Here's a Pretty Puzzle...What are These Trees Doing Here? An Evening at Calaveras Big Trees

When the trees were discovered by people of European descent in the 1850s, few believed the stories of their immense size. There were of legends and tall tales emerging from the explorations of the American West, but trees that towered 300 feet high with diameters of 35 feet just seemed beyond the pale. Eventually promoters stripped the bark off one of the really big ones, took the pieces to an exhibition back east and reconstructed the tree. Many still considered it a hoax anyway.

The poor tree that was stripped still stands today, a dead snag in the Sequoia Grove at Calaveras Big Trees State Park in the northern Sierra Nevada along Highway 4. I didn't get images of that tree, but there were plenty of other living ones to enjoy. We were there the other day on a lark. We had a couple of hours to see the sinking sun and lengthening shadows in the forest before a late dinner in Angels Camp.

The Sequoia Trees (Sequoiadendron gigantea) are an enigma. They exist today only in a series of 65 individual groves scattered across mainly the southern Sierra Nevada. They are relatives of the Coast Redwoods, and the Dawn Redwood of China, a tree that existed in a single grove which was only scientifically described in the 1940s. Yet the trees have existed since the age of the dinosaurs and were once distributed widely across the northern hemisphere. Their Sierra home is their last refuge. About half the original Sequoia trees were cut down prior to receiving protection, but because the wood was brittle and tended to shatter, they only found use as grape stakes and the like. Nearly all the remaining trees are protected, either in Sequoia/Kings Canyon National Park, Yosemite National Park, or Giant Sequoia National Monument.

Aside from human attack, they are not easily killed. Their bark is thick and lacks easily burnable sap so most wildfires don't hurt them (high burning "crown" fires are an important exception). The bark is thick, keeping them safe from insect attack. The trees are thought capable of living more than 3,000 years. Their greatest liability is a shallow root system that lacks a large taproot, so they can topple on uneven slopes or during intense windstorms.

The cool mystery about these trees is the one of their biogeography. How did they get to where they are today, and how did they survive when most of their closest relatives did not? Calaveras Big Trees is an even greater mystery, along with a small grove in Placer County consisting of a mere six mature trees. Looking at the map below, one can see their isolation from the others of their species, more than fifty miles of deep gorges and canyons.

At least one part of the explanation is clear. They migrated over the Sierra Nevada crest. Every time I say that I envision the gigantic trees walking like some of Tolkien's Ents, but it is better to see them as propagating along pathways where seeds could thrive and grow. This would be impossible with the present day Sierra, given the crest topping out at elevations over 10,000 feet. But the Sierra Nevada is a young mountain range, and it's probably only been a few million years since the range rose and tilted to the west (opinions on this scenario, it should be noted, vary). The trees that once thrived across Nevada had an uninterrupted slope towards the west. As the mountains continued to rise, they cut off the precipitation into Nevada's Basin and Range Province, turning the region into the semi-arid and desert environment that it is today.

Perhaps the main factor in the decline of the Sequoia trees across the hemisphere was the Pleistocene Ice Ages. A dozen times or more the ice advanced and receded across the northern parts of the continents and in the high mountains. The habitat for the trees was simply erased across much of the former range and the trees couldn't propagate quickly enough to escape the ice. In the Sierra Nevada, however, the unique geography, the westward tilted block of rock, probably saved the trees. When conditions grew colder, the seeds could propagate in soils lower on the westward slopes, and when the ice receded, they could propagate uphill.

Still, one has to wonder what the Calaveras grove is doing here, fifty miles north of their relatives in Yosemite National Park (who are in turn fifty miles north of the bulk of the Sequoia groves). And those six mature trees in Placer County? How have they survived? For the record, there were historically eight trees, but two fell in 1862. It's a pleasant mystery to contemplate as one wanders through the two beautiful groves at Calaveras.

Time Heals All Wounds. Or Does it Just Hide Them? The Ghosts of Nelder Grove (Reposted)

According to news reports, the Railroad Fire in the Sierra Nevada has reached the Nelder Grove of Sequoia Trees. It's uncertain what the outcome will be, as the trees are adapted to wildfires, but less so when the forest surrounding the trees is overgrown and stressed by five years of drought. Nelder is kind of a special grove, having been logged a century ago, and left out of the boundaries of Yosemite National Park. Abused, but precious. I wrote about Nelder when I visited for the first time a couple of years ago. Since it has been in the news, I thought you would like to learn of its threatened beauty. The original post follows...

