Wood

WOOD

As a natural material, wood is very different from what we have seen so far. For one, wood is not an even material, but a natural composite material made by trees and other woody plants. It has inconsistencies, grain, as well as softer and harder parts, which depending on the application, we should take into consideration.

Source

Most commercial wood comes from trees—either hardwoods (angiosperms, like oak, maple) or softwoods (gymnosperms, like pine, cedar).

Anatomy and Structure

Cellular Structure: Wood’s strength and properties come from its microscopic structure, which are mainly long, tubular cells which run parallel to the tree trunk.
Growth Rings: These are the visible rings you see when you look at a tree stump. Each ring represents a year of growth—springwood (lighter, less dense) and summerwood (darker, denser).
Grain: The pattern you see is caused by the orientation of the wood fibers. Grain affects strength, how wood splits, and its appearance.

Sapwood is the tree's active, water-transporting, and lighter-colored outer layer, while heartwood is the non-living, central, darker, and more durable core that provides structural support.

Types of Wood

Hardwoods: (e.g., oak, maple, mahogany)
- Generally denser, more complex grain.
- Used for furniture, flooring, and carving.
Softwoods: (e.g., pine, cedar, fir)
- Usually less dense, simpler structure.
- Used in construction, paper, and some carvings.

Key Properties

Strength & Stiffness: Varies widely. Wood is strongest along the grain, weaker across it.
Workability: How easy it is to cut, carve, or shape. Some woods are “buttery” (like basswood, which we will be working on), others splinter or resist (like oak).
Density: Affects weight and strength. Denser woods are usually harder and stronger but tougher to carve.
Moisture Content: Wood absorbs and loses water, causing expansion and contraction (warping, cracking).
Durability: Resistance to decay, insects, and weather. Some woods (like teak) are naturally resistant; others need treatment.
Aesthetic Qualities: Color, figure (patterns), and grain.

Composition

Wood is composed primarily of cellulose fibers (which give it strength) embedded in a matrix of lignin (which resists compression and makes them rigid and "woody").

Why Wood can be Great... and Terrible

Sustainable (with responsible forestry).
Biodegradable.
Vastly Variable: No two pieces are the same—variation in color, grain, knots, even “defects” can be beautiful or problematic.
Used for millennia: Tools, art, construction, technology.

Wood for Carpentry

Softwoods (e.g., pine, spruce, fir):

Used for framing, structural components, and general construction.
Affordable, easy to work with, widely available.
Grows quickly—often from sustainable sources.

Hardwoods (e.g., oak, maple, cherry, walnut):

Used for finish work—floors, cabinetry, furniture, decorative trim.
More durable, attractive grain, harder to work, usually more expensive.

Here is an awesome video on woods and where to use them.

Engineered Woods (these are made by people!)

Plywood: Thin wood veneers glued in layers. Strong, stable, resists warping.
MDF (Medium-Density Fiberboard): Wood fibers + resin, very smooth, great for painted finishes, not strong for structure.
OSB (Oriented Strand Board): Big wood flakes compressed with glue. Strong, cheap, mostly used for subfloors/walls.
Laminated Veneer Lumber (LVL): Layers of wood veneer for beams—super strong.

Best for Carving

Best Woods: Basswood, butternut, and tupelo (for beginners); cherry, walnut, and mahogany (for more experienced carvers).
Choosing Wood: Look for straight, tight grain and minimal knots. Moisture content matters—too wet, it’s gummy; too dry, it’s brittle.
Tools & Safety: Sharp blades are safer; cut with the grain; respect wood movement.

8 Basic Cuts

Wood in Science for Citizens

Let's watch the movie below and see how citizen science (and effort) can change a community: