A

Air Dried

Lumber that has been dried naturally in the open air, as opposed to kiln-dried lumber.

Alaska Yellow Cedar (AYC)

A premium species of cedar (Chamaecyparis nootkatensis) known for exceptional durability and natural resistance to decay and insects.

Annual Rings

The yearly growth layers visible in a cross-section of a tree trunk, which affect the grain pattern in lumber.

B

Board Foot (BF)

A unit of measurement for lumber volume, equal to a piece 1 inch thick, 12 inches wide, and 12 inches long.

Bow

A warp along the length of a board where the ends curve away from a straight line.

Burl

A large, irregular growth on a tree trunk that creates highly figured wood grain patterns.

C

Cambium

The growing layer of a tree between the bark and the wood, responsible for tree growth.

Checking

Small splits or cracks that develop in lumber as it dries, usually running along the grain.

Clear Grade

The highest grade of lumber with minimal defects, knots, or other imperfections.

Common Grade

Lower grade lumber containing more natural characteristics like knots, suitable for utility applications.

Crook

A warp along the edge of a board where it curves away from a straight line.

Cup

A warp across the width of a board where the edges curl up or down.

Custom Milling

The process of cutting lumber to specific dimensions or profiles according to customer requirements.

D

Decay Resistance

A wood species' natural ability to resist fungal decay and rot.

Dimensional Lumber

Lumber cut to standardized sizes, typically used for framing (2x4, 2x6, etc.).

Douglas Fir

A strong, versatile softwood species commonly used for structural applications and framing.

Durability Class

A rating system (1-5) that indicates a wood species' natural resistance to decay, with Class 1 being most durable.

F

Figure

The distinctive grain pattern or markings in wood that affect its appearance.

Finger Joint

A woodworking joint made by cutting interlocking rectangular cuts in two pieces of wood.

Flat Sawn

A sawing method where boards are cut parallel to the tree's growth rings, producing a cathedral grain pattern.

G

Grade

A classification system for lumber quality based on strength, appearance, and defects.

Grain

The direction, size, arrangement, and appearance of wood fibers in lumber.

Green Lumber

Freshly cut lumber with high moisture content that has not been dried.

H

Hardwood

Lumber from deciduous trees (trees that lose their leaves seasonally), generally denser than softwood.

Heartwood

The mature, inner wood of a tree that no longer conducts water, often darker and more durable than sapwood.

Heavy Timber

Large dimensional lumber typically 5 inches or larger in any dimension, used for structural applications.

I

Insect Resistance

A wood species' natural ability to repel or resist damage from wood-boring insects.

K

Kiln Dried (KD)

Lumber that has been dried in a controlled oven environment to reduce moisture content to 19% or less.

Knot

A natural characteristic in lumber where a branch was attached to the tree trunk.

L

Linear Foot

A measurement of length, used for pricing lumber products like trim and molding.

Live Edge

Lumber that retains the natural, uncut edge of the tree, including bark and natural curves.

Lumber Grade

A standardized classification system that rates lumber quality based on appearance, strength, and intended use.

M

Mill

A facility where logs are processed and cut into lumber products.

Moisture Content (MC)

The amount of water in wood, expressed as a percentage of the wood's dry weight.

Modulus of Elasticity

A measure of wood's stiffness or resistance to bending under load.

O

Old Growth

Timber from mature forests, typically producing lumber with tighter grain and greater stability.

Overstock

Surplus lumber inventory offered at discounted prices due to production overruns or order changes.

P

Planed

Lumber that has been smoothed on one or more surfaces using a planing machine.

Pressure Treated (PT)

Lumber that has been chemically treated under pressure to resist decay, insects, and moisture.

PSI

Pounds per square inch, a unit of measurement for wood strength properties.

Q

Quarter Sawn

A sawing method where boards are cut perpendicular to the growth rings, producing straight grain and greater stability.

R

Reclaimed Lumber

Previously used lumber that has been salvaged and repurposed for new construction or projects.

Rough Sawn

Lumber cut to approximate dimensions but not planed smooth, retaining saw marks on all surfaces.

S

Sapwood

The younger, outer wood of a tree that conducts water, typically lighter in color than heartwood.

Seasoning

The process of drying lumber to reduce moisture content and prevent warping or splitting.

Select Grade

High-quality lumber with minimal defects, suitable for finish work and visible applications.

Softwood

Lumber from coniferous trees (evergreens), including species like Douglas Fir, Cedar, and Pine.

Sticker

Thin strips of wood used to separate layers of lumber during the drying process, allowing air circulation.

Structural Grade

Lumber graded for strength properties and suitable for load-bearing applications in construction.

T

Timber

Large pieces of wood used for construction, typically referring to heavy structural lumber.

Twist

A warp in lumber where one corner of a board is not in the same plane as the other three corners.

W

Wane

The presence of bark or lack of wood on the edge or corner of a piece of lumber.

Warp

Any distortion in lumber from its intended flat, straight form, including bow, crook, cup, and twist.

Western Red Cedar

A naturally durable softwood species known for its resistance to decay and distinctive reddish-brown color.

Wood Grain

The pattern of wood fibers and growth rings visible on the surface of lumber.