What future is the forest growing?

The outlook for forests being planted now By Dan Ridley-Ellis Head of the Centre for Wood Science and Technology, Edinburgh Napier University

Our future is in growing forests. The timber supply for the next few decades is already in the ground. When the new trees we are planting now come to harvest age, we will be in 2050 and beyond – a time for which important promises have been made about net zero carbon and use of renewable resources in place of carbon intensive and fossil-based materials. Forest management and planting decisions made today have consequences for decades to come – so at least some of our future has already been written.

In looking forward we can consider, therefore, two horizons: the horizon of our current growing stock and the horizon of trees yet to be. For the first, we can expect that spruce will remain the major part of our useful wood resource, but with a gradually increasing proportion of other softwoods. Most of these are probably similar enough they can fill the same markets as the spruce, as part of a mixture (if we plan ahead). That said, we cannot be confident the resource is not changing in some way. Even familiar species are changing as a consequence of forest practices, tree selection and breeding, climate change, and the use of more effective methods of tree and log segregation.

The changes are incremental, but there are still tipping points – most crucially maintaining the required mean stiffness for C16 construction timber without large reject rates. It will be increasingly necessary to pay attention to the real indicators of timber quality and overcome misconceptions about growth rates, density and knots. Indeed, the current ‘quality’ perception of certain types of wood product can be very counterproductive, socially and economically – not everyone can afford solid wood home-grown native hardwood furniture, or low density housing. Marketing can develop more affection for ‘hero’ products, that use high amounts of recycled wood, and material from the kind of forests that the public like to see.

“The timber supply for the next few decades is already in the ground.”

Relative to softwood, the amount of available useful hardwood will remain small, but it will grow significantly from current levels. There are opportunities here to make better use of species such as sycamore, beech and birch – although the amount considered suitable for traditional products will be severely limited. Perhaps this use can be in the form of engineered and modified wood products, and manufacturing streams that can deal with a wider range of wood – including the increasingly important resource of recycled and recovered wood. Wood fuel has an uncertain future, thanks to concerns over air quality and the rise of ever more effective renewable alternatives. There is perhaps more of a future in the form of wood-based liquid fuels in the longer term.

Climate change impacts are also coming quickly. In the UK, we can expect more summer drought and periods of more intense rainfall. Trees will have to cope with feast-famine cycles for water, with risks to wood quality as well as tree health. In this horizon, we can also expect more market disturbances. We can try to reduce the risk of forest fire, storm damage, pest and diseases in our own country, but since the timber trade is global, there will be more feast-famine cycles for the wood supply – large volumes reaching markets as a result of disasters, and shortages and demand pull from other parts of the world. We also know the enormous effect politics can have and should not forget how much of the global forest resource is controlled by single countries. Trying to move our value chains to a more diverse diet of wood will help mitigate the risk.

During this period, we will see a growing wood hunger. Efforts to use wood in the place of more carbon intensive materials will continue. There are also some basic, high volume, trends – such as the increasing demand for tissue as global living quality increases, and the growing need for textiles (never mind the need to produce a higher proportion from wood-based fibre instead of fossil-based synthetics and water hungry cotton). There is also hunger in the literal sense, with the use of wood derivatives in food.

Despite restrictions on combustible building materials, the use of sawn timber and board products in construction will grow, but there will be gradual changes in the type of construction work, with more emphasis on renovation and retrofit of existing buildings, and design for disassembly and reuse in new ones. Perhaps technology will allow an economically viable shift back towards local supply chains and customisation, providing a niche for homegrown material against the backdrop of imports that we have no option but to rely on to satisfy the majority of the demand.

For the second horizon, resilience has been the watchword, encouraging us to plan ahead for forests that are diverse enough in species, genetics, age and structure, to be able to recover from disturbances. But we should not talk just about resilient forests, but also of resilient value chains – also robust enough to cope with disturbances, and adapt to changes in the natural, social, and economic environment. Value chains that rely on a consistent supply of a small number of species and narrow quality requirements will be exposed to ever-increasing risk. Fortunately, scientific developments ongoing now, such as new materials from cellulose, lignin hemicellulose and extractives, will come to the industrial stage in this horizon.

We are likely to see more forests being reserved for protection areas, perhaps offering income from recreation and tourism, but not able to provide much to satisfy the ever-growing wood demand. This means we will be expecting more from production forests, managed in intensive but resilient ways we have yet to figure out, but benefiting from new sciences such as genomics to accelerate tree improvement. It is impossible to say exactly what uses forest products will be put to several decades from now, in a world that will surely be very different. But experience has shown that trees, grown with no purpose in mind, do not lend themselves to high value products.

Dan Ridley-Ellis is head of the Centre Wood Science and Technology at Edinburgh Napier University.

He is one of the UK’s technical experts on guessing the strength of wood and can talk for hours on the topic – which he frequently does if nobody stops him.  His main area of research is understanding the properties of wood, and how they are influenced by tree growth, forest management, and climate. His most recent work has been focusing on the potential of lesser used, and lesser known, species, and preparing for the wood value chain of the future.

He represents the UK at European Standards Committees for grading of construction timber, and the majority of structural sawn timber produced in the UK is now graded with settings he developed. He is also active in online learning, public engagement and science communication. He is the lead organiser of Bright Club Edinburgh, where researchers do stand-up comedy.

This article was from The UK Forest Market Report 2021. Read more articles: