Where Does Your Timber Come From?Andrew Brandon
The first step in this process is what is known as felling, downing individual trees ready to be transported. It is important to make sure that the trees are cut down at the right time, and this is down to a forestry worker to determine. There is a large span of time in which trees can finish their growing process and therefore be ready to be cut down, this can range from between 40 all the way up to 150 years. This vast range is caused by a combination of tree species and the amount of nutrients in the soil they have been growing in, conifers for example grow a lot quicker than other species, making them ideal for mass production of timber. This length of growth is what often determines the price of timber made from a certain species, as a longer growth time makes the stock of timber harder to come by and therefore more sought after and more expensive.
The process of felling is usually carried out during the winter months, due to the lower moisture content of the wood compared to summer, making for an easier felling process.
The final part of this process is to replace the cut down tree with a sapling, creating a constant cycle of growth and regrowth for constant supply and minimising the effects of cutting down trees, such as deforestation. This felling and replacing of trees is what makes some timber (including ours) FSC Certified. This certification is awarded by the FSC (Forest Stewardship Council), provides peace of mind for anyone concerned about the environmental impact of the timber manufacturing process.
Preparation And Transportation
After all of the logs needed have been felled, they are kept in the forest until they need to be transported to a processing facility. This is done to allow any excess water held in the logs to evaporate, reducing the weight of the logs, making for a cheaper transportation process. The logs are then cut in to smaller, more manageable pieces and loaded on to a timber lorry.
On Site Work
When the logs arrive on site, they are debarked and go through a procedure known as bucking. Bucking is cutting the logs in to the sizes that will become the finished length of the timber battens or boards that will end up in lumberyards and builders’ merchants. After this, with the help of various saws, the logs are cut in to boards using a two-part process known as conversion. The logs first go through a rough sawing to achieve the initial size and shape of the board, either using a through sawn or quarter sawn technique. They then get re-sawn for a more precise and clean finish, more often referred to as planing. The last part of this stage includes making sure the edges of the boards are perfectly straight and curved edges are removed.
The cut boards are then put through a stage known as seasoning. Even though some of the water would have evaporated after the initial felling, the wood will still contain between 40% to 50% moisture, which is still far too high for any functional timber. This means that more water and moisture still need to be extracted from the wood. The water is held in two ways, free water and cell water. Free water is the type of water that is partially evaporated after felling, but seasoning is needed to extract all free water from the wood.
Cell water is practically impossible to let evaporate on its own, as the tree will naturally hold on to this water, due to it being an integral part of the trees cell structure. Through the seasoning process, all of the free water and a majority of the cell water is removed, and this is either done with a kiln (producing kiln-dried lumber) or the more traditional method of natural air drying.
The purpose of having less water content in the wood is to prevent deformation and warping of the wood, both of which can cause the wood to become unusable. Wood that has not had its moisture content extracted is known as green wood, and is notoriously hard to work with due to its tendency to change shape because of the high water content.
At this point, you will have standard timber that is ready to be shipped out to sell. However, if the wood requires further finishing and treatment made for certain purposes, a second processing stage must take place.
This stage is where all of the refining and final touches take place, finishing the wood to particular dimensions to be used for projects such as furniture. This is also the stage in which treatments are applied to add desirable qualities to the wood, such as fire and rot resistance. The scraps accumulated from the manufacturing of timber are not wasted, this wood will be used in the manufacturing of other boards such as MDF and OSB Boards. These boards are made by hot pressing glues and resins together to form a panel that can be used for purposes that will not be suitable for standard timber battens or boards.