The Mighty Oaks of California: A Keystone of the Golden State’s Ecosystem

Oak trees hold a profound presence in the landscape of California, constituting a living link between the state’s rich biodiversity and cultural history. Approximately 20 species of oak trees have been recorded in California, each filling a unique ecological niche and rendering the tree species an integral part of the state’s fabric.

Among the most significant species are the Coast Live Oak, the Valley Oak, the Blue Oak, and the California Black Oak. The Coast Live Oak, resilient against the salty sea breeze, thrives along California’s coastal regions. The Valley Oak, a symbol of endurance, dominates the fertile inner valleys, while the Blue Oak’s blue-green foliage characterizes the hot, dry foothills of the Sierra Nevada and Coast Ranges. Meanwhile, the California Black Oak, found primarily in mountain regions, is appreciated for its vibrant autumnal foliage and acorns, an essential food source for various wildlife.

Oaks in California boast a rich history that dates back millions of years, with fossil records suggesting their presence since the Miocene epoch. This rich lineage is intertwined with the tree’s biological traits, with each species evolving to inhabit specific ecosystems. As a result, oak trees have managed to extend their reach across the state’s diverse terrain, from the sun-bathed coasts to the crisp mountain ranges. Whether deciduous or evergreen – with most species in California being the latter – oaks have a remarkable ability to withstand the dry summer months. This resilience can be attributed to their deep root systems and hardy leaves, allowing them to survive and thrive in the region’s unique climate.

California oaks are not just a testament to natural resilience; they are an ecosystem unto themselves. They are the cornerstone of a vibrant biodiversity that encompasses hundreds of animal species. The trees provide shelter and serve as breeding habitats for various animals, from squirrels and deer to a myriad of bird species. The acorns, in particular, play a vital role as a food source. Insects, too, have carved out an existence around the oaks, with some species laying their eggs within the tree’s bark.

This intrinsic connection between the oaks and the animal kingdom extends to humans as well. Historical records show that indigenous tribes in the region used acorns as a staple food. In modern times, the strength and durability of oak wood have made it a preferred choice for construction and furniture-making. Oak is also used in the production of high-quality wine barrels, lending its unique character to the Californian wine industry. The top fifty most expensive wines in the world are oak-aged in some way.

The oak trees of California are renowned for their impressive size and longevity. The Valley Oak, the largest of California’s native oaks, can reach over 100 feet in height and live for several centuries. These grand trees also contribute significantly to carbon sequestration. A mature oak has the capacity to absorb up to 50 pounds of CO2 annually, thus helping mitigate climate change while improving air quality. A mature oak forest can store up to 50% more carbon than an equally-sized forest of other trees.

Despite their remarkable resilience, oaks in California face a myriad of challenges. Threats stem from habitat loss, climate change, and diseases such as Sudden Oak Death. Urban development often comes at the expense of oak woodlands, while shifts in climate patterns pose potential risks to the growth and distribution of oaks.

Coast Live Oak

Nonetheless, the oaks of California stand as ecological pillars. They are significant carbon sinks, wildlife supporters, and enduring symbols of the natural resilience ingrained in the state’s identity. Their significance extends beyond their physical presence, weaving into the cultural, historical, and environmental narrative of California, the Golden State.

Conservation efforts to protect California’s majestic oaks have become increasingly critical in recent years, shaped by a heightened understanding of the tree’s ecological significance and the mounting threats they face. Various local, state, and federal entities, as well as numerous non-profit organizations, have joined forces in these endeavors, harnessing a broad array of strategies to ensure the survival and thriving of California’s oaks.

One of the primary conservation strategies involves the protection of oak habitats, specifically oak woodlands. These regions are often hotspots of biodiversity, and their preservation is crucial for the health of many interconnected species, including oaks themselves. The Oak Woodlands Conservation Act, enacted by the state of California, provides funding to acquire oak woodland habitats for conservation purposes, ensuring these areas remain untouched by urban development or agriculture.

Leaves of California Black Oak

In addition to the legal protection of existing oak habitats, restoration projects are an important aspect of conservation efforts. These projects involve the replanting of oaks in areas where they have been lost due to disease, development, or other causes. Organizations such as the California Oak Foundation run regular planting programs, involving local communities in the process to raise awareness about the importance of oaks and fostering a sense of responsibility for their protection.

Research also plays a vital role in oak conservation. Scientists are continually studying the threats faced by oaks, including diseases like Sudden Oak Death, and developing ways to mitigate them. They are also exploring the potential impacts of climate change on California’s oaks, seeking strategies to bolster their resilience against rising temperatures and shifting weather patterns. This research informs management strategies and policy-making, ensuring conservation efforts are based on the best available science.

Community education and engagement is another key facet of conservation efforts. Many organizations offer resources for landowners on how to care for the oaks on their property, and there are numerous programs aimed at educating the public about the importance of oak conservation. By fostering a deeper connection between the people of California and their native oaks, these initiatives cultivate a broader culture of conservation that can help ensure the survival of these majestic trees for generations to come. The collective aim of these diverse conservation strategies is not merely the survival, but the flourishing of California’s oaks, securing their rightful place in the state’s rich and dynamic ecosystems.

The Desert Tortoise: A Resilient Survivor of the Mojave

a close-up of a desert tortoise

The Mojave Desert, a harsh yet strikingly beautiful landscape that extends across four western U.S. states, is home to an equally fascinating and resilient creature: the desert tortoise (Gopherus agassizii). This fascinating reptile has evolved to survive in one of the world’s most inhospitable environments, but today, it faces numerous threats that are jeopardizing its existence.

The desert tortoise is a tortoise species in the family Testudinidae native to the Mojave and Sonoran deserts. They are specially adapted to withstand the extreme conditions of their desert habitat. Desert tortoises can tolerate water, salt, and energy imbalances on a daily basis, which increases their lifespans. On average, adult desert tortoises measure between 10 to 14 inches in shell length and weigh from 8 to 15 pounds. They have a high-domed shell, typically brownish in color, which serves as protection from predators. Their strong, stocky limbs are adapted for digging, an essential behavior for both foraging and creating burrows for shelter.

