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Nursery growers and the garden centre community should be
supporting an alternate approach to Sudden Oak Death!
In September 2004 I wrote in detail about Sudden Oak Death
(SOD). Amongst other ideas, I said that the Canadian Nursery
Landscape Association was attempting “to develop and
implement a Canadian Nursery Certification Program for
exporting nurseries. The USDA is apparently considering
implementing a similar program to complement trade with
Canada. Only The Netherlands has such a certification
programme for growing nurseries in place at this time.”
I also cited the work of Lee Klinger who has degrees (MA and
PhD) from the University of Colorado. He has been
independently studying worldwide tree decline since the
mid-80s. He has researched ecology for more than 14 years at
the National Center for Atmospheric Research in Boulder,
Colorado, leading and conducting studies to characterize all
the major ecosystems, from arctic Alaska to central Africa.
Recognized as one of the worlds' leading scholars in this
area, Lee Klinger has presented novel works about: fate of
old-growth forests, origins of the peat lands and how they
all relate to ice age initiation. His achievements include
the discovery of the primary cause of forest decline.
In August, I wrote: “It is quite apparent that not all
scientists agree on what causes SOD (whether it is
Phytophthora ramorum alone, with other factors, or at
all). For example, disputing the idea that P. ramorum
is the primary cause of SOD, some scientists are dubious.
“Even if you take the strictest definition of SOD--the
Phytophthora pathogen--there are still problems, the
most serious one being that the mosses were not controlled
(or accounted for) in their test,” says Lee Klinger, who
built his career on studying mosses and first published
about their effect on tree roots in 1991. He maintains that
mosses might be killing the oaks.
“Additionally, Lee Klinger believes that only trees with SOD
are being studied. “If the trees don’t have SOD, they’re not
studying them.” And, he says, “Most of the trees that are
dying have no sign of Phytophthora.”
“In 1985, when he was researching tree death and forest
decline on Kruzof Island off the coast of Alaska,” Lee
Klinger “noticed that dying trees and the ground around them
were covered with moss.” His 20 years of research data
support his contention that moss runoff, which is highly
acidic, increases the acid content of the soil and
contributes to yellow cedar decline in Alaska, sudden oak
death in California and Europe, and similar epidemics of
dying trees and forests. The simple, non-toxic, and
universal solution to tree death and forest decline, says
Dr. Klinger, is to reduce soil acidity.
“There are many ways to reduce soil acidity. Scientists at
Hubbard Brook Research Foundation in New Hampshire, and at
Cornell University in New York, are doing it by treating
declining forests with calcium and other minerals. In the
1980s, German scientists reversed the decline of the Black
Forest by using lime to reduce the acidic content of the
soil. And long ago, Native Americans revitalized dying
forests with fire, which also decreases the acidic content
of the soil.”
Additional information is now available. For example, here
is a quote from a paper (by Lee F. Klinger, Ralph Zingaro
and Michael Coffey) for the Journal of Forest Ecology and
Management. “Data on pH from 34,700 soil samples taken
from a wide range of agricultural and forest soils in
California indicate that between 14 and 21% of the soils are
acidic (pH < 6.0) and 3 to 4% are strongly acidic (pH <
5.0). However, a subset of samples taken from SOD-affected
sites indicates that 72% of these soils are acidic and 4%
are strongly acidic. The soils from these sites were also
found to be consistently low in calcium and very high in
soluble aluminum and iron. These results lend further
support to the theory that systemic acidification is
adversely affecting the health of the trees and soils in
SOD-affected forests. The situation described here in
California is not unlike that in other regions of the world
where aging forests are experiencing decline. From this and
other work (e.g., studies at Hubbard Brook), we strongly
believe that the cause (and the definition) of SOD is still
an open question, and that the scope of SOD research should
be expanded to include studies of acidification by
cryptogams in the context of forest and soil ecology.”
Ralph Zingaro, whom I mentioned extensively in last year’s
item on this subject, was this year invited to the Acid Rain
2005 conference in Prague, the Czech Republic, to deliver
the paper from which the foregoing quotes are taken. As soon
as they saw the paper, they issued an invitation to attend
the conference at their cost. Over 1,400
delegates from all around the World were in attendance.
Among others, Ralph met with Paul G. Schaberg of the USDA
Forest Service Northeastern Research Station in Vermont. The
latter is heavily involved in work on calcium depletion and
how it has predisposed trees to forest infections. His work
ties in ever so well with that of Messrs. Klinger and
Zingaro.
