Cool temperate rainforest
Small patches of relict or remnant rainforest are found in the east of the state, some of them tiny areas only metres across. Unlike many Australian trees cool temperate rainforest species do not need disturbance such as fire to regenerate, and their seedlings can develop even in the shade of a relatively dense canopy.
Two of the features that distinguish cool temperate rainforest from other types are:
- It has fewer kinds of trees compared with warmer climate rainforests, and in Tasmania the dominant trees are myrtle, sassafras, leatherwood, deciduous beech, and the conifers celery-top pine, Huon pine, King Billy pine, pencil pine and Cheshunt pine;
- There is a high diversity of non-vascular plants such as mosses, liverworts and lichens.
Tasmania's cool temperate rainforests are quiet places, with less variety and far fewer numbers of vertebrate animals and birds compared with the teeming life associated with tropical rainforests. However, they have a high diversity of invertebrates and non-vascular plants. Many of these species have an ancient lineage, dating back 60 million years to origins in the super continent Gondwana.
There are four main types of cool temperate rainforest tin Tasmania, with trees from 10 to 30 meters high: callidendrous 'beautiful tree' forest has tall trees and an open, park-like understorey; thamnic 'shrubby' forest has tall trees with many shrubs beneath; implicate 'tangled' forest has shorter trees mixed with tangled shrubs; montane forest grows at high altitudes and is dominated by pencil pines and deciduous beech.
Some facts about Tasmania's cool temperate rainforests
The long tailed mouse is endemic to Tasmania. It is most abundant in high rainfall areas of western Tasmania. It is also found in wetter forests of eastern Tasmania and beneath screes in sub-alpine areas. It feeds on fungi, insects, spiders, seeds and fruits
- Other forest types can replace cool temperate rainforest where the fire-free interval is less than about 350 years.
- Cool temperate rainforest covers about 600,000 hectares or 10% of Tasmanias land surface.
- The main cause of death of myrtle trees is myrtle wilt, a disease caused by the fungus Chalara australis. Recent surveys of undisturbed cool temperate rainforest in Tasmania shows that annual mortality due to the disease was about 0.6% per annum. Most fungus infections occur through branch or stem wounds and root grafts with diseased trees.
- The earliest of the current rainforest trees to evolve were the ancestors of Huon, King Billy and celery-top pines around 135 million years ago. Of the flowering trees myrtle is one of the oldest with pollen records dating back 85 million years.
- The oldest living organism is a Huon pine which appears to have been reproducing vegetatively for about 10,000 years. Individual Huon pine stems can live well beyond 2,000 years. King Billy over 1,000 years and celery-top pine around 800 years. This compares with the eucalypts maximum lifespan of a little over 400 years in wet forests.
- Changing weather patterns can result in variations in the width of growth rings in trees. Changing climate patterns going back thousands of years have been identified using growth rings in rainforest pines.
- Although many Tasmanian mammals can be found in cool temperate rainforests no mammal is dependant on it. (This is also the case with birds, reptiles and amphibians and is a reflection of the very small quantities of food found in cool temperate rainforests.) Only the long tailed mouse makes its home primarily in rainforest.