One of the desert tortoise’s most fascinating adaptations is its ability to store water. They have a large urinary bladder that can store over 40% of the tortoise’s body weight in water, urea, uric acid, and nitrogenous wastes. During the hot, dry summer months, this stored water can be reabsorbed back into the tortoise’s system, effectively allowing them to survive up to a year without access to fresh water.

a close-up of a desert tortoise

Desert tortoises are a testament to survival, with their lineage dating back 15 to 20 million years. They are primarily herbivorous, with a diet consisting of a variety of desert grasses, herbs, and wildflowers, along with the occasional consumption of insects and new growth of cacti.

Tortoises spend much of their lives in burrows, which provide refuge from extreme heat, cold, and predators. They are most active during the cooler hours of the day, and their activity pattern shifts with the changing seasons. Mating typically occurs in the spring and fall, with females laying a clutch of up to 15 eggs, though the survival rate of these hatchlings is low due to predation and harsh environmental conditions.

In 2011, on the basis of DNA, geographic, and behavioral differences between desert tortoises east and west of the Colorado River, it was decided that two species of desert tortoises exist: Agassiz’s desert tortoise (Gopherus agassizii) and Morafka’s desert tortoise (Gopherus morafkai). The new species name is in honor of the late Professor David Joseph Morafka of California State University, Dominguez Hills.

Desert tortoises spend 95% of their lives in their burrow. Seeing them on the landscape is a rare treat.

Estimates suggest that the population of desert tortoises has plummeted by as much as 90% since the mid-20th century. This decline is due to a variety of factors, including habitat loss from urban development and agriculture, road mortality, predation by dogs and other introduced species, and disease. In particular, upper respiratory tract disease (URTD), caused by the bacterium Mycoplasma agassizii, has been responsible for significant mortality.

Recognizing the threats faced by the desert tortoise, the U.S. Fish and Wildlife Service listed the species as threatened under the Endangered Species Act in 1990. This has led to numerous conservation efforts aimed at preserving the desert tortoise and its habitat.

Habitat conservation is a key focus, with several Desert Wildlife Management Areas established to protect crucial tortoise habitats. Efforts are also being made to reduce the impact of roads and highways on tortoise populations, such as the construction of underpasses and fencing along known tortoise crossing areas.

Education and public engagement are also critical components of conservation efforts. Initiatives are underway to educate the public about the desert tortoise and the importance of not removing them from their natural environment, a practice that can lead to population decline and the spread of disease.

Over the past few decades, desert tortoise populations have declined significantly, with estimates suggesting a staggering 90% reduction in some areas of the Mojave Desert. This decline has led to the desert tortoise being listed as “threatened” under the U.S. Endangered Species Act.

Desert tortoise facts
Lifespan: 30-50 years, but some can live to be over 80 years old
Weight: 8-15 pounds (3.5-7 kilograms)
Length: 9-15 inches (23-38 centimeters)
Range: Only found in the Mojave Desert in California, Nevada, Arizona, and Utah
Conservation status: Listed as threatened under the Endangered Species Act

Nature Conservancy

Numerous factors contribute to this decline, including habitat loss due to urbanization, off-road vehicle use, and livestock grazing. Additionally, the introduction of non-native predators, such as the common raven, has led to increased predation on juvenile tortoises.

Conservation organizations, government agencies, and local communities have come together to implement various strategies aimed at protecting and preserving the desert tortoise. These efforts include habitat restoration, fencing off sensitive areas, and developing educational programs to raise awareness about the species.

One such initiative is the “Adopt-a-Tortoise” program, which allows individuals and organizations to symbolically adopt a tortoise, with the proceeds going towards conservation efforts. Another important initiative is the “Head Start” program, which raises hatchlings in captivity until they reach a size less vulnerable to predators before releasing them into the wild.

The return of Lake Tulare – once the largest lake West of the Mississippi

The massive atmospheric snowstorms that pummeled California this year have been a boon to ski slopes throughout the Sierra Nevada mountains. But the rains have had an unusual result: The torrents of rain have drowned thousands of acres of farmland in California’s Central Valley and resuscitated a lake that vanished decades ago. Standing in an area that was dry as a bone just a year ago, right now, as far as the eye can see, water stretches to the horizon. It has covered roads, and crop fields, and submerged homes and buildings.

The lake is called Lake Tulare.

Lake Tulare, once the largest freshwater lake west of the Mississippi River, is a compelling example of the delicate balance between human activity and natural forces. Located east of Interstate 5 from Kettleman City, Lake Tulare was also the second-largest freshwater lake in the United States, based on surface area. At its peak, Lake Tulare covered an area of nearly 700 square miles and was a critical component of the region’s complex hydrological system.

The lake’s disappearance over a century ago can be traced back to multiple factors, including agricultural development, water diversion, and climate. Fed by the Kaweah, Tule, and Kern Rivers, the lake supported a vibrant ecosystem teeming with fish, waterfowl, and other wildlife. Native American tribes, including the Yokuts, relied on the lake’s abundant resources for sustenance and trade.

Lake Tulare began to shrink in the late 19th century as European settlers moved into the area and agriculture took hold. The burgeoning need for water to support the growing agricultural industry led to the construction of canals and dams, which diverted water away from the lake. As a result, the lake’s surface area shrank rapidly, and by the early 20th century, it had disappeared almost entirely.

Spanish captain Pedro Fages led the first excursions to the southern San Joaquin Valley in 1773 and wrote this account:

This plain will exceed one hundred and twenty leagues in length and in parts is twenty, fifteen and even less in width. It is all a labyrinth of lakes and tulares, and the river San Francisco, divided into several branches, winding in the middle of the plain, now enters and now flows out of the lakes, until very near to the place where it enters into the estuary of the river.

Pedro Fages
Fulvous whistling-duck

Today alfalfa is grown on the southern basin and there is invasive saltcedar, a common species that has also impacted regions of the Colorado River Delta. Animal life includes the Buena Vista Lake shrew (Sorex ornatus relictus), the southwestern pond turtle (Actinemys pallida), fulvous whistling-duck (Dendrocygna bicolor), and the California red-legged frog (Rana aurora draytonii). Other species native or present in the area are sandhill cranes and tricolored blackbird.

