BOTANY – PACIFIC YEW
By Julie Kierstead
Illustrations by Obi Kaufmann
Have you ever been baffled by seeing what looked like a fir tree or a scraggly redwood with red berries? Conifers have cones, right?
Meet Pacific yew, the western North American conifer whose cones look a bit like red huckleberries. Pacific yew (Taxus brevifolia) has a single-seeded “cone” surrounded by a juicy bright red aril. The seeds and arils are relished by many species of songbirds and small mammals, who disperse the seeds. The seeds are poisonous to humans. Yew’s drooping branches provide cover for wildlife, and shade for streams to maintain cool water temperatures. The root systems stabilize the soil. Yews are dioecious, meaning that individual plants are either male or female; only the females have berry-like cones.
If no red arils are present, yew can be distinguished from other single-needled conifers by its thin, peeling, reddish or purplish bark. Because of its thin bark, it is sensitive to heat damage, and yew plants are generally killed by even light ground fires. The presence of yews is a reliable indicator that a forest has not burned for a while.
Pacific yew, one of thirteen species of Taxus worldwide, is distributed from southern Alaska to California, where it reaches the southern end of its range near San Francisco Bay and the central Sierra Nevada and also occurs in the northern Rockies as far south as Montana and Idaho. Here in California, it is most common along streamsides as an understory forest plant, thriving in the shade.
Yew grows very slowly, producing dense, durable, attractive, elastic wood that was much used by Native Americans for tools, paddles, and bows. Yew is still considered among the finest woods for making bows.
Following the discovery of anti-cancer properties in Pacific yew bark in the 1970s, many thousands of the trees were killed for their bark. Thankfully, methods were developed to synthesize the chemicals in the lab, so harvesting Pacific yew bark is no longer necessary to create these life-saving cancer treatments.
Pacific yew has an “Entish” vibe—if you are a fan of J.R.R. Tolkien’s Lord of the Rings, you’ll know what that means. Next time you are fishing in the mountains of northern California, keep your eye out for this magical tree.
GEOLOGY – KLAMATH MOUNTAINS
By Jeff Ludlow
The Klamath Mountains are a geologic mess. Covering nearly 10,000 square miles from Northern California to Southern Oregon, the area known as the Klamath Geomorphic Province is comprised of several mountain ranges, including the Salmon, Siskiyou, Marble, Scott, and Trinity Mountains1. Via continental drift, this assembly of ranges results from rotational and accretionary mountain building starting in the Devonian Period about 400 million years ago2, known in evolutionary terms as The Age of the Fish.
During this time, eight series of accretionary episodes of oceanic lithospheres (ocean floor), volcanic arcs, and mélanges collided to form the Klamath Mountain ranges. This concept is best explained by the celebrated author John McPhee in his book Assembling California:
“For an extremely large percentage of the history of the world, there was no California… the continent ended far to the east… then, a piece at a time according to present theory—parts began to assemble. An island arc here, a piece of continent there—a Japan at a time, a New Zealand, A Madagascar—came crunching in upon the continent and have thus far adhered.”
These mountain-building episodes created terranes bound by faults and each having a unique geology depending on where the rocks were formed thousands of miles away from one other. As a result, a plethora of rock types, including sedimentary, igneous, and metamorphic, are all found in the Klamath Mountains. Unique among these are ultramafic rocks. Rich in iron and magnesium, ultramafic rocks are from the Earth’s mantle, where they are brought up along ocean crust-spreading ridges and are typically found in orogenic (mountain-building) belts such as the terranes of the Klamath Mountains. The star of ultramafic rocks in California and well represented in the Klamath Mountains is serpentinite.
SERPENTINITE – THE GOOD, THE BAD, AND THE UGLY
The Good—Serpentinite is the official State Rock of California. Owing to its particular chemical composition, rich in heavy (toxic) metals and poor in typical plant nutrients, soil formed from erosion of serpentinite rock creates a unique ecological habitat for floral and fauna not found overlying other rock types in the State. On serpentine soil in the Klamath region, unique flora3 evolved especially adapted to the hardships of drought, heavy metals, and nutrient stress. Complex islands of plant endemism and rarity developed in isolated communities on this severe Klamath serpentine landscape⁴. It is estimated that serpentine soil covers less than 1 percent of the state yet contains about 10 percent of the state’s endemic plant species⁵.
