Trees to 72m; trunk to 2.5m diam., straight; crown broadly conic to rounded. Bark yellow- to red-brown, deeply irregularly furrowed, cross-checked into broadly rectangular, scaly plates. Branches descending to spreading-ascending; twigs stout (to 2cm thick), orange-brown, aging darker orange-brown, rough. Buds ovoid, to 2cm, fully 1cm broad, red-brown, very resinous; scale margins white-fringed. Leaves 2--5 per fascicle, spreading to erect, persisting (2--)4--6(--7) years, 7--25(--30)cm ´ (1--)1.2--2mm, slightly twisted, tufted at twig tips, pliant, deep yellow-green, all surfaces with evident stomatal lines, margins serrulate, apex abruptly to narrowly acute or acuminate; sheath 1.5--3cm, base persistent. Pollen cones ellipsoid-cylindric, 1.5--3.5cm, yellow or red. Seed cones maturing in 2 years, shedding seeds soon thereafter, leaving rosettes of scales on branchlets, solitary or rarely in pairs, spreading to reflexed, symmetric to slightly asymmetric, conic-ovoid before opening, broadly ovoid when open, 5--15cm, mostly reddish brown, sessile to nearly sessile, scales in steep spirals (as compared to Pinus jeffreyi ) of 5--7 per row as viewed from side, those of cones just prior to and after cone fall spreading and reflexed, thus well separate from adjacent scales; apophyses dull to lustrous, thickened and variously raised and transversely keeled; umbo central, usually pyramidal to truncated, rarely depressed, merely acute, or with a very short apiculus, or with a stout-based spur or prickle. Seeds ellipsoid-obovoid; body (3--)4--9mm, brown to yellow-brown, often mottled darker; wing 15--25mm.

Pinus ponderosa is the most economically important western yellow pine. Its wood is more similar in character to the white pines, and it is often referred to as white pine. The taxonomy of this complex is far from resolved.

Ponderosa pine ( Pinus ponderosa ) is the state tree of Montana.

Common Name: ponderosa pine

Duration: Perennial

Nativity: Native

Lifeform: Tree

General: Trees up to 30+ m tall, truck to 2.5 m in diameter, crown broadly conic to rounded; bark yellow to reddish brown, deeply and irregularly furrowed, broken into scaly plates; branches descending to spreading-ascending, orange brown and aging darker orange brown, rough.

Needles: Buds ovoid to 2 cm, 1 cm broad, red-brown, very resinous, scale margins white fringed; fascicled leaves with 2-5 per fascicle, usually 2; spreading to erect, persisting 4-6 years, 7 -25 cm long, 1.2-2 mm across, slightly twisted, deep yellow-green, all surfaces with evident stomatal lines, serrulate margins, with an abrupt or acute apex.

Cones: Pollen cones ellipsoid-cylindric, 1.5-3.5 cm, yellow or red; seed cones mature in 2 years, solitary or in pairs, spreading to reflexed, generally symmetric, conic-ovoid before opening, broadly ovoid when open, 5-15 cm, reddish brown; scales in steep spirals of 5-7 per row.

Seeds: Ellipsoid obovoid, body 4-9 mm, brown to yellow-brown, often mottled darker, with wing 15-25 mm.

Ecology: Found on open, generally drier slopes throughout the mountains from 5,000-9,000 ft ( 1524-2743 m).

Notes: Two varieties in the region: var. scopulorum and var. arizonica. Var. scopulorum is delineated by only having 2-3 leaves per fascicle, while var. arizonica has 3-5 leaves per fascicle. Both varieties are sympatric, but the latter is by far the more uncommon of the two. Some botanists call into question the conflation. The most recent phylogenetic studies of Gernandt et al. 2009 separates the species out entirely, leaving P. scopulorum as the ponderosa across much of the southwest and P. arizonica across southeastern Arizona and into northern Mexico.

Ethnobotany: Inner bark and seeds were used as a famine food, the wood and timbers were widely used for construction, the needles and sap were used as an emetic, the pitch is used on cuts and sores, and the needles were used for basketry.

Etymology: Pinus is the ancient Latin name for pines, while ponderosa means ponderous, referring to its heavy wood.

Synonyms: Depending on which variety, there are a few. Refer to Tropicos for further clarification.

Editor: SBuckley, 2010