But what is the future of Lake Tulare?

Last summer, UCLA climate scientist Dan Swain published a paper that predicted more intense weather patterns on a gradually warming planet. He told CNN that the worst-case scenario of relentless atmospheric rivers could actually make Tulare Lake permanent again, turning it into a vast, inland sea.

We’ll have to wait and see.

And in the meantime, check ut this recent before and after satellite image of the central valley and Lake Tulare.

California’s Strangest Catastrophe

In 1905, a catastrophic accident occurred in California when a canal system failed and caused the Colorado River to overflow into the Salton Sea basin. The result was the creation of a massive lake that came to be known as the Salton Sea.

The accident occurred as a result of a series of mistakes and oversights in the construction and maintenance of the irrigation system in the area. At the turn of the century, the Imperial Valley in California was a desert wasteland, with no reliable water source for agriculture. To remedy this, engineers devised a plan to divert water from the Colorado River into the area via a series of canals and irrigation channels.

One of these canals, the Imperial Canal, was completed in 1901 and began diverting water from the Colorado River into the Imperial Valley. However, the canal was poorly constructed, and its walls were made of weak and porous materials. Over time, the walls began to erode and collapse, causing water to overflow and flood the surrounding areas.

On the morning of February 20, 1905, disaster struck. The Imperial Canal had been carrying water at full capacity for several weeks, and the walls were weakened by constant erosion. Without warning, the canal walls gave way, and a torrent of water rushed into the desert below.

Over the next several months, the Colorado River poured into the Salton Sea basin, creating a massive lake that covered more than 380 square miles. The water was brackish and contained high levels of salt and other minerals, making it unsuitable for drinking or irrigation.

The creation of the Salton Sea was both a blessing and a curse for the people of the Imperial Valley. On the one hand, the lake provided a new source of water for irrigation, and the fertile soil around its shores proved ideal for growing crops. On the other hand, the water was highly saline, and the lake became increasingly polluted over time, posing a threat to both human health and the environment.

Recently, with most flows diverted from the Salton Sea for irrigation, it has begun to dry up and is now considered a major health hazard, as toxic dust is whipped up by heavy winds in the area. The disappearance of the Salton sea has also been killing off fish species that attract migratory birds. 

The New York Times recently wrote about the struggles that farmers face as the Salton Sea disappears, and how the sea itself will likely disappear entirely at some point.

“There’s going to be collateral damage everywhere,” Frank Ruiz, a program director with California Audubon, told the Times. “Less water coming to the farmers, less water coming into the Salton Sea. That’s just the pure math.”

Several historical figures were associated with the Salton Sea disaster. One of the most notable was George Chaffey, an engineer and entrepreneur who played a key role in the development of the Imperial Valley. Chaffey was one of the primary architects of the irrigation system that caused the accident, and his company was responsible for building the Imperial Canal.

Another figure associated with the Salton Sea was Charles Rockwood, a civil engineer who was brought in to help manage the crisis. Rockwood oversaw the construction of emergency levees and channels to help divert water away from populated areas, and his efforts were instrumental in preventing further damage from the flood.

The area around the Salton Sea is located in a geologically active region, with the San Andreas Fault running through the area. The San Andreas Fault is a major plate boundary, where the Pacific Plate is moving north relative to the North American Plate. The fault is responsible for the earthquakes and other tectonic activity in the region. The Salton Sea is also located in an area of active crustal extension and subsidence, which has played a key role in the formation of the lake.

The Man Who Saved the Owens Pupfish

Owens pupfish

51 years ago today a man named Edwin Philip Pister rescued an entire species from extinction.

Less than 2.5 inches in length, the Owens pupfish is a silvery-blue fish in the family Cyprinodontidae. Endemic to California’s Owens Valley, 200 miles north of Los Angeles, the fish has lived on the planet since the Pleistocene, becoming a new species when its habitat was divided by changing climatic conditions, 60,000 years ago.

For thousands of years, the Owens Valley was largely filled with water, crystal-clear snowmelt that still streams off the jagged, precipitous slab faces of the Sierra Nevada mountains. Pupfish were common, with nine species populating various lakes and streams from Death Valley to an ara just south of Mammoth Lakes. The Paiute people scooped them out of the water and dried them for the winter.

In the late 19th century, Los Angeles was a rapidly growing young metropolis, still in throes of growing pains that would last decades. While considered an ugly younger sibling to the city of San Francisco, Los Angeles had the appeal of near year-round sunshine and sandy beaches whose beauty that rivaled those of the French Riviera.

William Mulholland

But by the late 1900s, the city began outgrowing its water supply. Fred Eaton, mayor of Los Angeles, and his water czar, William Mulholland, hatched a plan to build an aqueduct from Owens Valley to Los Angeles. Most Californians know the story. Through a series of shady deals, Mulholland and Eaton managed to get control of the water in the Owens Valley and, in 1913, the aqueduct was finished. It was great news for the new city, but terrible news for many of the creatures (not to mention the farmers) who depended on the water flowing into and from the Owens Lake to survive.

One of those animals is the Owens pupfish.

So named because they exhibit playful, puppy-like behavior, the Owens pupfish rapidly began to disappear. Pupfish are well-known among scientists for being able to live in extreme and isolated situations. They can tolerate high levels of salinity. Some live in water that exceeds 100° Fahrenheit, and they can even tolerate up to 113° degrees for short periods. They are also known to survive in near-freezing temperatures common in the lower desert.

But hot or cold are one thing. The disappearance of water altogether is another.

As California has developed, and as climate change has caused temperatures to rise, thus increasing evaporation, all of California’s pupfish populations have come under stress. Add to these conditions, the early 20th-century introduction by the California Department of Fish and Wildlife of exotic species like largemouth bass and rainbow trout to lakes and streams in the eastern Sierras, and you get a recipe for disaster. And disaster is exactly what happened.

The remains of the Owens River flowing through Owens Valley in California. Credit: Erik Olsen

Several species of pupfish in the state have been put on the endangered species list. Several species, including the Owens pupfish, the Death Valley Pupfish and the Devils Hole pupfish are some of the rarest species of fish on the planet. The Devils Hole pupfish recently played the lead role in a recent story about a man who accidentally killed one of the fish during a drunken spree. According to news stories, he stomped on the fish when he tried to swim in a fenced off pool in Death Valley National Park. He went to jail.

