Hardwood Softwood Species

Overview

Engineering reference data for Hardwood Softwood Species in material science and properties.

Key Formulas

Stress

$\sigma = \frac{F}{A}$

Force per unit area.

Strain

$\varepsilon = \frac{\Delta L}{L_0}$

Change in length per original length.

Hooke's Law

$\sigma = E \varepsilon$

Stress proportional to strain in elastic region.

Thermal Expansion

$\Delta L = \alpha L_0 \Delta T$

Length change due to temperature.

Variables

Symbol	Description	Unit
$\sigma$	Stress	Pa
$\varepsilon$	Strain	—
$E$	Young's modulus	Pa
$\alpha$	Thermal expansion coefficient	1/°C
$\Delta T$	Temperature change	°C

Wood Classification

Woods are classified into two primary categories based on their botanical origin:

• Hardwood — Wood from angiosperms (flowering plants), typically deciduous trees with broad leaves
• Softwood — Wood from gymnosperms (mostly conifers), typically evergreen trees with needles

Note: The terms "hardwood" and "softwood" refer to botanical classification, not actual wood hardness. Some softwoods (e.g., yew) are harder than some hardwoods (e.g., balsa).

Common Hardwood Species

Common Name	Scientific Name
Alder, red	Alnus rubra
Ash, white	Fraxinus americana
Basswood, American	Tilia americana
Beech, American	Fagus grandifolia
Birch, yellow	Alleghaniensis
Cherry, black	Prunus serotina
Cottonwood	Populus deltoides
Hickory (various)	Carya spp.
Maple, sugar	Acer saccharum
Oak, white	Quercus alba
Oak, northern red	Quercus rubra
Walnut, black	Juglans nigra

Common Softwood Species

Common Name	Scientific Name
Cedar, western red	Thuja plicata
Douglas-fir	Pseudotsuga menziesii
Fir, white	Abies concolor
Hemlock, western	Tsuga heterophylla
Pine, ponderosa	Pinus ponderosa
Pine, sugar	Pinus lambertiana
Redwood	Sequoia sempervirens
Spruce, Sitka	Picea sitchensis

Species Count Summary

• Hardwoods: ~30+ common North American species listed
• Softwoods: ~30+ common North American species listed

References

• Original Source