Return to Native Trees of the Southern Rocky Mountains

Limber pines have a way of growing in dramatic places, taking picturesque attitudes, and getting themselves photographed, written about, and cared for, even becoming the core of a legend. This Pine so constantly occurs in the historically significant passes of the Rockies that it was destined to link up with human history. Donald Culross Peattie

This pine is best known as a tree of high, cold, windy ridges. Limber pine can grow on high forest sites that are too rugged, dry and windy for most other trees. It is typical of summits with coarse dry thin soil, rocky hills and ridges, and other exposed and windy sites, especially above 9000 feet. Limber pine forms permanent groves where conditions are too severe for other species. It is also found in sheltered canyons, even among Lodgepole and Ponderosa, and it is found at elevations as low as the Pawnee Buttes on the plains northeast of Fort Collins, below 5000 feet elevation. It grows in the Black Hills.

Limber pine commonly has the same bushy form and branching trunks as the Bristlecone pine with whom it is often found, but Limber pine is much more abundant and reaches a larger size, commonly 20 to 50 feet tall.The upper crown may be wide-spreading,in outline exactly the opposite from the shape of neighboring Subalpine firs and Engelmann sprucse. On windy sites Limber pine may be short and twisted. It has a deep tap root and is hard to blow down, and like most trees in these conditions is slow growing. Old trees can have very stout trunks!

Thin Limber pine branches can be bent completely back on themselves without strain or cracking. The tree can be twisted and bent by the wind in exposed locations, having an irregular form with a wide round top or a flat top. Limber pine exposed to strong winds from a single direction will have few or no limbs on the windward side, and the bark on that side is smooth with a reddish-brown tint. Lodgepole pine can also show these bark characteristics.

Several Limber pines in Colorado exceed 1000 years in age. The oldest known Colorado Limber pine is a small 1660-year-old individual in South Park.

This tree is a very effective pioneer in colonizing disturbed sites. Limber pine stands, often mixed with Bristlecone pine, may give way to aspen or the climax evergreen tree varieties, appropriate for the altitude, after being established following a fire or other disturbance. In places with severe conditions Limber pine can persist in permanent groves.

Limber pine has been used for construction timber and railroad ties. It is occasionally damaged by bud worms, bark beetles, and dwarf mistletoe.

Limber pine seeds, like Pinyon pine seeds, are large and lack wings. They must be distributed by wildlife. The seeds are eaten by nutcrackers, who also make seed caches, burying the seeds in moist soil, where they may sprout if undisturbed. Sometimes several seedlings will sprout from a single cache, and grow together into what appears to be a single tree with several main stems.

The presence of Limber pine at Pawnee Buttes raises interesting questions. It is far from any other stand of Limber pine. Did they grow from seeds left by Indians traveling from the mountains, like the Owl Creek cache of Pinyon pines? Or by a bird caching seeds? Alternately, the trees may be a vestige of a time when the climate was cooler and wetter, and Limber pine grew in an unbroken forest from the mountains onto the Plains, during the last Ice Age.

The Limber pine was first described by Edwin James, the naturalist on the Stephen Long expedition to Colorado in 1820. James first mentions the "flexile pine" on July 14, 1820, the day James and others of the expedition completed the first ascent of Pike's Peak, then called the Great Peak. The same day the main party was camped near Manitou Springs, where they were chased into the bushes by a grizzly bear. James noted that the seeds of the Limber pine were eaten by "the Indians and French hunters about the Rocky Mountains." Almost nothing is known of the early independent fur traders from French Canada. They named Laramie Peak in Wyoming, among other contributions to early exploration of the area. We know they were here in Colorado, before any visits by English-speaking parties, but who they were, what they saw and did, and what was their fate, is almost entirely lost.

The scientific name is Pinus flexilis , referring to the flexible small branches.

Identifying features of Limber pine

Needles

Needles in bundles of five; sometimes three or four; stout or rigid, 1 1/2 to 3 inches long; often 2 inches or more. Needle clusters tend to be tufted on the end of each branch. The papery sheath around the base of each new needle bundle soon weathers away. The needles lack the resin specks found on Bristlecone pine needles. The needles' color is lighter and paler than Bristlecone pine needles.

Cones

3 to 6 inches long, sometimes more, oval in outline, with no bristles. Mature cones are pale or light brown, open, with scales broad and thick at the ends with no bristle. Seeds 3/8 to 1/2 inch long, edible, dark brown, and wingless. The lack of the bristle distinguishes this tree from the Bristlecone pine, as does needle length, and the large wingless seed. It may be hard to find a cone or a seed in a cone.

Mature cones have drops of sticky resin on the ends of each scale. Cones grow near the ends of branches, at the base of each new year's growth.

Bark

On most trees the bark is pale gray, or sometimes silvery-white. Until it reaches 6 inch diameter the bark is smooth, without scales, furrows, or resin blisters.Where exposed to strong winds, smooth bark on trunk and limbs may be reddish-brown, almost with a purplish cast. Above 6 inches the bark becomes pale gray and scaly. On thick stems and old trees it is dark grey or grey to blackish and broken into large or small scaly plates. The oldest trees may have a reddish-brown tinge to the bark.

Branches

The small branches are flexible and may be bent without breaking, more so than in other pine trees,. Thin branches often can be bent back on themselves without cracking. The branches are fairly widespreading and can droop.