Seeing the wood from the trees

Previous Musings have looked at methods and materials that we would never consider using for house construction, were we not constrained by mental inflexibility, vested interests and ‘tradition’. Thankfully things are now changing with a dawning realisation that modern methods of construction offer advantages of speed, flexibility and considerably lower carbon emissions, along with the chance to use more renewal materials. Headlining renewability is timber, with the simple theory that if you plant trees they absorb carbon, you harvest the trees for the wood and then plant more; the carbon being locked into your building materials. It’s a virtuous circle.?

Unfortunately it is not quite as simple as this, and there is no such thing as easy virtue.?

Any successful industry requires standardisation and an efficient production line, so commerce demands that timber 'factories' are created, monoculture blocks to be harvested by mechanisation; planted and cut on mass. The flaw in this plan is that a successful forest is diverse, as it is a false assumption that trees compete with each other, in fact they are a co-operative. Trees lean on each other in storms, easing the strain of gusts, they communicate through their roots and they warn each other of pest attack so others can prepare themselves and they can even pass nutrients to an ailing neighbour; for it is to the benefit of all for everyone to be healthy. Trees even grow better when they start out in the shade of adults, taking their time to mature, to set firm roots and grow their bodies steadily, all the time linking up to the trees around them through a web of Mycorrhizal fungus within the rhizosphere, which takes decades to establish. Without this time to mature you end up with the equivalent of junk fed adolescents who grow quickly, but are sickly inside, lacking resilience to adversity.?

In a commercial operation, blocks of trees are felled and a horde of youngsters are planted, completely exposed without the support of older trees around them. This exposure brings many perils, the most dangerous being drying out, which even adults struggle to cope with, let alone these turkey twizzler trees. European forests are already suffering from drying out, with annual mortality rates increasing (particularly for Norwegian spruce that is frequently grown in plantations outside its natural range) and this becomes self-fuelling destruction as dying trees fall to create more ground biomass, which is further dried as it is exposed to the sun, creating more opportunity for wild fires.?

The more that land is cleared, by felling or fire, the more heat from solar radiation the bare ground absorbs and the faster the ground dries, a process accelerated by the lack of a root network to reduce drainage when it does rain. An established forest is a self-protecting entity as leaves reflect around 50% of the sun’s rays, as well as shading the ground to reducing drying, whilst trapping moist air beneath the canopy. It also establishes a biotic pump which, although it sounds like something that Gwyneth Paltrow might be into, is actually an astonishing geo-mechanical mechanism. It works like this.?

Trees draw water from the ground and release it as vapour to rise and condense into clouds, in the process changing it from a gas to a liquid and thus creating a drop in air pressure, allowing even more water vapour to rise. The uplifting air current caused by the rising vapour draws in horizonal air currents, lower to the ground from the sides of the forest, sucking in air from higher air pressure areas such as the ocean, carrying moisture with it. So, the bigger and more contiguous the forest, and the bigger the trees, the more rainfall it creates. Oh, and of course, a mature forest traps more of this rainfall in the ground, making the forest healthier and helping to slow run off and consequent flooding.?

There are ways of creating more sustainable forests and the Fins are having a good go at doing this, helped by the 60 percent private ownership of forests and encouragement to manage them with an eye on biodiversity, along with less mass block felling; the aim being to create a circular wooden economy. However, it is less easy to see this responsible model being adopted by most other countries, particularly with the massive calls on timber from around the world, which brings us onto the next point – the supply chain crisis.?

Congested container ports, rocketing commodity and goods prices, and the USA and China demanding ever greater supplies of timber, all these place huge strain on the materials we need to build with modern methods of construction; timber framing and SIP panels to name just two. Yet this does not mean we should be returning to the old fashioned way of building houses with bricks and blocks, as this would be like going back to building more coal fired power stations, which would be a really daft thing to do.?

Instead, we need to look at using new technology to construct our houses, taking advantage of advances in material science to create new construction products. Graphene offers one route, through its ability to add strength to other materials, enabling us to use less whilst lightening the structural components that we use to construct the houses. It also offers us a possible way out of the supply chain crisis as the components for products can be produced in this country, rather than shipping them in and shipping out our money to pay for them. We just need to be bold, clever, and above all have faith that we have the ability and talent to manufacture them in this country; the home of the industrial revolution.?

With forests around the world under stress and increasing demands for timber, from people with deeper pockets than us, there is another reason for keeping them where they are. Each mature tree removes over 1 kilo of particulates every year and dust particulates are reduced by 75% on the sheltered side of a tree. Now here is the kicker. A study by Harvard University found that each extra 10 micrograms of PM2.5 per cubic metre of air over 28 days was linked to an increase of 11.7 per cent in coronavirus cases and a 52.8 per cent in Covid-19 deaths.?

So, it’s not all about commerce, which we have seen is not that practical unless you set up monoculture blocks and treat forests like fields of wheat, and at what point do we exhaust the land and have to intervene to continue to grow our ‘crop’? At the risk of going all Feng Shui on everyone, being amongst trees has been shown to reduce blood pressure and stress hormones such as cortisol and adrenalin, a reason the Japanese have a phrase, Shirin-Yoku, meaning Forest Bathing. This connection with the natural world is impossible in a harvestable forest, have you ever tried to stroll amongst densely packed trees in a forestry block, or listened to birdsong in a monoculture??

It is all laid out before us. We need more trees to create rain and clean the air, to create biodiversity and cleanse our spirits, whilst it is getting more and more expensive to buy timber products from felled trees in other countries. So, surely it is time to apply our famous inventive spirit and manufacturing prowess and come up with new ways of making building products for ourselves which don't involve felling forests, as the last thing we need is to see even more wood from the trees.