Editing Sclerophyll (section)

==Australian bush==
{{see also|Flora of Australia}}
[[Image:Bush Eagle-Bay WA.jpg|thumb|left|Bush around Eagle Bay, [[Western Australia]] ]]
Most areas of the [[Australian continent]] able to support woody plants are occupied by sclerophyll communities as [[forest]]s, [[savanna]]s, or [[Heath (habitat)|heathlands]]. Common plants include the [[Proteaceae]] ([[grevillea]]s, [[banksia]]s and [[hakea]]s), [[Melaleuca|tea-trees]], [[acacia]]s, [[boronia]]s, and [[eucalypt]]s.

The most common sclerophyll communities in Australia are [[savanna]]s dominated by grasses with an overstorey of eucalypts and acacias. Acacia (particularly [[Acacia aneura|mulga]]) [[shrubland]]s also cover extensive areas. All the dominant overstorey acacia species and a majority of the understorey acacias have a scleromorphic adaptation in which the leaves have been reduced to [[phyllode]]s consisting entirely of the [[Petiole (botany)|petiole]].<ref>{{Cite book |last=Simmons |first=Marion H. |title=Acacias of Australia |date=1982 |publisher=Nelson |isbn=978-0-17-005779-0 |edition=Reprint |location=Melbourne, Vic}}</ref>

Many plants of the sclerophyllous woodlands and shrublands also produce leaves unpalatable to herbivores by the inclusion of toxic and indigestible compounds which assure survival of these long-lived leaves. This trait is particularly noticeable in the eucalypt and ''[[Melaleuca]]'' species which possess oil glands within their leaves that produce a pungent volatile oil that makes them unpalatable to most browsers.<ref>{{Cite book |last=Florence |first=Ross G. |title=Ecology and silviculture of eucalypt forests |date=2007 |publisher=CSIRO Publ |isbn=978-0-643-05799-9 |location=Collingwood}}</ref> These traits make the majority of woody plants in these woodlands largely unpalatable to domestic livestock.<ref>Mott, J. J., and J. C. Tothill. 1984. Tropical and subtropical woodlands. in G. N. Harrington and A. D. Wilson, editors. Management of Australia's Rangelands. CSIRO Publishing, Melbourne</ref> It is therefore important from a grazing perspective that these woodlands support a more or less continuous layer of herbaceous ground cover dominated by grasses.

Sclerophyll [[forests]] cover a much smaller area of the continent, being restricted to relatively high rainfall locations.  They have a eucalyptus overstory (10 to 30 metres) with the understory also being hard-leaved. ''Dry sclerophyll'' forests are the most common forest type on the continent, and although it may seem barren dry sclerophyll forest is highly diverse. For example, a study of sclerophyll vegetation in Seal Creek, [[Victoria (Australia)|Victoria]], found 138 species.<ref>{{Cite journal |last1=Parsons R. F. |last2=Cameron D .G. |year=1974 |title=Maximum Plant Species Diversity in Terrestrial Communities |journal=Biotropica |publisher=The Association for Tropical Biology and Conservation |volume=6 |issue=3 |page=202 |doi=10.2307/2989653 |jstor=2989653}}</ref>

Even less extensive are ''wet sclerophyll'' forests. They have a taller eucalyptus overstory than dry sclerophyll forests, {{Convert|30|m|abbr=}} or more (typically [[Eucalyptus regnans|mountain ash]], [[Eucalyptus delegatensis|alpine ash]], [[Eucalyptus grandis|rose gum]], [[Eucalyptus diversicolor|karri]], [[Eucalyptus obliqua|messmate stringybark]], or [[Eucalyptus viminalis|manna gum]], and a soft-leaved, fairly dense understory ([[tree fern]]s are common). They require ample rainfall—at least 1000&nbsp;mm (40&nbsp;inches).

===Evolution===
[[File:Yellow_box_2.jpg|thumb|250px|Yellow Box (''[[Eucalyptus melliodora]]'') in a sclerophyll woodland, [[Melbourne]] (''[[Oceanic climate|Cfb]]'' climate)]]
Sclerophyllous plants are all part of a specific environment and are anything but newcomers. By the time of European settlement, sclerophyll forest accounted for the vast bulk of the forested areas.

Most of the wooded parts of present-day Australia have become sclerophyll dominated as a result of the extreme age of the continent combined with [[Indigenous Australians|Aboriginal]] fire use. Deep [[weathering]] of the crust over many millions of years leached chemicals out of the rock, leaving Australian soils deficient in nutrients, particularly [[phosphorus]]. Such nutrient deficient soils support non-sclerophyllous plant communities elsewhere in the world and did so over most of Australia prior to European arrival. However such deficient soils cannot support the nutrient losses associated with frequent fires and are rapidly replaced with sclerophyllous species under traditional Aboriginal burning regimens. With the cessation of traditional burning non-sclerophyllous species have re-colonized sclerophyll habitat in many parts of Australia.{{Citation needed|date=November 2014}}

The presence of toxic compounds combined with a high carbon : nitrogen ratio make the leaves and branches of scleromorphic species long-lived in the litter, and can lead to a large build-up of litter in woodlands.<ref>{{Cite book |title=The greening of Gondwana |date=1988 |publisher=Reed Books |isbn=978-0-7301-0154-3 |editor-last=White |editor-first=Mary E. |edition=Repr |location=French's Forest |editor-last2=Frazier |editor-first2=Jim}}</ref><ref>{{Cite book |last=Flannery |first=Tim F. |title=The future eaters: an ecological history of the Australasian lands and people |date=2002 |publisher=Grove Press |isbn=978-0-8021-3943-6 |edition=1 |location=New York, NY}}</ref> The toxic compounds of many species, notably Eucalyptus species, are volatile and flammable and the presence of large amounts of flammable litter, coupled with an herbaceous understorey, encourages fire.<ref>{{Cite journal |last1=Burrows |first1=W. H. |last2=Carter |first2=J. O. |last3=Scanlan |first3=J. C. |last4=Anderson |first4=E. R. |date=1990 |title=Management of Savannas for Livestock Production in North-East Australia: Contrasts Across the Tree-Grass Continuum |url=https://www.jstor.org/stable/2845383 |journal=Journal of Biogeography |volume=17 |issue=4/5 |pages=503–512 |doi=10.2307/2845383 |jstor=2845383 |issn=0305-0270}}</ref>

All the Australian sclerophyllous communities are liable to be burnt with varying frequencies and many of the woody plants of these woodlands have developed adaptations to survive and minimise the effects of fire.<ref>Harrington, G. N., M. H. Friedel, K. C. Hodgkinson, and J. C. Noble. 1984. Vegetation ecology and management. in G. N. Harrington and A. D. Wilson, editors. Management of Australia's Rangelands. CSIRO Publishing, Melbourne.</ref>

Sclerophyllous plants generally resist dry conditions well, making them successful in areas of seasonally variable rainfall. In Australia, however, they evolved in response to the low level of phosphorus in the soil—indeed, many native Australian plants cannot tolerate higher levels of phosphorus and will die if fertilised incorrectly. The leaves are hard due to [[lignin]], which prevents [[wilting]] and allows plants to grow, even when there is not enough phosphorus for substantial new cell growth.<ref>{{Cite web |last=R. Major |year=2003 |title=Sclerophyll forests |url=http://www.amonline.net.au/factsheets/sclerophyll_forests.htm |access-date=February 14, 2005 |publisher=Australian Museum}}</ref>