A burning issue: what’s the best firewood to burn?

Conservative estimates put the amount of firewood consumed by Victorians at more than half a million tonnes a year.

That’s more wood than we used to export as woodchips!

Such enormous use is environmentally unsustainable from current firewood sources. The same forests that supply much of our firewood are also some of the most important forests in Victoria. They harbour threatened plant and animal species which need these forests to survive.

The bulk of firewood burnt by Victorian homes comes from native forests both here and in NSW. Victorian forests, such as red gum forests at Gunbower, and the Wombat, Wellsford and Mount Cole forests in central and western Victoria, are exploited for firewood, both by commercial operators and domestic self-collectors.

The removal of a permit system for domestic firewood collection in Victoria’s state forests in 2015 – previously in place since 1958 – has also increased pressure on traditional firewood sources.

There is no genuine environmental accreditation for firewood sourced from these forests, so the wood you burn may be contributing to the loss of habitat for our threatened wildlife.

But there are sustainable alternatives. Farm-grown firewood, particularly in largely cleared landscapes such as Victoria’s Goldfields and the Riverina, has a range of benefits for both the natural environment and the health of farming communities.

It creates much-needed habitat, can provide shelter for sheep and cattle, and helps keep salinity in check.

Farm-based woodlots purposely grown for firewood are also likely to reduce demand for firewood sourced from our precious native forests, leaving these areas more intact as healthy habitat for threatened species.

What are the impacts of firewood from our forests?

  • If left on the ground in a forest, fallen branches form valuable shelter for native species. Removing them for firewood results in habitat loss.
  • Taking firewood from native forests particularly threatens reptiles, birds and mammals. It can impact upon threatened species such as the Squirrel Glider, Carpet Python and Brush-tailed Phascogale (Tuan).
  • Firewood harvesting from native forests can destroy native understorey plants and introduce weeds.
  • The use of firewood from native forests threatens the viability of other sustainable firewood producers such as farm-based woodlots.
  • Firewood sourced from native forests is largely unregulated and poorly monitored.

Collecting firewood from the forest is an Aussie tradition, but what we see as ‘dead wood’ and fuel, birds, mammals and insects use as shelter and food sources.

Across Australia 21 species of native birds are considered threatened by firewood collection – 19 of them are found in Victoria.

Victoria’s hollow-nesting Brown Treecreeper, for example, forages mostly among standing dead trees and logs, searching out insects that hide in fissures and hollows.

In River Red Gum forests, densities of the Brown Treecreeper have been found to be substantially higher in areas where fallen timber on the ground exceeded 40 tonnes per hectare.

In our Box-Ironbark forests, bird numbers have been found to be nine times greater, and the number of bird species present three times higher, in areas containing piles of fallen timber.

Mammals also need ‘dead wood’ in the form of hollow-bearing trees, both dead and alive, for shelter and nesting.

The removal of wood from the forest floor exposes soil to wind and water, potentially leading to an increase in soil erosion and sedimentation.

It also has negative impacts on our native plants. Nine Victorian plant communities likely to be affected by firewood harvesting are listed under the state’s Flora and Fauna Guarantee Act (FFG), which lists our most vulnerable species.

At a federal level, three ecological communities likely to be affected by firewood harvesting are listed under the Commonwealth Environment Protection and Biodiversity Conservation Act (EPBC). And about 60 plant species that occur in forests or woodlands of concern are listed under the EPBC, FFG or both.

What about air quality?

When burnt properly, using firewood from sustainable sources to warm your home can be less polluting and more environmentally sustainable than other methods.

  • An efficient firewood burner produces less carbon dioxide than other forms of fossil fuel energy, but to minimise pollution your firewood must be dry – less than 20% moisture content is recommended.
  • Firewood burners must be correctly flued, ventilated and operated.
  • Burning firewood in small, hot fires produces less air pollution than large, smouldering fires containing large firewood logs.
  • Wood with high moisture content, burnt in a poorly ventilated heater, can cause high levels of particulate matter to be emitted.

What are the carbon impacts of firewood?

Most fuels used to produce energy (gas, oil, coal and wood) release CO2 emissions into the atmosphere that are helping to drive dangerous climate change.

But unlike the other three energy sources, burning firewood from renewable plantations is greenhouse neutral. The carbon released from burning the wood is taken back in (sequestered) by the plantation trees as they regrow.

In terms of CO2 emissions, wood can be classified as a renewable energy resource, but only when accompanied by a tree replacement program. VNPA supports the use of wood grown in woodlots and through private farm forestry in existing agricultural areas.

Some wood does not burn well – types of firewood

  • Weight for weight, all eucalypt species have approximately the same calorific (heat) value.
  • Density is the factor that tends to determine preference for different species. Roughly half as much wood with a high density such as Grey Box (1121kg/m3) is required to produce the same heat as a lower density species like Alpine Ash (600kg/m3).
  • Wood that forms glowing coals radiates more heat than wood that burns quickly. Quick-burning wood gives off heat in the form of hot gases that often pass up the chimney and are wasted. Modern wood heaters are becoming better at utilising this heat.

 Firewood is available in different forms

These include:

  • Traditional firewood from native forests such as red gum or box.
  • Farm-grown firewood from sustainably managed plantations such as sugar gum or blue gum.
  • Compressed native forest waste products. Some of these ‘brix’ are made from recycled materials, others are from native forests.
  • Compressed forest waste product derivatives imported into Australia. Some of these come as far away as Malaysia.

How does your wood stack up?

Choose wisely when buying your firewood. Ask your supplier, service station or hardware store for the most sustainably produced firewood.

To choose environmentally sustainable firewood and firewood alternatives, ask these questions:

  • Is it sourced from outside native forests?
  • Is it a local Victorian product, sustainably produced?
  • Is from a tree-replanting program plantation based or woodlots on private land?
  • Is is recycled or offcuts?

Finding the right type of firewood can sometimes tricky/ difficult, but it is good to support suppliers trying to do the right thing and help build a market.