Push to close Australia's native timber industry to 'save' forest carbon based on flawed science

Keith et al have determined this figure from just one year's harvest sales records for the whole of Victoria, including from the full suite of forest types. Using the same methodology, VicForests' sales records over the past three-years show sawlog comprising a significantly higher average of 37% of statewide log production.

Furthermore, this statewide figure doesn't reflect the greater proportional sawlog production from the higher quality ash regrowth forests of the Central Highlands' study area.

According to VicForests, the sawlog proportion of all logs harvested from the study area's ash regrowth forests typically varies from 35 – 40%, but can be as high as 50%, depending on the forest quality in the particular harvesting coupe.

This error significantly understates how much harvested wood is actually made into solid timber products capable of long-term carbon storage.

An erroneous conclusion that sawn timber ultimately comprises only 4% of the total merchantable above-ground tree biomass of the harvested forest.

This is a consequence of the first two mistakes and grossly understates the reality.

If these mistakes are corrected to reflect the real situation, the sawn timber component is actually likely to be three or more times greater than the 4% figure used by Keith et al in their carbon accounting calculations.

A critically wrong assumption that mountain ash forests being used for wood production in Victoria's Central Highlands are being managed on a 50-year cycle of harvest and regeneration, rather than the reality of 80 years.

While Victoria's Timber Industry Strategy (2009) was cited as the source of this claim, a search of this document found that it contained no reference to a 50-year harvest rotation. In fact, it is well-known that VicForests are planning an 80-year rotation length for that proportion of Central Highlands mountain ash forests which is available for future use.

This is another significant error because it assumes that forest waste from future timber harvesting will be burnt and emit carbon at nearly twice the actual planned frequency.

Major over-stating of the area of Central Highlands' ash forest that is being annually harvested and regenerated.

Keith et al (2014) has based its carbon accounting on 20,600 ha of forest being harvested over the five years from 2011 – 16. This is around three times greater than the reality. Part of this period has already passed and the actually harvested areas for the first three years total 4,200 ha – in 2010/11 – 1600ha; 2011/12 – 1300ha; and 2012/2013 – 1300ha.