Few people dispute wood’s underlying environmental credentials. Recent life cycle analysis (LCA) studies have provided scientific confirmation that wood has many environmental benefits compared with other building materials.

The most comprehensive LCA data available in the UK has been compiled by the Building Research Establishment (BRE) in its study “Environmental Profiles of Building Materials, Components and Buildings”. BRE scores timber highly in the 13 environmental impacts covered – from climate change, pollution to air and water, waste disposal and transport pollution and congestion. Timber was recognised as the only building material to have a positive impact on the environment due to trees’ ability to absorb CO2.

When questions are raised over wood’s environmental performance, they usually relate to forest management. Hardly surprising given the intensity of environmental campaigns seeking to link the timber trade to tropical deforestation and the loss of biodiversity.

The implication is that if the industry were able to provide assurances of good forestry practice, the environmental credentials of timber would be unassailable.

70 years of data

The American hardwood industry is in an enviable position in its ability to provide such assurances. It can draw on reliable forest resource data gathered over the past 70 years to demonstrate that management of the resource is sustainable. Every 10 years the US government is required under federal law to undertake a nationwide inventory of forest resources.

The most recent inventory, published in 2000 and referred to as the “RPA Assessment”, shows that during the past 50 years the volume of hardwoods standing in the US forests has increased by over 90% while the area of American hardwood forests has increased by 18%. These figures reflect the simple fact that hardwood harvesting levels in the US have consistently been well below the level of growth. This is despite a progressive rise in consumption of American hardwood lumber.

Forest expansion

Several factors have contributed to the expansion of US hardwood forests. Agricultural efficiency improved considerably during the 20th century, reducing the need to convert forests for food production. At the same time, demand for American hardwoods provided a strong economic incentive for US landowners to manage and conserve forests for the supply of timber. Meanwhile, wood use efficiency has improved dramatically. American sawmills today can produce twice the amount of usable lumber and other products per log than they could a century ago. And the US has evolved an effective and fully enforced regulatory framework to deliver sustainable forest management.

&#8220The implication is that if the industry were able to provide assurances of good forestry practice, the environmental credentials of timber would be unassailable”

Nor are American hardwoods sourced from plantation monocultures sometimes criticised for lack of aesthetic appeal and diversity. Instead they derive from managed natural forests which have high natural biodiversity, provide a habitat for a wide range of species, and are resilient to fire and pests. In fact, US hardwood forests offer a greater diversity of timber species than any other temperate hardwood forest resource. In fact, they can supply commercial volumes of over 20 species.

Architectural interest

Over recent years there has been increased interest among architects in independent forest certification to provide assurances of good forest practice. The US has been a pioneer in the development of these schemes. It is host to the world’s first forest management scheme, the American Tree Farm System launched more than 60 years ago. In 1996 another scheme, the Sustainable Forestry Initiative, was launched to promote good forestry practice throughout the US. The US can also boast the third largest national area of forest land certified by the Forest Stewardship Council.

But forest certification remains a major technical challenge in the US where much of it is owned and managed by millions of private individuals. This has meant that it is extremely difficult to trace wood from individual forest to point of sale. A single hardwood sawmill in the US will typically source logs from thousands of forest owners.

Strong link

It is ironic that a major factor preventing widespread forest certification in the US hardwood sector has also made a significant contribution to the sustainable management of the nation’s forests. The dominance of small non-industrial forest owners has meant there is a strong link between US rural communities and forests. Through living and working in the forests all their lives, many US citizens have gained a deep understanding of forest management.

So lack of certification does not imply lack of sustainability. In the case of American hardwoods, the forests are themselves living proof of sustainability. Seventy years of forest inventory data provides ample evidence that the resource is thriving.