Serpentinite could also play a future role in mitigating climate change on our planet. Studies suggest that in situ sequestration (injection) of CO₂ in these ultramafic rocks has been proposed as a method to reduce the amount of this greenhouse gas in the atmosphere. By means of carbon capture and storage-by-mineralization, serpentinite has been shown in laboratory studies to be a preferred host rock, due to its unique mineralogy to sequester CO₂ as an alternative to its release to atmosphere⁶. Just another example of California with its rocks leading the way in addressing climate change!
The Bad—Serpentinite contains the asbestos mineral, chrysotile, which can cause mesothelioma (lung cancer). Yet the physical properties of commercial grade asbestos—high tensile strength, flexibility, and resistance to heat, chemicals and electricity—have made it well suited to many products, including insulation, automotive parts, vinyl and roofing products, and caulking. This market drove the asbestos mining industry in the State from the late 1880s to 2002 when the last asbestos mine was closed in San Benito County⁷. Though partial government bans on asbestos in commercial products have been in place for the past 40 years or so, the Biden Administration in March this year announced a final rule prohibiting ongoing uses of chrysotile asbestos in the United States.
The Ugly—The California Air Resources Board, a government agency that promulgates environmental regulations concerning air quality in the State, knows this ugly fact of asbestos in our State rock. Following its rules, the pedants of government enforce dust control and monitoring regulations when excavating or grading in areas with Serpentinite where Natural Occurring Asbestos could occur⁸.
With the Klamath River dams gone, what geology is in store for the angler seeking new steelhead runs on the section of re-birthed river? The Klamath Geomorphic Province, with its mess of rocks and steep canyon topography, ends in the east at about Hornbrook, just below where the dams were removed. Upriver, the uniformity of volcanic rocks from the neighboring Cascade and Modoc Plateau Geomorphic Provinces will be evident. So, as you swing your fly somewhere in the new 400 miles of river, gaze upon the volcanic cones and table land of columnar basalt cliffs as you wait for a steelhead to inhale your fly.
About Obi
Illustrator Obi Kaufmann is an award-winning author of many best-selling books on California’s ecology, biodiversity, and geography. His 2017 book The California Field Atlas, currently in its seventh printing, recontextualized popular ideas about California’s more-than-human world. His next books, The State of Water; Understanding California’s Most Precious Resource, and the California Lands Trilogy: The Forests of California, The Coasts of California, and The Deserts of California present a comprehensive survey of California’s physiography and its biogeography in terms of its evolutionary past and its unfolding future. The last in the series, The State of Fire; Why California Burns was just released in September 2024.
1 Scollon, Dan 2022. Klamath Mountains Region of California (and Oregon) Physical Geography and Human-Environment Interactions. August 12.
2 Irwin, William P., Mankinen, Edward A., 1998. Rotational and accretionary evolution of the Klamath Mountains, California and Oregon, from Devonian to present time. U.S. Geological Survey Open-File Report 98-114.
3 Such plants include: Klamath Manzanita, Mt. Eddy Draba, Koehler’s Rock Cress, Lemon Colored Fawn Lilly, Dubakella Mountain buckwheat, Mt. Eddy lupine among many others. U.S. Forest Service, Rare Serpentine Endemic Plants of the Klamath-Siskiyou Bioregion
4 U.S. Forest Service, Klamath Siskiyou Serpentines
5 Lacinska AM, Styles MT, Bateman K, Hall M and Brown PD (2017) An Experimental Study of the Carbonation of Serpentinite and Partially Serpentinised Peridotites. Front. Earth Sci. 5:37. doi: 10.3389/feart.2017.00037
6 Van Gosen, Bradley S. et al, 2011. Reported Historic Asbestos Mines, Historic Asbestos Prospects, and Other Natural Occurrences of Asbestos in California. Open-File Report 2011-1188 U.S. Geological Survey.
7 Title 17, CA Code of Regulation Section 93105(c)(1)