It's a beautiful place, really. It was one of the most serene places I've been in my travels, away from busy roads, cities, tourist traps, and most of all, crowds. We were only 10 miles from Yosemite National Park on a Sunday afternoon, yet we shared the place today with just six other people, all of whom were quietly looking up as if in a a medieval cathedral.

Sequoia groves are like that. The ancient trees are so big and so tall, so grand, that they seem to inhabit a different universe than "normal" trees. They tower above, like placid gods looking down on their earthly domain. They are the only species in their genus,  Sequoiadendron giganteum. The species, or species very much like it, once grew across the northern hemisphere. Through habitat loss, perhaps related to the ice ages, they disappeared from most of their range. Only on the western slopes of the Sierra Nevada have they survived, living in 68 isolated groves, and numbering only in the few tens of thousands (the more widespread Coast Redwoods of northwest California are related, but are classed in a different genus).

We were walking through a mountain cathedral, marveling at the beauty and size of the incredible trees, but I realized there were ghosts all around us. There were only 16 mature Sequoia trees along the trail we were following, but there were dozens of gigantic stumps. This serene forest was a shadow of its former glory. Someone had cut down these forest giants. According to the Friends of Nelder Grove, the entire grove includes just over 100 mature trees spread over 1,540 acres (2.4 square miles). There are 277 stumps hidden in the shadows. Three quarters of the trees that had survived for 2,000 years or more were cut down in a few decades, between the 1890s and 1920s.

The sad part is that the wood, though resistant to rot, is brittle and was rarely used for anything more substantial than grape stakes and shakes, even toothpicks. As much as 75% of the wood went to waste, as most of the trees shattered when they hit the ground. Loggers would build trenches filled with tree branches for the trees to have a soft landing, but to no avail.

The remaining trees have been protected since the 1920s, but they still face some serious threats. The trees are adapted to fire. Their trunks are very thick and do not readily burn, so the wildfires that would burn through the grove every decade or so would kill off saplings of other trees and clear the forest duff, but would rarely kill the Sequoia trees. The nature of the fires has been changing. The policy of the Forest Service for decades was to suppress fires at all cost, allowing the other conifers like White Fir and Sugar Pine to grow very tall, reaching the lowest branches of the giant Sequoia trees.

Sugar Pines are especially susceptible to catching fire, and the fire rises up the trunk into the crown. Crown fires can kill the Sequoia trees by destroying their foliage. So by protecting the trees from fire, we've made it easier for fire to destroy them. The situation has not been helped by the growing effects of global warming. Ongoing drought has led to super wildfires on a scale never before seen in the Sierra Nevada. Several recent fires burned through 200,000 acres or more.

The deep conifer forests threaten the Sequoia trees in a different way. The seedlings need bare soil and sunny conditions to germinate, but the thick forest instead provides shade and thick forest duff. The remaining ancient giants are not being replaced by young trees, not at a rate fast enough to guarantee the future of the grove.

At least we've reached a point where we know what many of the problems are, and steps (sometimes baby steps) are being made to preserve the future of these incredible trees. In the meantime, the Nelder Grove is a quiet treasure, a beautiful place for meditation.

The Nelder Grove is off of Sky Ranch Road, about 8 miles off of Highway 140 north of Oakhurst, just a few miles from the south entrance of Yosemite National Park. The last two miles of road are unpaved, but the gravel is well-graded. Our walk was along the Shadows of the Giants trail, but there is a network of trails throughout the grove. The Mariposa Grove in Yosemite is presently closed to visitation as the site is being renovated to improve the visitation experience and protect the trees. Of course when it is finished, the grove will still be visited by hundreds of thousands of people yearly. If you want to see a Sequoia grove the way it should be, quiet and uncrowded, check out Nelder. For more information, check out the web pages of the Friends of Nelder Grove, or this Sierra Nevada Geotourism site.

Time Heals All Wounds. Or Does it Just Hide Them? The Ghosts of Nelder Grove

It's a beautiful place, really. It was one of the most serene places I've been in my travels, away from busy roads, cities, tourist traps, and most of all, crowds. We were only 10 miles from Yosemite National Park on a Sunday afternoon, yet we shared the place today with just six other people, all of whom were quietly looking up as if in a a medieval cathedral.

