Re: Some musings on current local tree diseases/Pinus radiata

--- Mark Brent <mark@lamorran.fsworld.co.uk> wrote:

> Some interesting observations. As a professional
> horticulturist something
> that is concerning me is the spread of disease
> between differing global
> regions and the sudden apparent susceptibility of
> certain species to
> disease. Currently we have a problem with Sudden
> Decline Syndrome on
> Cordyline species here in Cornwall (SW England)
> which appears to have made
> its way over from England. If anyone down under has
> an answer I'd love to
> hear about it.
> 
 The problem with
> Monterey Pine you cite would be of special relevance
> to this region of
> England as these magnificent pines are one of the
> principle sources of wind
> protection in Cornish Gardens and I'd welcome any
> further information you
> may have.

Mark,
Being only an amature horticulturalist and really more
focused on plants as elements of design, I usually
forget the details when talking about diseases and
insect problems.  You made me go look up "Pinus
radiata diseases in California" on google and I now
know that here in California there are  3 species of
native bark beetles which help spread Pitch Canker
Disease along with an introduced fungus called
Fusarium subglotinans f. sp. pini.  The bark beetles
seems to be the vector which spreads the other two
diseases.  

Trees under environmental distress from
drought/smog/too dry conditions are most prone to
attack in garden settings, and affected trees attract
even more bark beetles, decline can be fairly rapid. 
There are few successful old age plantings in
California where coastal humidity isn't present. 
Within affected stands, they seem to be finding some
trees that are more resistant to attack, not all trees
in an area are killed.  As far as I know, it IS bad
locally in the Monterey natural population, much less
so at the Ano Nuevo, San Mateo County population, and
no I've no idea of how the Cambria, Calif., and Cedros
Island and Guadalupe Island, Baja California
populations are being impacted.  (Goats are probably a
greater problem than diseases in Baja).  Some good
sites to find out quite abit more about the California
groves and most important diseases are at:

www.na.fs.fed.us/spfo/pubs/silvics_manual/Volume_1/pinus/
radiata.htm
and
http://www.cnr.berkeley.edu/departments/espm/grad/html/faculty_html/wood.html


I understand that this pine is widely planted around
the world, and often grows larger and faster overseas
than it does here.  I grew up with magnificent stands
of Monterey Pines planted out in the hills of San
Francisco suburbs such as Hillsborough, of similar age
to the urban park stands in Golden Gate Park, in what
was formerly all sand dunes swept by fog.  As current
folk wisdom,(as taught at any local university)
considers them either too large, too disease prone or
too short lived, (average age 100 to 150 years old),
they aren't being replaced as they die in most urban
plantings. (Similar to large Eucalyptus such as
E.globulus/viminalis/camaldulensis).  They are
certainly magnificent old canopy trees in conjunction
with Monterey Cypress and the large Eucalyptus
throughout Golden Gate Park.  Much of the Berkeley and
Oakland Hills are similarly planted to these trees,
most around the early 1900's.

They are still being massively planted for sheared
Christmas trees at cut and pick farms all along the
central and northern California coast.  Who can say if
the increased farming of these trees has not also
contributed to the spread of the diseases.  Certainly
few if any growers are farming these organically, and
they are subject to much more preventative spraying
than most garden or wild trees, much like a typical
golf course is heavily sprayed and fertilized.

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