Blitzing California’s Coastal Forests: And How You Can Help

BERKELEY—With California’s 2016 rain totals higher than they’ve been in more than four years, forestry experts say our coastal forests are at extreme risk of disease. They warn sudden oak death moves silently through forest and gardens, killing tree after tree where it stands—and death will be on the rise this year.

It is the primary cause of tree mortality in coastal California, researchers say, with more than 3 million trees having died already in 15 counties since its discovery in the mid-1990s. Dead trees mean loss of habitat and increased wildfire danger. There is no cure for the disease.

The killer pathogen, Phytophthora ramorum, a fungus, is spread by water and air, with rainwater being a major route for disease spread. No one is sure how the pathogen got into California’s coastal forests or how to stop its spread. It is killing trees from Big Sur to Humboldt County, with Santa Cruz, Marin and Sonoma counties being particularly hard hit.


Infected tree. Photo courtesy U.S. Forest Service

The pathogen will take advantage of bark wounding, but it’s not necessary for infection to occur. California bay laurel seems to be the main source of inoculum in forests. Green waste, such as leaf litter and tree stumps, are also capable of supporting P. ramorum and acting as a disease reservoir. Because P. ramorum can infect many ornamental plants, such as rhododendron, and can be spread by moving them, experts are calling for the public’s help in locating infected trees and tracking disease spread.

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Wild Rhododendron, among species susceptible to SOD infection, photo taken while camping at Big Basin Redwoods State Park, Santa Cruz County

Researchers have found infections concentrated around illegal marijuana grows and suspect movement of supplies and soil amendments in Northern California watersheds result in forests with high levels of disease. Hikers, mountain bikers and horseback riders may also help move the pathogen to uninfected areas through contamination of boots, clothes, animals and equipment.

With so much at stake, researchers need help with the 10th annual spring SOD Blitzes (citizen scientist surveys for SOD). They hope this year’s citizen surveys will generate record participation. If you live, hike, bike or ride the trails in coastal forests, your help is essential to tracking the disease.

“This year is going to be one of the most critical yet for monitoring the more than 500 miles of susceptible and impacted coastal landscapes for SOD,” said Matteo Garbelotto, UC Berkeley faculty member who runs the Blitzes.

“We’re calling for as many seasoned and novice SOD Blitzers as we can possibly get to join the cause,” he said last week. “Their help is critical to informing communities about disease encroachment, while also helping to determine how effective current treatment and management efforts have been at reducing infection rates and protecting at-risk trees.”

 How to Help: If you live or will spend time in coastal forests, parks or communities this spring, you’re encouraged to participate in the disease-spotting effort.

 When:  Spring 2016, Weekends, April 9 – June 4, 2016.

 Training: 1-hour training sessions – Required.

Where: For locations and local details, go to

Cost: FREE — Attendees should bring mobile devices or GPS units if they have them.


Symptomatic California bay laurel leaves generally precede oak and tanoak infections, and are often the first sign that P. ramorum is in a location. Participants will be trained to identify and collect symptomatic bay leaves and record sample locations.

Volunteers are encouraged to bring their smartphone to the training with the free “SODmap mobile” app already installed (SOD distribution map of laboratory-confirmed positive and negative samples in California, not including nurseries) as it can help in identifying potential collection locations.

Blitz samples will be taken to the UC Berkeley Garbelotto lab to determine the presence or absence of the pathogen. Results will be posted online in the fall to SODmap ( and to the SODmap mobile app ( When used as instructed, these two tools will help inform thousands of people as to the presence and risk of SOD at a given location.

SOD Blitzes are made possible by the work of local volunteers, along with funding from the PG&E Foundation and the USDA Forest Service, State and Private Forestry organizations.


SOD Blitz volunteers gathering suspect leaf material for lab analysis. Photo courtesy California Oak Mortality Task Force.

“Not only do these volunteers provide invaluable data for the fight against SOD, they also help lead the charge in proactive SOD management on private property, with Blitzers 10 times more likely to actively manage their properties, collectively helping to slow disease spread,” Garbelotto said.

For more information on SOD Blitzes, go to

For more information on Sudden Oak Death and P. ramorum, go to the California Oak Mortality Task Force website at  or contact Katie Harrell at (510) 847-5482 or


Planting Palms and Poetry – W.S. Merwin Forest Honors

Merwin and Palms PBS

In reverence, poet W.S. Merwin began planting trees nearly 40 years ago on land surrounding his home in Maui. He created and cultivated an 18-acre palm tree botanical garden, that has become one of the largest and most important collections of palms in the world.

The collection includes more than 2,740 individual palm trees, representing more than 480 taxonomic species and more than 125 unique genera, and featuring nearly 900 different horticultural varieties, the Merwin Palms and the land on which they live have been called Hawaii’s Walden Pond.

The plantation has become The Merwin Conservancy, which preserves the palm collection and the land from future development. The conservancy allows for scientific and botanical study of the palm species.

Merwin’s home on the property has been preserved as a place where art and nature intersect.  Many of the most famous poems and literary works authored by Merwin were written there. The Poet’s Home is now offered to poets, artists and authors as a retreat center.

