第 4 集

Australia's eucalypt forests are the subject of the fourth programme. In the tropical north, male frilled lizards fight over territory, but retreat to the trees as a kite passes overhead. Gang-gang cockatoos stay above the snowline of the southern mountains to feed on the seed capsules of snow gums. On the misty lower slopes, better soils enable the mountain ash to reach 100 metres, the tallest hardwood in the world. Animals of these forests include superb lyrebirds, Leadbeater's possums and mountain brushtail possums. Some gum trees survive in the arid conditions of the interior; the ghost gum even clings to rocky gorges. The eucalypts provide essential resources for wildlife. Their flowers attract nectar feeders such as lorikeets, honeyeaters and flying foxes, which also act as pollinators. The koala has a special digestive system which enables it to stomach the toxic leaves. Yellow-bellied gliders are shown licking sap and sailing between trees, while termites attack the trees themselves. Gum trees are highly flammable and are adapted to cope with bushfires: fresh shoots grow from buds protected by the insulating bark within weeks of a blaze. Regent parrots nest deep inside the river red gums along the Murray River to avoid predatory lace monitors. The boughs can drop without warning, and those that fall into the river provide shelter for Murray cod. The final scenes show red kangaroos bounding through a flooded forest – without periodic floods, the trees would not survive.