Nativist fantasies about redwoods

I love redwood trees.  I doubt there is anyone who doesn’t.  So, you might wonder why I am going to tell you why planting more of them in our public parks in the San Francisco Bay Area isn’t a good idea.  Read on…

History of redwoods in California

The native range of redwoods is very small.  According to the US Forest Service, “The redwoods occupy a narrow strip of land approximately 450 miles in length and 5 to 35 miles in width.  The northern boundary of its range is…in the Siskiyou Mountains within 15 miles of the California-Oregon border.  The southern boundary of redwood’s range is…in the Santa Lucia Mountains of southern Monterey County, California.” 

Many redwoods were destroyed for timber and many to clear land for other purposes, such as roads, agriculture, and development.  However, the primary reason for its small native range is the demanding horticultural conditions required by redwoods.  They don’t tolerate wind, particularly salty wind from the ocean.  They require a lot of water.  Where there isn’t enough rain, summer fog compensates for inadequate water.  They need well drained soil and plenty of space to grow to their prodigious size of over 200 feet.

Because of these horticultural requirements, there weren’t many redwood trees in the San Francisco Bay Area prior to settlement by Europeans in the 19th century.  There were no redwoods in San Francisco where the soil was sandy and strong wind from the ocean is salty.  In the East Bay, the pre-settlement redwood forest was less than 5 square miles. (1) In fact, only 2.3% of pre-settlement Oakland was forested and redwoods were a small fraction of the tree cover. (2)

Trying to defy nature

Despite their demanding horticultural requirements and the historical evidence of these limitations, redwoods are often planted where they cannot survive because they are beautiful, popular, and “native” to California.  As the climate changes, rising temperatures and drought have killed many of the redwoods that were planted in the past.  As the climate continues to change, the future of redwoods in California becomes even more doubtful. 

San Francisco’s 2017 Annual Report of the Urban Forestry Council reports that redwoods planted on public land in San Francisco are dying:

“Agencies such as SFO [San Francisco Airport], Zuckerberg General Hospital, and SFSU [San Francisco State University] reported concerns with declining health of redwood trees under their care.  This iconic California native tree is not drought tolerant and current research shows that specimens planted in landscape settings outside their native areas are suffering from water restrictions and irrigation with non-potable water throughout the Bay Area.  Redwood trees’ water and other cultural needs should be considered when planning future plantings since periods of extreme drought are expected to continue as the climate continues to change.”  (page 11)

Dead redwoods, Lake Temescal, March 2018

We see similar examples of planting redwoods in East Bay Regional Parks, where they are dying.  Redwoods were planted at Lake Temescal about 5 years ago.  Despite the fact that many of them are dead, the Park District continues to plant new redwood saplings adjacent to their dead relatives.  Although it is a relatively sheltered area, the trees may have been killed by salty irrigation water.

The growing gap between science and public policy

On March 10, 2018, I attended a conference about resiliency in Davis, California: “Deepening our Roots:  Growing Resilient Forests.” I went to hear Greg McPherson speak because I have read many of his scientific publications and I admire his work.  McPherson’s research at the US Forest Service about the economic value of ecosystem services provided by urban trees (carbon storage, reduction of energy use for heat/cooling, increased property values, removal of particulate pollution, etc.) has been vital to those who defend our urban forest.

McPherson lives in Davis, where he is conducting a 20-year study about the urban forests of the future, i.e., those that will survive predicted changes in the climate. Three years into the study, his research team has made some preliminary recommendations for the trees that are likely to survive anticipated changes in the climate.  None is native to Northern California. Most are foreign, particularly Australian.

McPherson also showed photos of trees being planted now that are destined to die in the near future. One was a densely planted row of redwoods in a median strip in Davis. Professor Arthur Shapiro, who lives in Davis, made this comment when I told him about McPherson’s presentation, “Redwoods are the walking dead here. I’ve known that forever and a year.”  McPherson said redwoods have no long-term future in most of California. None of the public land managers in the Bay Area seems to know that.

