Posted by: columbiahighlands | October 7, 2010

Highlands highlight – western larch

The Columbia Highlands boast the some of the greatest diversity of conifer tree species in the Northwest, but come autumn one tree is the star of the show: western larch.

western larch stand
A stand of old western larch on King Mountain. Photo: Aaron Theisen

Western larch is one of 11 species of larch and the only one whose distribution is largely confined to the Inland Northwest. Like other larch, the western larch is a deciduous conifer, meaning that it loses its needles every fall and produces a completely new set in the spring.

Western larch can be identified during the spring and summer by their tall form, narrow pyramidal crown and bright-green, soft needles that mostly grow in tufts from knobby spur shoots on the branch. However, during the fall, western larch are unmistakable, as their deciduous needles turn golden yellow before dropping.

Western larch has evolved several adaptations that allow it to survive, and thrive, among the dry evergreen forests of Eastern Washington. It is the fastest-growing conifer and can quickly colonize following disturbances such as wildfires; this fast growth, and the massive heights that larch can attain, allow it to tower over more shade-tolerant competitors.

Western larch is also remarkably tolerant of wildfire. Like Douglas-fir and ponderosa pine, western larch produces thick, protective bark—bark up to fourteen inches thick has been identified on some old trees. The bark on very old larches is often indistinguishable from that of old ponderosa, necessitating examination of the canopy for proper identification. Western larch can also regenerate branches and secondary trunks. And, because it loses its needles every fall, western larch is less susceptible to lasting damage from late-season crown fires. The 1988 White Mountain fire south of Sherman Pass bears witness to this advantage over evergreen competitors; because the fire occurred late in the season, many scorched western larch were able to produce a new set of needles the following spring.

Western larches can also compartmentalize decay through vigorous resin flow to wounds; many such fire-scarred and resin-filled trunks remain standing long after the tree has died, providing a home for cavity-dwelling animals. This quality also makes western larch prized among Eastern Washington trees for its high-quality firewood.

Right now is prime larch-viewing season in the Columbia Highlands, with the Sherman Overlook east of Sherman Pass providing one of the best panoramas. Do you have a favorite larch drive or hike?

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Responses

  1. […] mean that autumn colors are peaking in the Columbia Highlands. The star of the show, of course, is western larch. With its glowing gold needles, a panorama of these deciduous conifers is one of the iconic images […]

  2. […] Friends of the Columbia Highlands has a short, friendly introduction to western larch […]


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