Pilliga forest

From Wikipedia, the free encyclopedia

The State Forests of The Pilliga, commonly known as the "Pilliga Scrub" (see Pilliga), constitute the largest continuous remnant of semi-arid woodland in temperate New South Wales, Australia. The forest contains at least 300 native animal species, with at least 22 endangered animal species including such favorites as the Glossy Black-Cockatoo, Squirrel Glider, Koala and Rufous Bettong, and at least 900 plant species including species now widely grown in cultivation as well as many threatened plant species. The forest spans about 3,000 square kilometres of land. Some towns that surround the forest include Narrabri, Pilliga, Gwabegar, Baradine, Coonabarabran, Boggabri and Baan Baa.

A typical sandy creek in the Pilliga.
A typical sandy creek in the Pilliga.

The geology of the area is dominated by the Pilliga Sandstone, a coarse red/yellow Jurassic sandstone containing about 75% quartz, 15% plagioclase and 10% iron oxide,[1] although local variations in soil type do occur. Sandstone outcrops with basalt-capped ridges are common in the south, while the Pilliga outwash areas to the north and west are dominated by alluvial sediment from the sandy, flooding creeks. Gilgais occur in some areas. To the west of the forest Sand monkeys (abandoned creek beds) are common. To the east is a heavily eroded sandstone mountain range, visible in outcrops such as those around "Gin's Leap", between Baan Baa and Boggabri.

Some areas of the forest, particularly in the Western Pilliga, are completely dominated by "cypress pine" (Callitris spp.), however there are a vast number of distinct plant communities in the forest, some of which do not include Callitris pine. Another dominant sub-canopy genus are the Casuarinas, while Eucalypts dominate the canopy throughout the forest.

Dandry Creek Gorge towards the south of the Pilliga
Dandry Creek Gorge towards the south of the Pilliga

Eric Rolls wrote a seminal work on the Pilliga called A million wild acres,[2] which gives an insight into the history of the region. One of Rolls' most-cited conclusions is that the forest used to be an open woodland forest and that European influence has enabled the cypress pine to dominate. However, many scientific authors now disagree with much of Rolls' analysis, quoting historical records from as early as the 1870s which suggest that the plant communities in the scrub have not undergone the level of alteration that Rolls suggests.[3][4] However most of his history of the region is uncontested and his book remains an invaluable document for understanding the region.

There is a vast network of roads throughout the scrub, many of which are former forestry roads. The forest once supported a large forestry industry in the surrounding towns (harvesting mostly cypress pine and ironbarks) however this has been greatly scaled back since 2005 when much of the forest was "locked up" by the NSW government for environmental conservation.

Many plant species are skillfully adapted to fire.
Many plant species are skillfully adapted to fire.

There are many attractions in the forest to keep one entertained, such as:

  • The Salt Caves: Shallow sandstone caves in the middle of the Pilliga.
  • Dandry Creek Gorge: A very impressive sandstone cliff toward the south of the Pilliga.
  • Pilliga Pottery: Off the highway north of Coonabarabran.
  • Bird-watching: The forest contains many rare species of bird, the Baradine Visitor's Centre has some good leaflets about this.

Fire plays a major role in the ecology of the forest with many plant species depending on fire to regenerate. However in unfavorable conditions fire can be extremely intense, spread very quickly and threaten nearby properties as well as laying waste to entire ecosystems. If intense fires occur less than 15 years apart there can be a loss of plant and animal biodiversity.[5] The magnitude of historical Pilliga bushfires correlates extremely well with the El Nino Southern Oscillation phenomena, with El Nino (dry) years having the most severe fires.[5]

In 1997 a major fire burned close to 1,435 km² of the forest. An extremely dry winter and spring in 2006 saw a number of large fires develop, including the Pilliga 4 Fire in November/December which burned out 740 km² on just its first day.

[edit] References

  1. ^ Spectral analysis. Arizona State University. Retrieved on 2007-02-02.
  2. ^ Rolls, Eric C. (1981). A million wild acres: 200 years of man and an Australian forest. Melbourne: Nelson, 465. ISBN 0170053024. 
  3. ^ 'Vegetation changes in the Pilliga forests: a preliminary evaluation of the evidence', Norris, E. H., Mitchell, P. B. and Hart, D. M., in Vegetatio V.91, pp. 209-218, 1991.
  4. ^ 'The nature of pre-European native vegetation in south-eastern Australia: a critique of Ryan, D.G., Ryan J.R and Starr, B.J. (1995) The Australian Landscape - Observations of Explorers and Early Settlers', Benson, J. S. and Redpath, P. A., in Cunninghamiana V.5(2), pp. 285-328, 1997.
  5. ^ a b Pilliga Nature Reserve - fire management strategy. National Parks and Wildlife Service (2006). Retrieved on 2007-02-02.