East Bay Regional Park District ignores reality

East Bay Regional Park District is making a big investment in expanding redwood forests into places where redwoods did not exist in the past and where they are unlikely to survive in the future.  They are clear-cutting non-native trees and creating visual screens on the periphery of the clear-cuts by planting redwoods along the trails.  This photo was taken in Sibley Volcanic Reserve in March 2018 (the area is larger than shown in this photo):

Sibley Volcanic Reserve. Photo by Larry Danos, March 2018

These are areas that were a part of EBRPD’s “Wildfire Hazard Reduction and Resource Management Plan.”  The Fuels Management Prescription for this Recommended Treatment Area was supposed to thin the eucalyptus trees to spacing of 25 feet by removing only small trees with trunks less than 10 inches in diameter.  The original plan for this area did not include any replanting of trees.

The recent implementation of this project suggests that EBRPD’s strategy for tree removals has changed.  At least in this instance, the trees have been clear-cut, not thinned.  And redwoods were planted where none were originally planned. 

It is always risky to speculate about the motivations of other people, but I will venture a guess about this new strategy.  The Park District’s commitment to destroying non-native trees seems to have escalated from thinning to clear-cutting.  And the public’s opposition to the destruction of trees seems to have convinced the Park District that they must plant native trees to replace the trees they have destroyed.

Unfortunately, the Park District does not seem to have taken the changing climate into consideration.  The redwoods may survive long enough to placate the public, but they are unlikely to survive in the long-term.  It is a good public relations strategy, but not a good strategy for a landscape in transition in a changing climate.  It is also not a responsible strategy, given that the carbon stored by the trees being destroyed will contribute to the changing climate and won’t be replaced by dead redwood trees. 

(1) Sherwood Burgess, “The Forgotten Redwoods of the East Bay,” California Historical Society Quarterly, March 1951.

(2) Nowak, David, “Historical vegetation change in Oakland and its implications for urban forest management,” Journal of Arboriculture, 19(5): September 1993

A guest post addresses a nativist myth about redwoods

We are grateful to Keith McAllister for this guest post about the history of redwood trees in the East Bay.  One of many myths that we often hear repeated by native plant advocates is that all of our non-native trees can be and should be replaced by redwoods.* Although we like redwoods a great deal, this wish is unrealistic because redwoods cannot grow in most places where non-native trees are thriving because they require more water and they do not tolerate wind.  The strongest evidence that redwoods are not suitable substitutes for our non-native forests is where they grew before Europeans arrived in the East Bay and where they grow now.  Thank you, Keith, for this valuable contribution to our knowledge of the natural history of the East Bay.

Redwoods of the East Bay Hills

The first Europeans to visit the East Bay Hills late in the 18th century found forests of magnificent old redwood trees (Sequoia sempervirens), with some trees 32 feet in diameter and over 300 feet tall.  However, contrary to the mythology of native plant enthusiasts, the hills were never covered with redwoods.  The redwoods of 1776 were essentially where the redwoods are today, in three forests:  the western slopes where Joaquin Miller Park now sits, the canyon of Redwood Creek which now comprises Redwood Regional Park, and the canyon of upper San Leandro Creek near the town of Canyon. The entire forested region lay within an area about 3 ½ miles long and ½ to 2 miles wide, less than five square miles. For context, Oakland and Berkeley cover 95.7 square miles.  The hills were primarily grasslands.

The East Bay redwoods were first seen by the de Anza expedition in April, 1776, on its fruitless attempt to get “around” San Francisco Bay to Marin County.  The Carquinez Straits and the San Joaquin/Sacramento delta were an unpleasant surprise.  A map of the bay drawn a few weeks later by Jose de Canizares, pilot for Juan Manuel de Ayala on the ship San Carlos, showed forests on the east side of the bay.