Sequoia groves are like that. The ancient trees are so big and so tall, so grand, that they seem to inhabit a different universe than "normal" trees. They tower above, like placid gods looking down on their earthly domain. They are the only species in their genus,  Sequoiadendron giganteum. The species, or species very much like it, once grew across the northern hemisphere. Through habitat loss, perhaps related to the ice ages, they disappeared from most of their range. Only on the western slopes of the Sierra Nevada have they survived, living in 68 isolated groves, and numbering only in the few tens of thousands (the more widespread Coast Redwoods of northwest California are related, but are classed in a different genus).

We were walking through a mountain cathedral, marveling at the beauty and size of the incredible trees, but I realized there were ghosts all around us. There were only 16 mature Sequoia trees along the trail we were following, but there were dozens of gigantic stumps. This serene forest was a shadow of its former glory. Someone had cut down these forest giants. According to the Friends of Nelder Grove, the entire grove includes just over 100 mature trees spread over 1,540 acres (2.4 square miles). There are 277 stumps hidden in the shadows. Three quarters of the trees that had survived for 2,000 years or more were cut down in a few decades, between the 1890s and 1920s.

The sad part is that the wood, though resistant to rot, is brittle and was rarely used for anything more substantial than grape stakes and shakes, even toothpicks. As much as 75% of the wood went to waste, as most of the trees shattered when they hit the ground. Loggers would build trenches filled with tree branches for the trees to have a soft landing, but to no avail.

The remaining trees have been protected since the 1920s, but they still face some serious threats. The trees are adapted to fire. Their trunks are very thick and do not readily burn, so the wildfires that would burn through the grove every decade or so would kill off saplings of other trees and clear the forest duff, but would rarely kill the Sequoia trees. The nature of the fires has been changing. The policy of the Forest Service for decades was to suppress fires at all cost, allowing the other conifers like White Fir and Sugar Pine to grow very tall, reaching the lowest branches of the giant Sequoia trees.

Sugar Pines are especially susceptible to catching fire, and the fire rises up the trunk into the crown. Crown fires can kill the Sequoia trees by destroying their foliage. So by protecting the trees from fire, we've made it easier for fire to destroy them. The situation has not been helped by the growing effects of global warming. Ongoing drought has led to super wildfires on a scale never before seen in the Sierra Nevada. Several recent fires burned through 200,000 acres or more.

The deep conifer forests threaten the Sequoia trees in a different way. The seedlings need bare soil and sunny conditions to germinate, but the thick forest instead provides shade and thick forest duff. The remaining ancient giants are not being replaced by young trees, not at a rate fast enough to guarantee the future of the grove.

At least we've reached a point where we know what many of the problems are, and steps (sometimes baby steps) are being made to preserve the future of these incredible trees. In the meantime, the Nelder Grove is a quiet treasure, a beautiful place for meditation.

The Nelder Grove is off of Sky Ranch Road, about 8 miles off of Highway 140 north of Oakhurst, just a few miles from the south entrance of Yosemite National Park. The last two miles of road are unpaved, but the gravel is well-graded. Our walk was along the Shadows of the Giants trail, but there is a network of trails throughout the grove. The Mariposa Grove in Yosemite is presently closed to visitation as the site is being renovated to improve the visitation experience and protect the trees. Of course when it is finished, the grove will still be visited by hundreds of thousands of people yearly. If you want to see a Sequoia grove the way it should be, quiet and uncrowded, check out Nelder. For more information, check out the web pages of the Friends of Nelder Grove, or this Sierra Nevada Geotourism site.

An Invasion of Ents? No, Just the Biggest Living Things on the Planet

Giant Ent toes. Or Imperial Walkers. Run for your lives!

There are things in Yosemite National Park other than Yosemite Valley. One of the gems (out of a great many) is the Mariposa Grove, a forest of about 500 gigantic Sequoia Trees near the south entrance of the park. A visit to the grove is a delight, as I found out yesterday. I've been there a few times, but on this occasion we spent several hours wandering through the trees, having sworn ourselves to a leisurely pace, a bizarre concept with which I am unfamiliar. It turns out this will be our last visit (and everyone else) to the grove for at least two years. They are shutting it down so they can do right by the wonderful trees.

Until last year, there was a tram that offered tours of the grove (for a price, of course), so a paved road wound through the forest. There is a large parking lot within the forest, a small store (now permanently closed), and that staple of parks and monuments: pit toilets. The problem is that the trees have shallow root systems that are generally less than six feet deep, but which spread widely about the tree. The constant pressure of vehicles and feet damages the root systems. We have been slowly loving the trees to death.

