Nativist fantasies about oaks

San Francisco Bay Estuary Institute is promoting a “restoration” project they call “Re-Oaking California.”  The project is planning to plant oak trees in California cities, in particular.  They have published an elaborate brochure describing their project and they have published a brief description in the quarterly newsletter of California Releaf, the biggest non-profit advocacy organization for California’s urban forest.  Locally, they have made a presentation to Oakland’s Urban Forestry Forum and to the Bay Area Open Space Council.  The Open Space Council convenes meetings of hundreds of public land managers from all over the Bay Area.  In other words, the re-oaking project is being aggressively sold to those who determine the future of our public lands.  Therefore, it is a project that deserves our attention.

First, I must say that I love oaks.  I decided to buy the home I now live in before I stepped inside, because of the beautiful coast live oak in the front yard.  The loss of that tree would be devastating both emotionally and to the value of my home.

However, my opinion of the re-oaking project is based on the reality of climate change and its implications for the future of California’s urban forest.  Although the project brochure acknowledges that Sudden Oak Death has killed many oaks in California, it does not accurately reflect the scale of that epidemic.

Sudden Oak Death

Sudden Oak Death (SOD) killed 5 million oak trees in California from 1994 to 2015, when that number was reported by a study. (1)  The study also said that the SOD epidemic could not be stopped and would eventually kill all oaks in California.  More recent estimates are that 5 to 10 million oaks have been killed by SOD. (2)

Tan oaks killed by SOD. US Forest Service

SOD is caused by a pathogen that is spread by rain and wind.  We had a great deal of rain in 2016 and 2017, which greatly increased the spread of SOD infections.  In the past, SOD has been mostly confined to wildlands.  Now it is found in many urban areas, including San Francisco and the East Bay.  In the most recent SOD survey done in spring 2017, new infections were found on the UC Berkeley campus, the UC arboretum, and the San Francisco Presidio. (2)

The scientist at UC Berkeley who conducts the annual survey of SOD infections reports that “A dramatic increase this year in the number of oaks, manzanita and native plants infected by the tree-killing disease known as sudden oak death likely helped spread the massive fires that raged through the North Bay…” (3)

Brice McPherson, Associate Specialist in Organisms and the Environment at UC Berkeley, has been studying SOD infections in Marin County and the East Bay.  He made a presentation in November 2017 about the current status of SOD infections in East Bay parks.  Wildcat Canyon is the park in which Mr. McPherson has most recently inventoried infected and dead trees.  In 2017, Mr. McPherson found that 16.2% of coast live oaks were infected and 20.5% were dead.  The number of dead and dying oaks in Wildcat Canyon is staggering:  18,750 oaks are infected and 21,360 oaks are dead.  McPherson predicted that 50% of all oaks in East Bay parks would be dead within 20 years, depending upon the amount of rainfall.

Native bay trees are considered the main vectors of the pathogen that causes SOD.  The re-oaking project therefore suggests that SOD infections in urban areas can be avoided if bay trees aren’t planted in proximity to the oaks.  However, the source of the SOD infection recently found in the Presidio in San Francisco is said to have been rhododendrons, which should remind us that bays are not the only vectors of the SOD pathogen.  In fact, the USDA reports 46 confirmed hosts for the SOD pathogen, including both native and non-native shrubs and trees. (4)  Many of the hosts are commonly found in urban gardens.

Climate change kills oaks in Southern California

Sudden Oak Death infections have not been found south of San Luis Obispo.  However, that does not mean that oaks in Southern California are any less threatened by changes in the environment.  Several land managers in Southern California made presentations at the recent conference of the California Native Plant Society in Los Angeles about massive die-offs of oaks in Southern California.  Here is an example from the Santa Monica Mountains:  “Over 9,000 coast live oak and 114,000 riparian trees died from [2014 to 2017]…” (5) These deaths were caused by extremely high temperatures to which the trees are not adapted, associated drought and new insect predators, such as shot-hole borer.

The unsuitable climate conditions in Southern California are the anticipated climate conditions of Northern California.  Carbon storage in our urban forest is one of the few tools we have to combat climate change.  Although coast live oaks store carbon, they are not particularly long lived.  Their life expectancy is from 125 to 250 years in suitable conditions. (6) Planting trees with no long-term future is not a responsible response to climate change.  The US Forest Service predicts coast live oaks will be virtually gone in California by 2060:

Wildlife in our urban forest

Although oaks are clearly useful to wildlife, they are not significantly more useful than other urban trees.  Here are three studies conducted in the East Bay that compare the biodiversity of animal life in oak woodland to other tree species:

Dov Sax (Brown University) studied six forest plots of about 1 hectare each in Berkeley, CA, three of eucalypts and three of native oaks and bays.  The sites were not contiguous, but were selected so they were of similar elevation, slope, slope orientation, and type of adjacent vegetation.  He conducted inventories of species in spring and autumn.  He counted the number of species of plants in the understory, species of invertebrates (insects) in samples of equal size and depth of the leaf litter, species of amphibians, species of birds, species of rodents.  This is what he found:

“Species richness was nearly identical for understory plants, leaf-litter invertebrates, amphibians and birds; only rodents had significantly fewer species in eucalypt sites.  Species diversity patterns…were qualitatively identical to those for species richness, except for leaf-litter invertebrates, which were significantly more diverse in eucalypt sites during the spring.”  (7)

In 1975, Professor Robert Stebbins (UC Berkeley) was hired by East Bay Regional Park District to conduct a survey of vertebrate animals living in several parks (Sibley, Chabot, and Tilden). The forest types that Professor Stebbins studied were redwood, Monterey pine, eucalyptus, and oak-bay woodland as well as grassland and dry chaparral. Here is how he described his findings:

  • “Redwood and Monterey pine habitats are notably depauperate in vertebrate species.
  • “Eucalyptus habitat is far richer in vertebrates than either redwood or Monterey pine and vies with ‘dry’ chaparral and grassland in species diversity and ‘attractiveness.’
  • “Oak-bay woodland is the richest in both species and ‘attractiveness.’
  • “Grassland is a little less rich in species and ‘attractiveness’ than the other native habitats, but only slightly richer than eucalyptus habitat.” (8)

A wildlife study of Angel  Island prior to the removal of most eucalyptus trees found:

“The total number of birds observed in native stands was similar to that observed in eucalyptus stands…Few small animals were caught in any stand; captures were in native stands five Norway Rats…in eucalyptus stands one Norway Rat…in grassland one Norway Rat and six California Voles…about three times as many salamanders were located in eucalyptus stands compared to native stands.” (9)

As David Ackerly said in response to a question at the recent conference of the California Native Plant Society, “There are few mutually exclusive relationships in nature.”  It is a risky evolutionary strategy.  If an animal is dependent upon a single plant species, it won’t survive in the absence of that plant species unless it is capable of adapting to available vegetation.  Despite the handful of examples given in the re-oaking brochure, wildlife in California is using non-native vegetation as often as native vegetation.

