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Silviculture

Silviculture is the science of tree management within forests and the regeneration of the forest.  Because the rehabilitated mined areas are “new” forests they will require management to ensure they fulfil the desired land uses of the forest.  One of these land uses is to provide a future timber resource in the rehabilitated areas.  The jarrah forest has a 150 year history of silvicultural management (e.g. logging, thinning).  It has long been known by foresters that young forests that have high tree densities stop growing as the trees compete with each other.  Unlike many other eucalypt species such as karri (Eucalyptus diversicolor) jarrah is very slow to self-thin and thinning is required several times during the life of a jarrah forest if timber is to be produced.
 
Many of the rehabilitated areas from the early 1990’s were established at a density of about 2500 eucalypt stems per hectare.  By about 15 years of age the trees are competing strongly and growth slows down.  A thinning at this age removes smaller and poor form trees.  The retained trees can then resume good growth and are expected to provide the future sawlogs in the rehabilitated areas.  Another thinning may be required at 30-40 years of age.  Research into the best silvicultural treatments for the rehabilitated forests is ongoing.
 


Silviculture

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A 17 year old rehabilitated area that has been experimentally thinned from an original density of approximately 2000 to 625 stems per hectare.