sclerophyll forests dominate coastal and highland Australia from southern Queensland to south-western WA and Tasmania while open woodlands dominate the adjacent interior regions.
most of Australia that can support trees is dominated by sclerophyll (“hard leaf”) communities of vegetation which perhaps evolved in Australia some 15 million years ago, but did not dominate until Aborigines arrived perhaps some 40,000 years ago and practiced regular forest and grassland burn offs which favoured the sclerophyll species over non-sclerophyll species which struggled with the combination of Australia's low phosphorus soils combined with regular nutrient loss from fires.
the main areas in Australia where Eucalypts are absent are: the tropical rainforests of northern Qld, the highest alpine regions and the arid deserts.
only 9 species of Eucalypts are not found in Australia - these are in Papua New Guinea, Phillipines, Timor, & Sulawesi.
there are no species of Eucalypt native to NZ.
the sclerophyll plants tend to have a generally inedible toxic oil (eg. eucalyptus oil, melaleuca oil) which minimises grazing losses to only certain mammals (eg. koalas) and insects which are the main herbivores in the canopies.
indeed, the volatile nature of this oil combined with the often stringy barks and dry woods and leaves encourages fires to spread to their canopies where it stimulates their fruit (“nuts”) to open and seed on the forest floor which is newly replenished with nutrients from the ashes of the fire.
a source of major annoyance to the bushwalker and camper are the many species of ants which love the forests and sclerophyll woodlands, in particular, the bull ants and jack jumper ants which can give a painful sting to which some people are allergic.
the sclerophyll leaves are hard due to lignin which prevents wilting and allows plants to grow even when tehre is phosphorus deficiency.
by the time of European settlers in the early 19th century, Australia was dominated by sclerophyll forests, much of which has now been cleared and the reduction of regular fires has allowed the re-colonisation of non-sclerophyll communities.
the mix of animals depends on the type of forest and the stage of regeneration since the last major bushfire.
Australian sclerophyll forests can be divided into two main groups:
dry sclerophyll forests:
the majority of forests in Australia and restricted to areas of relatively high rainfall
generally drought tolerant and rejuvenate with bushfires
they have a eucalyptus overstory (10 to 30 metres) with the understory also being hard-leaved.
dominant trees include:
grey box (E. microcarpa)
yellow gum (E. leucoxylon)
red ironbark (E. sideroxylon)
messmate stringybark (eg. E. obliqua)
broad leaf peppermint (E. dives) - often dominate the upper slopes of gullies rather than lower slopes where messmate may dominate
narrow leaf peppermint (E.radiata)
wet sclerophyll forests:
these only occur in areas of higher rainfalls - usually > 1000mm (40“) per year
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They have a taller eucalyptus overstory than dry sclerophyll forests, 30 metres or more, and a soft-leaved, fairly open understory - often with tree ferns.
the seasons of the forests of the Dandenong Ranges near Melbourne as documented by the local indigenous peoples includes 7 annual seasons plus a fire season every 7 yrs and a flood season every 28yrs.
typical trees include:
mountain ash (E. regans)
rapidly grow to 100m, flowers in summer to winter with small white flowers
unlike most Eucalypts, it cannot regenerate after a bushfire but does seed new growth.
creates 2-3x as much leaf litter as other eucalypts
these tall Eucalypts are second tallest species in the world, second to the giant Californian Redwoods, and they take some 300yrs to mature and then by 400yrs start to die - these are the “old growth forests”.
the world's tallest flowering tree.
in Victoria, mountain ash forests are found in the ranges east of Melbourne, the Strezelecki Range in Gippsland, the southern-most parts of the Otways and scattered regions throughout the eastern part of the Great Dividing Range.
regeneration of the mountain ash forest after a bushfire:
germination 1-8wks - up to 2 million seedlings germinate per hectare
seedlings 0-4yrs
saplings 4-15yrs - grow to 12m within 1st 10yrs but high mortality rate
pole stage 15-30yrs
spar stage 30-100yrs
mature forest 100-300yrs
old growth forest 300-400yrs
death of mature trees 400-500yrs
if no further major fire to germinate new growth, by 600yrs, the forest will be possibly be replaced by southern beech trees
anywhere mountain ash exists there must have been a major bushfire to give birth to it.
each phase characterises continual successional change in the flora and fauna habitats
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alpine ash
brown stringybark (E. baxteri)
messmate stringybark (E. obliqua)
more frequent as soil quality improves
usually requires > 500mm rainfall pa, and confined to SE Australia - mainly Victoria
manna gum (E. viminalis)
Southern beech or Myrtle (Nothofagus cunninghamii):
Silver wattle (Acacia dealbata):
Blackwood (Acacia melanoxylon):
Southern Sassafras (Atherosperma moschatum):
slow growing, dense, conical, fire sensitive tree to 30m, grows in gullies.
velvety cream perfumed flowers in autumn & winter
leaves have distinct serrated edges & smell of nutmeg when crushed
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although young forests are densely packed with young trees, there is a natural thinning out process as the trees mature and the dominant trees survive at the expense of the less dominant as each compete for sunlight and water.
the wet sclerophyll forests are mainly on the coast side of the Great Dividing Range as this region tends to have the higher rainfall.
wet sclerophyll forests also occur on the western margins of north-east Qld tropical rainforests at altitudes above 600m where the high rainfall would normally support tropical rainforest but historic fires have kept the rainforest vegetation out. See
here.
sclerophyll woodlands:
cool temperate rainforests:
blackwood swamp forests:
Most wet sclerophyll forests were logged and dry forest and woodland converted to pasture and cultivated land following European arrival. Over 90 percent of temperate woodlands in Victoria have been cleared, mostly for agriculture, leaving less than 6,000 km2
Pine plantations, mostly Pinus radiata, are located in the cleared wet sclerophyll forests of this ecoregion