Location

Rob Blaker GWT The Great Western Tiers is an outstanding landscape feature of northern Tasmania being a series of towering cliffs and columns of Jurassic dolerite. These extend from Western Bluff above Mole Creek in the west to Tunbridge Tier, inland of Tunbridge in the south-east. (ref map) The Tiers form the escarpment to the Central Plateau region of Tasmania, an extensive area of alpine vegetation, lakes and tarns. The slopes at the western end represent the second highest climate gradients in Australia. This means many species living on the slopes may be able to survive climate change in sheltered gorges and high altitude niches.

History

Indigenous Cave There is evidence that Aboriginal people began using the Tiers many thousands of years ago as a route to the alpine areas, where there were rich summer hunting grounds. White settlers came in the early 1800's and the Aborigines were forced into smaller and less fertile environments. Eventually, white settlements took over all of the land, with wealthy graziers on the more fertile plains and the poorer settlers on smaller lots, around the fringes of the Tiers. Despite over 200 years of logging and pasture conversion in and around the mountains, many parts of the Great Western Tiers remain in almost pristine condition, due to the steep slopes and erodable soils.

Geology

Jade Hallam - Western CreekThe Great Western Tiers was formed by a major geological event during massive shifts in the plates between Antarctica and the Southern Continents. Lava oozed up between the layers of sedimentary rock to create an uplifted landform. This weathered over time until only the hard dolerite sill was left. Clefts have been deeply incised in this sill by glaciers which covered Tasmanian several times in the last 500 million years. These are now filled with rainforest along fast flowing streams. Limestone caves abound at the western end. More on the formation and the geology of the Great Western Tiers can be found here.

Forests

Wilderness The escarpment is covered with forest, tall forest on the lower slopes in wetter areas and short alpine forest at the top. Specialised plant communites exist in a variety of different niches. Some of this forest is protected in forest reserves and conservation areas but much of it remains unprotected. The forest provides habitat for many bird and animal species, the Tiers being a stronghold for a number of bird species in Tasmania. It also contains endemic micro fauna and many species of fungi and briophytes.

Land Use

RecreationThe forests and wildlife provided much needed income for early settlers living along the base of the Tiers. Trapping and logging were important additions to the family income of many early settlers. Small clearings on the lower slopes were used for crops and animal grazing. It is likely that these clearings were originally created as hunting grounds by Aboriginal people. A recent history of forestry activities, especially on the lower slopes has led to disturbance, fire and enhanced the already prone slopes’ capacity to result in landslips. Today the Great Western Tiers is used for a variety of recreational activities such as bush walking, picnics and fishing.

Environment

Trees Over the past 20 years a range of scientific studies identified significant natural and cultural values across the Great Western Tiers. The recent comprehensive assessment of Tasmania's native forests by the Independent Verification Group of scientists, chaired by Professor Johnathon West has identified that much of the Great Western Tiers is of World Heritage significance. Today the case for conservation is paramount to protect biodiversity and improve the world’s capacity to ameliorate climate change.The lower slopes are mostly privately owned with the upper slopes in a number of tenures including conservation areas, forest reserves and world heritage.