Australian forests can counter climate change: study

Australia could protect its forests to make deep and early cuts to green house gas emissions according Wilderness Society.

The society points to a study conducted by the Australian National University that assessed how much carbon could be stored in the world's forests. The study concluded that the most carbon-dense forest on earth was in Victoria's central highlands.

The Australian forest was compared other forests in United States Pacific Coast, Siberia, the central Amazon, Thailand and Cambodia, Venezuela, Finland and elsewhere in the study.

The results overturned conventional thinking with the finding that the Towering Mountain Ash forests covering Victoria state's cool highlands hold four times more carbon than tropical forests. This amounts to 1,900 tonnes of carbon per hectare.

The Victorian forest, which forms a part of the water catchment for Australia's second biggest city Melbourne is a large store as the area has been protected from logging. This points to the link between old growth forest felling and global warming according to environmental groups.

One reason for the carbon efficiency is the balance between plant growth rates and biomass decay, scientists believe. The balance is struck because the cool Victorian forests are conducive to high growth and have slower rates of decomposition.

According to the study, Australia's living and dead biomass carbon among Mountain Ash forest is assessed at 1,900 tonnes per hectare as against 650 tones per hectare in temperate US Pacific forests. Most forests across the world, have between 140 and 250 tonnes dead biomass per hectare carbon.

Professor Brendan Mackey, who along with his colleagues, conducted the study said the common understanding was that tropical forests stored most carbon as they are the most biologically productive and have the most plant growth. However, he said the lesser known fact, that has not been considered, is that nearly half of the carbon locked up in temperate forests like the mountain ash, is in fallen trees and other dead plant material.

In tropical forests, dead plant material undergoes rapid decomposition and carbon dioxide is released into the atmosphere through respiration.

But in moist temperate forests the warmth allows good growth rates at the same time dead plant materials decayed much slower and carbon-rich dead biomass therefore lasts much longer.

Mackey said the finding has reinforced the role of forests in countering climate change by acting as storehouse for carbon.

He said the research especially highlights the importance of protecting carbon-dense forests in developed countries.

However, the forest industry has a completely different take on the matter. It argues that if forests are not cut-down the risk that these forests will burn down increases and logging old growth forests is therefore important to reduce the risk of bushfire which releases carbon dioxide emissions. The industry points out that the amount of emissions from the fires is quite substantial.