The impact on the Owens pupfish habitat was so severe that in 1948, just after it was scientifically described, it was declared extinct.

That is, until one day in 1964, when researchers discovered a remnant population of Owens pupfish in a desert marshland called Fish Slough, a few miles from Bishop, California. Wildlife officials immediately began a rescue mission to save the fish and reintroduce them into what were considered suitable habitats. Many were not, and by the late 1960s, the only remaining population of Owens pupfish, about 800 individuals, barely hung on in a “room-sized” pond near Bishop.

On August 18, 1969, a series of heavy rains caused foliage to grow and clog the inflow of water into the small pool. It happened so quickly, that when scientists learned of the problem, they realized they had just hours to save the fish from extinction.

Edwin Philip Pister
Edwin Philip Pister

Among the scientists who came to the rescue that day was a stocky, irascible 40-year old fish biologist named Phil Pister. Pister had worked for the California Department of Fish and Game (now the California Department of Fish and Wildlife) most of his career. An ardent acolyte of Aldo Leopold, regarded as one of the fathers of American conservation, Pister valued nature on par, or even above, human needs. As the Los Angeles Times put it in a 1990 obituary, “The prospect of Pister off the leash was fearsome.”

“I was born on January 15, 1929, the same day as Martin Luther King—perhaps this was a good day for rebels,” he once said.

Pister had few friends among his fellow scientists. Known for being argumentative, disagreeable, and wildly passionate about the protection of California’s abundant, but diminishing, natural resources, Pister realized that immediate action was required to prevent the permanent loss of the Owens pupfish. He rallied several of his underlings and rushed to the disappearing pool with buckets, nets, and aerators.

Within a few hours, the small team was able to capture the entire remaining population of Owens pupfish in two buckets, transporting them to a nearby wetland. However, as Pister himself recalls in an article for Natural History Magazine:

“In our haste to rescue the fish, we had unwisely placed the cages in eddies away from the influence of the main current. Reduced water velocity and accompanying low dissolved oxygen were rapidly taking their toll.”

Los Angeles Aqueduct. Credit: Erik Olsen

As noted earlier, pupfish are amazingly tolerant of extreme conditions, but like many species, they can also be fragile, and within a short amount of time, many of the pupfish Pister had rescued were dying, floating belly up in the cages. Pister realized immediate action was required, lest the species disappear from the planet forever. Working alone, he managed to net the remaining live fish into the buckets and then carefully carried them by foot across an expanse of marsh. “I realized that I literally held within my hands the existence of an entire vertebrate species,” he wrote.

Pister managed to get the fish into cool, moving water where the fish could breathe and move about. He says abouty half the the population survived, but that was enough.

Today, the Owens pupfish remains in serious danger of extinction. On several occasions over the last few decades, the Owens pupfish has suffered losses by largemouth bass that find their way into the pupfish’s refuges, likely due to illegal releases by anglers. In 2009, the US Fish and Wildlife Service estimated that five populations totaling somewhere between 1,500 and 20,000 Owens pupfish live in various springs, marshes, and sloughs in the Owens Valley, where they are federally protected.

by Erik Olsen

Additional material:

Oral history video featuring Phil Pister recounting his career and that fateful day.

Read previous articles in the California Science Weekly.

Why bringing back California’s kelp is so important

Sea urchins have devastated kelp forests in California.

Two centuries ago, the waters off the California coast were home to a vibrant ecosystem of plants and animals. Vast forests of kelp provided habitat for thousands of species of fish and invertebrates. Some of these kelp forests were so dense that light hardly penetrated to the seafloor. But now, along much of the coastline, the kelp is all but gone.

The tragedy here goes far beyond species loss and a troubling decline in overall biodiversity in our coastal waters. Kelp are also great at taking up carbon dioxide from the atmosphere and they help reduce acidification of the oceans, essentially cleaning the water and bringing balance to the entire ecosystem.

But now, that balance is has been disrupted. A recent study says that California’s bull kelp (Nereocytis luetkeana) forests (one of several species that are endemic here) have declined by 93% in just the last five years.

It’s difficult to fathom the scale of this loss, and we are only beginning to understand what it will mean for the overall health of our coastal waters. When the kelp disappears, the entire complex web of organisms that rely on it for habitat and food is disturbed. That is to say, large swaths of the near-shore California coastal ecosystem depend upon kelp.

So, what is happening? Well, first a little history.

A healthy kelp forest in Channel Islands National Park (NPS)

Two centuries ago, when kelp forests along the coast were so abundant they stretched for hundreds of miles with thick canopies that could be seen at the surface. At the time, urchins existed, but their populations were held in check by sea otters, which have been known to eat 1/4 of their body weight in urchins in a day. But unrestrained hunting by trappers (often Russian and British) in the early 1800s and into the mid-century brought sea otter populations down so low, at one point they were considered extinct in the wild. With the otters gone, urchins flourished and along certain stretches of coast, the kelp disappeared. Remember, this was 200 years ago, long before California was even a state.

Otters have come back to certain stretches of the California coast, especially near Monterey, and in some cases, the kelp has come back. And, in fact, even now, some places around the state, things aren’t nearly so bad. One-third of southern California’s kelp forests are found within Channel Islands National Park and Channel Islands National Marine Sanctuary, where no-take marine reserves prohibit all take of living, geological, or cultural resources. In the reserve, California sheephead, spiny lobsters, and sunflower stars eat sea urchins and keep their population from exploding.

Bust most other regions are not so lucky. And things have gotten even worse. And this is where it gets more complicated.

An intense ocean warming period between 2014 and 2017 is the likely culprit in causing a mass die-off of starfish. Starfish prey on native purple urchins, keeping their numbers in check. With mass numbers of sea stars dead, the urchins proliferated, eating their way through the kelp forests. The result: disaster.

