Valley oaks in Walnut Creek, CA respond to fire mimicry

27 05 2019


I recently inspected a grove of sick valley oaks that have been treated with fire mimicry for the past two years. The results are very encouraging. Most of the oaks have responded with a noticeable increase in canopy greenness and density. Note that valley oaks do not contract sudden oak death disease, but are still declining in many places. They, too, are generally suffering from a lack of ground fires. Fortunately, these results point to a way forward for improving the health of our great valley oaks using fire mimicry practices.


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Recovery of oaks following the 2017 Sonoma fires

2 05 2019


Yesterday I inspected a grove of oaks that had burned during the 2017 Sonoma fires.  Previous to the fire these oaks had been treated with fire mimicry, which included pruning the lower branches (ladder fuel), clearing away underbrush, removing mosses and lichens from the trunks, fertilizing the soils with compost tea and soil minerals, and applying a limewash to the trunks. During the fires all of the ground vegetation burned, but none of the flames spread into the upper canopies. Thus, all of the oaks survived (as did several nearby homes), and, as the photos show, are doing well after 1.5 years. A caveat – these results are influenced by the spring flush of new leaves, and a better comparison can be made when I visit the site again this October.

These findings represent the combined effects of a ground fire AND fire mimicry treatments on improving the health of California oaks.

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Esalen oaks respond to fire mimicry

26 04 2019


On April 20, 2012 I gave an Earth Day workshop on at Esalen Institute in Big Sur, CA, where I initiated fire mimicry treatments on several coast live oaks. Since then I have been tending these oaks on a regular basis. Today I inspected the oaks and treated them again. The photos (above and below) show the response after 7 years . . .

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Oaks in Burlingame, CA respond to fire mimicry

22 04 2019


Last week I inspected a grove of oaks in Burlingame, CA that I’ve been tending with fire mimicry for five years. Here are recent photos showing their progress . . .

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Fire mimicry results after 7 years in Hillsborough, CA

17 04 2019


Today I inspected several coast live oaks that I began treating with fire mimicry in 2012. the photos above an below shoe the progress of these oaks over the past 7 years. If you believe that these results are due to the recent wet weather, please scroll down to see results from the drought years.


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Fire mimicry results on Marin County oaks

4 04 2019



This past week I checked on several coast live oaks in Marin County that I’ve been treating for the past 1 to 7 years using fire mimicry techniques. The photos above are of an oak that I’ve treated for the past 7 years. The next two photos are of an oak I’ve treated for the past 5 years. The remainder of the photos are results of oaks I treated last year. I trust you can see the benefits of using fire mimicry in aiding the health of oaks.

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Grandmother oak

5 03 2019

A few years ago I encountered an ancient coast live oak that was so magnificent, it took my breath away. At first sight the oak was barely noticeable, hidden behind a wall of young Douglas fir and bay laurel trees. But after slipping past the young trees Grandmother oak appeared. Her trunk was massive, at least 20 feet in girth, and was clearly pollarded by the native people. I estimated her age to be about 500 years, possibly older.




Grandmother oak has spent most of her life under the care of native people, who employed fire to manage the oak woodlands and other ecosystems. They would burn frequently enough to keep fuel loads down, so that the fires stayed on the ground and did not damage the canopies. These fires kept young trees, potential competitors for light and other resources, from encroaching on the oaks. They pollarded the oaks, a common practice of repeatedly cutting the lead stem so as to encourage multiple large spreading branches. This, as any orchard farmer knows, is the most efficient shape for maximizing fruit or nut production. In this case, the native people were managing for efficiency in the production and gathering of acorns.

After the California native people were forced from the land, ranchers followed in many places, such as here where Grandmother oak resides. For nearly a century this land was heavily grazed by cattle and horses, which, like fire, kept the young trees from encroaching.

The land was eventually sold about 30 years ago and stopped being a working ranch. Without any fire or grazing disturbance, dozens of young fir and bay trees quickly started growing around and under the oak. By the time I arrived in 2017 many of the fir were taller than Grandmother oak and were shading out the edges of her canopy. With the added competition for light, water, and nutrients, Grandmother oak was clearly beginning to suffer. Thus, the owner’s called on me for help.

I proposed trying fire mimicry, and they agreed. In early March of 2017 I, and my dedicated crew, began treating Grandmother oak, first clearing away the encroaching fir and bay trees, pruning the dead branches, and removing the mosses and lichens from the trunk. We then fertilized the soils beneath the canopy with compost tea, followed by alkaline-rich minerals, and applied a limewash (a kind of poultice) to the trunk.

The results after just two years of treatments are exciting. as the photos below show Grandmother oak is clearly recovering. If all goes well, she may live another 500 years!

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