Finnish forests are certified. Forest certification is a system that ensures the purchaser of timber products that the raw material originates from forests managed in a sustainable manner. The criteria for sustainable management are based on internationally approved methods of forestry that meet ecological, social and economic standards.
Building in wood is a good method to reduce the effect of climate change. The use of timber in products and buildings and its effect in absorbing and storing carbon is conducive to the concepts laid down in the Kyoto Protocol. Part of the carbon in wood is stored in the finished product, such as paper, wooden buildings, or furniture. Newspapers are recycled rather quickly and cannot be considered as long-term stores of carbon but a well-built wooden building may last through the centuries and function at the same time as a storage facility for carbon.
Wood products compare well in material life-cycle comparisons. In many surveys that compare the life cycle of materials, a building constructed of wood consumes fewer natural resources and causes less harm to the environment than a similar building constructed of concrete, brick, or steel.
A concrete element wall consumes about eight times more natural resources than a wall built of wood. During a life span of one hundred years the concrete element wall will consume twice the amount of natural resources as a wooden-built wall. A wooden building, in other words, is more eco-efficient. The degree of eco-efficiency is further increased by the fact that compared to a brick or concrete construction, the major part of the material is renewable.
Wood products are energy efficient. The production of wood products requires little energy. The main part is wood energy which is acquired as a side product from the bark and sawdust when sawing into timber.
The production of sawn goods consumes considerably less energy than the production of other building materials. The production of concrete requires double the amount of energy whereas the production of bricks requires four times the amount. The production of glass, steel and aluminium is the most energy intensive of all materials.
The biggest amount of renewable energy and the least amount of fossil fuel energy is used in the construction of a wall built from wood. It causes the least amount of greenhouse gases and sulphurous emissions. Walls produced as concrete elements consume the greatest amount of non-renewable resources and produced the largest amounts of carbon dioxide and sulphur dioxide emissions per square metre of wall.
Wood is an eco-effective material, as not only the trunk, but the bark, branches and crown can be utilised. When trees are harvested, the branches and needles that remain on the forest floor play an important role in the nutrition cycle of nature. The raw material for the saw-milling industry can be utilised 100%, either in the form of building materials or as a source of bio-energy.
Wood is a highly effective insulating material, the average fuel maintenance cost of a timber frame home is approximately 40% less than for masonry buildings.
When wood products are removed from service they can be used again and often without modification. For example, wooden doors, window sashes, skirtings and architraves that have been removed from old wooden houses are in great demand at recycling centres. Scrap wood can be burned and that converts the energy absorbed in the material into useful heat and at the same time returns the carbon back to the cycle of nature.
Wood is a clean and safe product. Sawn goods are mechanically processed. Boards and logs made from the typical species common to the Nordic countries are considered to meet the best standards for interior air quality.
When it is said that a wooden house "breathes", it refers to a structure that can easily transfer the humidity in the atmosphere by diffusion and with the aid of the hygroscopic properties of wood absorb that humidity or release it back into the atmosphere. Other gases in the atmosphere, such as carbon dioxide, can also pass through the material in the same way as humidity is diffused to the atmosphere. Wood possesses this hygroscopic property of being able to absorb humidity in a room atmosphere and also release it back to the atmosphere. In this way wood has the ability to balance the humidity of the room atmosphere and reduce the amount of peak levels. This feature enhances the comfort level of the atmosphere in a building, improves the quality of the interior air, reduces the need for ventilation and at the same time reduces energy consumption.
A modern wooden house is safe from fire. In tests carried out, the wooden frame of a building burns quite slowly. When burning, solid wood chars to around 0.8mm in depth. The charring of a wooden beam tends to reduce the speed of burning as the charred surface slows down the burning process under the surface. The heart of the wood can remain undamaged for a long period. The load-bearing beams and pillars in a wooden building do not suddenly collapse. Steel loses its load-bearing property when heated to 450º C which means that a steel-framed building can collapse in a fire. Steel structures have to be fire-protection shielded, whereas solid wood needs no protection if the thickness of the material conforms to the set norms.