“What we’re seeing now are millions and millions of purple sea urchins, and they’re eating absolutely everything,” said Laura Rogers-Bennett, an environmental scientist with UC Davis Karen C. Drayer Wildlife Health Center and California Department of Fish and Wildlife operating out of the UC Davis Bodega Marine Laboratory. “They can eat through all the anemones, the sponge, all the kelp, the fleshy red algae. They’re even eating through calcified alga and sand.”

The loss of kelp forests in California should be immediately recognized as a major ecological problem to solve, and while some projects are underway to do just that, much more needs to be done.

Several organizations, most of them California-based, are trying to reduce the number of urchins in Southern California. For example, UC Davis researchers are working with Bay Area shellfish company Urchinomics to explore “ranching urchins, removing them from the seafloor and fattening them up to be sold as sushi. Urchins are highly valued by Japanese consumers and are even sold in some California sushi restaurants. One problem is that purple urchins tend to be too small to harvest for human consumption, hence the need to increase their size via aquaculture. But will this be enough to stop the urchin’s march towards environmental saturation? Probably not.

The Bay Foundation in Santa Monica launched a program to restore kelp beds around 150 acres of urchin barrens along the rocky reefs off Palos Verdes. Scientists, recreational divers, and fishermen go down and smash the urchins with small hammers. The effort has shown promise, with kelp growing back in 46 acres of restored reef. Again, this is not nearly enough.

Other strategies are outlined in the Sonoma-Mendocino Bull Kelp Recovery Plan, released last June by the Greater Farallones Association and California Department of Fish and Wildlife. It includes measures such as creating a kelp oasis to preserve seed stock and repopulate bull kelp when conditions are conducive to restoration.

This may all be too little too late. But we believe state, local and federal agencies should redouble their efforts now to mitigate the loss of kelp in California waters. The implications for further, perhaps total, loss of California’s once-flourishing kelp forests are just too dire and action is required now. As the authors of the report write “it may take decades before the complex biological communities, associates, and the ecosystem services provided by macroalgal [seaweed] forests rebound.”

Why are California’s redwoods and sequoias so big and tall?

Photo by Spencer Backman on Unsplash

Part 2 of an ongoing series about California’s unique and remarkable trees.

California is a state of superlatives. The oldest living thing lives here. The largest animal in the history of the world swims off our shores. The hottest temperature ever recorded baked visitors at Death Valley’s Furnace Creek back in 1913. California boasts the highest point in the contiguous United States and arguably the tallest waterfall in the country.

We also have the world’s tallest and biggest trees.

California’s giant sequoias and redwoods are nature’s skyscrapers. Redwoods exist in a few narrow pockets in Northern and Central California and into Southern Oregon. Sequoias live exclusively in small groves in central and Northern California with the largest grouping of them found in Sequoia National Park. These two tree species are wonders of the biological world. They are also some of the most magnificent things to behold on the planet.

I have personally climbed the Stagg tree (see photo below), the fifth-largest sequoia in the world, and I will forever remember the experience.

Erik Olsen climbs the Stagg tree, a giant sequoia.
The author climbs the Stagg tree, the fifth-largest tree in the world. (Erik Olsen)

We are lucky to still have our big trees, what’s left of them, anyway. Just a century and a half ago, old-growth redwoods and sequoias were relatively plentiful. People marveled at them, with some early settlers in California spinning unbelievable yarns of trees that rise from the earth “like a great tower“. They also saw them as a bounteous resource, ripe for plunder.

By 1900, nearly all of California’s tall trees had been purchased by private landowners who saw in the trees not beauty, but dollar signs. By 1950, nearly all of the old-growth redwoods and sequoias had been cut down for timber and other purposes. Today, only 5 percent of the old-growth coast redwood forest remains. The largest surviving stands of ancient coast redwoods are found in Humboldt Redwoods State Park, Redwood National and State Parks and Big Basin Redwoods State Park. It’s a wonder and a blessing that there are some left. And even then, they face an uncertain future thanks to climate change.

Professional tree climber Rip Thompkins at the top of the Stagg tree, a giant sequoia.

Sequoias and redwoods are closely related. The primary difference between sequoias and redwoods is their habitat. Redwoods live near the coast, while sequoias live in subalpine regions of California. Redwoods are the tallest trees in the world. Sequoias are the biggest, if measured by circumference and volume. Redwoods can grow over 350 feet (107 m). The tallest tree in the world that we know of is called the Hyperion, and it tickles the sky at 379.7 feet (115.7 m). But it is quite possible another tree out there is taller than Hyperion. Redwoods are growing taller all the time, and many of the tallest trees we know of are in hard to reach areas in Northern California. Hyperion was only discovered about a decade ago, on August 25, 2006, by naturalists Chris Atkins and Michael Taylor. The exact location of Hyperion is a secret to protect the tree from damage.

The giant sequoia (Sequoiadendron giganteum) is Earth’s most massive living organism. While they do not grow as tall as redwoods – the average size of old-growth sequoias is from 125-275 feet – they can be much larger, with diameters of 20–26 feet. Applying some basic Euclidean geometry (remember C = πd?), that means that the average giant sequoia has a circumference of over 85 feet.

Many of the remaining sequoias exist on private land, and in fact, one of the largest remaining stands of Sequoias in the world – the Alder Creek Grove of giant sequoias – was just bought by the Save the Redwoods League conservation group for nearly $16 million

Sequoias grow naturally along the western slope of the Sierra Nevada mountain range at an altitude of between 5,000 and 7,000 feet. They tend to grow further inland where the dry mountain air and elevation provide a comfortable environment for their cones to open and release seeds. They consume vast amounts of runoff from Sierra Nevada snowpack, which provides groves with thousands of gallons of water every day. But some say the majestic trees face an uncertain future. Many scientists are deeply concerned about how climate change might affect the grand trees, as drought conditions potentially deprive them of water to survive.

General Sherman tree
The General Sherman tree in Sequoia National Park. Wikimedia.

The world’s largest sequoia, thus the world’s largest tree, is General Sherman, in Sequoia National Park. General Sherman is 274.9 feet high and has a diameter at its base of 36 feet, giving it a circumference of 113 feet. Scientists estimate that General Sherman weighs some 642 tons, about as much as 107 elephants. The tree is thought to be 2,300 to 2,700 years old, making it one of the oldest living things on the planet. (To learn more about the oldest thing in the world, also in California, see our recent feature on Bristlecone pines.) Interesting fact: in 1978, a branch broke off General Sherman that was 150 feet long and nearly seven feet thick. Alone it would have been one of the tallest trees east of the Mississippi.

