Climate Change and the Southern Foxtail Pine

Windward side of a southern foxtail pine snag.

The windward side of this foxtail pine snag has been blasted by the icy winds of a multitude of Winter storms. The wind has sculpted the mineral-like wood, exposing and accentuating its inner layers.

The photo is from last Saturday’s Cottonwood Pass – New Army Pass trail run. Nearly all of this route is above 10,000 ft. and 12 miles of it are above 11,000 ft. This relatively dry, high altitude habitat is home to the southern foxtail pine (Pinus balfouriana subsp. austrina).

One of the less common Sierra conifers, the tree is a long-lived species that is closely related to the bristlecone pine. The FEIS database references a southern foxtail pine 3400 years old, and the Gymnosperm Database a specimen with a crossdated age of 2110 years.

Because the tree grows so slowly, the wood is dense, and dead trees are slow to decay. In the vicinity of Cirque Peak, and a few other areas, dead foxtail pines and remnants are found above the current tree line. By crossdating tree ring sequences, a study published in 1997 found that over the past 3500 years the tree line in this part of the Sierra has generally been higher than it is now.

The study deduced that one period of reduced tree abundance and lowered tree line elevation was associated with warmer temperatures, and at least two severe multi-decade droughts. In contrast, the most recent decline has occurred during a cold, wet period that started about 450 BP.

It is remarkable that some of the dead foxtail pines studied here were alive during the Bronze Age, 4000 years BP.

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