The Eucalypts

    A forest may be said to resemble a city, constructed and populated with trees and birds, shrubs and mammals, reptiles, insects, fungi and the vital microscopic bacteria. 

    Among the trees there is competition for light and for crown space above; for root space and for water and minerals in the soil. Of the millions of seeds germinating, few struggle up to a place among the giants. Every plant and every creature of the forest must have its place: a niche, or space in the food chain, which it can hold against strong competition by showing some specific superiority. 

    A single tree may directly or indirectly supply a variety of birds, plus a host of other creatures, and each creature will concentrate on the part of the tree it is best adapted to exploit in its search for food. No on tree could long support the multitude of its dependents, but the segregation of feeding habits of which it is an example extends through the forest, and through other biomes - as the terrestrial life zones are known - from tropical rain forests to schlerophyll forests or to mallee or mulga scrub. 

    Flowers may attract lorikeets and honeyeaters. On the leaves tiny insects are taken by pardalotes and thornbills. Soft seed parrots bring parrots, but hardened woody gum nuts may require a more specialized bird, like the red-capped Parrot, which is able to extract the seeds without cutting through the capsule - a difficult if not impossible task.

Forest gums usually have small flowers, but in massed profusion these may hide the foliage and cover a tree.

     Seeds falling from dry gum nuts would be found by a ground-feeding rosella or one of the smal Neophemas, perhaps one like the Elegant Grass Parrot. Beneath of the bark shelter are spiders and insects, prey of those specialists of tree trunk and branch, the sitrellas and treecreepers. Upper branches may nourish a parasitic mistletoe, whose sticky and sweet berries are principally the food of the Scarlet-and-black mistletoe bird. Around the roots, in soil made fertile by the decaying leaves, worms, caterpillars and the like, are hunted by robbins which cling sideways to teh treetrunk, motionless but for the occasional flick of wings. They drop to the ground at intervals to take some nearly-invisible morsel. Which of the robins, would depend of the locality: Scarlet, Flame, Rose-breasted are among the many members of the group. 

     Green plants are the basis of every food chain.Upon these plants feed teh carnivorous insects, birds and animals. These in turn are food for predatory animals - or plants in the case of sundews and pitcher plants. Death brings scaverngers, from bird and animal carrion feeders to the fungi and bacteria which finally reduce the life materials to the simplest elements, plant foods to be taken for a further cycle. Dense coastal forests show greatest evidence of the struggle between plants. There the seedlings fight upwards through dense undergrowth towards the light; epiphytes, parasites and saprophytes steal food or a place in the sun; and climbing vines may strangle and kill great trees in their own upward race. A Queensland jungle fig which germinates on the branches and drops strong roots to the ground may kill its supporting host and be left standing on a hollow trunk of latticec roots after the dead support has rotted and fallen. From the start it's assured a place in the light. Not so obviously competitive is the life struggle of trees of the open, or of the scrub formations of the sandplains. There the fight is not for space and light, but for services of bird and insect pollinators, for the dispersal of seeds where they are most likely to germinate and for survival of seedlings which must get down their deep taproots to permanent supply of underground water before the next long period of drought. 

    There is competition between trees and shrubs for soil moisture, so that the spacing between plants becomes greater as conditions become more arid towards Australia's dry centre. These inland and sandplain gums, though but small and stunted mallees and shrubs in many instances, bear great flowers, made conspicuous only by their appearance in massed bunches. Some spectacular exceptions include the tropical "Ngainggar" or Scarlet Gum, E. Phoeinicia, from the Gulf of Carpentaria; the widely-cultivating red-flowering native to a very restricted area of teh south coast of Western Australia, and a red-flowered form of the White Ironbark of South Australia. Flowers of eucalypts are preceded by buds with which developing flower parts covered and protected by an operculum, may hang on the tree for half a year before the cap is dropped ad stamens unfold. Often the calyx tube from which the flower unfolds is brightly coloured and with sculptured shape, as seen in Eucalyptus tetraptera, teh square-fruited Mallee, and Eucalyptus Forestiana, Forrest's Marlock. With these forms the calyx is red and glossy, with buds and fruits hanging all over teh shrub for months before and after the flowering, and appearing as their most attractive feature, for the yellow and red filaments are relatively inconspicuous. With others the operculum may be ridged or indented, rounded, conical or with a long central spike. 

