Within determined limits of thinning, where only small and temporary canopy gaps are created, total production per ha should not deviate significantly from the carrying capacity of the site. If thinning is practiced late, the stand is affected by stagnation, with the loss of growth potential. If, on the other hand, the stand is thinned too early or too strongly, the trees tend to produce more side branches and epicormic shoots. This also implies a loss of growth potential, since the purpose is to produce as much timber in the main stem as possible, preferably free of knots and defects. Epicormic shoots may also be related to the genetic imprint of the seeds.
Erosion is a further threat when thinning is too strong.
Often the age at which the first thinning is practiced is determined by the dominant height , which in turn is determined by site quality. Dominant height is the average height of the 100 largest diameter trees per hectare. It may also be estimated from the average height of the five largest diameter trees in permanent sample plots, when these are of 0.05 hectares in size. As a general rule, teak should be planted only on the best site classes, with the first thinning taking place when the dominant height reaches 9 to 9.5 meters, and the second when the dominant height reaches 17 to 18 meters. The basal area of a stand is the average cross-sectional area of all trees per unit of stand surface, normally measured at breast height.