Australia — IN OUR transition out of fossil fuels we need renewable energy – cost-effective renewable energy that is easily and rapidly deployable. Residues from forest harvesting and processing, including those from managed native forests, form such a renewable energy source as they can be burnt in a boiler to generate heat and/or electricity.
Such technologies have rapid uptake and strong support internationally, yet, in Australia, using residues from managed native forests is opposed by green non-government organisations, so we are missing easy, proven opportunities to cut greenhouse gas emissions and our dependence on fossil fuels in a cost-effective way.
Forest residues include processing residues (for example, sawdust) that accumulate at mill sites, and harvest residues (for example, stem tops) left in landscapes after harvest. Processing residues can’t be left to accumulate on mill sites: they get in the way and are a fire hazard.
Story continues below While some harvest residues should be retained as habitat or to support regeneration burns in some forest types, a continuing supply of large amounts of harvest residues can be collected from sustainably managed forests. As harvested forests are regrown, harvesting and processing residues form a potential source of renewable energy.
Forest residues will eventually become greenhouse gases, whether they are used for biofuel or left in the landscape to burn or decompose. If forest residues are left in landscapes, then we miss the opportunity to generate renewable energy for society, forcing the use of alternative energy sources including fossil fuels.
Energy extracted from forest residues is among the most cost-effective forms of renewable energy and is supported by the Intergovernmental Panel on Climate Change, United Nations Food and Agriculture Organisation and the International Energy Agency. In the absence of this form of biofuel, we will either use more fossil fuels, thereby increasing emissions, or more expensive renewable energy sources, thereby increasing energy costs. Thus biofuel production from native forest residues will make it easier for Australia to meet its renewable energy targets and reduce greenhouse gas emissions.
This also places Australia alongside Europe and North America where such technologies have rapid uptake and significant investment. For example, the co-generation of heat and electricity from wood waste in on-site boilers is allowing schools, hospitals and other buildings to meet their energy needs.
Green groups argue that excluding support for biofuels from native forest residues is required to protect biodiversity. It is presumed that supporting the use of native forest residues as a biofuel will promote the harvesting of more native forests solely for biofuel with concomitant pressure on biodiversity values.
This position is reflected in the federal government’s Clean Energy Future and Carbon Farming Initiative, which exclude biofuels from native forest residues for renewable energy credits. However, this simplistic position ignores Australia’s highly regulated industry, which includes regulation for the management of biodiversity.
The National Forest Policy Statement, regional forest agreements, forest practice codes and international forest certification bodies require biodiversity values to be identified, managed and protected. In their current form, these instruments allow native forest residues to be used for biofuel while protecting biodiversity. They could be modified, if necessary, to deal with further concerns.
Harvesting native forests solely for renewable energy is neither economically attractive nor the best outcome for greenhouse gas mitigation with forest management. Sawlogs earn a far greater return for the land manager when used to produce structural or appearance-grade products than if sold as biofuel. Using wood in construction also dramatically reduces fossil fuel emissions when substituted for metal, concrete and plastic alternatives. Greenhouse gas mitigation from the use of structural or appearance-grade wood far outweighs the greenhouse gas mitigation benefit of using wood directly as a biofuel.
However, forest residues and obsolete wood products accumulate and form a readily available energy source that is otherwise lost as it decomposes to greenhouse gasses on the landscape or in landfill.
Leaving excess forest residues to decompose to greenhouse gasses on the landscape without generating energy for society will increase greenhouse gas emissions from the burning of fossil fuels. This is not a green outcome, whereas generating energy for society from excess forest residues is.