Decide what density of crop trees to retain. Calculate the proportion of trees to be culled. Fell unusable thinnings into every second row, to maintain access. Simple, low cost techniques are available for preserving posts and seasoning timber on the farm. If thinnings have no commercial value, they can be left on the ground to rot, pushed into heaps for burning or chipped for use as mulch.
Large knots reduce the value of timber.
The highest value wood has no knots and is known as clearwood . Knots form as the trunk grows outward, enveloping the base of the branches. If branches are removed, the trunk grows over the branch stubs, and then all further new wood is free of knots. This results in small branches, small knots, and high quality wood. The control of branch size is one factor to consider when deciding how heavily to thin a stand of trees.