Cleaning (forestry)

Cleaning and weeding are two similar terms referring to the practice of selecting particularly desirable trees in a young stand and removing or killing trees that threaten their survival or development.

Colloquially, these treatments are often referred to as crop tree release when they are practiced in sapling sized stands.

Cleaning is common in softwood plantations, clearcuts, and overstory removals, where the desired conifers are overtopped by rapidly growing early-successional hardwood species. Herbicides are often used in these cleaning operations because the correct chemical at the correct dose (e.g. glyphosate or triclopyr) and time will kill only broadleaved species, leaving the conifers unharmed and free to grow. Chemical treatments may be applied by foliage sprays, mists or pellets. This can be from a vehicle or by aerial spraying. Where chemicals are impractical or unpalatable to the landowner, a brush cutter is used to cut competing trees close to the ground.

Other methods of cleaning include mowing with brush hogs attached to a tractor.

Foresters will often conduct these treatments as early as possible, but not so early that new growth of hardwoods can overtake the planted seedlings again. Their goal is to maintain the health and vigor of tree species that are preferred for some use, often structural material.

Liberation cutting is similar to cleaning, with the exception that the competing trees are much older than the desired trees.

Cleaning is often done at a later stage, to allocate growing space to selected individuals that have demonstrated superior quality. This usually means a straight trunk that will make a good sawlog, or perhaps a healthy crown on a mast-producing tree. In any case, desirable qualities have been identified in each particular tree, and competing trees are removed to promote the desired trees.

...
Wikipedia