Hearst Castle oaks respond to fire mimicry – Part 1: 7-year results

7 01 2013


Last Friday I visited Hearst Castle to check on several oaks that have been undergoing fire mimicry treatments for the past seven years. The California State Park employees, led by Chris Takahashi, have been implementing the fire mimicry treatments, more-or-less following my guidelines. Last year the oaks were partially damaged by a severe windstorm in December of 2011 (see the 2012 results here).

There are several interesting sets of results from Hearst Castle that I will present in three separate posts. Part 1 shows the seven-year results of fire mimicry treatments. Part 2 will examine several oaks that were photographed in December of 1995, which I have re-photographed in 2006 (at the time of their first treatment) and in 2013. Part 3, will examine the response of a control (untreated) oak to an accidental treatment in 2012.

The photos posted here show that the Hearst Castle oaks have generally made a strong recovery from the windstorm and most are sporting healthy canopies indicating that oak health is much improved since fire mimicry treatments began seven years ago. Some of the oaks have lost branches over the years, so the shape of the canopies has changed a bit. The main thing to observe is the canopy density, which is a measure of oak health.

A few of the oaks have had bleeding stem cankers, possibly sudden oak death, for the entire seven years of treatments. Most of these have continued to show positive responses (e.g. Case Nos. 20060104.1 & 20060104.16), but one (Case No. 20060104.2) is severely infected and is clearly in decline despite regular fire mimicry treatments. This is yet another case showing that oaks with severe infections of stem canker disease have little hope of recovery. The key is to treat the oaks BEFORE they are exposed to infection.

Be sure to compare these photo sets of treated oaks with the last photo set of a control oak (Case No. 20060104.4) that has not been treated.













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