“Climate change cannot be won without the world’s forests. ”
Ban Ki-moon, UN Secretary-General,
Trees remove carbon dioxide from the atmosphere as they grow
and are widely recognized as a cost effective way to tackle climate change. A
recent UN FAO report shows that deforestation accounts for 17.4% of the world’s
CO2 emissions. This is greater than the emissions from all forms of transport. 13
million hectares are being deforested each year but 6 million hectares of new
forest is being planted.
protocol, with emissions trading, encourages more new forest planting and less
deforestation. Some see this as a short term solution because much of the
carbon can be returned to the atmosphere when trees are harvested, or if they
are left to eventually die and rot in the forest.
There must be another way. The best technology from New Zealand and Europe
shows that harvested wood products can be several times more effective than just
growing trees at tackling climate change. This happens when wood is used in 4
energy saving ways.
1/Use wood for long term purposes such as building
and furniture so that the carbon is stored for a long time. The more wood that is used the better.
2/Use wood instead of other more energy intensive
materials such as steel, concrete, plastics and aluminium.
3/Make use of the insulation and thermal mass
qualities of wood to create very energy efficient buildings which are very easy
to heat and cool.
4/Use wood waste as a carbon neutral fuel in
efficient heaters and boilers.
Solid wood buildings use more wood and less other materials than timber framed buildings. New Zealand has a great solid wood building tradition. The following press release tells the story.
40,000 NZ home owners were right all along
Many people who have lived in solid wood houses comment on
how warm and comfortable they are. This is in spite of these houses having
walls with a low R value. A group of companies wanting to promote solid wood
buildings asked Dr Larry Bellamy of University of Canterbury
and Don Mackenzie from LincolnUniversity to research
why these houses performed better than their R values indicated. The results of
this work was quite a surprise to the researchers , but probably no surprise to
the 40,000 families living in solid wood houses in New Zealand.
The first thing they found was that solid wood has
significant thermal mass giving it the ability to store the sun’s heat during
the day and releasing it at night. Brick and concrete are often used because
they provide useful thermal mass but wood has up to 2.5 times as much thermal
mass as concrete per kilo. Dr Bellamy was able to use a building simulation
model from Denmark
to show that when this thermal mass effect was added to the relatively low R
value of the external walls, a solid wood house compares very well to a light
timber frame house built to the NZ building code. The solid wood house
performed even better when solid wood internal walls and ceilings were used.
The merino effect
Probably an even more important discovery was the effect
solid wood walls have on the health of people living or working in such a
building. It has become well known among researchers that relative humidity in
buildings needs to be kept between 30% and 55% to avoid the build up of
bacteria, viruses, fungi and mites, and to minimize respiratory infections and
asthma. Dr. Bellamy found some research from the Fraunhofer Institute, near Munich in Germany,
which compared 2 identical rooms. One had walls lined with solid wood and the
other with painted plaster board. Water vapour was added at different times of
the day to simulate people living in the rooms.
The solid wood lined room was found to have a remarkable
ability to moderate over 50% of the moisture variations so that the room was
only outside the safe humidity zone for 3% of the time compared to 27% of the
time for the room with the painted plaster linings. This research from Germany
indicated that the health benefits of living in a solid wood house are likely
to be even greater than just the thermal comfort.
Many of us have become aware of the benefits of wearing
merino, especially for strenuous outdoor activities. The merino is able to work
naturally with the body to store and release moisture and stabilize body
temperature. Merino also has the ability to reduce the build up of unpleasant
odour. Wearing merino and living in solid wood houses both help keep the body
healthy and active.
Can you destroy a solid wood building?
Solid wood buildings have withstood severe storms and
earthquakes when nearby buildings have suffered catastrophic failure. Notable examples are Cyclone Tracy in DarwinAustralia
and the Edgecombe earthquake in New
Solid wood walls can take the hard knocks when used in
kindergartens or motels and can have minimal maintenance costs compared to
painted plaster walls. Solid wood even performs well in a fire and can be
restored after a minor fire.
Solid wood’s ability to moderate humidity and to breathe
means that it can survive, in a wide range of climates, probably for hundreds
of years. If it needs to be moved, it can be moved as a whole house, or
dismantled and rebuilt on a new site.
Tackling Climate Change with SolidWoodBuilding
While there is still uncertainty about the best way for New Zealand to tackle climate change and meet Kyoto commitments,
growing trees to store carbon is likely to be the most cost effective way. A
farmer can plant a low value steep piece of land and store over 20 tonnes of
CO2 per hectare per year for the next 30 to 50 years. When the trees are ready
to harvest, if the wood is used for a solid wood building, it can keep that
carbon stored for maybe hundreds of years. It also saves the use of energy
intensive materials such as concrete, steel and brick. And because solid wood
buildings are easy to keep warm, more energy can be saved. Solid wood building
saves considerable amounts of precious fossil fuel energy compared to other
building systems, as well as storing significant amounts of carbon over the
life of the building.
Exciting Future for SolidWoodBuilding
A revolutionary new solid wood building system using cross
laminated timber panels has been developed in Europe
because of concern for healthy living spaces and the need to tackle climate
change. One of these systems from Austria can be seen at www.klh.at. Panels up to 16.5 metres by 3 metres are
precisely cut in the factory so that a building can be erected very quickly on
An example is a 9 storey apartment block at Murray Grove
near the centre of London.
This 29 apartment building took just 9 weeks to erect and all units were sold
before project started – a property developer’s dream. It has a wood composite
exterior and the whole building, even the lift shafts were made of wood. This
means that it will be 21 years before the operational emissions equal the CO2
stored in the building structure. See picture of this building.
Another example highlighting the strength of solid wood is
an amazing café projecting out 12 metres over a river. This can be seen at http://www.openspacemurau.at/en.
Another example highlighting the versatility of solid wood
building was a whole Olympic village built for the winter Olympics in Italy. Each
unit was assembled and fitted out in a factory and then dropped into place by a
crane. After the Olympics, each unit was then picked and moved elsewhere.
Who benefits from SolidWoodBuilding?
Those living in Solid
Wood houses – They are fortunate enough to have a warm, healthy home.Living in a healthy house means less doctors
visits and less sick days. Solid wood houses are virtually indestructible and if
rising sea levels caused by climate change threatens their home in 100 years it
can be picked up and moved to higher ground.
The NZ Government and
taxpayer – Each house built with solid wood rather than steel, concrete or
brick saves many tonnes of CO2 emissions. This reduces the Govt’s and
liability. Reduced health costs will be an even greater saving when solid wood
is used instead of painted plaster.
sawmillers and manufacturers – Solid wood buildings use several times as
much wood as a timber frame building, as well as much less other building
materials. This leads to more demand for more forests, processing and
– Everyone benefits when sustainably grown materials, which need little
processing energy, are used instead of materials which make heavy use of the
earth’s limited resources. Wood is the world’s only renewable building
material so using more wood and less other materials will
help save the planet.
The NZ SolidWood
Group – Leading edge science around the development and performance of
solid wood building has been driven in New Zealand by the SolidWood Group,
a group of visionary companies seeking to bring to the users of buildings and
homes the healthiest living environment possible. For more information on these
companies go to www.solidwood.co.nz