Ponderosas are a species of pine tree found all over the mountains of the western US. They are tall, straight trees which are very valued as timber. They begin as conical-shaped trees but the tops get flattened out with age. Ponderosa pines have bark which smells like vanilla. These pines have evolved with fire and generally are fire resistant. the type of small fire which was once common in ponderosa forests burned off excess duff, returned nutrients to the soil, and removed competitors from the forest. However in the days of fire supression, dead wood has built up and there is the danger of crown fires which will destroy whole forests.

The Ponderosa Pine is a common tree in the Western United States. They prefer somewhat dry conditions and are found at moderate elevations throughout the Rocky Mountains, the Sierra Nevada Range, and the Cascade Mountains. They are usually found at elevations bellow the local spruce species (often Colorado Spruce in the central Rockies) and above the even drier elevations covered in juniper trees and piñon pines. Though, of course, these trees can be found intermixed in some locations.

Growing together they tend to form open sunny forests with wide spaces between the trees. Walking through one it may seem more like a park than a wild forest since the ground will be covered with grass and the lack of undergrowth or low branches that can make forests in the Eastern US so hard to penetrate.

A coexistence with fire is what causes this appearance, under wild conditions frequent ground fires sweep the forests floor of the pine needles that would otherwise smother small plants. The ponderosa pines resist these small fires with a thick bark made of interlocking pieces often described as puzzle like. They have also evolved to quickly loose lower branches as they grow so that it is unusual for a ponderosa to have a first branch lower than 3 meters.

They start out growing looking like a single pine branch stuck in the ground sprouted from a seed about the size of a BB (3 millimeters). As they get to about 10-15 cm they often grow a few side branches that later die off as the tree gets progressively taller and larger branches supercede them.

The dark green needles of the ponderosa are bundled in 3's most often, and if the associated needles are held together they form a round tube shape 10-15 cm long and about the width of a pencil lead. These small bunches stay on the tree for up to 4 years forming a needle covered section at the end of the finger width branches.

The trees can get up to 40 meters tall, but more often they reach a maximum height of 20 meters. The trees have the typical pine narrow cone shape when young and form a flattened out crown when mature. Some unusual trees reach ages over 300 years, but I know of none that has exceeded 500. As the tree grows it also begins to bear both male and female flowers. The male one release huge amounts of yellow pollen on warm late spring days. Over the next two years the fertilized female flowers develop into cone about the size of a baseball bearing many of the small seeds with a papery ‘wing’.

The wood of the ponderosa is straight, but filled with knots from dead branches lower on the tree, and so they are not often used for building anything but fences, barns, and other outdoor structures. They were used quite extensively in the building of early settlements of the Old West, giving them the stereotypical rough hewn look. They are very good as fire wood, as they are filled with pitch and are easy to ignite. Another interesting fact is they smell faintly like vanilla, especially on hot days in the summer.

I was first taught to identify Pinus ponderosa by looking at the needle bundles: 3 needles. You can bend the bundle to form a 'Y.' Y is for yellow, as in yellow pine. Only trouble was, I found out later, that the Jeffrey Pine (Pinus jeffreyi) also has 3 needle bundles, and goes by the common name of "yellow pine" as well. (In the Sierra Nevada, the two species can hybridize so it is difficult to tell the two apart. Guide books noting that Ponderosa bark is orange brown while Jeffrey pine is reddish brown aren't so helpful) A botanist taught us a miltary style call and response that proved more useful in identification:
Ponderosa Pine has puzzle piece bark!
(Ponderosa Pine has puzzle piece bark!)
Pine cones are prickly and they're sharp!
(Pine cones are prickly and they're sharp!)
My students dutifully repeated the chant, but it didn't help them in identification, until I held up a pine cone, turned to one student, and said "Here, catch this," as I tossed it to him.

As soon as it hit his hands he instinctively let the cone drop. The spines that curl outward from the cone make catching it very unpleasant.

Seeds are small (7,000 to 23,000 in one pound) and are eaten by insects, mice, birds, chipmunks. Native peoples would use the inner bark as food and its resin as a medicinal salve for rheumatism, backaches, and dandruff.

Sources: Lawrence Hall of Science Summer Science Camp; University of California Cooperative Extension

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