Sudden Oak Death researchers acknowledge fire suppression link to disease

24 04 2010

There is an exciting new video out titled – “The Teakettle Experiment: Fire and Forest Health” released by The Video Project.  A summary of the film states:

“The film documents the Teakettle Experiment, a ten-year collaboration of forest managers and scientists from diverse disciplines that investigated the effects of prescribed fire and forest thinning on restoring forest health.

A century of fire suppression has significantly changed many western forests, leaving them overcrowded and susceptible to disease, pests, and catastrophic crown fires that endanger lives and property.”

Here is the trailer (YouTube):

Besides describing the science behind the use of fire and fire mimicry practices in restoring forests, there is something else remarkable about this film.

It seems that the UC scientists who have vigorously opposed my efforts of using fire mimicry practices to help oaks with sudden oak death are now acknowledging that fire suppression is linked to the increased incidence of diseases, such as Sudden Oak Death. David Rizzo, professor at UC Davis and a leading researcher of Sudden Oak Death disease, comments on the overcrowding of forests due to fire suppression, stating (at 1 min 34 sec in the trailer):

“So during times such as drought there’s a lot of competition for moisture, trees are more stressed, they’re more susceptible to insects . . . and diseases.”

Wow! What a change in tone from a few years ago when any mention of fire in the context of Sudden Oak Death disease would set Rizzo and his colleagues into a fury. I applaud Prof. Rizzo for keeping an open mind in this matter.

It is no secret that fire suppression is linked to Sudden Oak Death. UC scientists Max Moritz and Dennis Odion published a paper in 2005:

Moritz, M.A., & Odion, D.C., 2005. Examining the strength and possible causes of the relationship between fire history and sudden oak death. Oecologia, doi: 10.1007/s00442-005-0028-1.

in which they concluded that the incidence of Sudden Oak Death disease was “extremely rare” within the perimeter and any area burned since 1950.

The science for implementing fire mimicry practices to restore California oaks is getting ever more solid.




4 responses

26 04 2010

Is that the same Dr. Dave Rizzo from UC Davis that said many years ago that California Oaks are perfectly healthy and there is no predisposition to sudden oak death?

26 04 2010
Lee Klinger

Hi Ralph,
Do you have a citation for that statement?

27 04 2010
27 04 2010
Lee Klinger

Thank you for this article. The statements by UC-Berkeley researcher Max Moritz are powerful, especially this: “Another factor is that soil chemistry changes with the length of time since the last fire. In particular, fire increases the amount of calcium in the soil, and calcium, Moritz says, is an important factor in disease resistance.”

With regards to Rizzo’s view, the article states “(Rizzo’s) own studies . . . have indicated that the healthiest trees are the most susceptible to infection.” In essence he’s saying that the healthier oaks ARE predisposed to Sudden Oak Death. We’ve heard this before, and it appears to be based on the observation that oaks with deep splits in the bark tend to get infected more than those without splits. That sure makes sense. But they assume the deep splits are ‘growth cracks’ arising from higher radial growth rates of those trees. I have seen no data to support higher growth rates. The cracks could just as easily arise from poor bark development due to depleted calcium and other minerals in the soil.

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