Appointed United States Poet Laureate by the Library of Congress in 2010, William Stanley Merwin has a career that has spanned six decades. A poet, translator, gardener and environmental activist, he is one of the most widely read and honored poets in America.

Awards include the Pulitzer Prize (twice), the Bollingen Prize, the Tanning Prize, the Lilly Prize and the Lannan Lifetime Achievement Award. His Migration: New and Selected Poems won the 2005 National Book Award for Poetry and Present Company, which closely followed it, earned him the Bobbitt Prize from the Library of Congress.

Now, in recognition of his botanical accomplishments, Merwin will be among 13 distinguished honorees at the 2015 Arbor Day Award ceremony on April 25 in Lincoln Nebraska.

Arbor Day is an annual observance that celebrates the role of trees in our lives and promotes tree planting and care. As a formal holiday, it was first observed in 1872, but tree planting festivals are as old as civilization.

Merwin will receive the Good Steward Award recognizing the value of the botanical garden he created. The Arbor Day Foundation said the impact of Merwin’s work reflects the values of wilderness, the stillness of nature, and our personal connection to the natural world.

Merwin Rain in Trees Cover


W.S. Merwin, 1993


On the last day of the world

I would want to plant a tree

what for

not for the fruit

the tree that bears the fruit

is not the one that was planted

I want the tree that stands

in the earth for the first time

with the sun already

going down

and the water

touching its roots

in the earth full of the dead

and the clouds passing

one by one

over its leaves

Merwin Conservancy

Text © 1988 by W.S. Merwin. Reproduced by permission of Georges Borchardt Inc. for the author. All rights reserved.

Information on the Arbor Day awards are online at

The work of the Merwin Conservancy is online at

Mother Trees: California Group Works to Save Survivors

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Sometime ago a Santa Barbara avocado grower invited me to take a walk to what he called the “Mother Tree.” I’d heard the term, but didn’t really know what it meant. I gathered it referred to an old tree that had been grafted to create more trees and then, with more grafting, more trees, eventually resulting in an orchard.

But, the way the farmer asked, his shy offer to show me his Mother Tree, implied more than simply visiting a hearty tree with prolific off-spring. His tone suggested something more.

He would have blustered at the suggestion it was something sacred, yet I couldn’t help feeling he was taking me someplace special. We walked quietly in the early evening deep into the grove, scuffling leaves and stepping over sprinkler lines. He carried a long pole with a gripper on the end.

As dusk gathered, we stood at the base of strong tree with lush canopy and looked up. Although the grove had recently been picked, this tree had lots of fruit. The farmer hoisted his pole and plucked the huge fruit, handing each piece to me, explaining he saved the fruit from this tree for family and friends.

I stuffed my backpack as he handed over the fruit, not realizing how much they weighed until I tried to lift my pack. The farmer gave me a hand with the load and we headed back to his truck. The fruit I brought home weighed a pound or more apiece and when ripe the flesh was smooth and creamy, flavored like nuts and honey.

The experience changed my way of thinking about trees. The fruit of some trees are bigger and better than others. I don’t know why, but today when I buy avocados, I secretly know what I’m getting isn’t the absolute, ultimate best and I listen closely when someone talks about Mother Trees to find out more, hungering for fruit that comes straight from the source.

And, now I know the beauty and abundance of California’s millions of acres of fruit groves and orchards are the product of strong, prolific mothers. Although the tree where I first tasted Mother Fruit isn’t actually the oldest avocado tree in California or the original mother, I’m convinced it’s her oldest daughter and worthy of protection.

The actual Mother Avocado Tree died in La Habra Heights in 2002. Every Hass Avocado tree in the world can trace its lineage to that one tree. The tree’s wood is currently stored in a Ventura nursery awaiting decision on a fitting commemoration of the original Hass Mother Tree.

Which brings me to the newly launched efforts of the Felix Gillet Institute. This newly formed group aims to properly place Gillet, who was a Nevada City nurseryman in the mid-1800s, in the history of California and United States agriculture through research and education. The foundation said it’s goal is to educate farmers and gardeners about the many tree and plant species he introduced because they continue to provide valuable genetic material for modern propagation. Gillet bred and sold Mother Trees.

Gillet brought cuttings from Europe for fruits, nuts, grapes, berries and ornamentals to the Sierra foothill’s and these original plants have provided food and fiber that play a strong role today in American agriculture. The Felix Gillet Institute is raising funds to search out and relocate the more than 100 original plant varieties imported and hybridized by Gillet.

Amigo Bob Cantisano, the Founder of FGI and a highly regarded organic farmer, described Gillet’s work this way: “pretty much everything that we eat in the perennial crops, except for citrus and olives, we can thank Gillet for. He did asparagus and artichokes and hops and raspberry and rhubarb, the whole nine yards.”

But his first love was fruit trees. The original tree stock he sold to early California settlers are scattered throughout the foothills. The group intends to gather these surviving specimens and replant them in a Mother Orchard on Heaven and Earth Farm on San Juan Ridge outside Nevada City. They will sell trees propagated from these Mothers or in most cases Grandmothers, which are now feral and endangered in the wild. Those who’ve tasted their fruit say the flavors are out of this world.

More information on the Gillet Foundation and the effort to save the Mothers is online at