A RECENT study published in the Journal of Agricultural and Forest Meteorology has examined the carbon footprint associated with the logging of Tasmanian forests.
The study, titled “Are there any circumstances in which logging primary wet-eucalypt forest will not add to the global carbon burden?” compares emissions from the logging of young and old-growth forests by different logging methods, such as clearfell and non-clearfell.
It found that the logging of wet-eucalypt Tasmanian forests by clearfell generated long-term emissions (LTE) of 2 Tg (teragrams) each year between 1999 and 2009.
And while logging of young and old-growth forests generates the same long-term emissions, the short-term emissions are two times higher for old-growth forests.
Clearfell is a logging method whereby a site is fully cleared of trees and any remaining stumps removed in a high-intensity burn. The site can then be ploughed and planted with germinated trees for plantations or sowed with native seed.
Logging of public wet-eucalypt forest by clearfell and burn generates the most amount of emissions as compared to other methods.
Co-author of the study Dr Christopher Dean says that “clearfelling of primary forest provides several advantages for the current industry.”
It is a relatively low-cost method compared to other methods and allows for a faster turnaround of wood product.
But as clearfelling removes the entire aboveground ecosystem in order to regrow forest that can be recleared at a young age, Dr Dean says this can cause long-term damage to the soil, landscape-level and biodiversity in the area.
“Other logging methods retain some of the aboveground components of the ecosystem, can have less impact on adjoining forest and, the lower-intensity burn (if any) releases less carbon,” he says.
Dr Dean says that under current forestry management practices emissions from primary-forests are not recovered in wood products.
To recover long-term emissions we would need to increase wood-product longevity ten-fold.
“For carbon already moved from the forest, an increased longevity can only be achieved through recycling,” he says.
“Recycling is the only way to reduce avoidable emissions from past logging, for the large amount of wood that has already been removed from the Tasmanian forests.”
“Future logging can be avoided by substituting for wood products with lower carbon footprint materials, such as e-crete and locally sourced stone.”
Dr Dean says that “a major reforestation campaign in Australia is decades overdue” and that investment in more sustainable forestry practices is required.