Spacing & Thinning

Spacing and juvenile thinning is typically performed on stands with developing trees, using brush saws for stems of up to 4-5 inches in size, and using chain saws for larger wood. Spacing usually doesn't happen until a stand has had several years to start to establish itself properly, once the crop trees are firmly established above the heights of any competing brush. One advantage of Spacing and Thinning compared to some other types of silviculture-related employment is that they can be done throughout most months of the year, save for during very thick snow cover.

During a spacing program, the workers will make assessments as they work through the stand, determining which trees have the most potential for future growth. Several factors are taken into consideration here: preferred vs acceptable species, the height and diameter of trees, proximity to other good crop trees, form, vigour, any evidence of potential disease, etc. Once the worker has determined which are the best trees to keep, depending on the previously mentioned considerations and on density requirements for the stand, all other competing trees will be cut and left on the ground to decompose. This process allows for more space and sunlight for the remaining good trees in the stand, so they will grow faster than they would have before the weaker competition was eliminated.

There is another type of thinning, commercial thinning (described further down this page) in which any cut trees are harvested, but that type of work usually happens in older stands. Spacing and juvenile thinning is appropriate in stands with a variety of ages ranging from perhaps five to twenty years after planting.

Although uncommon, sometimes instead of using brush saws to cut out the unwanted trees, a process called girdling is employed. Girdling happens when workers use curved knives or machetes to strip the bark from a ring around an unwanted tree, and several months later, the tree dies from lack of nutrients. This procedure is employed to kill deciduous species that compete with conifers, typically alder or aspen. The cambium layer (the bark) is completely removed in a thin strip all around the trunk of the tree, denying the tree the ability to feed and so killing it. Girdling is used when falling the tree would create too much damage to existing young conifers. It is also considerably more cost effective. Cutting the tree down would also just encourage growth of new shoots. Special girdling tools are also used sometimes.