Every wooden building is a carbon storage

The carbon footprint of a wooden building is small. Throughout its life-cycle, it causes considerably less climate and environmental burden than its sisters made from concrete, brick or steel.

Wood is an environmentally friendly and strong natural product that can be converted into diverse products that function as carbon storages. “Wood is applicable to almost anything that can replace fossil-based and other raw materials harmful for the environment in construction as well,” says Matti Mikkola, Managing Director of the Federation of the Finnish Woodworking Industries.

Wood is also the only construction material whose volume is increasing all the time: the wood material needed for a medium-size wooden high-rise grows in Finnish forests in 30 seconds.

Wood is applicable to almost anything that can replace fossil-based and other raw materials harmful for the environment in construction as well.


Wood will not run out due to construction

This means that we are not about to run out wood due to construction – as long as the wood comes from an area where forest management and utilisation are as professional and responsible as in northern Europe.

Nearly 90 per cent of the wood used by Metsä Group is certified. A forest certificate is a guarantee of responsibility. It is an indication of the sustainable management and use of forests. “Only some 10 per cent of the world’s forests are however certified,” says Armi Purhonen, Environmental Communications Specialist at Metsä Group.

“The wood we use comes from the densely forested areas in the north, where forests grow more than they are used and where the carbon storage of forests continue to grow,” adds Purhonen.

Cubic meter of wood stores 1000kg of co2

Metsä Group’s sustainability aims to increase the amount of carbon bound in forests to a significant degree. Metsä Group also aims to increase the amount of carbon stored in its products by 30 per cent by 2030. The amount of carbon stored in products is raised by increasing the production of products which store carbon for a long time, such as sawn timber and engineered wood products.

The amount of carbon bound in forests is increased by providing more forest management services that speed up the growth of forests and by encouraging forest owners to manage their forests.

“Metsä Group delivers 30 million seedlings to forest owners every year. Every tree harvested in a regeneration felling is replaced with four new seedlings,” says Purhonen.

“We’ve also carried out a vast amount of research and development work which allows us to provide the seedling with the best possible growth conditions after they are planted in the ground to replace a harvested tree and accumulate a new carbon storage,” adds Purhonen.

Wood construction

A wood product is a climate act

Wood has the unique ability to absorb carbon dioxide from the atmosphere and store it. To grow, one kilogram of wood needs approximately 1.55 kilograms of carbon dioxide, and the carbon from this is stored in the wood. The rule of the thumb is that one cubic metre of wood stores a tonne of carbon dioxide.

“Being renewable and recyclable, wood is the best construction material from the climate perspective, because it stores carbon within it,” says Jussi Björman, Director, Business Development, Construction, of Metsä Wood.

Wood’s ability to store carbon will therefore not disappear when a tree is felled. Processed wood will function as a carbon storage for as long as the product made from the wood exists. “A building constructed of wood will function as a carbon storage throughout its life-cycle,” adds Björman.

An average Finnish single-family house built from wood stores roughly 30 tonnes of atmospheric carbon dioxide within its wooden structures. This is equal to the carbon dioxide emissions generated by the average miles driven by one consumer over a period of 10 years.

Wood provides better urban construction

The benefits of wood construction – in other words the lightness of the material, fast construction and environmental friendliness – provide innovative and sustainable opportunities for modern construction, particularly in growing urban environments, where the need for housing is increasing at the same time as good building sites are growing increasingly scarce.

At the moment, wood accounts for approximately 5 per cent of construction in Europe. “The use of wood should be increased particularly in cities, because wood construction can reduce the carbon footprint of urban environments to a substantial degree,” says Björman.

“If the share of wood in urban construction increased, it would have an enormous climate impact – and there would still be no need at all to compromise on the quality of construction. The same structures that are made from concrete or steel could just as well be made more ecologically from renewable and sustainably grown wood,” adds Björman.

High rise
Wood construction

The right material to the right place

Not everything should be built from wood, though. Rather, the wisest solution in terms of resources is the selection of the right material for the right place. “Nowadays, concrete is the best material for foundations, and glass works in windows, but when designing a concrete building, we should also consider whether certain structures can be made from wood, which is lighter and stores carbon,” says Jussi Björman.

One square metre of wall built from wood creates a carbon stock of roughly 80 kilos and 30-kilo carbon dioxide emission. If a wooden wall replaces an equivalent concrete wall, some of the 120-kilo carbon dioxide emission attributable to the production of the concrete wall can be avoided.

“Every wooden element in a building is a step towards something better in terms of the climate,” says Björman.

One square meter of a wooden wall stores 80kg of carbon

Source: VTT

Read why is using wood a contribution to the environment