Many sequoias exist on private land. Just last month, one of the largest remaining private stands of Sequoias in the world – the Alder Creek Grove of giant sequoias – was bought by the Save the Redwoods League conservation group for nearly $16 million. The money came from 8,500 contributions from individual donors around the world. The property includes both the Stagg Tree mentioned above and the Waterfall Tree, another gargantuan specimen. The grove is considered “the Crown Jewel” of remaining giant Sequoia forests.

Redwoods (Sequoia sempervirens), also known as coast redwoods, generally live about 500 to 700 years, although some have been documented at more than 2,000 years old. While wood from sequoias was found to be too brittle for most kinds of construction, the redwoods were a godsend for settlers and developers who desperately needed raw material to build homes and city buildings, to lay railroads, and erect bridge trestles. The timber companies who profited from redwoods only began to cut them down in earnest a bit over a century ago. But cut them down they did, with vigor and little regard for the preservation of such an amazing organism. After World War II, California experienced an unprecedented building boom, and the demand for redwood (and Douglas fir) soared. Coastal sawmills more than tripled between 1945 and 1948. By the end of the 1950s, only about 10 percent of the original two-million-acre redwood range remained untouched.

So how did these trees get so big and tall? We don’t know for sure, but some scientists believe it has to do with the climate in which they grow. Sequoias benefit from Californa’s often prodigious snowpack, which seeps into the ground, constantly providing water to the roots of the trees. Redwoods get much of their water from the air, when dense fog rolls in from the coast and is held firm by the redwoods themselves and the steep terrain. The trees’ leaves actually consume water in fog, particularly in their uppermost shoots. According to scientists who study the trees using elaborate climbing mechanisms to reach the treetops, in summer, coast redwoods can get more than half of their moisture from fog. (In fact, fog plays a central role in sustaining several of California’s coastal ecosystems.) The reason is that fog is surprisingly dense with water. One study from scientists Daniel Fernandez of California State University, Monterey Bay, showed that a one-square-meter fog collector could harvest some 39 liters, or nearly 10 gallons, of water from fog in a single day.

Another answer to the redwood’s size may lie in the tree’s unusual, enormous genome. The ongoing Redwood Genome Project has revealed that the tree’s genome is ten times the size of the human genome (27 base pairs compared to three billion in humans), with six copies of its chromosomes (both humans and giant sequoias only have two copies) existing in a cell. It’s possible that by better understanding the redwood genome, we may uncover the precise genetic mechanism that explains how these trees have gotten so big and tall.

Yet another factor may be the trees remarkable longevity. They are survivors. The Sierra Nevadas have long experienced dramatic swings in climate, and this may be yet another of those swings that the trees will simply endure. Or maybe not. For most of the time that redwoods and sequoias have existed, they have done a remarkable job fighting off fires, swings in climate, as well as disease and bug infestations. Because their bark and heartwood are rich in compounds called polyphenols, bugs and decay-causing fungi don’t like them.

Giant sequoias in California. Erik Olsen

The thirst for fog and proximity to water sources could be the trees undoing, however. Although they have managed to survive for hundreds if not thousands of years, climate change could well be the one new variable that changes everything for the trees.

As the air heats up due to global warming, there is a rising threat to the trees’ survival. Warm air pulls moisture from leaves, and the trees often close their pores, or stomata, to maintain their water supply. When the pores close, that prevents carbon dioxide from nourishing the tree, halting photosynthesis. The climate in areas where the trees grow hasn’t yet experienced the kind of temperatures that might kill them, but we are really just at the beginning of this current era of global warming, and some scientists warn hotter temperatures could doom many trees.

That said, other studies that show the increased carbon that causes warming could actually be good for the trees. According to an ongoing study from Redwoods Climate Change Initiative, California’s coast redwood trees are now growing faster than ever. As most people know, trees consume carbon dioxide from the air, so, the scientists argue, more carbon means more growth.

We will see. The good news is that to date, no drought-induced mortality has been observed in mature coastal redwoods or giant sequoias. 

It all comes down to some kind of balance. Trees may benefit from more carbon, but if it gets too hot, trees could start to perish. That’s a bit of a conundrum, to say the least.

Photo by Nikolay Maslov on Unsplash

The prospect of losing these magnificent trees to climate change is a double whammy. Not only would a mass die-off of trees be terrible for tourism and those who simply love and study them, but trees are some of the best bulwarks we have on the planet to fight climate change. Redwoods are among the fastest-growing trees on earth; they can grow three to ten feet per year. In fact, a redwood achieves most of its vertical growth within the first 100 years of its life. Among trees that do the best job taking carbon out of the atmosphere, you could hardly do better than redwoods and sequoias.

Numerous groups are actively trying to plant more redwoods around the world in the hope that they might become a sink for carbon dioxide in the atmosphere. Indeed, there is some evidence that planting vast tracks of trees globally could have a major impact on climate change.

The Archangel Ancient Tree Archive, an organization out of Copemish, Michigan, has been “cloning” California’s big trees for nearly a decade. They take snippets of the trees from the top canopy and replant them, essentially creating genetically identical copies of the original tree. It’s more like propagating than cloning, but that’s what they call it. The group’s founder, David Milarch, believes fervently that planting large trees is our best bet in stopping climate change. This is the video story I produced about Milarch back in 2013. It’s worth a watch. He’s an interesting character with a lot of passion.

Preserving and protecting what’s left of these amazing organisms should be a priority in California. These trees are not only part of the state’s rich natural legacy, but they offer ample opportunities for tourism and strengthening the economies of the regions where they grow. It’s hard to visit Redwood National and State Parks or Sequoia & Kings Canyon National Parks and to come away with anything but awe at these magnificent organisms. California is special, and we are blessed to have these trees and the places where they grow in our state.

Other resources:

Save the Redwoods League has got a lot of interesting information about California’s redwoods, including some great YouTube videos.

