Native Plants are Flammable Too

Three of the most flammable plants in California landscapes are bay laurels, coyote brush, and chamise – all native. An evenhanded presentation of fire hazard ratings for all plants that does not downplay the danger of native plants or exaggerate the danger of non-native plants would better serve people working to address fire hazards. So we wrote this letter to the California Native Plant Society, which is updating its Fire Recovery Guide. (You can see it here as a 64-page PDF document: cnps-fire-recovery-guide-lr-040618 )

 

To: Daniel Gluesenkamp, Executive Director of the California Native Plant Society

Dear Mr. Gluesenkamp,

We have read the CNPS Fire Recovery Guide. Property owners will undoubtedly find it useful advice to prevent post-fire erosion and unnecessary destruction of trees and plants that are likely to survive in the long term. The specific advice about creating defensible space also seems helpful.

We understand that your organization is working on an update of this Guide. We are therefore writing to make a few suggestions for improving its accuracy and therefore its credibility.

If the Guide is going to suggest that home owners avoid planting specific plants within their defensible space, we would suggest a more neutral approach that would focus more on fire hazard and less on nativity. The Guide cites eucalyptus and non-native pines as presenting severe fire hazard. See pages 5, 30 and 52. However, the evidence from the recent fires does not implicate non-native trees. The documents cited in your guide (pages 44-45) show that the acreage of non-native tree species that burned in the recent fires was insignificant compared to the overwhelmingly native vegetation that burned. Two papers are cited to support the claim that non-native trees are more hazardous than native trees, Lambert and Landis. Neither paper presents and analyzes data to support the claim. Each paper contains a table of non-native plants considered to be fire hazards, but no information is presented to support them. There is a large quote about the fire hazard of eucalyptus on page 30, but with no indication who made the statement.

There are many available lists of flammable plants that should be avoided within defensible space. Marin Fire Safe lists both native and non-native plants on its list of flammable plants: http://www.firesafemarin.org/plants/fire-prone

The Oakland Firesafe Council also provides a link to that list on their website. Three of the most flammable plants in California landscapes are are bay laurels, coyote brush, and chamise. An evenhanded presentation of fire hazard ratings for all plants that does not downplay the danger of native plants or exaggerate the danger of non-native plants would better serve people working to address fire hazards.

Page 56 of the Guide dismisses the role SOD may have played in the fires. The Big Basin fires are discussed in support of this, but there is no analysis of the Napa, Sonoma and Mendocino fires. Matteo Garbelotto, 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…
http://digital.olivesoftware.com/Olive/ODN/SanFranciscoChronicle/shared/ShowArticle.aspx?doc=HSFC%2F2017%2F10%2F20&entity=Ar00101&sk=FE15FEB2&mode=text
It seems likely the vegetation killed by SOD did play a role in fires. Why downplay the possibility?
SOD is a terrible thing. We should not ignore its consequences.

When recommending that property owners plant oaks on their land (page 21), it might be wise to steer them toward other tree choices if the SOD pathogen is known to exist at their location. A detailed map of where SOD infections have been found is available here:
https://nature.berkeley.edu/matteolab/?page_id=4262

There is some confusion in the guide between plants that are flammable versus fire intolerant. BayLaurels are flammable, but fire tolerant. See page 56.

We hope you will take our comments into account,

San Francisco Forest Alliance

 

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