     This operculum is made of petals fused together as one structure, forming the cap over developing stamens. In fact teh name "Eucalyptus" means "well covered", and refers to this little cap. As the flower expands the operculum cracks around and falls, leaving a flower without petals, but with a radiating mass of coloured filaments, each capped with a golden, pollen-dusted anther. Sometimes t eh bud caps contrasts in colour: Eucalyptus erythrocorys a small, white-barked western tree where flowering may at first glance appear to be carrying both white and red flowers, for each operculum is bright red, the filaments bright yellow, and calyx tubes contrast in deep emerald green. Flower color in the Myrtaceae, the myrtle family to which eucalypts belong, is limited to the range of warm colours and whites - from crimson, scarlet, pink orange, and yellow to creamy white or greenish white. 

    Gums of Australian forests rank among the word's highest, topping three hundred feet. Smooth, sheer trunks rise one hundred feet or more to the first branch. Barks vary from the dark rough texture of blackbutts to the smoother, creamy white of the lemon-scented gum; the rich salmon pinks and tans of the Salmon Gum, and the pink-and-salmon-and-grey shades on the great cylindrical trunks of teh karris. 

     The bark may be patterned by cracks into squarish pieces marked by oozing red gum, lined by the zig-zag tunnels of insect larvae on the Scribbly Gum, or mottled by flaking sheets of old white and grey bark peeling to show paling yellow or fawn tints across teh solid trunks of the River Red Gum. So characteristic is bark formation that has become the basis of some keys to identification; very necessary when there are more than six hundred species and varieties of eucalyptus trees. Gums will readily hybirdize, particularly when disturbed by clearing and regrowth, or planted outside the natural regions. Even teh introduction of the larger, wider-ranging hive bees, which may carry pollen to wider areas than teh native bees, is thought to have increased hydridization among gums. Eucalyptus predominate in Australia's bushland, and extend in teh stunted but often most beautiful forms far inland, as well as adapted to extremes of heat and dessication as to ice and snow on peaks of the Australian ALps. 

     Under the harsh conditions of extreme dryness many gums assume a "mallee" form. From a large knotted root rise numerous slender stems which many not reach to more than ten or fifteen feet. Fire, always a feature of the dry scrub, may destroy stems and branches, yet in this bubous rootstock is always the potential of rapid regrowth. Many which grow normally as mallees may develop as trees with a single, larger trunk when planted in more favoured regions. 

      Eucalyptus are classified as members of the Myrtaceae, one of the largest plant families of the Australian continent, with more than three thousand species, and including not only gums, but also plants of Melaleuca, Beaufortia, Calothamnus, Kunzea, and Callistemon - which are a few of the most decorative groups. Also within the Myrtle family is a group characterized by seeds which germinade on the soil among loose leaf litter and debris. The single seed if retained in the withered flower, which if of light and fluffy form, and when dropped from the bush is not easily buried. The most conspicuous examples of this form are to be foudn among the feather flowers of teh Verticordia, in which the calyx lobes are finelt divided to form a soft, feather-like structure. Verticordia nitens, a tall western plant, bears its feathery flowers in mushroom crown massed above the foliage, which is completely hidden by their dense layer. Flowring in summer, and standing in close-packed on three-foot stems, it covers the sandy flats with gold brighter than any field of ripened wheat, stretching over acres at a time beneath scattered banksia

    In every way the eucalypt and its family forms a formidable group, not only containing the world's tallest hardwoods, and forests of great commercial value, but also a host of Australia's most decorative wildflowers, ranging from the massed spectacle of teh flowering gum to the delicately detailed structure in the feather flowers.