C6 - Wood Quality

wood quality

a measure of the aptness of wood for a given use. defined by the requirements of the user.

how do management goals depend on wood quality,

different measures relate to different wood qualities

log size: influence and effect

controls options, larger diameter, more planks

log form: influence and effect

volume recovery, slope of grain effect

knots: influence and effect

size, angle, affects structural performance

wood density: influence and effect

used as a predictor of strength, hardness, and stiffness. uniformity of density is IMPORTANT

grain angle: influence and effect

lose much strength if grain angle is not parallel to the force, anisotropy

microfibril angle: influence and effect

stronger in direction of MfA. Shrinks perpendicular to MfA

fiber(cell) length: influence and effect

clothing, bamboo, wood. used with pulping. difference in pulp creates differences in paper quality

reaction wood: influence and effect

affects appearance, shrinkage, machinability

sapwood proportion: influence and effect

drying, treating, decay resistance, gluability

one silvicultural way to control: log size

tree spacing, initial thinning, pruning, rotation age

one silvicultural way to control: knots

manage only for butt log.

one silvicultural way to control: wood density

rotation age and selection breeding

one silvicultural way to control: microfibril angle

species choice, breeding programs, silviculture has a large effect on rotation age

factors that explain rotation age has a such a large effect on how many wood properties

• wood grows upward and outward in shells

• once the vascular cambium makes wood, wood cannot change

• qualitatively different wood is made as the cambium becomes older

• outer wood % increases with rotation age