Black Gum - profile

Indicative distribution

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Key:

known

predicted

The areas shown in pink and/purple are the sub-regions where the species or community is known or predicted to occur. They may not occur thoughout the sub-region but may be restricted to certain areas. ( click here to see geographic restrictions). The information presented in this map is only indicative and may contain errors and omissions.

Scientific name: Eucalyptus aggregata

Conservation status in NSW: Vulnerable

Commonwealth status: Vulnerable

Gazetted date: 12 Feb 2010

Profile last updated: 11 Feb 2019

Description

Black Gum is a small to medium-sized woodland tree growing to 18 m tall. The the bark on the trunk and main branches is dark greyish-black, deeply fibrous or flaky. The bark does not shed annually. Only the uppermost branches and twigs have smooth whitish, cream or greyish bark that sheds yearly. The juvenile leaves are narrow or oval-shaped, dull green and arranged opposite to one another. The adult leaves are slightly curved and round-ended, about 12 cm long and 1 to 2 cm wide. They are glossy dark green and have the same colour on each surface. The buds, flowers and fruits occur in tight clusters of 7; the clusters are on stalks 3 to 4 mm long. The buds are egg-shaped, 3 to 5 mm long and 2 to 3 mm wide. The flowers are white and are followed by gum-nuts which are cone- or cup-shaped, 2 to 4 mm long and 3 to 5 mm wide. The disc on the surface of the gum-nut has processes (valves) which emerge from the disc.

Distribution

Black Gum is found in the NSW Central and Southern Tablelands, with small isolated populations in Victoria and the ACT. In NSW it occurs in the South Eastern Highlands Bioregion and on the western fringe of the Sydney Basin Bioregion. Black Gum has a moderately narrow distribution, occurring mainly in the wetter, cooler and higher parts of the tablelands, for example in the Blayney, Crookwell, Goulburn, Braidwood and Bungendore districts.

Habitat and ecology

Grows in the lowest parts of the landscape.
Grows on alluvial soils, on cold, poorly-drained flats and hollows adjacent to creeks and small rivers.
Often grows with other cold-adapted eucalypts, such as Snow Gum or White Sallee (Eucalyptus pauciflora), Manna or Ribbon Gum (E. viminalis), Candlebark (E. rubida), Black Sallee (E. stellulata) and Swamp Gum (E. ovata). Black Gum usually occurs in an open woodland formation with a grassy groundlayer dominated either by River Tussock (Poa labillardierei) or Kangaroo Grass (Themeda australis), but with few shrubs.
Also occurs as isolated paddock trees in modified native or exotic pastures.
Many populations occur on travelling stock reserves, though stands and isolated individuals also occur on private land.
There are very few stands in conservation reserves.

Regional distribution and habitat

Click on a region below to view detailed distribution, habitat and vegetation information.

Threats

Clearing for cropping and grazing.
The naturally small area and patchiness of its habitat is under pressure from further reduction in area.
Small-scale clearing as farming properties are subdivided for rural-residential use.
Lack of recruitment, especially as older trees are gradually being removed by wind-storms and natural attrition.
Lack of recruitment under current grazing.
Lack of recruitment because of competition by weeds, particularly Blackberry (Rubus spp.), Phalaris (Phalaris aquatica), Cocksfoot (Dactylis glomerata), willows (Salix spp.) and Scotch Broom (Cytisus scoparius).
In small populations, hybridisation with related species (e.g. Candlebark (Eucalyptus rubida) and Manna Gum (E. viminalis)), is causing lowering of genetic fitness, and is increasing the risk of extinction.
Climate change effects (i.e. increasing average temperatures and reductions in effective rainfall) may reduce the species' viability by reducing conditions suitable for recruitment and establishment of seedlings.
Climate change may also lead to increased invasion by seedlings of Candlebark and Manna Gum, which may lead to increased competition with Black Gum.
Herbicide control of fire weed & serrated tussock may negatively impact recruitment of the species.

Recovery strategies

Priority actions are the specific, practical things that must be done to recover a threatened species, population or ecological community. The Office of Environment and Heritage has identified 6 priority actions to help recover the Black Gum in New South Wales.

Activities to assist this species

Fence out mature stands to reduce or eliminate grazing pressures and to allow regeneration.
Control weeds that inhibit regeneration.
Reduce small-scale clearing pressures.
Encourage enhancement plantings around remnants of this species (using local-provenance seed sources).
Mark locations of this species on maps of catchment, shires, farms and/or reserves, etc.
Sign-post locally significant roadside populations.

Information sources

() NSW Flora Online - Eucalyptus aggregata
NSW Scientific Committee (2010) Eucalyptus aggregata (Black Gum) - vulnerable species final determination. DECCW, Sydney

IBRA Bioregion	IBRA Subregion	Known or predicted	Geographic restrictions region

NSW South Western Slopes	Capertee Valley	Predicted	None
NSW South Western Slopes	Inland Slopes	Predicted	None
Other State	ACT	Known	None
South East Corner	Bateman	Predicted	None
South East Corner	South East Coastal Ranges	Known	None
South Eastern Highlands	Bathurst	Known	None
South Eastern Highlands	Bungonia	Known	None
South Eastern Highlands	Capertee Uplands	Known	None
South Eastern Highlands	Crookwell	Known	None
South Eastern Highlands	Hill End	Predicted	None
South Eastern Highlands	Kanangra	Known	None
South Eastern Highlands	Kybeyan-Gourock	Known	None
South Eastern Highlands	Monaro	Known	East of a line that runs north to south about 5 km west of Bungendore
South Eastern Highlands	Murrumbateman	Predicted	None
South Eastern Highlands	Oberon	Known	None
South Eastern Highlands	Orange	Known	None
Sydney Basin	Burragorang	Known	None
Sydney Basin	Ettrema	Known	None
Sydney Basin	Moss Vale	Known	None
Sydney Basin	Wollemi	Known	None