Pinus occidentalis, or Hispaniolan pine, is a pine endemic to the island of Hispaniola, where it is the predominant species in the Hispaniolan pine forests of Haiti and the Dominican Republic. Hispaniolan pines are found mixed with broadleaf trees from 850 to 2,100 m (2,790 to 6,890 ft), and occur in pure stands above 2,100 m (6,900 ft) up to the 3,087 m (10,128 ft) summit of Pico Duarte, the highest point on the island. They are sometimes found in the lowland Hispaniolan moist forests ecoregion, in areas where poor acidic laterite soils predominate.
It is a medium-sized tree, growing to 20 to 30 m (66 to 98 ft) tall with an open crown. The leaves are dark green, needle-like, in fascicles of 3, 4, 5, 11–20 cm (4.3–7.9 in) long and 0.9–1.3 mm (0.035–0.051 in) thick. The cones are 5–8 cm (2.0–3.1 in) long, glossy brown, with a small prickle on each scale pointing forward; they mature in about 18 months and open to release the seeds, which are 4–5 mm (0.16–0.20 in) long with a 15 mm (0.59 in) wing.
Symbiotic relationships with ectomycorrhizal fungi enable Hispaniolan pines to grow on shallow, infertile soils.