The greatest threats to the Cumberland Plain Woodland include land clearing for agriculture, urban sprawl and the introduction of harmful weed species.

[8] The ecoregion contains clay soils derived from Wianamatta Shale to the west of Sydney CBD, where it receives 750–900 mm of annual rainfall.

[12] The Western Sydney Airport, currently under construction at Badgerys Creek, New South Wales, will require the clearing of a large area of Cumberland Plain Woodland.

[27] Eucalyptus species: Non-eucalyptus trees: Shrubs: Grasses and sedge: Bird species in the woodland include (which are mostly vulnerable and/or endangered):[28] Mammals:[29] In April 1788, Governor Arthur Phillip describes the land west of Parramatta:[2] The country through which they travelled was singularly fine, level, or rising in small hills of a very pleasing and picturesque appearance.

The trees growing at a distance of from 20 to 40 feet [6–12 metres] from each other, and in general entirely free from brushwood, which was confined to the stony and barren spots.In 1818, author and settler James Atkinson describes the plain as:[2] One immense tract of forest land extends, with little interruption, from below Windsor, on the Hawkesbury to Appin, a distance of 50 miles...Forest means land more or less furnished with timber trees, and invariably covered with grass underneath, and destitute of underwood...The whole of this tract, and indeed all the forest in this county, was thick forest land, covered with very heavy timber, chiefly iron and stringy bark, box, blue and other gums, and mahogany.In 1819, British explorer William Wentworth describes Cumberland Plain's natural landscape between Liverpool and Nepean River:[30] The soil changes to a thin layer of vegetable mould, resting on a stratum of yellow clay, which is again supported by a deep bed of schistus.

An endless variety of hill and dale, clothed in the most luxuriant herbage, and covered with bleating flocks and lowing herds, at length indicate that you are in regions fit to be inhabited by civilized man.

A rich loam resting on a substratum of fat red clay, several feet in depth, is found even on the tops of the highest hills, which in general do not yield in fertility to the valleys.

Coursing the kangaroo is the favourite amusement of the colonists, who generally pursue this animal at full speed on horseback, and frequently manage, notwithstanding its extraordinary swiftness, to be up at the death; so trifling are the impediments occasioned by the forest.