California’s urban forest is not native

The suggestion that California’s cities could be “refugia” for our threatened oaks is wishful thinking.  As Matt Ritter tells us in his book about California’s trees (A Californian’s Guide to the Trees Among Us), only 6% of California’s urban trees are native to California.  Thirty-three non-profit tree advocacy organizations in California (including California Releaf) told us why in their letter to California’s Natural Resource Agency about the Urban Greening grant program:  “Native trees are generally not suited to urban conditions.  They have difficulty adapting to the urban environment, thereby substantially reducing survivability…As an example, the approved list of street trees for the City of San Francisco includes no trees native to San Francisco.  In Oakland, two of the 48 allowed species are native.”

The future of California’s urban forest

So, what is the future of California’s urban forest?  Scientists with sufficient knowledge of trees are trying to answer that question and we would be wise to pay attention to their advice.  Greg McPherson gave a presentation in Davis on March 10, 2018 about “Growing Resilient Forests.”  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 climateNone is native to Northern California. Most are foreign, particularly Australian.  (10)

Nativists deny reality of climate change

When the climate changes, the vegetation changes, moves, or dies.  That has been one of the few axioms in nature since life has existed on Earth and we would be wise to assume that it will continue to be true.  The future of California’s urban forest depends on our willingness to plant trees that are adapted to the climate and to the anticipated climate.  Climate change is killing California’s trees and nativism is preventing us from replacing them with suitable trees.


  1. https://www.sciencedaily.com/releases/2016/05/160502161111.htm
  2. “Disease killing oaks spreads,” East Bay Times, October 24, 2017
  3. “Disease in trees pointed at in fires,” San Francisco Chronicle, October 20, 2017
  4. http://www.aphis.usda.gov/plant_health/plant_pest_info/pram/downloads/pdf_files/usdaprlist.pdf
  5. http://www.rcdsmm.org/wp-content/uploads/2016/04/Drought-and-Invasive-Beetle-impacts-RCDSMM-1.2.18.pdf
  6. http://ucanr.edu/sites/oak_range/Californias_Rangeland_Oak_Species/Coast_Live_Oak/
  7. Dov Sax, “Equal diversity in disparate species assemblages:  a comparison of native and exotic woodlands in California,” Global Ecology and Biogeography, 11, 49-52, 2002. http://elkhornsloughctp.org/uploads/files/1109813068Sax2002.pdf
  8. Robert Stebbins, “Use of Habitats in the East Bay Regional Park by Free-living Vertebrate Animals,” August 1975. In “Vegetation Management Principles and Policies for the East Bay Regional Park District,” June 1976 (this unpublished study is available on request)
  9. “Focused Environmental Study, Restoration of Angel Island Natural Areas Affected by Eucalyptus,” California State Parks and Recreation, July 1988, pg 96-97.
  10. http://climatereadytrees.ucdavis.edu/

Scientist says 50% of oaks in East Bay parks will be dead in 20 years

East Bay Regional Park District is in the process of selecting the projects that will be funded by the renewal of Measure CC, the parcel tax that has funded park improvements.  Measure CC will be on the ballot for renewal in November 2018 and will provide funding for “park improvements” for the next 15 years.  YOU can have some say about those projects by making your suggestions to the park district by the end of December.  Send your suggestions to publicinformation@ebparks.com.

The original parcel tax was passed in 2004.  Over 22% of the money raised by that parcel tax was used to destroy healthy non-native trees in the parks.  Meanwhile, many of our native trees, most notably our Coast Live Oaks, are dying of Sudden Oak Death.  Destroying our non-native trees, while our native trees are dying, predicts a treeless future for the Bay Area.  Since dead trees are more flammable than living trees, destroying living trees while leaving dead trees in the parks means that fire hazards are being increased.

We published a letter from a park advocate about Sudden Oak Death to the park district recently, which is available HERE.  Today we are publishing an update from the park advocate who has learned more about the dead oak trees in East Bay parks.  A scientist who is studying Sudden Oak Death in East Bay parks tells us that there are tens of thousands of dead oak trees in the parks and that the park district is not removing them.  The dead trees are now fuel for fires in the parks.  

It’s been a rough year and we are sorry to end it with this unhappy news about trees in the East Bay.  We send you our best wishes for a better year in 2018.  Thank you for your readership. 


Source: Brice McPherson, December 7, 2017

TO:                  Rick Seal, Fire Chief; Robert Doyle, General Manager; Board of Directors

CC:                   publicinformation@ebparks.org

FROM:            Park Advocate

RE:                  Please hire arborist/forester with Measure CC renewal

I attended the presentation of Brice McPherson to San Francisco IPM Technical Advisory Committee about Sudden Oak Death (SOD) on Thursday, December 7th.  Mr. McPherson is Associate Specialist in “Organisms & the Environment” at UC Berkeley.  He has been studying SOD since 2000 and more recently has inventoried the trajectory of the disease in 5 EBRPD parks and conducted experiments in those parks, with the park district’s permission.

Mr. McPherson began his study of SOD in Marin County, where SOD infections were first seen in 1994, before beginning his research in East Bay parks.  Comparing the progression of the disease from Marin County to the East Bay has enabled Mr. McPherson to project the future of SOD in the East Bay.

Wildcat Canyon is the park in which Mr. McPherson has inventoried infected and dead trees most recently.  In 2017, Mr. McPherson found that 16.2% of coast live oaks were infected and 20.5% were dead.  The number of dead and dying oaks in Wildcat Canyon is staggering:  18,750 oaks are infected and 21,360 oaks are dead.

