How to Identify Southern Yellow Pine (Loblolly/Longleaf) Wood (Pinus taeda / Pinus palustris)

Heartwood reddish brown; sapwood yellowish white (both loblolly and longleaf). Straight grained with a fine to medium texture. End grain: Large, evenly distributed resin canals with an abrupt earlywood-to-latewood transition and notable color contrast (loblolly); longleaf shows large, numerous, mostly solitary resin canals as well.

Janka hardness 690 lbf (side hardness: the force needed to embed a 0.444-inch steel ball to half its diameter). Specific gravity 0.51 at 12% moisture content, so a cubic foot weighs roughly 32 lb. Weight in the hand is one of the quickest checks: compare a piece of known size against a board you already know.

Southern yellow pines (loblolly, longleaf, shortleaf, slash) belong to the hard/yellow pine group and are notably denser and harder (690-870 lbf) with an abrupt earlywood-latewood color transition, versus white/ponderosa pines' lower density (380-460 lbf) and more gradual transition. The Eastern White Pine page has its own details.

Loblolly has no characteristic odor; longleaf has a distinct smell shared among most Pinus species; resin can gum up tools and clog sandpaper in longleaf.

Construction (stringers, roof trusses, poles, joists, piles) and interior uses like subflooring and sheathing; exterior use typically requires pressure-treatment.

Works fairly well with most tools and glues/finishes well; resin can gum up tools and clog sandpaper (especially longleaf); pine reported to cause allergic skin reactions and/or asthma-like symptoms in some people.

Photograph a freshly cut or sanded face in daylight, not a finished or stained surface, since stain hides color and finish flattens grain. Add a close-up of the end grain: cut a clean end, wet it or sand it to 220, and shoot from straight on; pore pattern and rays are the most reliable marks. Put a ruler in frame. The app suggests the likely species; confirm with the end grain and weight.