When finished, the grove will be a different place. Parking will be moved to the edge of the grove, and trams will provide free access from an even larger parking lot two miles away. The grove will be traversed by footpaths only, including an ADA access trail to the largest tree in the grove, the Grizzly Giant. There will be flush toilets at the parking area. If these changes work like similar actions that have been taken in other national parks, visitors will have a much different experience, including better chances to observe wildlife in the groves.

The cars are tree-killers

There is a bit of confusion about the Giant Sequoias (Sequoiadendron gigantea), because California has two gigantic tree species. The other tree is the Coast Redwood (Sequoia sempervirens), which grows in a narrow coastal corridor between Big Sur and the Oregon state line. The Coast Redwood grows to immense heights (nearly 400 feet), but is usually slimmer. The tallest Sequoia trees usually don't exceed 300 feet (the tallest is 311 feet), but the trunk is more robust to a high level, so the shorter trees have the greater bulk, making them the largest living thing on the planet. The state legislature didn't know the difference (a big red tree is a tree, right?), so they made the "native redwood" into the official state tree without defining which of the trees they meant. The attorney general of the state eventually got involved, making a final ruling declaring both species to be the state tree. Both tree species live for thousands of years, but neither is the oldest living thing in existence. That honor goes to the Bristlecone Pine which is found in several western states. The oldest, a recently discovered 5,000 year old survivor, is also a California resident.

The trees have a geological story. They once thrived across the northern hemisphere, and in North America fossils of the trees are preserved in Yellowstone and Petrified Forest National Parks (the direct ancestors are preserved in Nevada). The petrified trees in Yellowstone are several tens of millions of years old, but the trees in Petrified Forest are several hundred million years old! Ancestors to the Sequoia date at least to the Jurassic Period, so the trees were witness to the evolution of the dinosaurs and their extinction. Climate change seems to have been the tree's nemesis, and the Pleistocene ice ages probably eliminated them from most of their former range. The trees were able to survive in the Sierra Nevada in part because they could propagate downslope and upslope in response to the advancing and receding glaciers (see this National Park Service article for the details on the origin and distribution of the Sequoia trees).

Not much can kill the trees, as they are resistant to fires, insects, and disease. Their main enemies are humans, gravity, and geology. Humans cut them down of course, for a while, but their wood is useless for most purposes. They made pencils and grape stakes out of them. The logging was put to an end, but in protecting the groves wildfires were suppressed, allowing big Sugar Pines to grow among the Sequoias. Fires can't burn through the bark of the Sequoia trees very well, but the Sugar Pines go up in flames easily, allowing the fires to "crown", burning away the foliage of the Sequoias and killing them. Fires have always been part of the ecology of the trees, as the small ground fires burned away invasive saplings of other trees, and cleared the duff from the forest floor, allowing the Sequoia seeds to germinate properly.

Most trees die by toppling over, in the occasional violent windstorm, or because erosion has undercut part of their root system. The fallen trees take centuries to decay away, as the Fallen Giant in the picture above illustrates. It fell long before the grove was discovered by European settlers.

We saw several forest species on our stroll through the Sequoia grove, including Juncos (above), and the White-headed Woodpecker, a purely western species. It's found only in California, Nevada, and the Pacific Northwest. There were the requisite rodents, the squirrels and chipmunks, and the ever present deer. The deer are dangerous; they've killed more people in Yosemite National Park than the Black Bears (bears: 0 / deer 1).

There was also some kind of creature at the base of the big tree in the picture below...

Walking through a Sequoia grove is like walking back in time. One can imagine Velociraptors hunting prey in the shadows of these forests. Or, if you will, Imperial Storm Troopers looking for Luke Skywalker ("A long time ago in a galaxy far away").

Perhaps the most eloquent reminder of the antiquity of these incredible trees was a discovery made by my colleague at Modesto Junior College. During the Jurassic period, there was an ancestral Sierra Nevada, a mountain range that would have resembled today's Andes in South America, with high mountain ridges and active volcanoes. Rivers flowed through the mountains and onto the coastal plains, and dinosaurs wandered through forests of Sequoia-related species of trees. Some trees would occasionally fall into the rivers, and woody debris would be carried into the adjacent sea. Some of the needles and stems would be preserved as fossils that would later be uplifted and exposed by erosion in the foothills of the modern Sierra Nevada. And a twig of Sequoia needles is what my colleague Noah found in 2013 as we searched for fossils in the Foothills Terrane of the Sierra Nevada Mother Lode. A tree that was once widespread across the northern hemisphere now exists only along the California Coast, and in a few dozen scattered groves in the Sierra Nevada.