Map of San Francisco bay by Canizares, 1776
Map of San Francisco bay by Canizares, 1776

Some timbers from East Bay trees were used in the construction of Mission San Jose at the beginning of the 19th century, but logging operations did not affect the forests for some time.  Contrary to urban legend, East Bay redwoods were not used to construct the presidio or mission in San Francisco.  Redwood lumber was exported from Ft Ross, Monterey, and the Santa Cruz area in the 1820’s, primarily to the Sandwich Islands (now Hawaii), but there is no historical evidence of any export from the East Bay.

Redwood trees in Oakland. Creative Commons
Redwood trees in Oakland. Creative Commons

There is evidence of logging in the East Bay from 1840-41, with the lumber sent to Yerba Buena (now San Francisco) for export.  With a mere twenty houses in Yerba Buena, local demand couldn’t support much logging.  East Bay logging virtually ceased from 1842 to 1846 when John Sutter expanded his logging operations at Fort Ross and flooded the market with lumber at lower cost than East Bay lumber.

East Bay redwood logging flourished in 1848 and 1849 as the Bay Area population grew with the discovery of gold in the Sierra foothills.  Yerba Buena and other towns around the bay grew rapidly, and some disappointed gold seekers found they could make a living selling lumber for the building boom.  Some of the lumber was hauled east, into Contra Costa County and the towns of Benicia and Martinez.  Still, at the end of 1849, after almost ten years of on-and-off logging, the East Bay redwood forests were essentially intact.  Up to this point all sawing was done with the power of human muscle.

Logging changed radically in the East Bay in 1850 with the introduction of steam-powered sawmills.  The early 1850’s witnessed a frenzy of boom-and-bust logging.  Lumber mills were the center of economic activity in the East Bay.   Lumber prices cycled through periods of $350-$600 to $150-$300 to $40-$50 per 1000 board feet.  There were many bankruptcies.  But through it all, the powerful and efficient steam sawmills chewed through the forests. By 1860 the magnificent redwood forests were reduced to “a sea of stumps.”

Although we will not see giants like those of 1776 in our lifetimes, the redwoods have grown from resprouts of their predecessors  in the same locations they formerly inhabited.  The needs of redwood trees are the same as they were in 1776, primarily water and shelter from the wind.  Those requirements are still met in the same locations, and those locations now have fine second and third growth forests.  There is even an “old growth” tree on a steep, over-grown slope above the York trail in Leona Heights Park.  It’s stunted and straggly looking, and only 450-500 years old, but still it is a tree that survives from 1776.  There are also many redwoods where they didn’t exist in 1776; they were widely planted in the early and middle 20th century.  We are fortunate to have handsome redwood groves on the UC campus, the Mountain View Cemetery, and landscaped areas throughout the East Bay.

Keith McAllister

Notes on sources:

  • Most of the information in this article is taken from “The Forgotten Redwoods of the East Bay” by Sherwood D. Burgess, published in the California Historical Society Quarterly, March 1951.
  • Further information was provided by Dennis Evanosky on a walk sponsored by the Oakland Heritage Alliance in July, 2016.
  • A good visual representation of the historical locations of redwoods, and other vegetation types, is provided by an interactive, touch-screen map in the Natural Sciences section of the Oakland Museum of California.

*There are many comments on Million Trees from native plant advocates about replacing all non-native trees with native trees, including redwoods. Here is just one example: “The East Bay Regional Park Wildfire Hazard Reduction and Resource Management Plan is shrouded in bureaucratic speak but does not seem (I can’t get through the many segments down-loadable only one at a time) to incorporate the idea of replacing highly flammable eucalyptus with elegant redwoods and sequoias that are the most enduring and least flammable of trees.”