Redwood National and State Parks

A lovely short film part of Nat Geo’s Short Film Showcase on redwoods.

Video by California Through My Lens: 36 Hours in Redwood National Park

The Majesty and Mystery of California’s Bristlecone Pines

Bristlecone Pine

Lying east of the Owens Valley and the jagged crags of the Sierra Nevadas, the White Mountains rise high above the valley floor, reaching over 14,000 feet, nearly as high as their far better-known relatives, the Sierra Nevadas. Highway 168 runs perpendicular to highway 395 out of Big Pine and leads up into the mountains to perhaps the most sacred place in California.

Far above sea level, where the air is thin, live some of the most amazing organisms on the planet: the ancient bristlecone pines. To the untrained eye, the bristlecone seems hardly noteworthy. Gnarled and oftentimes squat, especially when compared to the majestic coastal redwoods and giant sequoias living near the coast further west, they hardly seem like mythical beings. But to scientists, they are a trove of information, offering clues to near immortality and to the many ways that the earth’s climate has changed over the last 5,000 years. 

In the January 20 edition of the New Yorker, music writer Alex Ross writes about the trees and the scientists who are trying to unlock the secrets of the bristlecone’s unfathomable endurance. The trees, he writes, “seem sentinel-like”.

Bristlecones are the longest living organism on earth. The tree’s Latin name is Pinus longaeva, and it grows exclusively in subalpine regions of the vast area known to geologists as the Great Basin, which stretches from the eastern Sierra Nevadas to the Wasatch Range, in Utah. Bristlecones grow between 9,800 and 11,000 feet above sea level, where some people get dizzy and there are few other plants or animals that thrive. The greatest abundance of bristlecones can be found just east of the town of Bishop, California in the Ancient Bristlecone Pine Forest. There, a short walk from where you park your car, you can stroll among these antediluvian beings as they imperceptibly twist, gnarl and reach towards the heavens. 

Video of ancient bristlecone pine that I shot and put together.

While most of the bristlecones in the national Ancient Bristlecone Pine Forest are mere hundreds of years old, there are many that are far older. Almost ridiculously so. Methuselah, a Great Basin bristlecone, is 4,851 years old, as measured by its rings, taken by scientists decades ago using a drilled core. Consider that for a moment: this tree, a living organism, planted its tentacle-like roots into the soil some 2000 years before the birth of Christ, around the time that the Great Pyramids of Egypt were built. By contrast, the oldest human being we know of lived just 122 years. That’s 242 human generations passing in the lifetime of a single bristlecone that still stands along a well-trodden trail in the high Sierras. 

Bristlecone and starry sky: National Park Service
National Park Service

That said, if you were to try and see Methuselah for yourself, you are out of luck. The Forest Service is so protective of its ancient celebrity that it will not even share its picture. What’s more, it’s probably the case that there are bristlecones that are even older than Methuselah. Scientists think there could be trees in the forest that are over 5,000 years old. 

How the bristlecone has managed this incredible feat of endurance is a mystery to researchers. Many other tree species are prone to insect infestations, wildfires, climate change. In fact, over the last two decades, the vast lodgepole pine forests of the Western United States and British Columbia have been ravaged by the pine beetle. Millions of acres of trees have been lost, including more than 16 million of the 55 million acres of forest in British Columbia.  

But insects don’t seem to be a problem for bristlecones. Bristlecone wood is so dense that mountain-pine beetles and other pests can rarely burrow their way into it. Further, the region where the bristlecones live tends to be sparse with vegetation, and thus far less prone to wildfire. 

Jeff Sullivan
Jeff Sullivan

So how do the trees manage to live so long? 

A recent study by scientists at the University of North Texas looked at the amazing longevity of the ginkgo tree, examining individuals in China and the US that have lived for hundreds, perhaps more than a thousand years. One thing they found is that the trees’ immune systems remain largely intact, even youthful, throughout their lives. It turns out the genes in the cambium, or the cylinder of tissue beneath the bark, contain no “program” for senescence, or death, but continue making defenses even after hundreds of years. Researchers think the same thing might be happening in the bristlecone. This is not the case in most organisms and certainly not humans. Like replicants in the movie Blade Runner, we seem to have a built-in clock in our cells that only allows us to live for so long. (I want more life, f$@$@!

Scientists at the University of Arizona’s Laboratory of Tree-Ring Research (LTRR) have built up the world’s largest collection of bristlecone cross-sections, which they carefully examine under the microscope, looking for clues about how the trees have managed to survive so long, and how they can inform us of the many ways the earth’s climate has changed over the millennia.

The LTRR houses the nation’s only dendrochronology lab (the term for the study of tree rings), and the researchers there have made several discoveries using tree cores that have changed or confirmed climate models. For example, in 1998, the climatologist Michael E. Mann published the “hockey stick graph,” that revealed a steep rise in global mean temperature from about 1850 onward (i.e. the start of the industrial revolution). There was intense debate about this graph, with many scientists and climate change skeptics saying that Mann’s projections were too extreme. But numerous subsequent studies, some using the trees’ rings new models, confirmed the hockey-stick model. 

The bristlecones will continue to help us understand the way the earth is changing and to see into the deep human past in a way few other living organisms can do. They also improve our understanding of possible future environmental scenarios and the serious consequences of allowing carbon levels in the atmosphere to continue to grow. 

In this sense, they truly are sentinels.

But setting aside the science for a moment, it should be said that the trees themselves, in their gnarled, frozen posture, are truly are beautiful. They should be protected and preserved, admired and adulated. Indeed, Federal law prohibits any attempt to damage the trees, including taking a mere splinter from the forest floor. The trees have also become an obsession for photographers, particularly those who favor astrophotography. A quick search on Instagram reveals a stunning collection of images showing the majesty and haunting beauty of these ancient trees. 

So, if you are ever headed up highway 395 into the Sierras, it is well worth the effort to make the right-hand turn out of Big Pine to visit the Ancient Bristlecone Pine Forest. The air is thin, but the views are spectacular. And where else can you walk among the oldest living things on the planet?

Note: there is a wonderful video produced by Patagonia on the bristlecones and some of the scientists who study them. It’s well worth watching. 