Source: Brice McPherson, December 7, 2017

The number of dead and dying trees in the other 4 East Bay parks that Mr. McPherson is studying is smaller.  However, his inventories in those parks are much older. Since SOD infections have increased exponentially in 2016 and 2017, we should assume that his data underestimate the current status of oaks in those parks.  As you probably know, the pathogen that causes SOD is spread by rain and wind.  For that reason, the rate of SOD infections has soared during the past two wet winters.

Mr. McPherson predicts that the infection rate in Wildcat Canyon will increase 10.2% per year in the future, causing 10,600 new infections per year.   Mr. McPherson predicts that +/- 50% of all coast live oaks will be lost in East Bay parks in the next 20 years, resulting in “major changes in stand structure.”  In other words, most oak forests will be replaced by other vegetation types.

Source: Brice McPherson, December 7, 2017

In response to a question, Mr. McPherson said that the park district is not doing anything about the dead oak trees because there are not sufficient funds available to remove the dead trees.  He was also asked how the dead wood can be removed without spreading the infection and/or creating piles of dead fuel throughout the parks.  He could not answer that question.

This new information requires that I repeat what I have written to you on earlier occasions:  “These changes in the environment require the park district to revise its strategies for fire hazard reduction because dead trees are significantly more flammable than living trees that contain more moistureRemoving trees infected with or killed by Sudden Oak Death should now be a higher priority than continuing to destroy healthy trees, as the park district has done in the past.  Protocols for removing the dead wood must be developed because the wood is fuel when left on the ground…”

As you know, the park district has spent about $22 million dollars destroying healthy, living trees in the parks with Measure CC funding.  If the park district has the money to destroy living trees based on the claim that it will reduce fire hazards, it obviously has the money to remove dead fuel in the parks.

Finally, we learned from Mr. McPherson that the park district does not employ a single certified arborist or forester.  Given the resources the park district devotes to native plant “restorations” and spraying pesticides, surely it can also employ someone who knows something about trees.  The landscape in the East Bay is undergoing a radical change to species that are adapted to current climate conditions that, sadly, will replace our beautiful oak forests.  We need the guidance of qualified arborists to identify the most hazardous trees and make the transition to a new landscape.  The employment of such expertise about trees would be a worthy expenditure of new Measure CC funding.

Thank you for your consideration.

 

Lessons learned from fires in the North Bay

Recent wildfires in the North Bay were devastating.  44 people were killed by the fires and over 8,000 structures were destroyed, including homes and businesses.  We don’t want to portray that fire as anything other than a tragedy.  However, for those with a sincere interest in fire safety, there are many lessons to be learned from that fire.  If people will open their eyes and their minds to the reality of those fires, there are opportunities to reduce fire hazards revealed by those fires.

What burned?

Watching videos of the fires is the best way to answer the question, “What burned?”  Here are two videos of the fires that we found on the internet by doing a search for “videos of wildfires in Napa and Sonoma counties.”  If you weren’t watching the news during the fires, you might start by looking at these videos.  There are many more videos on the internet of those fires.

Here’s what we can see in these videos:

  • The fire front moved rapidly through native conifers and oaks as well as through grassland and chaparral. After watching hours of these videos, we did not see any eucalyptus trees on fire.
  • Many homes burned without igniting the trees and vegetation around them. If the photo was taken while the home was still burning, the vegetation is rarely engaged in the fires.  If the photo was taken after the home burned, much of the vegetation is burned as well.  In other words, the vegetation was ignited by the burning homes, not vice versa.
  • In videos of actively burning homes, the air is filled with burning embers. The source of those embers cannot be determined from the videos.

Nothing in these videos suggests that native vegetation is less flammable than non-native vegetation.  Nothing in these videos suggests that the vegetation is more flammable than the structures that burned. 

CalFire has identified the specific locations where four of the fires originated.  Two are in groves of oak trees and two are in grassland and chaparral.  Photos of those specific locations are available HERE.


UPDATE:  On November 16, 2017, the Bay Area Open Space Council held a symposium about the fires in the North Bay that was billed as a “Community discussion on the impacts of the recent wildfires.”  Bay Nature magazine moderated a panel of experts representing CalFire and 8 managers of public and private open space reserves. 

The Director of Conservation for the Bay Area Open Space Council showed a slide of the vegetation types that burned in the fires.  With the exception of vineyards, only 2% of the burned vegetation was “urban.”  All other vegetation was native grassland, chaparral, and native trees. 

Vegetation that burned in the North Bay files of October 2017. Source: Bay Area Open Space Council

The speaker from CalFire said that we must learn to live with fire.  He suggested that the way to accomplish that goal is with better land use planning, using fire and ember resistant building materials, creating defensible space, and improving the health of our forests. 

The slides of the presenters and an audio recording of their presentations is available  HERE


What role did the weather play in the fire?

All sources of information about the fire reported that strong winds were the biggest factor in the rapid advance of the fire.  The wind was associated with very high temperatures and it came from the east.  This type of wind is called a Diablo Wind in Northern California.  In Southern California it is called Santa Ana Winds.  In the Mediterranean, it is called Mistral Winds.

In coastal Mediterranean climates such as California and the Mediterranean regions of France and Spain, the wind ordinarily comes off of the ocean.  Because the ocean is cooler than the land, the wind is usually a source of moisture and cooler temperatures.  During periods of high summer temperatures, the wind sometimes shifts direction and starts to blow off the hot interior, drying the vegetation and increasing temperatures.

Such winds were also the main cause of the wildfire in the Oakland/Berkeley hills in 1991Jan Null was the lead forecaster for the National Weather Service in the Bay Area in 1991.  He recently said of the 1991 fire:  “At the time a fire starts, the really relevant conditions are the wind speeds, the temperature and the humidity. Again, the humidity goes to the dryness of the fuel. The temperatures also go to the dryness of the fuels and the wind speeds go to what the spread of the fire is. If we’d had that same Oakland Hills fire without any wind, we wouldn’t be talking about it now.”

Most wildfires in California are caused by strong, dry, hot winds.  Everything burns in a wind-driven fire.  Both native and non-native vegetation burns in a wind-driven fire.  Homes in the path of a wind-driven fire are more likely to burn than the vegetation that surrounds the homes because the vegetation contains more moisture.

Why are wildfires becoming more frequent and more intense?

Wildfires are becoming more frequent and more intense all over the world because of climate change.  Temperatures are higher, drought is more frequent, strong winds are more frequent.

