Sudden Oak Death

Richard McGuiness armich at
Fri Mar 2 05:25:12 EST 2001

A new disease is devasting oak trees in the Bay Area of California. It
arrived about 6 years ago  and is spreading throughout the area. It is
an invader eerily similar to chestnut blight. It currently is attacking
three native species of oaks, but has now been found on rhododendrums in
Germany and Holland, and may have been brought in on nursery stock. They
found it on rhodies in a Sonoma County nursery. It is related to
chestnut blight, potato blight, Port Orford Cedar blight and European
grapevine blight. However, this seems to kill the trees outright in a
few weeks, as far as I can tell the trees are dead and will not stump
sprout like chestnut-blighted trees do. The rhodies and oaks get aerial
cankers, but movement of wood or mud is advised against, as they are
just learning what vectors it uses. The science and programs are just
getting started. Check put for articles, links,
and great photos of what to look for in the field. Here in Humboldt,
lots of watersheds are held together by remnant oaks, especially canyon
live oaks, left behind by tanbarkers and Doug fir logging. These trees
hold tremendous amounts of soil in highly erosive watersheds, and a lot
of instream restoration depends on holding the sediment  up on the
hillsides. They are worried about a huge jump in fuel loading,
especially in interface areas. And in view of chestnut blight, another
disaster in the making for the whole country, although only three oak
species seem to be hit so far. Acorns also play critical roles in
natural systems, and the multitude of insects feed other animals.
                                                Rich McGuiness, Middle
Mattole Conservancy

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