Describe the directional dependence of shrinkage in wood and how does this affect the shrinkage of a quarter sawn and plainsawn board? Solution Hello, Wood is hygroscopic it losses and sometimes gains moisture from the surrounding environment. It shrinks longitudinally, Tangentially and Radially and we can observe its shrinkage throughout volume. and while coming to wood it comes in basically plainsawn, quartersawn depending on the way the lumber cuts. It only depends on the angle of cutting based on rings in a log. simply if a log is cutted parllel to its rings its plainsawn and if cutted perperdicular is quarter sawn. Let us observe its shrinkage directionally. let me illustrate with an example and there is a well known illustration as 0-1-2 rule in action of each panel of wood. The proportions of shrinkage in low humid and high humid environment is same proportions as they do. let us consider its fractions accross width . Flatsawn lumber shrinkage is 2 over 1 and we can equalize as 2/1 which is 2 simply. And where as in Quartersawn lumber shrinks1 over 2 it means 1/2 which is 0.5 fraction. Now comparing them Plainsawn lumber shrinks 4 times the Quartersawn lumber. so quartersawn lumber is considerd to be more stable for shrinkage..

1. Describe the directional dependence of shrinkage in wood and how does this affect the
shrinkage of a quarter sawn and plainsawn board?
Solution
Hello,
Wood is hygroscopic it losses and sometimes gains moisture from the surrounding environment.
It shrinks longitudinally, Tangentially and Radially and we can observe its shrinkage throughout
volume.
and while coming to wood it comes in basically plainsawn, quartersawn depending on the way
the lumber cuts.
It only depends on the angle of cutting based on rings in a log.
simply if a log is cutted parllel to its rings its plainsawn and if cutted perperdicular is quarter
sawn.
Let us observe its shrinkage directionally. let me illustrate with an example and there is a well
known illustration as 0-1-2 rule in action of each panel of wood. The proportions of shrinkage in
low humid and high humid environment is same proportions as they do.
let us consider its fractions accross width .
Flatsawn lumber shrinkage is 2 over 1 and we can equalize as 2/1 which is 2 simply. And where
as in Quartersawn lumber shrinks1 over 2 it means 1/2 which is 0.5 fraction.
Now comparing them Plainsawn lumber shrinks 4 times the Quartersawn lumber. so quartersawn
lumber is considerd to be more stable for shrinkage.