[Fwd: Re: Is water-wise fire foolish?]

I am sure Moira intended this for the forum . . .

Seán A. O'Hara
sean(at)gimcw.org
www.hortulusaptus.com
(ask about mediterranean climate gardening forum)


------------------------------ Original Message ------------------------------
Subject: Re: Is water-wise fire foolish?
From:    "Tony and Moira" <tomory@xtra.co.nz>
Date:    Wed, November 21, 2007 3:30 pm
To:      sean@gimcw.org
------------------------------------------------------------------------------


Tony & Moira Ryan, Wainuiomata, New Zealand
Climate ( US Zone 9). Annual averages:-
Minimum -2°C; Maximum 28°C Rainfall 2000mm
----- Original Message -----
From: "Sean A. O'Hara" <sean@gimcw.org>
To: <medit-plants@ucdavis.edu>
Sent: Thursday, November 22, 2007 6:01 AM
Subject: RE: Is water-wise fire foolish?


> Welcome Ben -
>
> What an interesting and very appropriate topic for this forum!
>
> There has been far too much generalization about what can be done to
> prevent
> fire damage - site specifics always need to be considered, and the
> specifics
> of individual fire events also play an important role.
>
> Fire is a fact of life in most mediterranean climates.  The ecology is
> adapted
> to this reality - we should be also.  To imagine that somehow we can be
> 'safe'
> from fire danger is foolish.
>
> Living through the Oakland Hills fire, I have some observations.
>
> A friends house, which is still standing, was one of the spots
> firefighters
> chose to make a stand.  Their reason for doing so was the protection
> afforded
> by the specific site.  This was an older house, stucco with a slate roof.
> It
> was also surrounded by more space than other homes in this very congested,
> hilly area where properties were divided and divided again (because of
> their
> high value and desirable views) and homes were often 'too large' for the
> property.  The garden was full of a diversity if unusual plants, some more
> flammable than others, all of it burned, some was lost, some has come
> back.
>
> The fire was so hot on this property that a greenhouse was reduced to a
> few
> blobs of glass slag, a large tree shredder was completely incinerated (a
> few
> bolts and mechanical parts that fell into the soil were all that
> remained).
>
> The soil was baked dry and water had to be injected into the subsoil in
> order
> to gradually get it to accept water again.
>
> This garden still has some of the original oaks, which are native to the
> area.
> They survive fire pretty well.  Most, if not all, of the pine trees in the
> area were destroyed.  Some redwoods were scarred, but have come back well.
> Acacias started sprouting everywhere - a rare event except for a few of
> the
> weedier types - their seeds lying dormant in the soil until heated by the
> fire.  This garden had a virtual 'lawn' of purple A. baileyana seedlings -
> something I had never seen happen before! (Snip)

Hi Sean
I noticed you saying how the native oaks often survive fire.
There are undoubtedly some parts of the world whose vegetation is naturally
geared to withstanding burning. In the African Savanna, for instance most of
the vegetation is small scrubby bushes whose tops may be destroyed almost
every year by grass fires in the dry season, but which possess enormous
perennial root systems rhat sprout and grow vigorously with the coming of
the rains.

In Australia I think fire survival of vegetation reaches a peak. I have
visited there several times and on two occasions  I remember in particular
seeing evidence of fire damage. One was my very first view of the country
riding by train from Melbourne to Sydney where we went through extensive
eucalypt forest just recovering from one of the frequent burns and every
tree we saw was covered with newly-emerging leaves over its blackened stems.
The other occasion was many years later on the hills outside Adelaide which
had suffered some really devastating fires about three years previously. As
one drove up into the hills the vegetation looked green and lush -not just
trees but all the undergrowth as well-  but bowered in this growth every so
often one would see the burnt-out ruins of a substantial house. I remember
one in particular, obviously built largely from concrete or some other
resistant material, but nevertheless reduced to a sad shell.  At that time
there had been no rebuilding and I wonder what has happened since (this was
about twenty years ago) Maybe they have decided to build out among the trees
like this is too dangerous. As to your experience of the mass germination of
Acacia, several Australian native plants (Not trees only) are so geared to
germination after fire exposure that they will not break dormancy without it
(Or in some cases I understand not so much fire as _smoke_)  Obviously
another natural way of combatting frequent burns.

Things are rather different in NZ. Our natural vegetation is usually
described as temperate rainforest. Much of this, particularly in the South
Island, is permanetly very wet and in general very difficult to burn. We do
occasionally get fires menacing houses and indeed the odd house burns, but
almost always because of the proximity of introduced pines or, around
Wellington in particular, from the  (also introduced) gorse scrub*. Both
these growihs are inherently severe fire risks. We do have very extensive
commercial pine plantations in some areas, but these are strictly managed
with no houses allowed. and they have observation towers manned by fire
watchers, so they only occasionally run into trouble.

One of the likely effects of global warming though is that the climate will
get drier as it gets hotter and if it does I guess most forested areas will
become more vulnerable, as they seem to be already in Australia,  America
and southern Europe.

*And gorse is another "survivor" which can be burnt to the ground yet
readily re-sprout,\ while young seedlings spring up like mad from the burnt
ground. I gather this figures as it comes originally from Spain, a typical
Mediterranean country

Moira
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