Re: More garden photos:Medit plants for a California hillside garden

Nan,

Observation in the field doesn't lie...  The trees that survived the Oakland 
Hills Fire were those that didn't immediately go up in flames when the wall of 
fire rolled over them.  Driving all around the Oakland Hills fire zone, which 
destroyed over 500 homes, it is a consistent fact that the few landscape trees 
that survived the fire were almost always Coast Live Oaks and Coast Redwoods.  I 
would in fact expect this to be the case, as both these tree species are adapted 
to fires, and have developed the thicker bark and less flammable foliage(in the 
case of oaks), as a response to fire.  The fact that the Coast Live Oaks and 
Coast Redwoods were primarily only singed and may have had some bark killed on 
the down slope sides of horizontal branches is immediate and obvious 
confirmation that these tree's foliage and bark is slower to burn than many of 
the other ornamentals in the landscape.  


As to the more general suggestion that plants with less woody mass and more 
water retentive succulent foliage are slower to burn is also intuitive, but 
these sorts of plants obviously do still burn and did not generally survive the 
fire in the Oakland Hills conflagration.  What they did do, was to slow down 
the  fire progress because they had less fuel load to spread the fire further, 
essentially slowing down the spread of the fire.  Even if they in fact did not 
burn any less slowly because of the intense heat, they didn't tend to spread the 
fire further with fuel that would blow in the intense winds and carry it to 
places further away such as larger woody trees and shrubs such as the Pines and 
Eucalyptus and trees with volatile oils.

If you need scientific field tested data to make the sort of conclusions I made 
here, I can't help you.  My thoughts on this have more to do with close 
observation of actual circumstances in the field, and I stand by my conclusions 
as they relate to how I promote more fire safe gardens for locations in the 
hills at greater risk of urban forest fires.  Of course, the bigger issue is 
people still fail to realize that any tree planted within 30 feet of a house on 
a hill increases the fire risk, and that all trees should be regularly pruned 
and thinned to reduce fuel loads.  As I drive through the Oakland Hills these 
days almost 20 years after the fire, I can observe that very few people have 
taken these concerns to heart.  Even the newer rebuilt homes landscaping often 
has big trees left unpruned too close to structures, with no attempt to create 
defensible space around buildings, especially on the downslope side.  I 
generally advise any new client in the hills to more seriously consider fire 
safety as more important than aesthetic issues, period.  When they are unwilling 
or unable to remove/thin trees, at the very least I make damn sure the new 
plantings don't increase the fire risk, but minimize it.



----- Original Message ----
From: Nan Sterman <TalkingPoints@PlantSoup.Com>
To: david feix <davidfeix@yahoo.com>
Cc: Medit-Plants listserv <medit-plants@ucdavis.edu>
Sent: Sat, March 12, 2011 12:00:33 PM
Subject: Re: More garden photos:Medit plants for a California hillside garden

Wow David, another wonderful garden!

I am curious about your statement regarding slow burning plants.  From all the 
research I've done, there have been  no studies nor documentation of 
flammability of plants, native or otherwise, in California.  All the 
organizations and individuals I spoke with said they'd gotten their lists of 
"fire resistant" plants from someone else who, when I contacted them, said it 
was from someone else, and so on.  Finally, one of the botanic gardens told me 
that years ago, a volunteer took leaves home and put them in his oven - then 
based their list on that.  Fire departments told me it was based on firemen's 
observations in the field, but of course the conditions vary so much from fire 
to fire and region to region, that those observations make a good starting point 
but don't tell you anything about predicting flammability.

So  Im very curious to know what resources did you use to base your selections 
in terms of fire resistance.

Nan
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