Dry Sclerophyll Forest

Dry Sclerophyll Forest (DrySF) is found on a range of clay-loam, sandy-loam and shallow rocky soils of exposed hillsides, mostly between 200 and 1000 m above sea level, with rainfall between 550 and 1000 mm a year.  About half of the area once supporting DrySF in Victoria falls on public land while a little over one fifth is represented in conservation parks and reserves.  About 45% of all DrySF has been permanently cleared for agriculture or urban development.

DrySF is an ecosystem with relatively small and often crooked, spreading trees, usually less than 25 m tall, over a normally sparse understory of wattles and small-leafed shrubs, and a dense and species-rich ground cover of grasses and small herbs.  The tree canopy is usually a mixture of stringybarks (commonly Eucalyptus macrorhyncha - Red Stringybark, Eucalyptus obliqua - Messmate, Eucalyptus globoidea - White Stringybark), boxes (commonly Eucalyptus polyanthemos - Red Box, Eucalyptus goniocalyx - Long-leaf Box), peppermints (commonly Eucalyptus radiata - Narrow-leaf Peppermint, Eucalyptus dives - Broad-leaf Peppermint) and gum-barked species (commonly Eucalyptus viminalis - Mannah Gum, Eucalyptus cypellocarpa - Mountain Grey-gum, Eucalyptus melliodora - Yellow Box).  The composition of the canopy varies from place to place and sometimes according to the history of forest use but in any area of forest there is seldom fewer than five eucalypt species.

Dry Sclerophyll Forest
Dry Scleophyll Forest 

The mammalian fauna consists primarily of large grazers (kangaroos - often very common in this ecosystem), medium-sized browsers (wombat, wallaby - most abundant where the shrub layer is dense), small ground insectivores and omnivores (antechinus, native rats), arboreal species, (koala, possums and occasional gliders - not as abundant as in taller forest) and bats.  Most of the birds are common forest species across Victoria (fantails, thornbills, treecreepers, whistlers, honeyeaters, rosellas, currawongs, robins, pardalotes, cuckoos, Kookaburra, owls, parrots, wrens).  The reptiles are mostly small arboreal skinks and dragons, blue-tongued lizards, and occasional Eastern Brown Snakes,  Red-bellied Black Snakes and Tiger Snakes.  All common frogs are small, principally terrestrial species.

DrySF was the most desirable forest ecosystem for early European settlement.  After the gold rush years of the 1850s there was a huge population in Victoria looking for somewhere to work and the government of the day was keen to use those numbers to develop an already promising agricultural industry.  Most of the productive Grasslands and grassy woodlands of the broad, lowland plains had already been assigned to a few wealthy grazier families but there was plenty of unoccupied forest for those who were prepared to work the land.  DrySF, unlike the dauntingly tall and fern-dominated Wet Sclerophyll Forest (WetSF), the often dense and shrubby Damp Sclerophyll Forest, and the harsh and heavily damaged Box-Ironbark Forest of the goldfields, was almost immediately suitable for the establishment of a small farm.  The climate was mild so year-round work outside was possible and rainfall was usually enough to provide a reliable water supply for humans and stock. The hillsides were mostly gently-sloped so traversing them was relatively safe and easy.  The understory was principally made up of luxuriant grasses and herbs, which although not as palatable and nutritious as European species, were suitable for grazing sheep, horses and sometimes cattle.  The trees were a ready source of timber for building materials, fencing and firewood.  The soils, although poor by European standards, were usually good enough to develop vegetable gardens and fruit orchards for sustaining a household.  And the native wildlife - kangaroos and wildfowl - was abundant and provided a supplement to the dinner table when money was short.

Today nearly half of the original area that supported DrySF at the time of European settlement is farmland, most of the trees are gone and the pasture grasses that dominate the ground-cover have their origins in Europe, the USA and southern Africa.  Nevertheless there is still a surprisingly large number of native plant species remaining in this pasture country, particularly if there has been little physical disturbance of the soil, and populations of native wallaby grass, kangaroo grass, spear grass and tussock grass will often persist in paddocks that have been grazed by domestic stock for 100 years.

Where DrySF persists, mostly on public land, its degree of disturbance varies considerably, but in most places there is a high proportion of non-native plant species in the understory.  It is the weediest Victorian forest ecosystem and rabbits, foxes, thistles, gorse, blackberries and introduced grasses are abundant.  In contrast, the trees in DrySF are often comparatively old, despite heavy pressure in earlier times, as most parts of the forest are currently uneconomical for timber logging and cutting for firewood is very low compared what it was in the early 1900s.

Fuel-reduction burning, which is commonplace as a management tool in Damp Sclerophyll Forest (DampSF), is also regularly used as a wildfire prevention measure in DrySF.  In DampSF, bracken and wire-grass usually come to dominate the understory after frequent low-intensity fires.  In DrySF, however, the native wallaby, spear, kangaroo, tussock and weeping grasses respond well to the burns, at the expense of shrubs, and the pasture quality improves as a result.  This is a technique well-known to the Koories and was used as a method for maintaining high kangaroo populations for centuries before European settlement.

DampSF and WetSF often grow in large, relatively unbroken tracts, but a significant proportion of DrySF is fragmented into smaller blocks of native forest which is surrounded by agricultural and urbanised land - the source of a large number of weeds and invasive animals.  In many places the areas of native vegetation are linked by narrow strips of forest and woodland along roadsides and fencelines.  These strips are often referred to as wildlife corridors and much has been written about their importance to the ecological integrity of fragmented vegetation.  Many authors describe them as if they were just like corridors in a house which native animals, particularly birds and mammals, use to move, in relative safety, from one patch of vegetation to another, and there are many projects in place across rural Victoria to maintain, enhance and even create new tree-lined linkages.

Whether these linear pieces of near-native forest actually work in the manner that ecologists would like them to is open to debate.   Most of them are very weedy, and many have only a very small percentage of native plants in the understory, as a consequence they can just as easily provide a corridor for the movement of undesirable plant and animals species from one area to another.  Non-native predators such foxes and cats, may use the corridors as a hunting ground with better prospects of success due to the limited options for evasion of their prey.  And in some cases the corridor is there to act as a mask to hide whatever is taking place behind it.  Nevertheless they are often the only parts of a rural landscape that contain any remnants of the native ecosystems and their loss or damage, due to road maintenance, widening and construction, rubbish-dumping, stock-grazing, fuel-reduction burns and landscaping with non-native species, will inevitably lead to a lowering of the regional biodiversity.

© Paul Gullan, Viridans Biological Databases