April 20, 2020

Working with our favourite timber

The overstood Sweet Chestnut that was most recently cut for Capco

The timber that's used in our adventure play construction is something that's easy to take for granted. For some, the choice of timber with which to build is more to do with what's available than what's right, sustainable and the most suitable for the application.

We prefer to do things a little differently and have teamed up with the hugely experienced Andrew Falcon of East of England based New Woods Forestry, who supplies and helps us create a stock of our own, locally sourced Sweet Chestnut (Castanea sativa). So, let's walk you through the process of how and why we select our timber.

1. The first thing to consider is the location

We like to choose timber harvested within an hour of our Norfolk base. This means that most of it comes from Norfolk and Suffolk. It keeps our 'wood miles' down and helps us build good working relationships with local landowners and private woodland owners. We only work with estates who have a sensible and sustainable forestry management plan in place.

Most importantly, amid a world of mushrooming tree diseases, there's a deadly blight (Cryphonectria parasitica) on Sweet Chestnut in some parts of the country at the moment. It is most prevalent in the south of England, from where Chestnut is traditionally supplied. So felling, peeling and age drying our local Chestnut close to home eliminates the risk of our adding to the spread of this unfortunate and damaging fungal disease throughout the country.

2. When's the right time to harvest the wood?

Who knew there was even a right time to harvest trees? But the time of year timber is felled has a significant effect on the quality of the final product. If harvested between April and June, when the sap is rising, timber will be full of sugars. This is NOT a good thing and can lead to fungal growth all over the timber. It can also lead to severe splitting of the wood as it dries and in extreme cases, encourage the growth of Pinworm. Every wood type has its own peculiarities in when and how it should be harvested - apparently in France, in the 17th century, it was a crime punishable by death to fell oak during the time of a waxing moon.

The trees are felled before being cut to size and being organised

3. Which wood is right for us?

We mainly use our own Chestnut for the upright support poles and for the exterior finishing on projects such as Skelf Island. They suit our quirky style as we do like to avoid straight edges and steer clear of machined timber where projects and designs allow. It grows quickly, and is super sustainable as we can use it without any need for chemical treatment.

For some of our finishing pieces where a good smooth or moulded finish is required, such as for the decking and the rounded edge boards we use Scots Pine (Pinus Sylvestris).

If we can't use Chestnut, then we do sometimes also use Norway Spruce or Silver Fir (Picea Abies, Abies Alba) for some of the structural C24 timbers.

These come to us from Scandinavia, Germany, Russia or the Baltics and are often chemically treated and tanalised. We'd rather avoid these where possible, as it's better for the environment and to us, feels more at home in the often natural environments we work in.

4. Coppicing

Coppicing is a traditional method of woodland management that can be traced back as far as nearly 4,000 BC. It exploits the capacity of many species of trees to put out new shoots from their stump or roots if they are cut down. In a coppiced wood, young tree stems are repeatedly cut down to near ground level. This creates a stool. It allows new growth to emerge, and after a number of years, the coppiced tree is harvested, and the cycle begins again. It's a similar process to Pollarding, which is where the tree is cut back at a higher level on the tree.

The main attraction of coppicing is that no planting is required. This again mitigates the risk of spreading disease on transplants. Importantly, by harvesting Chestnut coppice on a 25-year rotation, Carbon sequestration is maximised. The cutting is carried out when the quantity of carbon being captured begins to tail off due to canopy closure. Felling at this point and using this very durable material for building projects, maximises the effectiveness of these areas of woodland as carbon sinks.

The wood is cut and stacked to begin the drying process

5. Permissions

Even ignoring seasonal issues, it's not just a case of chopping the wood down whenever and wherever you like. Every forestry is bound by very tight rules on harvesting. There needs to be an agreed management plan for the woodland and you need a felling license in place from the Forestry Commission. If you don't have this plan in place for coppicing or replacing what you harvest, you will be breaking the law. Interestingly to us, there's far more woodland lost to development than there is to unplanned and illegal felling.

6. Planning in advance

Working with our own locally sourced timber does involve much more planning, especially when compared to buying what's readily available through traditional timber yards. Wood we coppice and cut will be transported to our workshop, peeled, then stored and seasoned for up to a year. This allows the timber to dry naturally and minimises the natural splitting that occurs with any timber. We're going to cover that process in far more detail soon and show you how and where we work.

7. It's a long game

Even though Sweet Chestnut is considered a fast-growing timber, it still takes a long time from planting it to children playing on it in one of our structures. The most common pole we use is 6-8" in diameter at its thickest and around 20ft in length. These timbers take up to 25 years to grow. So if you do want to grow Chestnut commercially, you need to be in it for the long game. There are other timbers that grow faster and forests across Europe that can be harvested for more immediate return, but we like this slow, more sustainable approach. Most of the coniferous timber being used is derived from thinnings i.e. they are a product of a longer rotation. It suits our style for development and suits our thinking of how we run our business too.

Grow slow, grow strong.

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