Wildfires in the west have become more severe because of increased temperatures and lower humidity at night.  When it doesn’t cool off at night, the trees don’t have an opportunity to regain the moisture they have lost during the high daytime temperatures.  In the past, firefighters could count on wildfires to die down at night.  Now they can’t count on colder nights to make the fires less severe. (2)  Since the fires in the North Bay started in the middle of the night and did the most damage that first night, this observation about warmer nights is particularly relevant to those fires.

Deforestation is the second greatest source of the greenhouse gases causing climate change Every healthy tree we destroy releases its stored carbon as it decomposes.  Every tree that dies of drought releases its carbon as it decomposes.  Every tree that burns in a wildfire releases its carbon as it burns.

What role did power lines play in the fire?

The investigation of the recent wildfires in the North Bay is not complete, but early indications suggest that power lines probably ignited some of the fires.  Some power poles fell over in the strong winds, causing the power lines to break and spark ignitions.  Some trees were blown into the power lines, causing them to break or spark.

California State law requires that trees be pruned at least 4 feet from the power lines.  Although PG&E says they are inspecting thousands of miles of power lines to identify potential interference with trees, these inspections are apparently not adequate.  After the fires started, PG&E claimed they had removed 236,000 “dead and dying” trees and “destroyed or pruned” 1.2 million healthy trees in 2016.  These destroyed trees contribute to climate change.

California State law also requires that power poles are capable of withstanding winds of a certain velocity.  However, power poles fell over during the recent fires when wind speeds were below that standard set by State law.

Apparently PG&E’s efforts to inspect and maintain power lines were inadequate and State laws intended to ensure the safety of power lines are not being enforced.

Did Sudden Oak Death contribute to the fire?

Sudden Oak Death (SOD) killed 5 million oak trees in California from 1994 to 2016, when that number was reported by a study.  The study also said that the SOD epidemic could not be stopped and would eventually kill all oaks in California.  More recent estimates are that 5 to 10 million oaks have been killed by SOD. (2)

SOD is caused by a pathogen that is spread by rain and wind.  We had a great deal of rain in 2016 and 2017, which has greatly increased the spread of SOD.  In the past, SOD has been mostly confined to wildlands.  Now it is found in many urban areas, including San Francisco and the East Bay.  In the most recent SOD survey done in spring 2017, new infections were found on the UC Berkeley campus, the UC arboretum, and the San Francisco Presidio. (2)

The scientist at UC Berkeley who conducts the annual survey of SOD infections reports that “A dramatic increase this year in the number of oaks, manzanita and native plants infected by the tree-killing disease known as sudden oak death likely helped spread the massive fires that raged through the North Bay…” (3)

Dead trees are more flammable than living trees because living trees contain more moisture.  In addition to more than 5 million dead oak trees in California, 102 million native conifer trees in the Sierra Nevada foothills were killed by drought, warming temperatures and native beetle infestations during the drought years. All of these trees are native to California.  This is another indication that native trees are not less flammable than living non-native trees.

The ranges of native plants and animals are changing because of climate change.  They must move to find the climate conditions to which they are adapted.  Native plant “restorations” that attempt to reintroduce plants where they existed 250 years ago, prior to the arrival of Europeans, do not take into consideration that the plants may no longer be adapted to those locations.  That’s why many “restorations” are not successful.

If you haven’t seen the Sutro Forest, you should do so soon. The plans are to destroy about 50% of the trees and most of the understory.

Native plant advocates have their heads in the sand about Sudden Oak Death.  The recently published Environmental Impact Report for San Francisco’s Sutro Forest announced UCSF’s intention to destroy about 50% of the non-native trees on Mount Sutro and replace some of them with native trees, including oaks and bays.  Bays are the vector of the pathogen causing SOD.  The EIR said NOTHING about Sudden Oak Death, nor did it acknowledge the existence of the disease in Golden Gate Park and the arboretum, less than a mile away from Mount Sutro.  What’s the point of destroying healthy trees and replacing them with trees that are likely to die in the near future?

Where to go from here?

We are not powerless against bad decisions of public utilities and the forces of nature.  There are things we can do to address these causes of wildfires in California:

  • We must address the causes of climate change. We must stop destroying healthy trees and we must plant more trees.  We must choose species of trees that have a future in the changed climate.  The trees must be adapted to current and anticipated climate conditions.  We must quit destroying trees simply because they are not native.  Non-native trees are not more flammable than native trees and many are better adapted to current climate conditions.
  • We must regulate our public utilities and demand that regulations be enforced. The Public Utilities Commission initiated an effort to improve the safety of power lines in 2007, after destructive wildfires. The utility companies have been actively dragging their feet to prevent new regulations because they would increase costs, despite the fact that they would improve safety.
  • Improved regulation of utilities should minimize the need to destroy healthy trees, by undergrounding power lines in the most high-risk areas, improving insulation of the wires, replacing wooden power poles with metal and/or concrete poles, installing sensors that identify breaks in the power lines, etc.

Demonizing non-native trees is preventing us from addressing the causes of climate change and the closely related issue of increasing frequency and intensity of wildfires.  Let’s open our eyes and our minds to the reality of wildfires in California and develop the policies that will reduce fire hazards.


(1) The Detwiler Fire is active at night, and a scientist says that’s relatively new,” Fresno Bee, July 22, 2017

(2) “Disease killing oaks spreads,” East Bay Times, October 24, 2017

(3) “Disease in trees pointed at in fires,” San Francisco Chronicle, October 20, 2017

California’s Urban Greening Grant Program: An opportunity to speak for the trees

In September 2016, the State of California passed a law that allocated $1.2 billion to create a cap and trade program to reduce Greenhouse Gas (GHG) emissions.  The California Natural Resources (CNR) Agency was allocated $80 million to fund green infrastructure projects that reduce GHG emissions.  The CNR Agency is creating an Urban Greening Program to fund grants to cities, counties, and other entities such as non-profit organizations in URBAN settings.  75% of the funding must also be spent in economically disadvantaged communities.

These grants must reduce GHG emissions using at least one of these specific methods:

  1. Sequester and store carbon by planting trees
  2. Reduce building energy use from strategically planting trees to shade buildings
  3. Reduce commute, non-recreational and recreational vehicle miles travelled by constructing bicycle paths, bicycle lanes, or pedestrian facilities.

