1. Wood Structure
Hardwood
Softwood

2. Variability in wood products
Solid wood
frequency
strength

3. Variability in wood products
mean
lower 5th percentile
Solid wood
÷ safety factors
frequency
allowable design stress
strength

4. Variability in wood products
mean
mean
lower 5th percentile
÷ safety factors
Solid wood
lower 5th percentile
Wood composite A
frequency
÷ safety factors
strength
allowable design stress
allowable design stress

5. Anisotropy
(St. Regis Paper Co.)
(Indospectrum.com)
(Côté)

6. Anisotropy
Parallel to grain
Perpendicular to grain

7. Wood sections/surfaces/planes
Longitudinal section
Transverse section T T R R R R T T L L L
T = tangential R = radial L = longitudinal

8. Anisotropy – perpendicular to grain
Radial
Tangential

9. Hygroscopicity
Hydrogen
Bond  H  O  H H   O H
Water 

10. Hygroscopicity
Hydrogen
Bond  H
Wood O   H  O H 

11. Water in cell wall O H O H

12. Water in wood Free water Bound water Cell wall Cell lumen
Oven dry > Fibre saturation point 0% m.c – 30% m.c > 30% m.c.

13. Effect of moisture content on wood properties
Fibre Saturation Point

14. Comparative Environmental Impact Assessment Life Cycle Analysis
Canadian Wood Council

15. Comparative Environmental Impact Assessment
Canadian Wood Council