ravine topography 260 - 1460 80 - 300 Dendritic 1.5
PRESENT LAND USE	Mostly uncleared: hardwood forestry (quality variable, some ash and general construction timber); apiculture; small area in Baw Baw National Park

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

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

LAND COMPONENT Percentage of land system Diagnostic features	1 70 Slopes	2 15 Protected slopes	3 10 Terraces in major drainage corridors	4 5 Minor drainage depressions
PHYSIOGRAPHY Slope %, typical and (range) Slope shape	20 - 25, (10 - 60) Straight	20 - 25, (10 - 60) Straight	<5, (0 - 10) Straight but uneven	Variable, (5 - 30) Concave
SOIL
Parent material	Granodiorite, granite and associated gneiss		Mixed alluvium	Locally derived alluvium and colluvium
Description	Mainly brown or red, some yellow, gradational, acidic soils; sandy clay loam to light clay subsoil, usually with fine blocky structure. On protected slopes topsoil is darker coloured and much deeper		Limited observations — probably mainly undifferentiated brown sand	Variable: brown sandy loam to sandy clay loam; high surficial organic matter and very stony in places
Classification	Red, Brown and Yellow Earths, some Yellow Podzolic Soils and Lithosols Gn2.11, Gn4.11, Gn4.34, Gn4.54, Gn3.74, Um5.52		Alluvial soils Uc1.44	Brown Earths Uc6.11
Surface texture	Loamy fine sand to sandy clay loam; sandy loam common		Sand to sandy clay loam	Sandy loam to sandy clay loam
Surface consistence	Friable to firm when moist		-	Friable when moist
Depth (m)	>1.5		>2.0	>2.0
Nutrient status	Low to moderate		Low to moderate	Low to moderate
Available soil water capacity	Moderate; high for more organic soils		Variable, depending on texture	Moderate
Perviousness to water	Rapid		Moderate	Rapid
Drainage	Good		Good	Moderately good
Exposed stone (%)	Generally 0		0	Variable; 0 - 40
Sampled profile number	-		-	-
NATIVE VEGETATION Structure of vegetation and characteristic species of dominant stratum (+ Predominant species)	Highest elevations — layered open forest III: E. dives, E. delegatensis, E. rubida Lower elevations — open forest II, III, often shrubby: E. sieberi+, E. cypellocarpa and/or E. obliqua	Open forest III, IV, often layered: Highest elevations — E. delegatensis Lower elevations — E. regnans occasionally with E. nitens; E. regnans and/or E. obliqua, E. cypellocarpa; E. sieberi sometimes associated on upper slopes	Open forest III, IV, often layered: E. viminalis usually predominant; Nothofagus cunninghamii may be associated in higher rainfall areas	Open forest III, IV, often layered or ferny: Highest elevations — E. delegatensis Lower elevations — E. regnans with or without E. cypellocarpa, E. obliqua, E. rubida; Dicksonia antarctica often present

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	Reduced transpiration, resulting in: a) increased deep percolation b) increased regolith wetness	Nutrient loss Landslip	Not determined 12; low	Not determined Uncommon	Removal of trees Accelerated by major disturbance of native vegetation	Increased movement of water to groundwater; increased base-flow of streams Increased sediment load
Increased exposure of surface soil	Increased overland flow and soil detachment	Sheet and rill erosion	1,2; moderate 4; very low	Uncommon	Clearing, logging, burning, overgrazing, road and dam building and other earth-moving activities, rabbit burrowing, trafficking by stock and vehicles.	Increased flash flows and sediment load.
Increased physical pressure on soil	Increased compaction With Reduced infiltration	Structure decline Sheet and rill erosion	1,3; moderate 2,4; high 1,2; moderate 4; very low	Uncommon Uncommon	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 Streambank erosion	1,2,4; moderate 3; high	Uncommon Uncommon	As for sheet and rill erosion above As for sheet and rill erosion above	Increased sediment load Increased sediment load
Comments: Local occurrences of rill and gully erosion occur on road batters, log landings and tracks. Good growing conditions result in rapid regeneration of vegetative cover except on exposed sites at high elevations.

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