Clearly, planting trees is one of the primary objectives of this grant program.  That sounds like good news for the environment and everyone who lives in it until you read the draft program guidelines which are available HERE.

Unfortunately, as presently drafted, the grant program will NOT increase California’s urban tree canopies, because the program requires the planting of “primarily” native trees.   That requirement is explicitly stated several times in the draft guidelines, but there are also places in the draft where the reader might be misled to believe the requirement applies only to plants and not to trees.    Therefore, I asked that question of the CNR Agency staff and I watched the public hearing that was held in Sacramento on October 31st.  CNR Agency staff responded that the requirement that grant projects plant “primarily” native species applies to both plants and trees.

The good news is that the grant program guidelines are presently in draft form and the public has an opportunity to comment on them.  If you agree with me that we need our urban forest, you will join me in asking the CNR Agency to revise their grant program guidelines to remove restrictions against planting non-native trees.   Public comment must be submitted by December 5, 2016.  Send comments to:  Urban Greening Grant Program c/o The California Natural Resources Agency Attn: Bonds and Grants Unit 1416 Ninth Street, Suite 1311 Sacramento, CA 95814 Phone: (916) 653-2812, OR Email: urbangreening@resources.ca.gov Fax: (916) 653-8102

Here are a few of the reasons why limiting trees to native species will not increase tree canopies in urban areas in California:

Many places in California were virtually treeless prior to the arrival of Europeans.  Non-native trees were planted by early settlers in California because most of our native trees will not grow where non-native trees are capable of growing.  According to Matt Ritter’s California’s Guide to the Trees Among Us, only 6% of California’s urban trees are native to California:

urban-trees-origins

Draft guidelines for the Urban Greening grants refers applicants to the California Native Plant Society for their plant palette (see page 24 of guidelines).  If applicants use this as the source of their plant palate, they will find few trees on those lists.  This is another way to understand that if you want trees in California, most of them must be non-native.

Most California native trees are not suitable as street trees because of their horticultural requirements and growth habits. 

  • The approved list of street trees for the City of San Francisco includes no trees native to San Francisco.  There are many opportunities to plant more trees in San Francisco because it has one of the smallest tree canopies in the country (12%).  The US Forest Service survey of San Francisco’s urban forest reported that 16% are eucalyptus, 8% are Monterey pine, and 4% are Monterey cypress.  None of these tree species is native to San Francisco.
  • The approved list of street trees for the City of Oakland includes 48 tree species of which only two are natives. Neither seem appropriate choices:  (1) toyon is a shrub, not a tree and the approved list says it will “need training to encourage an upright form.”  It is wishful thinking to believe that toyon can be successfully pruned into a street tree; (2) coast live oak is being killed by the millions by Sudden Oak Death and the US Forest Service predicts coast live oaks will be virtually gone in California by 2060.

coast-live-oak-current

coast-live-oak-2060

Climate change requires native plants and trees to change their ranges if they are to survive.  One of the indicators of the impact of climate change on our landscapes is that 70 million native trees have died in California because of drought, insect infestations, and disease.  The underlying cause of these factors is climate change.

  • 66 million native conifers have died in the Sierra Nevada in the past 4 years because of drought and native bark beetles that have spread because winters are no longer cold enough to keep their population in check.  Update:  A new survey of California’s trees now reports that 102 million trees are now dead.  That’s one-third of California’s trees.  62 million trees died in 2016 alone, which is an accelerating rate of death.  These trees are still standing and they pose an extreme fire hazard.  These are NATIVE TREES being killed by a combination of drought and NATIVE BARK BEETLES.  
  • 5 million native oaks have died since 1995 because of Sudden Oak Death. A study of SOD by University of Cambridge said in spring 2016 that the SOD epidemic is “unstoppable” and predicted that most oaks in California would eventually be killed by SOD. The Oak Mortality Task Force reported the results of its annual survey for 2016 recently.  They said that SOD infections increased greatly in 2016 and that infections that were dormant in 2015 are active again.  This resurgence of the pathogen causing SOD is caused by increased rain in 2016.
  • Scientists predict that redwood trees will “relocate from the coast of California to southern Oregon” in response to changes in the climate.

If you care about climate change, please join us in this effort to create a grant program that will expand our urban forests and reduce the greenhouse gas emissions that are causing climate change.  Restrictions against planting non-native trees must be removed from grant guidelines in order to increase our tree canopies in California’s urban environments. 

Update:  Final guidelines for California State Urban Greening grant applications were published on March 1, 2017, and are available HERE.  That program will distribute $76 million to cities that reduce greenhouse gas emissions by planting trees or reducing fossil fuels emissions.  The deadline for grant applications is May 1, 2017.  There will be a workshop for applicants at the Lake Temescal Beach House (6500 Broadway, Oakland) on March 27, 2017.

Final guidelines are improved from the draft guidelines.  Draft guidelines would have required applicants to plant only native trees.  The State agency received 62 public comments on the draft.  27 of those comments asked that the guidelines be revised to permit planting non-native trees as well as native trees.  One of the 27 comment letters was signed by 33 tree-advocacy non-profit organizations. 

Final guidelines reflect the public’s opposition to prohibiting the planting of non-native trees, which would have severely limited the number of trees that would survive.  Native trees have specific horticultural requirements that limit the places where they can be planted.

Final guidelines now say that only “invasive” trees cannot be planted by grant projectsIf the granting agency uses the classification of the California Invasive Plant Council to determine “invasiveness,” applicants would not be allowed to plant 15 specific tree species.  However, the California Invasive Plant Council is revising its inventory of “invasive” plants, so we don’t know if the number of “invasive” trees will be increased by that revision.

Update #2:  The California Invasive Plant Council has published the proposed revision to its list of “invasive” species.  There were about 200 plants on the existing list.  Now they propose to add another 99 species.  Ten of those species are added based on their current impacts in California.  One of the ten is a tree (glossy privet).  87 of the species are proposed for addition “based on risk of becoming invasive” in the future in California.  Twelve of the 89 potentially invasive plants are trees. 

There were 15 trees on the original list of “invasive” species.  That means that the revised list of “invasive” trees will now include a total of 28 trees that cannot be planted by Urban Greening projects that are applying for grant funds. 

