PinFlex_info.html

Pinus flexilis (Limber pine): Information.
Identifying characteristics: The flexible nature of the twigs has given this pine its common name ("limber pine") as well as its species name ("flexilis"). Growing 20 to 50 feet tall, the limber pine has a tapering trunk with a low, broad, flat-topped crown. Older trees have low, drooping branches with ascending tips. The bluish-green needles are 1.5 to 3.5 inches long, occur in fascicles of 5, and are densely crowded at the ends of the branches, pointing forward. The needle margins are smooth (without minute teeth). The leaf sheath is deciduous, and 3 to 4 lines of stomata occur on each leaf surface. The ovoid-elongate cones are 3 to 6 inches long, with thickened, spoon-shaped scales without a prickle protruding from the umbo. Cones are yellow-brown, grow at right angles to the branch and are shed in winter. Buds are ovoid and sharply pointed. Bark is smooth and light gray when young, becoming grayish-brown and deeply furrowed into almost square, scaly plates. Similar species: white pine (P. strobus) Ecology: Distribution: The limber pine is native to the Rocky Mountains from Canada to northern New Mexico, but not abundant anywhere in its range. It grows well in northwestern Iowa and on the ISU Campus. Habitat: This pine is found on dry, rocky ridges and peaks. It has a large taproot and is remarkably windfirm. Growth is slow, but trees are long-lived (to 300 years). Growth is best on moist, well-drained soils in full sun. Damage is caused by fire, white pine blister rust, bark beetles, budworms and dwarf mistletoe. Uses: Wood: The wood is a pale yellow color, becoming reddish on exposure to air. It is light, soft, close-grained and generally harvested without distinction from ponderosa pine. The wood is relatively unimportant, but is used for boxes, railroad ties, poles and mine timbers. It is used locally for firewood. Wildlife: Good seed crops are produced only every 2 to 4 years. Seeds are eaten by birds and rodents. The low-growing branches often provide the only cover for wildlife at high elevations. Horticulture: The limber pine forms a handsome specimen tree. It withstands wind and cold and ought to be more widely planted in the Midwest, even though it is slow-growing. It is useful for reforestation, and for protection of valuable watersheds on exposed sites. The variety 'Glauca Pendula' has a wide-spreading, irregular form and blue-green foliage. 'Van de Wolf's Pyramid' has twisted needles and a vigorous, upright habit. The southwestern white pine (P. flexilis var. reflexa), with reflexed cone scales, is native to the southwestern US and New Mexico. Some botanists classify it as a separate species (P. strobiformis).

Pinus flexilis (Limber pine): Information.

Identifying characteristics:
The flexible nature of the twigs has given this pine its common name ("limber pine") as well as its species name ("flexilis"). Growing 20 to 50 feet tall, the limber pine has a tapering trunk with a low, broad, flat-topped crown. Older trees have low, drooping branches with ascending tips. The bluish-green needles are 1.5 to 3.5 inches long, occur in fascicles of 5, and are densely crowded at the ends of the branches, pointing forward. The needle margins are smooth (without minute teeth). The leaf sheath is deciduous, and 3 to 4 lines of stomata occur on each leaf surface. The ovoid-elongate cones are 3 to 6 inches long, with thickened, spoon-shaped scales without a prickle protruding from the umbo. Cones are yellow-brown, grow at right angles to the branch and are shed in winter. Buds are ovoid and sharply pointed. Bark is smooth and light gray when young, becoming grayish-brown and deeply furrowed into almost square, scaly plates.

Similar species:

white pine (P. strobus)

Ecology:
Distribution: The limber pine is native to the Rocky Mountains from Canada to northern New Mexico, but not abundant anywhere in its range. It grows well in northwestern Iowa and on the ISU Campus.

Habitat: This pine is found on dry, rocky ridges and peaks. It has a large taproot and is remarkably windfirm. Growth is slow, but trees are long-lived (to 300 years). Growth is best on moist, well-drained soils in full sun. Damage is caused by fire, white pine blister rust, bark beetles, budworms and dwarf mistletoe.

Uses:
Wood: The wood is a pale yellow color, becoming reddish on exposure to air. It is light, soft, close-grained and generally harvested without distinction from ponderosa pine. The wood is relatively unimportant, but is used for boxes, railroad ties, poles and mine timbers. It is used locally for firewood.

Wildlife: Good seed crops are produced only every 2 to 4 years. Seeds are eaten by birds and rodents. The low-growing branches often provide the only cover for wildlife at high elevations.

Horticulture: The limber pine forms a handsome specimen tree. It withstands wind and cold and ought to be more widely planted in the Midwest, even though it is slow-growing. It is useful for reforestation, and for protection of valuable watersheds on exposed sites. The variety 'Glauca Pendula' has a wide-spreading, irregular form and blue-green foliage. 'Van de Wolf's Pyramid' has twisted needles and a vigorous, upright habit. The southwestern white pine (P. flexilis var. reflexa), with reflexed cone scales, is native to the southwestern US and New Mexico. Some botanists classify it as a separate species (P. strobiformis).