n. Thinning that removes trees of the dominant and codominant crown classes in order to favor the best trees of those crown classes (Helms 1998).
The term “high thinning ” is synonymous with the preferred term crown thinning. An important component of crown thinning is that the best, most vigorous dominant and codominant trees are retained, while the least vigorous of those crown classes are removed. Few suppressed and intermediate trees are removed in a crown thinning according to the theory that they do not compete with the best dominant and codominant trees.
Crown thinning or low thinning that does not remove non-marketable trees are stand manipulations that serve similar purposes: both result in a "thinning from the middle."