You can read the whole story of our little fossil adventure here: http://geotripper.blogspot.com/2013/02/hunting-for-fossils-in-sierra.html.

And if your plans this summer include Yosemite, try and visit the Mariposa grove before they shut it down. If you are too late, you can still hike to the smaller Tuolumne and Merced groves in the western part of Yosemite, or you can visit spectacular groves in Sequoia and Kings Canyon National Parks to the south, or Calaveras Big Tree State Park on Highway 4 to the north. There are a few other groves tucked away in the national forests that lie between the other parks.

A Merry Christmas and a Really Big Christmas Tree

Merry Christmas and Happy Holidays to all! To celebrate, I offer up a very big Christmas tree, the General Grant Tree in Kings Canyon National Park. The tree is so large (268 feet high, 40 feet across at the base) that it took three pictures to capture it.

The tree was declared by Calvin Coolidge in 1926 to be the nation's Christmas Tree. At an early ceremony, park superintendent Colonel John White said ""We are gathered here around a tree that is worthy of representing the spirit of America on Christmas Day. That spirit is best expressed in the plain things of life, the love of the family circle, the simple life of the out-of-doors. The tree is a pillar that is a testimony that things of the spirit transcend those of the flesh."

I hope that you all have a wonderful and safe holiday. I'll be on the road, so blogging will be sporadic for a while.

Oh, if you think Christmas trees should be decorated, I don't have one of the Grant Tree all dressed up for the holiday, but here is a nicely flocked Sequoia tree from a different trip...

Even More Beautiful Trees, and a Sequoia Story

The mini-meme on trees grew larger today when I wasn't looking....here are some more that I noticed when I got online tonight (in addition to the links mentioned in my previous post). I am really enjoying your contributions; it's great to see that we geologists can sometimes step back and appreciate the "overburden" that sometimes obscures our all-important outcrops. Of course, all these trees exist at the consent of geology, and I can't help but add some geological notes at the end of the post tonight...

Hypo-theses offers some beautiful tree shots from the Lake District in England (including some Norwegian pegmatite to keep things geological)

Eric at Dynamic Earth added two posts, one of some Junipers, which are also high on my favorites list, for the same reasons, and the other a case of some trees squeezing the life out of some boulders.

Chris at Highly Allochtonous contributed some great pictures of trees growing on very old rocks in South Africa (including one of my favorite landscaping species, the Jacaranda)

Callan Bentley at NOVAblog has some beautiful fall colors here. I haven't had the privilege of seeing fall colors in the northeast US yet, and would very much like to some day.

Pools and Riffles provides some more information about species in the eastern U.S. that I am not too familiar with.

In Terra Veritas offers some photos of trees revealing something out of whack with the underlying geology (really, though, you weren't obligated, but I appreciate the contribution!)

UPDATE: RockGlacier at Cryology and Co adds some comments about the role of dendrochronology in geology studies.

I especially appreciated the return of Ron Schott and his Gigapan camera view of a Sequoia Tree in the Lost Grove within Sequoia National Park (along with a great macrogigapan shot of the underlying granodiorite). I love the Sequoias, and have included their geological story in two of my trip guides (for Fall 2006 Tuolumne Meadows and and Fall 2005 Kings Canyon).

In short, the Sequoias have existed as a genus for 200 million years or more and once existed in groves across North America, Europe and Asia. The trees of Petrified Forest National Park were probably a related species, and I have this wonderful image in my mind of giant dinosaurs wandering among the giant trees. Today the genus exists only as 60 or so groves of Sequoia trees in the Sierra Nevada, as the coast redwoods in northern California, and as the Dawn Redwood in the smallest corner of China, in a single grove of no more than 5,000 trees that was only discovered in 1944, and described in 1948. It had been thought to be extinct in the Miocene epoch.

The Sequoias were apparently wiped out elsewhere by climate change, especially the Pleistocene ice ages, but in the Sierra, they survived, barely, by propogating up and down the gentle western slope of the mountains as the climate alternated between glacial and interglacial periods. Some pollen work suggests they may have been on the very verge of extinction, but luckily for us they survived, and now are appreciated as the largest living things on the planet. Nearly all of the existing groves are protected in National and State Parks, including the recently created Giant Sequoia National Monument.

I have ideas for two or three more blogs on the subject of trees and geology, but I have vigorously been avoiding the pile of grading in my living room, so keep watching later this week....thanks again to everyone for your contributions!