1. WOOD SCIENCE

2. Parts of a Tree
Pith
Heartwood
Sapwood
Cambium
Bark

3. Lumber Surfaces

4. Growth Rings One complete growth ring equals one year of growth.
One growth ring is made up of earlywood (spingwood) and latewood (summerwood).
Earlywood is the part of a growth ring that is soft and light in color.
Latewood is the part of a growth ring that is hard and dark in color.

5. Lumber Sawing Plain Sawed Quarter Sawed
Boards are cut tangent to the annual rings.
Yields wider boards.
Most common.
Quarter Sawed
Yields narrower boards.
Has the most figured lumber.

7. Hardwoods and Softwoods
Hardwoods are broad leaf trees and are known as deciduous.
Hardwoods.
Oak
Maple
Walnut
Cherry
Mahogany
Ash
Birch
Softwoods are needle and cone-bearing trees and are known as coniferous.
Softwoods.
Pine
Spruce
Fir
Cedar
Redwood

8. Softwoods Samples

9. More Softwoods Samples

10. More… Softwoods Samples

11. Hardwood Samples

12. More Hardwood Samples

13. More… Hardwood Samples

14. Exotic Hardwoods

15. More Exotic Hardwoods

16. More… Exotic Hardwoods

17. Expansion vs Contraction
Moisture causes wood to expand or swell.
Dryness causes wood to contract or shrink.
Repeated exposure to dry and moist conditions causes defects, such as, warping, splitting, checking, and winding.
Climate conditions must be considered when designing a project.
Most lumber today has been kiln dried. This lumber has been placed in a lumber kiln and specially, treated with steam, heat, and air, to greatly, reduce the drying time and the amount of defective material.

19. Lumber Grading Hardwoods are graded by their poorest face.
This insures that both faces of the lumber are of furniture quality.
Softwoods are graded by their best face.
Hardwoods are usually, selected for a project due to their excellent visual qualities and their ability to withstand wear.
Softwoods are chosen usually, for heavy construction projects because they have very good structural qualities.

20. Common Woodworking Abbreviations
KD = kiln dried
AD = air dried
Clear = free of knots and defects
Highest grade lumber. Used by mills to make trim.
FAS = first and seconds
High grade lumber used for cabinet and furniture making
Sel+Btr = select & better
Not found often. Grade slightly below FAS.
#1 com = #1 common
Lower grade of lumber, but if ordered in quantity there is a lot of useable stock.
#2 com = #2 common
Grade below #2 COM.
SHOP = shop grade
Lowest grade of lumber. Can be graded low because length is too short, which means the lumber could be high quality.
RWL = random widths and lengths
S2S = surfaced on 2 sides
S4S = surfaced on 4 sides
RGH = rough