This is a blog about the native conifers of the Pacific Northwest. It is a companion to the Northwest Conifers site. The blog will focus on timely and interesting details about our conifers, their connections to the rest of the environment, and our connection to them.

Wednesday, July 4, 2018

Focus on Lodgepole Pine

Lodgepole pine has adapted to several very different habitats in the Pacific Northwest. It grows along the Pacific Coast, where it is often called “shore pine.” But it also grows in the mountains, occasionally right up to the timber line. This split in its range may be explained by the fact that it does not compete well with most other conifers. So it is often limited to locations where other conifers cannot grow, in one case along the coast where the trees are buffeted by wind and salt spray, and in the other, sites with poor soils or frequent severe fires. The conditions where it grows also explain its different growth forms. Growing in dense stands subject to frequent fires, it grows straight and tall to a height of 160 feet (50 meters), in character with its “lodgepole” namesake. Along the coast and on windy mountain ridges, it is usually much shorter and rarely straight. It is short and bent, even shrub-like in form, in character with its scientific name, Pinus contorta.






Recognizing lodgepole pine

  • Needles: Lodgepole pine is easy to identify, because it is the only pine native to the Northwest with 2 needles per bundle.
  • Cones: The egg-shaped cones are 2 inches long and have sharp prickles on the scales.
  • Bark: The bark is dark gray and scaly with small furrows.

Fire

Lodgepole pine is often characterized as a fire-dependent species, because the mature cones remain closed until heated by a fire, a feature called serotiny. After a fire, the serotinous cones open and disperse their seeds, generating a new stand of pines. This is what happened in 1988 when spectacular fires burned large stands of lodgepole pine in Yellowstone National Park. In the years after the fires many of the burned areas were alive with new seedlings, the beginnings of a new lodgepole pine forest.


However, this feature of the cones is variable. It varies between the different varieties described below and varies as the tree ages with older trees producing more serotinous cones. It also varies based on the local fire history. Trees growing in areas where there are frequent fires are more likely to produce serotinous cones. This is no surprise. It’s just another example of the adaptability of lodgepole pine. Serotiny is even variable among the cones growing on one tree, enabling its offspring to adapt to changing conditions. Evolution rules! And lodgepole pine is perhaps its most ardent agent of change among the conifers.


Varieties

As lodgepole pine has adapted to different environments, many of its features have changed, especially the cones. Writers* generally identify three varieties:
  • Shore pine (var. contorta) grows all along the Coast from California to Southeast Alaska. The cones are curved, and they usually open and disperse their seeds when mature. The needles are shorter (less than 2 inches – 6 cm) and thinner than the other varieties (with needles up to 3 inches – 8 cm). After seed dispersal, the cones may remain on the tree for some time.
  • Sierra-Cascade lodgepole pine (var. murrayana) grows in the Cascades of Oregon. It also grows in the Sierra Mountains of California. Its cones are nearly symmetrical, and they nearly always open and disperse their seeds as soon as they mature, dropping the cones soon after.
  • Rocky Mountain lodgepole pine (var. latifolia) grows in the Cascades of Washington and the mountains in the northeast corners of Oregon and Washington. It also grows throughout much of the Rocky Mountains. The cones are curved and variably serotinous, often remaining closed until heated by a fire. The non-serotinous cones can remain on the tree for some time after dispersing its seeds.


Note that the borders between the varieties are not necessarily recognized by the trees. Try as we will to classify all of nature into tidy little boxes with clearly drawn lines, nature doesn’t usually color inside the lines. Lodgepole pines are no exception. They interbreed at the borders between the varieties and adapt to local conditions.  
Shore Pine at Oceanside, Oregon
Uses

Native Americans used this pine for teepee poles (lodge poles) wherever the trees were available in the western U.S. Some traveled great distances to find suitable poles in the mountains where they grew. Today lodgepole pine is used to make paper, paneling, plywood and fiberboard, and to build barns and other post-and-beam structures.


Chief Joseph pine in the Winter
Garden at Hoyt Arboretum
 
Chief Joseph Pine

The Chief Joseph pine is a dwarf variety of lodgepole pine that surprisingly turns golden-yellow in the winter. Doug Will of Sandy, Oregon discovered this amazing golden tree growing in the Wallowa Mountains and named it for the famous leader of the Nez Perce tribe. It looks like a normal lodgepole pine in spring and summer. But in late fall, the needles turn to a bright golden color. You might expect it to shed its needles like a larch, but they remain on the tree all winter and then turn green again in the spring. Its striking color and extraordinary growth habit have made it a popular item at nurseries across the country.

You can see a Chief Joseph pine in its winter color here.






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*Chris Earle (www.conifers.org), Aljos Farjon, A Handbook of the World’s Conifers, James Eckenwalder, Conifers of the World, Zsolt Debreczy and Istvan Racz, Conifers Around the World. Common names from Eckenwalder and the USFS Silvics Manual 

1 comment:

  1. I love this thought-
    "Try as we will to classify all of nature into tidy little boxes with clearly drawn lines, nature doesn’t usually color inside the lines. Lodgepole pines are no exception.

    ReplyDelete