About the Catchment Area : Flora and Fauna

White Gums

Mountain Gum, (Eucalyptus rubida) is a straight trunked tree to between 15 and 45 metres tall. The bark is strikingly smooth and white with mottled grey to pink patches in places. Manna Gum (Eucalyptus viminalis subsp viminalis) is a tree 15 to 40 metres tall, the bark is rough, fibrous and brown for a metre or two, otherwise smooth and white to grey.

NB: There is currently some debate as to whether Mountain Gums in the Adelaide Hills bioregion are actually Eucalyptus dalrympleana or E. rubida, or whether both occur. In this publication we will adhere to the name E. rubida, as appearing in Florlist, the official botanical listings of the Department of Environment and Heritage.

The Onkaparinga Catchment could arguably be the home of the White Gum forest in South Australia. It was once found along the main channel from near Mount Torrens to Clarendon, and from near Lenswood to Kangarilla.

“White Gum” and “Candlebark Gum” are names that have been applied to both Mountain Gum (Eucalyptus rubida) and Manna Gum (Eucalyptus viminalis subsp viminalis).

Interestingly, the Onkaparinga Catchment is one of the only areas where both the White Gums occur together. Manna Gum (E. viminalis subsp. viminalis) is restricted to the high parts of the Central Mount Lofty ranges, whereas Mountain Gum (Eucalyptus rubida) is found in the higher parts of the Mount Lofty Ranges from Gumeracha to Mylor, with isolated occurrences to the south near Kyeema CP, Mount Compass and Parawa. Isolated populations are also known from the eastern hills at Mount Torrens, Birdwood and further east towards Hartley.

Unlike the Stringybark Forest which once covered vast areas of the Adelaide Hills, White Gum Forest was a relatively rare forest type even before European settlement, as it was mainly restricted to colder areas and fertile soils.

Since settlement, agricultural activities have resulted in a dramatic decline in White Gum Forest. Large intact forest areas are no longer readily found within the State or catchment, although individual trees and small clumps persist throughout their original range.

The best remaining examples of White Gum Forest can be seen at ‘The Cedars’ (Hahndorf), Bushland Park (near Lobethal), Porters Scrub (near Birdwood), The Wottons Scrub block (of Kenneth Stirling CP) and also in Mount George CP and the Mark Oliphant CP among others.

These few locations where remnant White Gum Forest persists show us that the understorey consisted of species including Blackwood, Swamp Wattle, Swamp Form, Red-fruit Cutting Grass, Prickly Tea-tree, Hop Goodenia, Prickly Moses and Long Purple Flag.

For South Australia, Mountain Gum Forest has recently been declared endangered while Manna Gum Woodland is considered to be vulnerable.