Here are some considerations which are particularly important in choosing cut timber for outdoor use:
How far away from your locality did the tree grow, as transport can have a large carbon footprint: the species of tree will indicate whether it has travelled a few miles, several hundred, or several thousand, and your supplier should have information too;
What environment did the tree grow in - a well managed woodland, or an old growth mature forest which might have taken centuries to form intricate layers of habitat;
Is it certified.
Is it durable for use outdoors
Increasingly, engineered wood products such as Glulam and Cross Laminated Timber (CLT) are becoming available, and composites which use waste products such as sawdust. However there are still many occasions when felled trees provide the ideal material. Scroll down for information to help you choose sustainably sourced timber.
Our Cedar of Lebanon, shown in the photo at the bottom of the page, was planted nearly 400 years ago, adjacent to Holbrook Manor in Wincanton. Sadly the tree had to be felled for safety reasons. Cedar of Lebanon makes a beautiful and durable timber - and using it in this way means the carbon stored within remains largely locked up. Our contributor Reclaimed Design sources older trees which have to be felled as well as sustainably grown younger trees and reclaimed woods.
FSC and PEFC Certification
The FSC (Forest Stewardship Council) label shows that they have assessed the forest or plantation and found that it is being managed in a way that preserves biological diversity and benefits the lives of local people and workers, while ensuring it sustains economic viability. This is the certification scheme with the greatest global reach. The FSC sets strict environmental, social and economic standards. FSC certification also extends to timber products such as paper and furniture. The PEFC (Programme for Endorsement of Forest Certification) is the alternative certification scheme. The PEFC does not set standards for timber producers, but it looks at local certification and standards schemes around the world and attempts to verify that they promote responsible forest stewardship. The standards and laws within the country of origin are relevant when considering either type of certification. In countries with strict regulation and easy access to their forest systems it is more likely that certification can be completely relied on than in countries where regulation is more lax, penalties for breaching sustainability standards less severe, and forests more impenetrable.
risk of extinction
The International Union for Conservation of Nature (IUCN) takes a data led approach to monitoring the health of plants and animal species across the globe. Established in 1964, its Red List of Threatened Species has evolved to become the world’s most comprehensive and respected information source on the global extinction risk status of animal, fungus and plant species. Looking up the most commonly found tropical hardwoods for sale in the UK, there is a sense that despite certification, tropical hardwoods are under threat:
Balau - 14 species on the list (of which many are used for timber): 3 species Critically Endangered; 2 species Endangered; 9 species Vulnerable /Near Threatened and Decreasing
Meranti – 84 species on the list (of which many are used for timber): 18 species Critically Endangered; 15 Endangered; 36 Vulnerable/ Near Threatened, of which 33 are Decreasing; 15 Least Concern, of which 13 Decreasing
Iroko – 2 species listed: Milia regia Vulnerable and Decreasing; Milia excelsa Near Threatened - common but heavily exploited
Teak: Endangered and Decreasing
In tropical rainforests, extensive and continuous cover from long established trees is essential to maintain the systems which keep the forests healthy, locking up carbon dioxide, providing oxygen, regulating rainfall within global weather systems which extend far beyond the are of the rainforests themselves.
British and European timber
Well managed British woodlands and plantations and sustainably grown timbers from mainland Europe yield timbers suitable for outdoor use which have a minimal carbon footprint from transport. These timbers are durable and offer a choice of natural variations in colour and appearance. Sawn timber offers a rustic look, whereas planed timber gives a smoother surface and brings out the grain. Natural oils and waxes can offer further variations - some are listed below.
By choosing FSC and PEFC certified timbers from the UK and Europe rather than tropical hardwoods you can feel certain that you are not inadvertently using timbers from old growth tropical forests with rich and balanced ecosystems in which every tree plays a part.
UK and European tree species suitable for outdoor use
Used for cladding
Uses: joinery, fencing, structural
Uses: joinery, fencing, structural and trims
British sweet chestnut
Uses: joinery and cladding. Slow growing. Only sustainable if fallen, or felled for safety reasons.
Cedar of Lebanon
Uses: joinery and cladding
Uses: flooring, fencing, joinery, structural and trims
Uses: joinery and structural
Uses: fencing, cladding, roof shingles. US timber is more durable but grows on the Pacific coast so has a high carbon footprint for transport
Western red cedar (UK grown)
From further afield, Siberian larch (from Siberia and Iceland) has a higher carbon footprint for transport, but appears to be planted faster than it is used, and is listed as Least Concern by the IUCN making it sustainable currently. FSC certification is important to ensure the timber is not from ancient boreal forest. It is suitable for joinery and decking.
Reusing is a great way to be sustainable. Some things to check for or ask about before buying are:
Rot: check for soft areas which may make the timber unsuitable for use
Insect damage which may have weakened it
Nails and screws - check so as to avoid injury
Preservatives, such as creosote which was formerly used on sleepers and should not be used with edibles or where it will be touched.
A reputable supplier will be able to check this with you and supply good quality reclaimed wood for use in a variety of outdoor projects
Between them these suppliers offer a range of stains, paints, decking oil (including anti-slip oils), including finishes which work with cedars and oak. Although treatment is not necessary for the timbers described above, these products will extend their lifespan:
Paint specialists include:
Sources for this page: Wood Campus: Wood Database; Timbersource; IUCN Red List