The revised inventory of “invasive” plants was just published.  Public comments can be submitted on the proposed revisions by May 8.  The proposed revisions and how to make comments on the proposal are available HERE

Personally, I object to the introduction of a new category of 89 plants that are not presently having any “impact” according to Cal-IPC but are predicted to in the future.  These revisions will increase the inventory of “invasive” plants by 50%.  It represents a significant escalation of the crusade against non-native plants in the California. 


Nativist bias is not entirely absent from the revised guidelines for the Urban Greening program.  Applicants are required to explain why they plan to plant non-native trees.  However, applicants are also required to have a certified arborist or comparable horticultural expert certify that the plant list is appropriate to the planting location.  Hopefully, that will prevent the wasteful planting of native trees where they will not survive. 

Sudden Oak Death (SOD) Update 2013

Scientists at UC Berkeley held a public workshop last week to announce the results of the 2013 SOD Blitz.  A video of the workshop is available here.  The annual SOD Blitz engages citizen volunteers in identifying bay laurel trees infected with the pathogen that causes Sudden Oak Death.  Bays are tested because the infection is more easily identified in bays than oaks.  Scientists who study SOD believe that although the pathogen doesn’t kill bays, they are considered the primary vector of the disease to oaks that are killed by the pathogen.   

SOD mortality - Sonoma County
SOD mortality – Sonoma County

About 500 volunteers participated in the 2013 SOD Blitz which took place last spring.  The pathogen is most easily identified in the spring when it is still wet and cool.  Over 13,000 samples were taken from about 2,000 trees.  The samples were tested in laboratories for the pathogen.  Thirty-one percent of the samples were symptomatic for the disease. 

The infection rate was lower in 2013 than some previous years because it was a dry year.  The infection rate was highest in 2011, which was a particularly wet year.  Infection rate correlates positively with rainfall and lower temperatures.  Therefore, infection rates are higher in coastal locations and lower in inland locations.  Infection rates increased significantly in 2013 in Santa Cruz and South Skyline Blvd in San Mateo County.

SOD mortality - US Forest Service
SOD mortality – US Forest Service

Mortality rates vary by oak species.  Tan oaks are most vulnerable to the disease, which is expected to kill 100% of infected tan oaks.  Coast live oaks are slightly less vulnerable to the disease.  About 90% of infected coast live oaks are expected to die.

The results of five years of SOD Blitzes have been mapped and can be viewed here

SOD Workshops are scheduled all over California in October and November to advise the public about preventative treatments for oaks: 

10/12 Sat 10am Burlingame Hills – 120 Tiptoe Lane (off Canyon Rd.), Burlingame, CA Steve Epstein – steve@burlingamehills.org

10/20 Sun 10am East Bay – Spillway picnic area, Tilden Regional Park (near Lake Anza) Map Link Amelia Marshall – Amelia.marshall@att.net

10/23 Wed 1pm UC Berkeley – UC Berkeley Campus, SOD Treatment Training Workshop Webpage Link

11/1 Fri 7:30pm Atherton – Los Altos Library, S. San Antonio Rd, Los Altos, CA Arvind Kumar – arvind.kumar@cnps.org

11/2 Sat 10am Sonoma – Location TBA, Lisa Bell – lkbell@ucanr.edu

11/9 Sat 10am Los Altos Hills – Foothills Park 3300 Page Mill Road, Los Altos Hills, CA Sue Welch – sodblitz09@earthlink.net

 11/12 Tue 8:30am San Francisco Presidio – Location TBA

11/12 Tue 6:30pm Mendocino – Fort Bragg Town Hall, Fort Bragg, CA Lori Hubbart – lorih@mcn.org

11/13 Wed Santa Lucia Preserve – Time and Location TBA

11/14 Thur 6 pm Potluck, 7 pm talk by Matteo Garbelotto from UCB on “Biology of the SOD pathogen and disease control strategies”, UCSC Arboretum, 1156 High St, Santa Cruz, CA Map Link Brett Hall – brett@ucsc.edu

11/16 Sat 10am Marin – Dominican University, 155 Palm Ave., Joseph R. Fink Science Center, Room 102, San Rafael, CA Kristin Jacob – kristinjakob@att.net

11/16 Sat 1pm Napa – Pelusi Building, 2296 Streblow Drive at Kennedy Park, Napa, CA Bill Pramuk – info@billpramuk.com

11/17 Sun 10am South Skyline – Saratoga Summit Forestry and Fire Protection (CalFire) CDF fire station, Jane Manning – skyline_sod@yahoo.com

11/23 Sat 10am Montalvo – Montalvo Arts Center, 15400 Montalvo Road, Saratoga, CA Kelly Sicat – KSicat@montalvoarts.org

11/24 Sun 1pm Oakland – Joaquin Miller Park, Oakland, CA Kimra McAfee – coordinator@sausalcreek.org

FEMA projects could result in a treeless landscape in the East Bay

Although we are often accused of being “euc-lovers” by native plant advocates, we actually prefer native oaks to eucalypts.  Unlike native plant advocates, we don’t think our preference justifies the destruction of eucalypts.  Because of our fondness for oaks, informing our readers of the rampant spread of Sudden Oak Death that is killing our oaks is not a pleasant chore.  But we want the public to understand that when we destroy all of our non-native trees, we may be dooming ourselves to a treeless landscape.  

Hundreds of thousands of non-natives will be destroyed by FEMA projects

The projects of UC Berkeley, the City of Oakland, and the East Bay Regional Parks District (EBRPD) that are being evaluated for FEMA funding will destroy hundreds of thousands of non-native trees, as reported here.  According to the Draft Environmental Impact Study (DEIS) that claims to evaluate those projects, “Oak-bay woodlands total 320.6 acres in the proposed and connected project areas and represent the second largest vegetation community identified in the proposed and connected project areas.” (DEIS 4.2-17)  Also, the “vegetation management goals” for the Recommended Treatment Areas (RTAs) in EBRPD’s FEMA applications are predominantly oak-bay woodland.   Thirty-seven of the 47 (80%) RTAs in the EBRPD’s FEMA grant application are destined to be oak or oak-bay woodland when this project is implemented.