There are also similar suggestions from nativists in the public comments on the FEMA grant Environmental Impact Statement, available here:

Contradictory Mission of the National Park Service

As we have reported on Million Trees, the National Park Service (NPS) is eradicating most non-native trees on its properties in the Bay Area.  (see “Our Mission”)  We were therefore taken aback when we stumbled on a news report in the Martinez News-Gazette about the NPS destroying 20 redwoods at the John Muir National Historic Site, which is an NPS property.  It seems these redwoods are the victim of the confused, sometimes contradictory mission of the NPS.

Update:  The links in this article are no longer functional.  We therefore provide a new link that corroborates the statements we have made in this article:  “John Muir National Historic Site:  Strentzel-Muir Gravesite Plan”

Redwoods are, of course, one of California’s most revered native trees.   However, in this particular location, the NPS chooses to destroy them because they were not planted by Muir’s family.  Therefore, the NPS does not consider them “historically accurate.”  NPS says their mission requires that they cut them down.

Ironically, it is the NPS that planted those particular redwoods only 20 years ago.  They planted them after destroying the non-native eucalyptus trees that were in fact historically accurate because they were planted during Muir’s lifetime.  The eucalyptus trees were presumably destroyed because they aren’t native to California.  The redwood trees were planted in their place because NPS says their policies require them to replace every tree they destroy.

Are you confused by this story?  So are we.  We think NPS must be confused as well.  They seem to have several contradictory policies.  Their obsession with native vegetation required them to destroy eucalyptus trees 20 years ago.  Their policy requiring them to replace every tree they destroy obligated them to plant native redwoods.  Twenty years later their policy requiring them to adhere to the historical record has obligated them to cut the redwoods down.  Presumably, that same policy will require them to replant eucalyptus trees.  Where will they go from there?  One wonders.

John Muir National Historical Site, NPS photo

A little historical perspective

The NPS website for the John Muir National Historic Site describes John Muir as the “Father of the National Park Service.”  They also credit him with the creation of the Sierra Club and as the person who convinced President Teddy Roosevelt to create many of our most famous national parks:  Yosemite, Grand Canyon, Sequoia, and Mt. Rainier.  Is the destruction of two generations of mature trees any way for the NPS to honor its father?

The John Muir National Historic Site in Martinez is the home that was built by Muir’s wife’s parents in 1882.  Muir and his wife moved into the home in 1890 after his wife’s father died.  Muir lived in the home for the last 24 years of his life.

Muir’s daughter reported that her father bought about a dozen different varieties of eucalyptus from a neighbor and she helped to plant them on the property.  The property was planted with many non-native plants and trees, including palms that now tower over the property.  Clearly, the Muir family didn’t share the NPS obsession with native plants.  Nor did he think too highly of those who destroy trees:

Any fool can destroy trees.  They cannot run away; and if they could, they would still be destroyed, chased and hunted down as long as fun or a dollar could be got out of their bark hides, branching horns, or magnificent bole backbones.”

–John Muir, Our National Parks, pg 364

As public policy and horticultural fads lurch from one extreme to another, the trees are the losers in man’s conceit.   And those who love trees stand helplessly by, watching the destruction, powerless to prevent it, although we pay for it with our taxes.

Climate Change: Not just global warming anymore

When climate change first became a hot topic (pardon the pun) about 10 years ago, it was consistently described as “global warming.”  When scientists observed the effect that global warming was having on plants and animals in California, they reported that the ranges of native plants and animals were moving to higher elevations and northern latitudes in search of cooler temperatures. 

A study published in Nature magazine in December 2009 found that plants and animals must move as much as 6 miles every year from now to the end of the century to find the conditions they occupy now. When the plants move, the animals that depend on them must adapt or move with them to survive.  Professor Art Shapiro (UC Davis) has been studying California butterflies for over 35 years.  He reported (1) that native butterflies are moving to higher elevations, where temperatures are lower, but that ultimately, “There is nowhere else to go, except heaven.”

