Ponderosa Pine

Ponderosa Pine (Pinus ponderosa), sometimes called Bull Pine or Western Yellow Pine, is a widespread and variable pine native to western North America. It was first described by David Douglas in 1826, from eastern Washington near present-day Spokane.

Modern forestry research identifies four different taxa of Ponderosa Pine, with differing botanical characters and adapted to different climatic conditions. These have been termed "geographic races" in forestry literature, while some botanists historically treated them as distinct species. In modern botanical usage, they best match the rank of subspecies, but not all of the relevant botanical combinations have been formally published.

The bark of the Ponderosa Pine has a smell similar to vanilla. The Ponderosa Pine has a very distinct bark. Unlike most conifers, it has an orange bark, with black lining the crevasses, where the bark "splits". This is very noticeable amongst the older Ponderosa Pines that live along the west coast of Canada. Its needles are the only known food of the caterpillars of the gelechiid moth Chionodes retiniella.

The National Register of Big Trees lists a number of large Ponderosa Pines up to 227 feet tall. and 294 inches in girth.

Subspecies

 * 1) Pinus ponderosa subsp. ponderosa Douglas ex C. Lawson - North Plateau Ponderosa Pine.
 * 2) *Range & climate: southeast British Columbia, Washington and Oregon east of the Cascade Range, northeast California, Arizona, northwestern Nevada, Idaho and western Montana. Cool, relatively moist summers; very cold, snowy winters (except in the very hot and very dry summers of central Oregon, most notably near Bend, which also has very cold and generally dry winters).
 * 3) Pinus ponderosa subsp. scopulorum (Engelm.) E. Murray - Rocky Mountains Ponderosa Pine.
 * 4) *Range & climate: eastern Montana, North Dakota, South Dakota, Wyoming, Nebraska, northern and central Colorado and Utah, and eastern Nevada. Warm, relatively dry summers; very cold, fairly dry winters.
 * 5) Pinus brachyptera Engelm. - Southwestern Ponderosa Pine
 * 6) *Range & climate: southern Colorado, southern Utah, northern and central New Mexico and Arizona, and westernmost Texas. The Gila Wilderness contains one of the world's largest and healthiest forests. Hot, relatively moist summers; mild winters.
 * 7) Pinus benthamiana Hartw. - Pacific Ponderosa Pine
 * 8) *Range & climate: Washington and Oregon west of the Cascade Range, California except for the northeast, and just into westernmost Nevada. Hot, dry summers; mild wet winters.

The distributions of the subspecies, and that of the closely related Arizona Pine (Pinus arizonica) are shown on the map. The numbers on the map correspond to the taxon numbers above and in the table below. The base map of the species range is from Critchfield & Little, Geographic Distribution of the Pines of the World, USDA Forest Service Miscellaneous Publication 991 (1966).

Before the distinctions between the North Plateau race and the Pacific race were fully documented, most botanists assumed that Ponderosa Pines in both areas were the same. So when two botanists from California found a distinct tree in western Nevada in 1948 with some marked differences from the Ponderosa Pine they were familiar with in California, they described it as a new species, Washoe Pine, Pinus washoensis. However, subsequent research has shown that this is merely a southern outlier of the typical North Plateau race of Ponderosa Pine.

Table of characters distinguishing the subspecies of Pinus ponderosa and Pinus arizonica
Notes: Taxon numbers refer to the map Needles per fascicle - the most frequent number is in bold Seedwing : seed length ratio - high numbers indicate a small seed with a long wing; low numbers a large seed with a short seedwing