Sudden Oak Death in the East Bay

The pathogen (Phytophthora ramorum) that causes Sudden Oak Death (SOD) was reported on the UC Berkeley campus in 2002. (1)  At that time it also existed at the UC Botanical Garden, which is proximate to UC Berkeley’s FEMA projects. By 2011, the SF Chronicle reported that the infestation of SOD was spreading rapidly in the East Bay and had been found in North Berkeley, the Claremont district in Berkeley and the Montclair area in Oakland.  That article predicted that 90% of the native live and black oaks in California will be dead within 25 years. (2)  There is no known cure for oaks that are infected with SOD.  A preventative treatment is recommended, but it is expensive and is therefore not being used on our public lands.

One year later, based on the sampling done by thousands of volunteers participating in the 2012 SOD Blitz, the California Oak Mortality Task Force reported these findings: (3)

  •  “The USDA FS 2012 annual aerial detection survey for California mapped 376,000 new dead oak (Quercus agrifolia) and tanoak (Notholithocarpus densiflorus) over 54,000 acres in areas impacted by SOD.”
  • “Most of the Bay Area locations sampled had increased levels of infection, with the East Bay infestation found to have transitioned from a newly arrived status (in 2011) to epidemic levels on California bay laurel (Umbellularia californica) (in 2012).”

We participated in the 2013 SOD Blitz in the East Bay on April 27, 2013.  This volunteer effort is led by Matteo Garbelotto who is a scientist at UC Berkeley studying Sudden Oak Death.  He has organized the SOD Blitz throughout Northern California to determine the spread of the disease.  Hundreds if not thousands of citizens attend his workshops to learn how to identify the disease and take leaf samples of native bay trees for testing in Garbelotto’s laboratory.  Oaks aren’t sampled because that requires cutting into the bark of the tree which can damage the tree if not done properly.  Based on previous studies, bays that are infected with the pathogen are assumed to infect oaks within 200 feet of infected bays.  So, based on the SOD map that identifies infected bays in the East Bay, we should assume that all oaks within 200 feet of those infected bays are doomed to die eventually. 

 SOD Map2

This is a detail of an area south of Lake Anza and west of the Tilden Botanical Garden from the SOD Map which is available on the internet.  Infected bay trees identified by the 2012 SOD Blitz are indicated with red triangles. This small portion of the SOD Map shows that 6 infected bay laurel trees were found in 2012 in four of the FEMA project areas:  TI010, TI020, TI011, and TI1012.  This is not a complete list of the infected bays in all project areas.  It is only an illustration of how the DEIS could have reported the existence of SOD in the FEMA project areas.

The oak woodland in the East Bay is called the oak-bay woodland for a reason.  The oaks and bays grow together, in close proximity.  Although bays are hosts of the SOD pathogen, they are not killed by it.  However, bays are considered the primary vector of the disease to the oaks which are killed by it:  “Bay laurels are not thought to die from P. ramorum infection, but these trees are a major source of inoculum for the pathogen and appear to play an important role in spreading disease to other plants in California.” (4)  For that reason, property owners and managers of public lands are being advised by scientists to remove bay laurels growing in proximity to oaks:  “Scientifically-tested recommendations for managing forests impacted by P. ramorum are still in development, although at least three promising directions have emerged:  application of systemic fungicides, forest thinning to remove susceptible hosts, and targeted removal of the main carrier, California bay laurel, near coast live oak.” (5)

To summarize these reports:  the spread of SOD in the East Bay has reached epidemic proportions and is expected to kill most of the oaks.  Meanwhile, one of the few treatments being recommended by scientists to limit the spread of the disease is to remove bay laurels that grow near oaks.  The future of the oak-bay woodland in the East Bay is indeed dim. 

The cause and the consequences of SOD

Scientists studying SOD have determined that the spread of the disease is facilitated by warm rainy days, most likely to occur in the spring.  And models of climate change, predict just such conditions in the future. (6)  How ironic that the destruction of hundreds of thousands of trees in the East Bay will contribute to climate change by releasing hundreds of thousands of tons of carbon dioxide to the atmosphere.

SOD researchers have also reported that SOD deaths are increasing the risk of severe wildfire:

“Not only does SOD alter fuel quantity in these forest types, but it can also change the arrangements of fuels, posing serious challenges to firefighter response in infested stands. After trees die from the disease, they can remain standing with dry, dead leaves for several years, greatly increasing the likelihood of crown fire under extreme weather conditions. Likewise, the increased fuels on the forest floor can take a long time to break down, posing a long-term fire hazard and additional risks to firefighters. In many cases, modeled wildfire conditions in SOD-impacted forests exceed safety thresholds for hand crews, calling for changing suppression tactics and strategies, such as more heavy equipment, aircraft use, and indirect lines.” (7)

 Putting our heads in the sand

The DEIS makes no mention of Sudden Oak Death.  Seven written public comments submitted during the scoping process expressed concern about SOD, but the DEIS ignores the issue.  (A word search of the 3,000 page DEIS finds SOD and Sudden Oak Death only in the Scoping Report (DEIS Appendix K1), not in the study itself.)

Since the scoping process in 2010, we now have overwhelming scientific evidence that Sudden Oak Death is rampant in the East Bay, that it is spreading rapidly, that its spread is associated with climate change, and that it is increasing the risk of severe wildfire, yet the DEIS ignores these serious threats to the oak-bay woodlands.  This omission verges on incompetence, if not negligence.  One wonders why the government bothers with a public comment period such as the scoping process, when the public’s concerns are obviously ignored.

If the consequences of Sudden Oak Death in the oak-bay woodland in the project areas are not adequately explained by the Final EIS, FEMA should assume that it will be legally challenged by the taxpayers.  At the very least, taxpayers need to know if there will be any trees left in the East Bay hills, either native or non-native.  If the expansion of oak woodland increases the risk of wildfire, funding of these FEMA grants would be entirely inappropriate.

Please sign the petition in opposition to these projects which is available HERE.  Please send FEMA your public comment about these projects by the June 17 deadline.  Information about how to submit public comments in available HERE.

UPDATE:  The final version of the EIS has added a section about Sudden Oak Death, with this introductory paragraph:

“If SOD is present within the proposed and connected project action area, vegetation treatment could exacerbate SOD by causing it to spread to unaffected areas. A protocol for fuels treatment in areas with SOD was developed using information from U.C. Berkeley Forest Pathology and Mycology SOD workshops. The summary includes identification, mapping, and isolation of infected trees.”  (page 5.1-34 Available HERE)

The final EIS confirms that the entire project “could” spread Sudden Oak Death.  Then it describes how that spread can be “mitigated” by using certain methods designed to limit that spread.  This is the technique used throughout the EIS to essentially dismiss our concerns.  It acknowledges potential problems, then waves them away with elaborate “protocols” which even if they are effective, are unlikely to be followed by people in the field who are usually ignorant of them.

