Гибкая сосна: долгожитель Северной Америки

Pine tree found in North America

Pinus flexilis, the limber pine, is a species of pine tree the family Pinaceae that occurs in the mountains of the Western United States, Mexico, and Canada. It is also called Rocky Mountain white pine. A limber pine in Eagle Cap Wilderness, Oregon, has been documented as over 2,000 years old, and another one was confirmed at 1,140 years old. Another candidate for the oldest limber pine was identified in 2006 near the Alta Ski Area in Utah; called "Twister", the tree was confirmed to be at least 1,700 years old and thought to be even older.

Its pliant branches gives it the common name "limber" and specific epithet flexilis. Its needles are about long and a dark, blueish green. Its bark is heavily creased and dark grey. Its pale wood is lightweight and soft. Pinus flexilis is typically a high elevation pine, often marking the tree line either on its own, or with whitebark pine (Pinus albicaulis), either of the bristlecone pines, or lodgepole pine (Pinus contorta). In favorable conditions, it makes a tree to , rarely tall. On exposed tree line sites, mature trees are much smaller, reaching heights of only In steeply sloping, rocky, and windswept terrain in the Rocky Mountains of southern Alberta, limber pine is even more stunted, occurring in old stands where mature trees are consistently less than in height. One of the world's oldest living limber pine trees grows on the banks of the upper North Saskatchewan River at Whirlpool Point in Alberta. Recent measurements give a maximum girth of 185". In 1986, a core sample 10 cm was retrieved by two researchers who counted 400 rings. Extrapolating this data gives an age close to 3,000 years.

Pinus flexilis is a member of the white pine group, Pinus subgenus Strobus, and like all members of that group, the leaves ('needles') are in fascicles (bundles) of five, A useful clue is that whitebark pines almost never have intact old cones lying under them, whereas limber pines usually do.

In the absence of cones, limber pine can also be hard to tell from Western white pine (P. monticola) where they occur together in the northern Rockies and the Sierra Nevada east slope. The most useful clue here is that limber pine needles are entire (smooth when rubbed gently in both directions), whereas Western white pine needles are finely serrated (feeling rough when rubbed gently from tip to base). Limber pine needles are also usually shorter, long, while western white pine needles are , though the ranges overlap.

The largest part of the limber pine's range is in the Rocky Mountains, from southwest Alberta and in the Black Hills of South Dakota. In a relic, low elevation population, seeds are also dispersed by small rodents. American black bears and grizzly bears may raid squirrel caches for limber pine nuts. The species is generally shade tolerant and resistant to fire, but does not thrive in dense habitats, instead occurring in areas relatively hostile to other species. and were reportedly consumed by Native Americans in Montana.