Welcome to the NZ Wood Frequently Asked Questions
- Buyers Guide (25)
- Environmental (7)
- Forestry (9)
- Pine (9)
- Processed Wood (33)
- Using Wood (47)
- NZ Wood (3)
Wood: the most renewable of all building materials
- Growth and production of one tonne of wood absorbs a net 1.7 tonnes of CO2 from the atmosphere. (Based on the amount of carbon stored in the timber – making an allowance for all the energy used, and CO2 produced, in its growth, harvesting and processing.)
- One tonne of steel has added 1.2 tonnes of CO2 into the atmosphere.
- A typical steel house frame has added 4.5 tonnes of CO2 into the atmosphere – the equivalent to the emissions from driving 22,500 kms in an average car.
- A typical wooden house frame has absorbed 9.5 tonnes of CO2 from the atmosphere – the equivalent of 47,500 kms of driving in an average car.
- Timber frames mean years of CO2 “in the bank”
- Energy usage of a well-built, properly insulated home will be similar whether built with a steel or wooden frame (although steel frames will “leak” more heat than wooden frames if not properly insulated).
- The choice of wood or steel makes the difference between starting with either a healthy CO2 credit or deficit.
- An average house uses around 10,000 kWh of energy per year for heating and lighting, which represents CO2 emissions of 2.3 tonnes (based on electric power).
- Choosing a wooden house frame will provide over four “free” years of CO2 emissions.
- Using a steel frame is the same as adding an extra two year’s worth of average household CO2 emissions into the environment. Steel and timber: the afterlife
- Most construction timber is buried in a landfill at the end of its life. Up to 97 percent of the carbon in the wood is permanently stored under the ground – capturing CO2 released by fossil fuels and returning it back beneath the earth’s surface.
- At the end of the building’s service life, steel frames can be recycled for other uses. This requires significant processing energy, although this is a fraction of what was required to produce virgin steel.
Many forest growers in New Zealand are certified by the internationally recognised by the Forestry Stewardship Council (FSC) which sets a demanding benchmark for environmental protection.
All forestry management practices are bound by the requirements of the Resource Management Act, a level of environmental responsibility that does not exist in a number of other countries.
In 2007 the New Zealand Forest Owners’ Association released a comprehensive Environmental Code of Practice which covers areas such as the protection of waterways, endangered species, historical sites, sediment control and the management of fuel, oil and wastes – to name just a few. This was acknowledged by the NZ Fish and Game Council, the Ministry of Agriculture and Forestry, and other organisations as leading the way for other sectors.
While pine is the predominant planted forest type in New Zealand, NZ Wood supports all plantation forestry. NZ Wood supports the growth of diverse plantation species in New Zealand.
The harvesting of trees in plantation forests involves careful planning and evaluation, and plantation forestry is a more environmentally friendly, and is more effective in managing erosion, than competing land-uses.
As an example an independent study by Hawkes Bay Regional Council in the Pakuratahi Catchment provides some information on land and water effects of pasture compared with forests.
Cutting down trees only helps the environment if the trees that are harvested are replaced with new plantings (even if these are not on the same site).
As trees grow, they absorb carbon dioxide through the process of photosynthesis.
The carbon dioxide absorbed by the growing forest remains stored as carbon within the wood products after the tree is harvested and remains stored throughout the lifetime of the product. (Wood is 80 percent carbon.)
If another tree is planted when the first tree is harvested, this will absorb more carbon.
At the end of the wood product’s lifetime when the wood decays or is burnt as fuel the carbon is released back into the atmosphere as carbon dioxide. If, however, the wood is properly buried at the end of its life, most of the carbon content of the wood will remain underground indefinitely.
Over its lifetime a single tree can absorb much more than its own weight of CO2 from the atmosphere. The tree breaks the CO2 down into carbon and oxygen. The carbon is retained and the oxygen mostly expelled. The processed timber that eventuates is deemed to have absorbed the equivalent of 1.7 tonnes of CO2 for every tonne of its weight.
New Zealand’s native forests are protected by law. Comprising 6.4 million hectares (64,000 square kilometres, the NZ Government is the major owner and around 77 percent of the forest estate is managed by the Department of Conservation for conservation, heritage and recreational purposes. Twenty-three percent is in private hands but are required by law to be managed sustainably.
None of these forests are being harvested and replanted with exotic species.
The NZ Government’s emissions trading scheme can be explained by using a simple example:
- Firm A is an oil company. It needs to buy emission units to cover the greenhouse gas emissions it is responsible for.
- Firm B is a large forestry company that receives emission units for land it is planting in forests. It is also undertaking some deforestation, leading to emissions for which it has to surrender emission units. Initially, Firm B has a shortfall of units but, as the new forest matures over time, it will have an overall surplus of units.
- Firm C is a major industrial user of electricity. Its costs increase with the introduction of the emissions trading scheme. To help Firm C adapt to these higher costs, the government gives Firm C an allocation of emission units, which Firm C can sell to offset its increased electricity costs.
Under the emissions trading scheme, Firm A and Firm B both buy Firm C’s units in the short term to cover their emissions. Because it now has to pay higher energy prices, Firm C finds it is cheaper to invest in energy efficiency. Alternatively, any firm can import or export eligible units from other countries. Over time, as its forest matures, Firm B has spare units available and sells them to Firm A.
From the Ministry for the Environment
For more information on the government’s climate change work, including information about the emissions trading scheme, visit www.climatechange.govt.nz or call 0800 CLIMATE (0800 254 628).
While NZ Wood itself is not eligible for membership of the Forest Stewardship Council (FSC), as it is merely a promotional body and information resource, one of its main members, the New Zealand Forest Owners’ Association, is an active member of the FSC international council.