In the early years, all wood is juvenile because trees are open grown. Commercial thinnings or late pre-commercial thinnings have less impact on wood quality because crowns usually have lifted . Tree quality is defined by characteristics such as log diameters, branch diameter and distribution, stem taper and straightness. For example, large tree and log size lowers logging and hauling costs and more lumber is recovered per cubic metre. However, increasing branch diameter for a given log diameter adversely affects structural lumber grade recovery.
Silviculture decisions can strongly affect the characteristics defining tree quality.
Managing for low stocking density through initial spacing or subsequent thinning operations may increase average piece size. For example, the mean DBH of the prime trees shown in Figure 12c is about 8 cm larger for the very wide as compared to narrow spacing. However, the resulting increase in crown length, particularly in the early years, will produce larger diameter branches and increase both bole taper and the proportion of juvenile wood. Stand density management decisions affect various links in the value recovery chain, including both tree and wood quality, harvesting and milling costs, product value and financial return. The optimal combination of stocking density and harvest age for each species varies widely with end products produced.