Ancient Bristlecone Pines by Drone


Last week we had the opportunity to head up Highway 395 into Big Pine where we made a left up to the Ancient Bristlecone Pine Forest. Because of the coronavirus, the place was empty. Not a soul to be seen anywhere.

We did a feature on bristlecones a few months ago in which we marveled at the majesty and seeming immortality of these incredible organisms, probably the longest living things on the planet. We brought along a drone to get some shots of these trees, whose gnarled, swirling branches are like something out of a fantasy novel. Take a minute (literally a minute) to enjoy.

Saving the White Abalone is Part of a Much Bigger Story

White Abalone - NOAA

The current effort to bring back the white abalone is one of numerous projects underway in California to revive the state’s once-thriving marine environment.

If you grew up in Southern California in the 1970s, there were a few things that defined California: surfing, skateboarding, the Eagles (preferably on the radio while driving down the Pacific Coast Highway) and abalone.

The abalone was an iconic totem of beach culture, celebrated in poetry and song, a wondrous gift from mother nature. Almost every house near the coast had upturned abalone shells on the coffee table or as decorative items in a garden, their opalescent mother-of-pearl interior shells glistening jewel-like beneath the warm California sun. They hung near front doors or in backyards by the half dozen from string or fishing line, acting as wind chimes when the cool breezes blew in from the Pacific, tousling the sunbleached hair of surfers and bringing a reassuring cooling to the bare skin, which even today seems such a unique California phenomenon. Our air, our light is different than other places.

As the Los Angeles Times put it in a recent story, “Abalone once were to California what lobster is to Maine and blue crab to Maryland, so plentiful they stacked one on top of another like colorful paving stones.” 

But then something terrible happened. The white abalone fishery went out of control. Commercial abalone fishing from 1969–1972 was so lucrative and so unrestrained that the catch went from roughly 143,000 pounds per year to just 5,000 pounds per year in less than a decade. Millions of pounds were harvested by commercial fishermen, and diving for abalone was a common and favored pastime. In 1997, state officials in California ceased all white abalone fishing because population levels had reached perilous lows. By 2001, the numbers of white abalone found along the coast were so low that they became the first marine invertebrate listed as endangered on the Endangered Species Act. But it was too late. The population had declined by almost 99 percent.

California is home to seven species of abalone (red, pink, black, green, white, pinto, and flat), none of them are plentiful any longer in California waters, but it is the white abalone, in particular, that became the most prized for its tender, flavorful flesh. We loved white abalone. And then they were gone.

White abalone. Credit: NOAA
White abalone. Credit: NOAA

Now, scientists at UC Davis’ Bodega Marine Lab in Bodega Bay are in the midst of one of the most important species restoration efforts in the history of the state. On November 18, researchers from the marine lab, in cooperation with the National Oceanic and Atmospheric Administration (NOAA) carefully released thousands of baby white abalone into the waters of Southern California. Biologists measured and marked each one with a unique numbered tag affixed to their shell to distinguish them from wild white abalone (of which there are perilously few). This marked the first release of endangered white abalone into the wild in coastal waters. What’s crazy is that the white abalone that has been bred in the lab constitute the largest population of the slow-moving mollusks in the world. That’s right, there are more white abalone living in captivity than there are in the wild. Until now.

“Early on we knew that this species was really in danger of going extinct and that the only viable alternative to save it was starting a captive breeding program,” said Ian Taniguchi, a biologist with the California Department of Fish and Wildlife (CDFW) who has been involved in white abalone restoration since 1992.

The success or failure of the reintroduction program could mean life or extinction for the iconic species, and a great deal of money and years of effort have gone into the recovery program. Over the coming years, divers will visit the sites on a weekly basis to monitor their survival and growth. Every six months, additional releases are planned, with the goal of placing tens of thousands of juvenile white abalone in the sea over the next five years. 

“Early on we knew that this species was really in danger of going extinct and that the only viable alternative to save it was starting a captive breeding program.”

Ian Taniguchi, a biologist with the California Department of Fish and Wildlife (CDFW)

Abalone are far more valuable than merely as a food item. They are keepers of the kelp forest. According to scientists, the abalone eat kelp, but they also clear rocks of any dominant species and thus increase kelp diversity so that multiple kelp species can flourish. When the kelp is healthy and diverse, coastal waters see an explosion of diversity in fish and other animals that depend on kelp forest habitat.  

While the success of the abalone recovery program hangs in the balance, its mere existence needs to be recognized as part of a much larger tapestry of species and ecosystem recovery projects currently underway that are aimed at restoring California’s coastal ecosystem to some semblance of what it was centuries ago.

That is, of course, impossible. The numerous written accounts by early California settlers (many of them Spanish) describe plants and animals in such unfathomable abundances, the likes of which we will never be able to return. But we can reclaim some of it. And after decades of witnessing severe declines in fish species, kelp, water quality and coastal habitat, it seems we may be finally turning a corner. Maybe.

Some of the projects underway include bringing back white sea bass, protection of sea lions, whales and dolphins under the Marine Mammal Protection Act, a rise in white shark populations, kelp restoration, and, perhaps the most significant achievement of all, the creation of a vast (and enforced), network of Marine Protected Areas (MPAs).

Alone, each of these efforts is a small step in the right direction in making our seas healthy and fruitful. Together, they represent the most significant set of achievements to reverse the impact of human settlement on the ocean environment in the history of the world. Of course, we are nowhere near done, and the growing (and terrifying) threats from climate change could render all of this moot. Warming seas, the spread of new diseases (and old ones), acidification, all these things together could unravel these accomplishments in mere decades.

There are still many challenges ahead. Recent kelp die-offs in Northern California due to the explosion in purple urchin populations are extremely worrisome. Phenomena like sea star wasting disease and the marine heatwave of 2013-2015 may have wrought permanent change to our marine ecosystem. But the fact that we are now acting so aggressively to apply science and ingenuity to solve the myriad problems we ourselves caused should give us some hope that positive change is possible.

There is no time for rest. If anything now is the time to redouble our efforts to make our oceans cleaner, to help species recover and to restore the lost balance so that future generations can experience the incredible beauty and bounty of the sea.