Although the Tarkine region contains a wide variety of landscapes, it is mostly known for the rainforest – which is an excellent way to experience some day walks Tasmania or our customisable adventure tours. However, it’s worth having a closer look at what defines Temperate Rainforests.
Unsurprisingly, average rainfall is the key factor, with over 1400mm annually spread throughout the year, this is less than tropical rainforests. The other factor is the broader climate, with tropical rainforests having less defined changes between winter and summer. Temperate forests have four seasons and typically much colder winters.
Overall, rainforests in Australia can be divided into Temperate Rainforest, Monsoon, Tropical and Subtropical. They can be further divided into warm and cool temperate zones. There are notably fewer vascular woody plants in the Tasmanian forests; during the 1980’s the area was further defined from Cool Temperate to Tasmanian Cool Temperate Rainforests, which helped clearly separate it from mixed forest. The current definition is for trees usually greater than 8m in height and capable of regenerating in the absence of fire or other large-scale catastrophic events.
The origins of these rainforests date back over 60 million years, and the most common tree is the Nothofagus cunninghamii (Myrtle Beech), which is part of the evidence of Australia being part of Gondwana, the southern super continent, some 130 million years ago.
The other common tree species of angiosperms, Atherosperma moschatum (Sassafras) – prized for craft timber in certain conditions and Eucryphia lucida (leatherwood) the source of the distinctive honey. Gymnosperms such as Athrotaxis selaginoides (King Billy Pine), Lagarostrobos franklinii (Huon pine) and Phyllocladus aspleniifolius (Celery-top pine) are also valuable timber sources and were used extensively in boat building due to the high oil content.
Collectively they can be referred to as climax vegetation, describing how the community of species that is best adapted to the average conditions will dominate the area without events such as fire altering the forest type. This type of forest would have covered large parts of Gondwana, but as the super continent broke up and conditions became drier, the forests dissipated. The eucalyptus forests evolved, however, and were much more adaptable to fire, developing strategies to take advantage of more frequent fires.
Conversely, the cool temperate species are more susceptible to fire because it would kill the mature trees as well as seeds and saplings in the soil. The new forests eventually replaced most of the older forests leaving only small remnants in southeast Australia and Tasmania.
However, it has not always been a linear progression. Pollen samples taken from lake sediment in western Tasmania can provide a record up to17,000 years, and indicate that the dominant species could change back and forth if fire was absent for long enough.
The fires that the eucalyptus forests adapted to so readily for seed dispersal and germination meant that without them the mature trees would die off after 250 to 300 years. Provided there was a reservoir of rainforest seeds, the longer-lived climax forest would take shelter in the eucalyptus forest waiting its turn to become kings of the forest once more.
The tall trees are only part of the forest; ferns, mosses, lichens and fungi all have their place in the ecosystem. The mix of tree, shrub and other species can refine the Tasmanian Cool Temperate Rainforest even further and is such a good environment for day walks Tasmania. They are known as callidendrous, thamnic, implicate and open montane and I will delve into these in a future blog. See our other blogs here.
SEO, content writing and digital marketing by Online Marketing Group.