 **************************

(1)     http://www.universityofcalifornia.edu/news/article/3880

(2)     Fimrite, Peter, “Sudden oak death cases jump, spread in the Bay Areas,” San Francisco Chronicle, October 2, 2011

(3)     “Sudden Oak Death and Phytophthora Ramorum, 2011-2012 Summary Report, California Oak Mortality Task Force

(4)     UC Davis IPM Online:  http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74151.html

(5)     Janice Alexander, Christopher Lee, “Lessons Learned from a Decade of Sudden Oak Death in California:  Evaluating Local Management,” Environmental Management, 2010, 46:315-328.

(6)     Kliejunas, J.T. 2011. A Risk Assessment of Climate Change and the Impact of Forest Diseases on Forest Ecosystems in the Western United States and Canada. Gen. Tech. Rep. PSW-GTR-236. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 70 p. (4/12)

(7)      Valachovic, Y.S.; Lee, C.A.; Scanlon, H.; Varner, J.M.; Glebocki, R.; Graham, B.D.; and Rizzo, D.M. 2011. Sudden Oak Death-Caused Changes to Surface Fuel Loading and Potential Fire Behavior in Douglas-fir-Tanoak Forests. Forest Ecology and Management. 261:1973-1986. (3/12)

SOD Update

The San Francisco Chronicle recently published an update  about Sudden Oak Death (SOD) that was both misleading and inaccurate.

The article inaccurately claimed that “the mysterious pathogen…has killed tens of thousands of oak trees from Big Sur to southern Oregon.”  This is a gross underestimate of the number of trees that have been killed by SOD.   The California Oak Mortality Task Force reported in the announcement of their 2009 annual symposium that “Since the 1990s more than a million oak and tanoak trees have died from this pathogen and at least another million are infected.”  Since there is no known cure for the disease, we must assume those trees will die. 

Hillside in Big Sur, Wikipedia Commons

Secondly, the article quotes Matteo Garbelotto of UC Berkeley—who is described as “the nation’s foremost expert on sudden oak death”—as recommending that “homeowners in infected areas can remove bay trees…[to] increase the survival rate of nearby oaks.”   We doubt that this is an accurate quote because it is not consistent with the advice Garbelotto gave at one of his SOD workshops. 

One of the many professional gardeners attending that workshop asked if he should remove the bays in the gardens in which there are also oaks to protect the oaks from infection.  Mr. Gabelotto’s response was that the bays would resprout ten-fold and that the immature leaves of the resprouts would be more susceptible to infection than the mature leaves.  The gardener asked if he could prevent resprouts with Roundup.  Mr. Garbelotto replied that Roundup would not prevent resprouts. 

In other words, removing bay trees is easier said than done.  Attempts to do so can result in even more bay trees unless toxic chemicals such as Garlon are used repeatedly to prevent resprouts.  Since the immature leaves of the resprouts are more susceptible to SOD infection, this is not a wise strategy.

Garbelotto may have told the Chronicle that removing bay trees already infected with SOD may prevent the spread of the pathogen to oaks.  Although it seems to us a risky strategy, it is apparently being done in the Santa Cruz Mountains, according to the San Jose Mercury (“’Sorry baby, but you gotta go’,” December 17, 2009).  This is an important distinction:  removing healthy bay trees is likely to do more harm than good, while removing infected bay trees may make some sense, although we would prefer to avoid the use of toxic chemicals.   

Journalism is a powerful tool that can strengthen democracy if used responsibly, reporting the facts faithfully and balancing competing opinions when necessary.  The author of this article grossly underestimates the number of native trees killed by SOD and offers bad advice about killing healthy trees.  Those who still subscribe to the dwindling San Francisco Chronicle will not be surprised by such sloppy journalism.  It is an example of the death throes of the Bay Area’s local newspaper.

Sudden Oak Death

Coast live oak, Mountain View Cemetery, Oakland

The coast live oak that is native to the Bay Area is one of our favorite trees and we would be happy to see more of them.  However, the epidemic of Sudden Oak Death that is killing oaks in California and Oregon makes us question the wisdom of replacing non-native trees with oaks that may not survive that epidemic.  Since any dead tree is more flammable than any living tree, we are also skeptical about claims that restoration of the oak-studded grassland will reduce fire hazard in the Bay Area.

Sudden Oak Death, US Forest Service photo

 The pathogen (Phytophthora ramorum) that causes Sudden Oak Death (SOD) was reported  on the UC Berkeley campus in 2002.  At that time it also existed at the UC Botanical Garden and the researcher who identified the pathogen speculated that it probably existed throughout the East Bay.  By 2008, the SF Chronicle reported   that the infestation of SOD existed in several parks in the East Bay.  The researcher estimated that about 20% of all coast live oaks in the East Bay are infected with the pathogen that will eventually kill them.

In February 2008, the California Oak Mortality Task Force estimated  that ”millions of tanoak and coast live oak” have been killed by SOD in California.  Thirty four other species of trees and shrubs are also infected with the pathogen, including bay laurels and redwoods.  Although these species are not usually killed by the pathogen they are vectors of the disease.  The bay laurel is singled out by the scientific literature as being particularly effective at transmitting the pathogen to the oaks that are then killed.

The “Wildfire Hazard Reduction and Resource Management Plan” of the East Bay Regional Park District proposes to destroy most non-native trees on over 1,500 acres of parkland.  The “vegetation management goal” for most of these acres is the restoration of “oak-bay woodland.”  And so we ask these rhetorical questions:

  • What is the probability that coast live oak will survive the deadly SOD pathogen in the Bay Area?
  • Does the proximity of bay laurel to the local oak population increase the probability of infection?
  • If the oaks are killed by SOD will the risk of wildfire in the East Bay hills increase?
  • If the non-native trees are destroyed and the oaks are killed by SOD will the resulting landscape be entirely treeless?

We believe these are legitimate questions and when we have asked them of native plant advocates we have not heard an adequate answer.  We believe that eradicating non-native plants and trees without a clear understanding of the future of the natives, is irresponsible.