5 Stages of Harvesting Trees
Trees are essentially the most important part of nature's ecosystem. They provide us with the air we breathe, absorb harmful gasses, stabilize soil, provide us with food, conserve water, and so much more. So why should we harvest trees? Well here are a few reasons why harvesting trees is extremely important!
Management for wildlife habitat
Aesthetics and control of overgrowth
Enhance soil & water quality
Native biological diversity
Recreational opportunities & forest products
In order to harvest trees, there are 5 main stages which we have outlined below.
Stage One – Felling
Felling is the process of downing individual trees. The person cutting the tree is called a feller. A harvesting machine is called a feller buncher.
Felling is done normally in the winter – when the trees have less water content.
Felled trees should be replaced with saplings.
Stage Two – Storage & Transportation
Logs are stored in a clearing to allow the evaporation of water to reduce the weight of the log which results in lowering the cost of transport and handling.
Trees are usually cut into smaller lengths on-site and then picked up by timber lorries to processing sites: sawmills, paper mills, pallet or fencing producers.
Stage Three – On-Site Processing
Logs are debarked & bucked or cut into required lengths. This is called conversion which is done in 2 stages:
Stage 1: Rough Sawing - breaking down process
Two types of rough sawing can be used in the breaking down process – through sawn and quarter sawn. The ends of each log are trimmed to ensure they are straight and cut into boards, removing the curved edges.
Stage 2: Re-sawing
This refers to a more precise cutting and finishing such as planing and further machining.
Stage Four – Seasoning
Seasoning is the process of removing excess water/moisture content. When a tree is felled it still contains a large proportion of moisture, usually between 40-50% water content.
Type of water in trees:
Free water – water that is held in the vessels and cells in order to distribute nutrients inside of the tree.
Cell water – also known as “bound” water, is an essential part of the tree’s cell walls.
During the seasoning process, a tree loses its free water and a high proportion of its cell water and as a result, is less likely to warp or deform.
Wood that has not been seasoned and still has a high water content is called “green”.
Green wood can be more difficult to work with because it has a tendency to change shape.
Stage Five – Preparing for Market
After turning trees into timber through sawmilling, the market value of timber can be further increased through manufacturing sawn timber products. This stage is called secondary processing:
Fencing
Furniture or doors
Treated for fire
Or rot resistance is added
Once this secondary processing is added, they are now ready for market.
