Woody > Pinus > Pinus attenuata > Pinus attenuata
Pinus attenuata
Knobcone Pine
Origin: Naturally found growing in only a few populated areas on the Pacific coast of North America, situated on rocky mountain slopes in Oregon where it is native, stretching further south in largely discontinuous populations near Baja California.
Mike's
Opinion
"
A notable characteristic of this pine tree is its remarkable ability to survive the ongoing changes to the ecosystem. Known as the tree that devours its own cones, it essentially has an additional layer of protection for the seeds, which will only release from the cone after an extreme high heat event, such as a forest fire. After such an event occurs, the likelihood of the majority of the species' trees burning down is very high, which allows for the seeds to flourish and create a new-growth forest afterwards.
Michael Pascoe, NDP., ODH., CLT., MSc. (Plant Conservation)
"
| Family |
| Pinaceae |
| Genus |
| Pinus |
| Species |
| attenuata |
| Category |
| Woody |
| Type |
| Tree (evergreen) |
| USDA Hardiness Zone |
| 7b |
| Canadian Hardiness Zone |
| 7a |
| RHS Hardiness Zone |
| H5 |
| Temperature (°C) |
| (-17.7) - (-12.2) |
| Temperature (°F) |
| (-27.6) - (-24.5) |
| Height |
| 9 - 24 m |
| Spread |
| 3 - 5 m |
Photographs
Cultivars
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Description and Growing Information
Flowering Period
| General Description |
| Narrow and irregular form. Branches grow nearly horizontally, turning up at the ends. Cones are laboriously spiked, very resinous, and tightly closed. They grow very close to the trunk, which may result in the bark growing around the cone. |
| Landscape |
| Not often used in the landscape, though planted for slope protection where needed. |
| Cultivation |
| These closed-cone pines require heat (naturally from forest fires) to open up cones to release seeds. Without this, the cones are essentially glued shut with resin; this method is known as serotiny. After a fire, seedlings are released en masse and thrive because of a lack of competition. In the case of fire being absent for years, the cones will eventually open up and release seeds (usually after 20+ years). |
| Shape |
| Narrow pointed conic crown, slender branches that are almost horizontal which turn up at the ends, becoming more gnarled with age. |
| Growth |
| Medium |
| ID Characteristic |
| The trunk appears to be “eating” the cones, whorls of plenty of knobby closed cones. |
| Pests |
| Rarely subject to suffering from insects or diseases, although it has been noted to become infected by Dwarf-Mistletoe (Arceuthobium campylopodum). Feral pigs can cause significant damage by using their tusks and removing the bark at the base of the tree, which leads to further issues and the decline of the tree. |
| Habitat |
| Broadly distributed along the West Coast of the United States of America, growing in mild climates; often on rocky mountain slopes which have poor and coarse soil. |
| Bark/Stem Description |
| Smooth grey bark at a young age, becoming dark grey with narrow fissured, large, scaly ridges. The upper section of the trunk is closely smooth. |
| Flower/Leaf Bud Description |
| Buds are 1.5 cm in size, very resinous, close to an oval shape, and a dark red-brown colour that gets darker with age. |
| Leaf Description |
| Needles are 7.5 cm - 18 cm long 1.3 mm - 1.8 mm thick, fine stomatal line and margins are serrulate. Grown in three per cluster, slender, stiff, appearing yellow-green, straight to slightly curved and twisted. Falls off after 4-5 years. |
| Flower Description |
| Pollen cones are round cylindrical shapes that are 10 mm - 15 mm long, lighter bronze to orange colour. |
| Fruit Description |
| Female cones are 8 cm - 15 cm in length, very asymmetrical, eggshaped, and clustered in plenty of rings or whorls. Scales are knobby on the exposed side, with inner or stem side scales being flatter. Cones are produced closer to the trunk and are unlikely to be found near the tips of branches. |
| Colour Description |
| The bark is grey turning darker with maturity. Needles are evergreen to yellow-green. Cones are glossy yellow-brown with blackish seeds. |
| Texture Description |
| Shallowly fissured bark, large scaly ridges, and cone scales are raised and keeled. |
| Notable Specimens |
| Former “champion”, 36 m tall with a spread of 20 m -- got downed in 2010. It was located in Shasta County, California. Oregon's largest is 35.6 m tall, spreading close to 16 m. |
| Propagation |
| Propagation can be achieved by using a scion or graft union and grafting onto another Pinus species. Seeds are released from cones 1-12 hours after fire. Germination occurs after seeds are cold-stratified for 60 days. |
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