Before the arrival of large numbers of British settlers, most of Australia was covered with vegetation, unique in nature and well adapted to local soil and climatic conditions. The bringing of sheep, cattle, horses, and rabbits introduced a new element that has led to widespread alteration of natural cover in many parts of the continent. The continued expansion of cultivation has also resulted in the nearly complete destruction of natural vegetation over many millions of acres. Forest industries and man-caused fires have changed the cover on additional large areas. Native vegetation has thus undergone many significant changes in 150 years of vigorous occupation by a people whose livelihood has been won in large measure from the land, although much of Australia is still covered with some semblance of its original plant cover.
GENERAL VEGETATION PATTERN
In its most general aspect the pattern of natural vegetation in Australia shows first a rim of eucalyptus forests along the north, east, and south coasts. Inside this "horseshoe" is a somewhat wider belt of grasslands dotted with eucalyptus and acacia trees. A central area of sand ridges and flats supports only sparse desert vegetation.
Australia is a hot and dry continent, and only a very small part of its area was originally covered with dense forests. Less than 30,000 square miles of land are available today for commercial timber production. The extreme southwest corner of the continent and the Eastern Highlands, including Tasmania, contain the best forest lands. Large tracts of open eucalyptus forests of poorer quality occupy less favorable sites in the highlands and along the northern coast. Isolated tracts of dense tropical hardwood forests occupy favorable soils along the moist eastern Queensland coast.