A natural part of our environment, wood is a renewable resource that provides wide-ranging benefits – from habitat, employment and recreational activities to carbon sequestration.
Tackling climate change with wood
Forests and wood products can effectively reduce the process of climate change in several ways. Growing trees absorb carbon dioxide from the atmosphere and store the carbon so efficiently that about half the dry weight of a tree is carbon. This carbon remains locked up in the wood even when we use it for building products or furniture. Using wood instead of other materials can be an advantage too. The production of wood products uses less energy (usually sourced from finite fossil fuels) compared with other building materials. As a fuel, sustainably grown and harvested wood (and other biomass) provides a renewable alternative to fossil fuels.
Wood and the greenhouse effect
The term “greenhouse effect” refers to the way trapped infrared radiation from the earth is warming the atmosphere. If you’ve walked into a real greenhouse, even on a cold sunny day, you’ll know it feels a lot warmer inside. This is where the name originated. Solar radiation reaches the Earth through the atmosphere and warms the surface. The stored energy is then sent back to space as infrared radiation. However, as this has a different wavelength to the incoming radiation, less of it can penetrate the barrier of specific atmospheric gases known as greenhouse gases.
The most important greenhouse gas is carbon dioxide (CO2) but others include water vapor (H2O), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs) and sulphur hexafluoride (SF6).
Since the start of the industrial revolution, there has been a sharp increase in greenhouse gas emissions into the atmosphere, mainly due to CO2, from the burning of fossil fuels, but also from changes in land use. Many scientists agree that CO2 concentrations in the atmosphere have increased by 30% since the middle of the 19th century.
Sustainably harvested timber has a very low carbon footprint compared to other building materials.
A carbon Footprint is a measure of how much impact a particular product or component has in relation to global climate change.
The use of sustainably harvested timber as a building material creates a much lower carbon footprint than does the use of other common building materials.
Recent research by the Cooperative Research Centre for Greenhouse Accounting compared the amount of greenhouse gas emissions generated by the manufacture of timber products with the amount of greenhouse gas emissions generated by the manufacture of common alternatives. The research showed that more than 25 tones of greenhouse gases could be saved if timber products were used instead of the common alternatives, to build a family home.
The graph clearly shows that the manufacture of timber building components uses considerably less energy than the manufacture of other major products such concrete, brick, ceramic tiles, aluminium and steel. It therefore follows that when you build your home, wherever you choose to use timber and timber products over the common alternatives, you will leave a smaller carbon footprint.
Greenhouse gas emissions from the manufacture of different building components in a family home (Source: CRC for Greenhouse Accounting)
Timber production also makes a positive contribution to reducing carbon emissions by being part of the short term carbon cycle that involves trees absorbing carbon dioxide from the air, releasing oxygen and storing the carbon in the wood.
Using trees for timber and other wood products in this way creates space in plantations and hardwood production forests for replacement trees to absorb more carbon from the atmosphere (this is called carbon sequestration).
What little energy is needed to process and dry wood to make timber is commonly produced from sawmill residues such as bark and sawdust generated by converting a tree into sawn timber. Excess sawmill residue is either used in the manufacturer of long-life panel products such as particleboard or medium density fibreboard (MDF).
The carbon in the timber, which has been absorbed from the atmosphere, is stored for long periods of time in an array of timber products such as house frame, roof trusses and flooring.
Energy Efficiency is about ensuring that the minimal amount of energy is needed to heat or cool a building over its lifetime. While timber and wood products are good insulating materials themselves, when used together with fiber or foil insulation in a well designed building, minimal external energy is needed to keep a building within the thermal comfort zone of its inhabitants.
There are many ways to design successful thermally comfortable homes and they can be constructed from many materials. Lightweight timber construction can be easily designed to capture the sun in winter and prevailing breezes in summer to assist heating and cooling. Furthermore, timber framed walls, roofs and platform floors of lightweight timber construction can be easily insulated.
Waste and Recycling
When timber and wood products reach the end of their first life in a building or other use they either end up being reused, recycled or removed to waste. Fortunately, wood is such a versatile material that there are plenty of ways people can choose from to get a second, third and even a fourth life from their wood product, and reduce the environmental impacts even further.
What’s better than recycling your building waste? How about using a building system that reduces waste on site to next to nothing! Prefabricated plantation pine frames and trusses little or no waste is produced on-site so there’s nothing leftover to recycle.
Getting your measurements and resulting timber orders right will contribute to reducing timber waste and save you both time and money. At the factory – modern frame and truss manufacturers employ sophisticated computer programs to minimize off cuts and to help reuse all the smaller off-cuts. Over 95% of timber is converted into frames and trusses.