More recently we have experienced extreme weather that cannot be adequately described as “global warming.”  We have seen epic storms that have resulted in unprecedented flooding, while other places have experienced prolonged drought.  We are as likely to have an extremely cold winter as we are to have an extremely hot summer.  So the phrase “global warming” has evolved into the more accurate description:  “climate change.”  Aside from our anecdotal observations of these extreme weather events, science is beginning to catch up to provide an analytical understanding of our observations.  The story of climate change is now much more complex and the challenges it presents have become correspondingly more difficult and unpredictable.

Changes in Precipitation

Although places like Pakistan, Australia and some states in the US have recently experienced more rain and flooding than history has recorded, scientists have been reluctant to attribute this to climate change until very recently.  Computer modeling of nearly 50 years of weather data has finally enabled scientists to confirm that these increases in precipitation are the result of “…the effects of greenhouse gases released by human activities like the burning of fossil fuels.” (2)

And, like increases in temperature, changes in precipitation also result in the movement of plants and animals to “find” the conditions to which they are adapted.  Scientists have recently challenged previous assumptions about the movement of plants and animals to higher elevations.  They now report (3) that in some places in California in which precipitation has increased, plants have responded by “moving” to lower elevations.  Scientists acknowledge that the affect on the animal populations in their historic ranges is unpredictable because insects, for example, are more sensitive to changes in temperature and may not be able to move downhill with the plants they presently depend upon. 

Changes in Fog Patterns

Fog is another weather event that is important in California, particularly along the coast, where the warm air from the interior meets the cold air from the ocean.  The result of this confluence of cold and warm air is fog, particularly during the summer when the difference in temperatures is greatest. 

The redwood is our native tree that is closely associated with the foggy coastal conditions in California.  The redwood requires the fog drip to irrigate it during the dry California summer and its range is limited to sheltered areas because it does not tolerate wind.  The range of the redwood in California is therefore limited to a few hundred miles along the coast.  Its narrow range makes it particularly vulnerable to climate change. 



Redwood National Park, NPS photo



In Muir Woods, for example, higher temperatures have reduced coastal fog by 30% in the past century.  Scientists expect this loss of summer fog drip to result in a significant loss of water to the trees and they predict that it will affect the survival of the redwoods in the long-run.(4)

Implications of climate change for native plants?

Clearly, we still have much to learn about climate change:

  • Which weather events are indicators of long-range trends?
  • Climate change is apparently not just one trend, such as increased temperatures.  It is probably many different types of weather events, such as increases or decreases in snow and rainfall, hurricanes and typhoons, fog and wind.  Obviously, we don’t yet have the complete picture of what or where long-range changes have occurred or which are likely in the future. 
  • We know little about the affect that climate change will have on the natural world.  How will plants and animals respond to climate change?  Which plants and animals will survive and, if so, where will they survive?

We marvel at the confidence that the local native plant advocates have in their agenda.  How did they select the pre-European landscape of the late 18th century to replicate?  What makes them think that plants and animals that lived here 250 years ago are still sustainable here, let alone that they will be sustainable in the future? 

These are rhetorical questions, which we will presume to answer for our readers:  Native plant advocates may compensate for radically changed environmental conditions by using intensive gardening methods.  The use of herbicides, irrigation systems, prescribed burns, constant weeding, soil amendments, fences and boardwalks, etc., may artificially mimic the conditions of 250 years ago.  However, the result is a native plant garden that is neither natural nor more biodiverse than what can be achieved with less effort, with less toxicity and fewer scarce resources.  While we can see the value of a native plant garden to preserve our horticultural heritage, we find it more difficult to justify the large-scale efforts that we currently find in all of our public lands.  Is it realistic to garden all of our public lands in perpetuity? 

(1) Arthur Shapiro (UC Davis), Contra Costa Times, 1/19/10

(3) “Mountain plant communities moving down despite climate change, study finds,” Los Angeles Times, 1/24/11,0,4119552.story

(4) “Fog burned off by climate change threatens to stunt Muir Wood’s majestic redwood,” Marin Independent Journal, 2/5/11