Australia’s buildings are made largely from plantation timber, not native forest wood. That simple fact is missing from a claim now circulating that logging native forests is good for the climate.
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Native forests store vast amounts of carbon, and protecting them is recognised as being crucial for tackling climate change, along with the deep cuts needed in fossil fuel emissions. Yet, some native forest logging industry lobbyists have claimed that logging native forests is good for the climate and a superior climate solution to forest protection. Is this true? Should we be logging more native forests to stop climate change? The science is clear that the answer to this question is no.
The recent approval by the Clean Energy Regulator of a methodology on forest management under the Carbon Farming Initiative is based on, and highlights, the scientific fact that native forest logging is a highly emissive industry. That is, logging releases large amounts of carbon emissions that would not occur if native forests were not logged. One way for people to understand this is through equivalence to the emissions from motor vehicles. For example, native forest logging in Victoria before it was supposedly halted in 2024 has been estimated to generate gross emissions equivalent to that from 1.2 million motor vehicles each year.
Why does native forest logging generate large amounts of carbon emissions? There are several key reasons. First, cutting down native trees requires an extensive road network to transport heavy machinery to cut blocks or coupes where trees are logged. Building roads, using heavy machinery for harvesting, and trucks for transporting logs create greenhouse gas emissions.
Second, a very large amount of the total biomass in a native forest – typically per cent actually is left in a logged area and not carted to a sawmill or pulp mill (to make paper or packaging). This biomass can be up to 450 tonnes per hectare of logged forest and includes tree crowns, lateral branches, understorey plants, bark, stumps and roots, dead trees and logs on the forest floor, and other material that is not used by the forest industry. Approximately half of this biomass remaining on-site is either burnt in a fire deliberately lit to create a bed of ashes to promote the regeneration of a new stand of trees, or it remains on the ground and undergoes accelerated decomposition. Both the regeneration burn and the decomposition of logging debris create greenhouse gas emissions that would not have occurred if the forest had not been logged.
Third, about 40 per cent of the biomass of a native forest is removed to create wood products. But the vast majority of that material is used to manufacture products like paper and packaging, and these have a short lifetime before they go to landfill to decompose and begin emitting greenhouse gases. There is a large amount of waste (sawdust, offcuts, etc) in those manufacturing processes which also quickly become greenhouse gas emissions. A small amount of the biomass of a native forest – roughly 4 per cent – goes to make high quality wood products like floorboards, roof trusses and furniture that store carbon for a long time.
Indeed, in Australia, very little native forest timber actually goes into housing and construction. The reality is that 90 per cent of all sawn timber in Australia is from plantations, especially exotic softwood dominated by pines. Our wood supply is dependent on plantations, not native forests. This matters for the building industry in particular. Ending native forest logging would take almost nothing from the timber that goes into housing and construction, because that timber already comes from plantations – including the engineered wood products, such as glulam and cross-laminated timber, that are now common in modern buildings.
The bottom line is that logging native forests is not good for the climate because it generates large amounts of emissions. By contrast, most carbon is stored in the woody biomass and soil of old native forests. And contrary to statements from some forestry lobbyists, the large old trees in old growth native forests continue to grow throughout their lives and add extra girth and therefore store increasing amounts of carbon. For example, our long term studies in the giant Mountain Ash forests of south-eastern Australia – the world’s tallest flowering plants – show that the largest and most carbon dense trees are still growing at 2 cm in girth every year over an age of over 200 years. The only way a native forest can become old is for it to grow through from being a younger forest. This can happen only if a forest is not logged.
A significant amount of carbon emissions nationally can be avoided each year, plus allowing ongoing carbon sequestration, by properly protecting native forests, including through National Parks and other conservation reserves. Protecting native forests, not logging them, is best for the climate – and the timber the building sector relies on would be all but unaffected.
