The trees that are farmed for timber production consist of a main trunk, with smaller limbs that branch outwards, all of which is anchored into the ground by the roots of the tree. The roots provide stability to the tree, also serving to absorb water and nutrients from the soil. The roots do not typically exceed 2 metres in depth below the surface of the ground and will generally extend horizontally away from the trunk approximately 2-3 times the radius of the total canopy span of the tree. There are exceptions to these rules based on the factors such as the species of tree, climate, soil type, and water scarcity, with some roots extending as far as 5 metres and more from the trunk. A large percentage of the total roots of the tree fall within the “drip line” of the canopy - an approximate vertical circumference relating to the outer edges of the canopy. Roots within this zone are often thicker and travel deeper than those that extend beyond it and provide the primary stability to the tree. As we’ll see later, more than simply understanding where wood comes from, this specific information comes into play during groundwork procedures, as trees and their roots are a very common consideration.  

In the interest of preserving the life of a tree during groundwork operations, whether through desire or necessity, it's important to understand the allowance of root trimming. It’s not uncommon for the roots of a tree close to a digging location to extend within the dig, in accordance with the approximate root radius diagram. Roots that fall within the drip line are integral to the health and stability of the tree. Those that fall outside of this range can be trimmed sparingly if required, though in many instances the exact procedures are mandated by external surveyors as a part of the planning stage of the job.  

Trees that grow naturally in fields or forests can take on a number of irregular shapes if subjected to external forces acting upon them. Instances where trees have been damaged during their growth can lead to interesting physical appearances such as split trunks or trunks growing along the floor/alongside other objects. These unique shapes can create beautifully figured grain patterns in the timber that is milled from the tree.

In terms of the timber machining process, the main trunk of the tree consists of 3 primary components - heartwood, sapwood, and bark. Here we can see a through section of a tree trunk, with the individual annular rings of the trunk. Around the outside of the trunk is the thick bark layer that provides protection to the outer ring of the trunk as it grows. Trees grow more rapidly during the spring as the temperature begins to warm after the cold winter. The fibres that grow during this fast growth period are less dense, and are known as early wood, in reference to it being grown early in the year. Comparatively in the summer and autumn when the growth rate slows, the fibres are more dense, and slightly darker in appearance in contrast to the lighter early wood. These denser fibres are known as late wood. In the autumn and wintertime, the temperature begins to cool again, the growth slows down considerably. As such, after each year and every growth cycle, the tree can be seen to create a new distinct ring, called an annular ring. Due to the nature of annular rings forming once a year, the age of a tree can be determined by counting the number of rings within the trunk. As the tree grows its circumference during each growing cycle, the tree also grows in height, lengthening its own internal fibres that form the harvestable wood within. 

At the core of the tree is the heartwood, typically darker in colour, harder, less resinous and more stable than the sapwood that surrounds it. The heartwood provides a sturdy core to the tree as it grows in width and height. It was once sapwood, but through a series of chemical changes, it steadily changes into heartwood as the tree grows. Within the very centre of the heartwood lies the pith - a soft singular ring that was once a small sapling. 

The sapwood that surrounds the heartwood is often lighter in colour and primarily serves to transport water and other nutrients up and down the tree throughout its fibres. This wood contains a lot of sap and is not yet as strong or stable as the inner heartwood.  

The bark is a rough, irregular external layer that serves to protect the interior of the tree from outward predation, as well as protection from weather, temperature, and other external forces. Directly behind the layer of bark is the phloem, a thin and spongy layer that serves to transport the nutrients produced by the leaves during photosynthesis to other parts of the tree as it grows. A thin layer known as the cambium sits between the last sapwood growth ring as the phloem, and serves as a reproductive layer, aiding the formation of the latest annular ring. This entire section beyond the sapwood is removed during the machining process, as it is unstable in comparison to the growth rings. 

The branches that extend from the main trunk of the tree comprise of the same makeup as the trunk, and thicker branches are often machined in the same way as logs from trunks when refining the timber. The branches act as a platform for leaves or pines to grow from and extend away from the tree to expand the footprint of the canopy, allowing for more exposure to sunlight. The leaves or pines convert light from the sun into energy and nutrients for the tree to grow, through a process called photosynthesis.