Glossary
Swelling and Shrinkage
The timber volume changes when it absorbs or emits moisture. It shrinks when losing moisture from the cell walls and swells when gaining moisture.
With regard to the shrinkage characteristics, wood shrinks most in the direction of the annual growth rings (tangentially), about half as much across the rings (radially), and only slightly along the grain (longitudinally):
| Max. Shrinkage in % | |||
| Wood Species | tangentially | radially | longitudinally |
| Spruce | 0,33 | 0,16 | 0,01 |
| Pine | 0,29 | 0,17 | 0,01 |
| Oak | 0,35 | 0,20 | 0,01 |
| Beech | 0,45 | 0,22 | 0,013 |
