Nature conservation

Threatened species

Blue Mountains Basalt Forest in the Sydney Basin Bioregion - profile

Indicative distribution

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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: Blue Mountains Basalt Forest in the Sydney Basin Bioregion
Conservation status in NSW: Endangered Ecological Community
Commonwealth status: Not listed
Gazetted date: 20 Mar 2015
Profile last updated: 23 Mar 2022


Blue Mountains Basalt Forest is usually a tall eucalypt forest (over 30 m in mature stands) with a dense shrub or small tree layer, often including tree ferns (Cyathea spp.) and moist herbaceous ground cover (Tozer et al. 2010). The canopy composition is variable but usually dominated by one or more of the species Eucalyptus fastigata,E. blaxlandii, E. cypellocarpa or E. radiata subsp. radiata. Other canopy species which may be locally common or dominant include E. oreades (which is often dominant on south-facing slopes at the transition to a sandstone substrate) and E. viminalis (Tozer et al. 2010, D. Connolly pers. comm. Nov. 2013). A eucalypt canopy may be absent from previously cleared or otherwise highly disturbed stands.

Blue Mountains Basalt Forest may grade into Intermediate Temperate Rainforest (map unit p116) on sheltered sites, into Shale-Basalt Sheltered Forest (map unit p168) where basalt adjoins shale or into Sandstone Scarp Warm Temperate Rainforest (map unit p114) on steep, south-facing sandstone slopes (Tozer et al. 2010). Intergrading vegetation is considered part of this determination if it is floristically more similar to Blue Mountains Basalt Forest than these adjoining communities. Shale-Basalt Sheltered Forest includes Blue Mountains Shale Cap Forest in the Sydney Basin Bioregion, an Endangered Ecological Community under the Act.

Blue Mountains Basalt Forest is floristically similar to two other communities listed as Endangered Ecological Communities under the Act, Robertson Basalt Tall Open Forest in the Sydney Basin Bioregion and Mount Gibraltar Forest in the Sydney Basin Bioregion but may be distinguished from these by differences in species composition and relative abundance of characteristic species. For example, species which are usually more common in Blue Mountains Basalt Forest compared to the two other communities include Acacia elata, Cyathea spp., Doryphora sassafras, Geranium homeanum, Indigofera australis and Senecio linearifolius (D Binns in litt. July 2012; M Tozer in litt. Nov 2013). Blue Mountains Basalt Forest is geographically disjunct from these communities (by at least 70 km for known occurrences) and occurs at generally higher altitudes. It also differs from Mount Gibraltar Forest because the latter occurs on syenite. Blue Mountains Basalt Forest is also distinct from Tablelands Basalt Forest in the Sydney Basin and South East Highlands Bioregions (map unit p20 of Tozer et al. 2010).


Blue Mountains Basalt Forest has been recorded south of the Wolgan and Colo Riversin Wollemi IBRA subregion (SEWPaC 2012). The major area of distribution is the Blue Mountains including the basalt caps of Mount Irvine, Mount Wilson, Mount Bell, Mount Tomah, Mount Banks, Mount Caley and Mount Hay. However, there may be isolated outliers north to Mount Cameron and Mount Monundilla. Blue Mountains Basalt Forest occurs mostly between 750 m and 1050 m altitude, in areaswith annual rainfall of 950 to 1350 mm (Tozer et al. 2010).

Occurrences of the community at the northern end of Wollemi need to be considered closely for alignment to this community and may meet EPBC definition but not TSC definition.

Habitat and ecology

  • Found on highly fertile soils derived from basalt.
  • Found mostly on rolling hills on gentle to steep slopes.
  • Occurs in areas with rainfall between 950 mm to 1350 mm.
  • Disturbed remnants (including areas without eucalypt canopy) are considered to form part of the community if the vegetation is likely to respond to assisted natural regeneration.
  • Between 30 and 50% of this community's original occurrence has been estimated to remain, although the potential distribution is highly localised on account of the substrate.
  • Many remnants are small and isolated pockets on private land. Some larger areas exist in Crown Lands including National Parks and under control of Local Government.

Regional distribution and habitat

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


Recovery strategies

Activities to assist this species

IBRA Bioregion IBRA Subregion Known or predicted Geographic restrictions region
Sydney BasinBurragorang Predicted None
Sydney BasinWollemi Known None