Wednesday, February 9, 2011

The Other California: What do you do with a used forest?

Humans have cast a long shadow over Sierra National Forest (oh, sorry about literal metaphors).

The Sierra Nevada is a world-class mountain range. Scenic, in turns rugged and visitor-friendly, spectacular, destination of millions of travelers from around the planet, the mountains host one of the earth's most precious parks in Yosemite, and the only slightly lesser-known (but no less incredible) Sequoia/Kings Canyon National Park. Regular readers of this blog will certainly know of the explorations we have covered in those parks, but my Other California series is about those significant places that aren't quite so famous. They are the places that don't always show up on the postcards...

There is a huge swath of mountain territory between the south boundary of Yosemite, and the northern reaches of Kings Canyon. This is the drainage of the San Joaquin River, and to most travelers it is terra incognita, a blank spot on the map.

Structurally the Sierra Nevada is a 400-mile-long block of mostly granitic rock that is tilted towards the west, with a long gentle western slope and a very steep eastern flank. Most of the major rivers start at the crest and flow west through deep canyons to the Central Valley. Due to a geological glitch of sorts, the San Joaquin has its headwaters more or less east of what by all rights should be the Sierra Crest. The high rugged ridge of Mts. Ritter and Banner and the jagged Minarets extends south from Yosemite, and reaches elevations exceeding 13,000 feet. This would seem to be the crest, but the river flows in a deep canyon around the south end of the Minarets, and the actual Sierra Crest off to the east is a somewhat uninteresting ridge of volcanic rock that barely exceeds 10,000 feet in elevation. Mammoth Mountain (that of the ski area) is the high point on that part of the crest, and from the west it doesn't look like much. Even the John Muir Trail skips this part of the crest and winds along the lakes and ridges below Ritter, Banner and the Minarets. The headwaters of the San Joaquin is a spectacular area, and Devils Postpile National Monument draws many visitors. But that's not the region I want to talk about today.

The blank spot I speak of is downstream, west of the Minarets, and between the national parks. The land is administered by the Department of Agriculture as Sierra National Forest, and there aren't generally a vast number of tourists to be seen there. That's not to say that the land is not known. It is known quite well by some. It is a landscape that has been fully utilized under the doctrine of multiple-use, the operating principle used by the Forest Service to justify any money-making enterprise that anyone can think of. The vast conifer forests have been logged heavily, huge dams have been constructed, herds of cattle graze the meadows, and mining took place, especially in the metamorphic rocks near the Minarets. In land-use terms, this is a used-car lot of a natural environment.
So what do you do with a used forest? What do you do when the biggest trees have been cut down, and the mills shut down? The mines have been abandoned for years even though they were probably the reason the Minarets were left out of Yosemite's boundaries in the first place (although a desire to build another paved trans-Sierra highway might have been another motivation). It starts with the understanding that time is a healer. Trees are growing back, and logging has left a network of roads through the region, some paved, others not, but somebody got creative and linked a series of utility roads into a rather marvelous route that explores some very scenic and interesting country. The public relations people labeled it the Sierra Vista Scenic Byway. We explored the road last fall, and I can give it a thumbs-up as a great place to explore.
Much of the region is a densely forested plateau pockmarked by green meadows and the occasional granitic dome. The San Juaquin River has carved a deep gorge through the bedrock, which is mostly an intrusion of granitic rock called the Mt. Givens granodiorite. It is one of the largest single intrusions of the Sierra Nevada batholith, with a length of about 50 miles and a width of 10 to 20 miles. It was emplaced about 90 million years ago (Bateman, P., 1992, Plutonism in the Central Part of the Sierra Nevada Batholith, California; USGS Professional Paper 1483). Glaciers carved the rugged peaks of the Ritter Range, and extended across much of the area betwen the parks.
The whole loop is more than 70 miles, and is paved road for the most part. Several sections were once paved, but they sort of gave up trying about 40 years ago, so there are a few bumps here and there, but most cars will have no problems. The road is closed during the winter and spring until the snow melts. The Forest Service has a handy map and guide online here, and America's Byways has a guide here. A number of interpretive displays have been constructed, and there are a few chemical/pit toilets at the picnic stops, but don't look for much in the way of amenities or gas stations. Supplies can be had down the hill at North Fork, Bass Lake, and Oakhurst.
Mammoth Pool Reservoir (above) impounds the waters of the San Joaquin River. A side road provides access. A second side road near the southern end of the loop road visits the geographic center of California. The Eagle Peaks (below) are exfoliating slopes of granitic rock seen at the Mile High Overlook, one of the best view points on the road. The Overlook provides the spectacular views of the Minarets seen in the pictures above as well (photos courtesy of Susan Hayes; first photo is mine, standing in Jackass Meadow, appropriately enough). Globe Rock, a huge balanced boulder, was discussed in a previous post.
Check it out! In a few months, that is. I didn't get a chance to visit the Nelder Sequoia Grove on our last trip out, so we might run into each other this summer...


Anonymous said...

Great entry. I haven't done this road yet, but plan to do it this summer. As a backpacker, it appears to offer easy access to south Yosemite and a host of other cool locations.

This topic also brings to mind something I've been meaning to ask: Have certain geologists overstated the role of glaciation as a geologic shape-maker in Yosemite? The reason I ask is because Jeffery Schaffer, in his (excellent hiking) book Yosemite National Park, notes in several places that early surveyors misattributed some geological features, such as Turtleback Dome, to glaciation. He also feels that the traditional Sierran uplift story is not quite right, that geologists have over emphasized the role of glaciation and have even invented "corroborative, often nonexistent evidence throughout the 1900s and beyond" (p. 35).

I regularly plan my backpacking trips to Yosemite using Schaffer's book. While his hiking trail details are damn good, I don't know what to think about his geology. I'm curious, assuming you're familiar with the book, what do you think?

Garry Hayes said...

Jeff writes good hiking guides, but his assertions about the geology of Yosemite and the Sierra are not based on peer-reviewed research and are not accepted by most Sierra-based geologists. There are certainly issues about when and how fast the Sierra Nevada rose, and how quickly the canyons were carved, but I would look in other venues for accurate information. The Far Western Section of the NAGT (see links on the sidebars of my blog) has several field guides that discuss Sierra geology research, especially the meeting from last fall, hosted by Fresno State University.

Anonymous said...

Thanks for the comment, Gary. Again, I love Schaffer's book as a hiking guide, but just am not so sure about the geology part of it. However, as a nongeologist, it's tough for me to make an adequate evaluation of the claims other than to be generally suspicious of them given what I learned in school. I'm curious, has anyone ever engaged him on the issue at a conference or other venue given the popularity of his books?

Garry Hayes said...

He's made a few presentations at GSA conferences but I haven't seen most of them so I don't know how the response was. I have a few criticisms and critical reviews of his biggest book from quite a few years ago.

Andrew Alden, Oakland Geology blog said...

Schaffer has spoken to my local geological society, a group that is generally easy to entertain. I would say that the audience heard him out and appreciated the fact that consensus is always worth critiquing; nevertheless, none of us were experts and it was not really an occasion to have an argument.