In a recent Oecologia (a peer-reviewed journal from
Springer-Verlag) a lengthy paper by Max A. Moritz and Dennis
C. Odion, discusses “Examining the strength and possible
causes of the relationship between fire history and Sudden
Oak Death.” Amongst many findings and conclusion they found
“that wherever a fire has occurred within the past 50 years
there is no SOD".
The single-minded focus of California (and other) scientists
on a fungus is difficult for Lee Klinger to understand,
particularly since he sees the same fungus as an
opportunistic species that takes advantage of trees that are
already dying of other causes. Explaining that P. ramorum
kills a tree by growing a canker around the trunk, and that
the canker "bleeds" black sap, Lee Klinger says, "Most of
the oaks that are dying do not have bleeding cankers. Given
this, P. ramorum is not the best explanation for why
the oaks are dying." A better explanation for the cause of
tree death, according to him, is a bit more complex,
involving mosses, soil acidification and tree roots.
Professor Klinger adds, “I have not seen any peer-reviewed
published papers on soil chemistry or root analyses related
to SOD,” he says. “Mosses, which are clearly implicated in
soil acidification and the mortality of fine roots, and are
abundant in all areas of SOD, have not been carefully
investigated or controlled in any of the research or
experiments on SOD. These analyses are basic science that
should be done in any forest decline situation. Until they
are done, the cause of SOD cannot be determined."
The discovery of a red oak tree in New York State infected
with SOD could force changes in a nationwide quarantine of
California nurseries as scientists re-evaluate the spread of
the mysterious microbe.
In response to Ralph Zingaro’s discovery of P. ramorum
in New York State, the local USDA people located an infected
tree at the same location in July last year. He also found
oak trees infected with SOD in Pennsylvania and New
Hampshire. The New York State find was in the Tiffany Creek
Preserve, a 77 hectare (192-acre) nature park in Nassau
County, nowhere near any nurseries that might have received
diseased flora from California. Incidentally, Ralph’s
research trip to the eastern U.S. was sponsored by the
California Association of Nurseries and Garden Centers.
Forestry experts are at a loss to explain how the pathogen
got to the preserve or how long it has been there. The
fungus-like organism has, until now, never been found in the
wild, outside of the coastal regions of Northern California
and southern Oregon.
"The finding in New York raises more questions about the
distribution of P. ramorum throughout the United
States," said Don Dillon Jr., chairman of the board of the
California Association of Nurseries and Garden Centers. "If
it has been there for some time, it raises questions about
the whole nature of the pathogen. It may be naturally
occurring in other places. It could have come from back east
and spread here."
The New York oak tree's lack of any apparent connection to
California is particularly troubling to regulators and
puzzling to scientists. It could mean that Phytophthora
ramorum is a naturally occurring pathogen that already
exists throughout the country and, possibly, throughout the
world. If that is the case, then there is no reason for
California nurseries (or others elsewhere) to face
restrictions. In fact, the tack taken by the Canadian
Nursery Landscape Association, which is bound to be costly,
may be fruitless. It might well be better if they were to
help fund an independent research project such as that I’ll
mention at the end of this article.
Lee Klinger believes sick oak trees just need a healthy dose
of vitamins. Now he just needs to convince a skeptical
science community that he has an easy cure to Sudden Oak
Death.
He tried to do just that January 18 - 21 this year during
the Sudden Oak Death Science Symposium at the Marriott Hotel
in Monterey, California where hundreds of scientists
converged to share their findings about the disease that has
killed thousands of trees since the mid-1990s.
Much of the talk centered on where the infections have
occurred, possible ways the disease is spread and what type
of trees are affected. Research on treatment is still
preliminary and will take years to sort out, scientists say.
But Lee Klinger says he can help save many of the sick trees
if he can just get researchers to listen to him. But so far
researchers in California are not convinced. He said
scientists are going down the wrong path by looking at
pesticides and fungicides as possible cures. Ralph Zingaro
said much of the work being done by sudden oak disease
researchers is a waste of taxpayer money.
“We need more common sense injected into the discussion,”
Ralph says.
Lee Klinger and his compatriots (including Ralph Zingaro)
who believe the other scientists are entirely on the wrong
track as regards looking for a cure for SOD presently are
relying on small donations from small- to medium-sized
nursery growers and garden centres to fund their own
research. There is at present an application by Lee Klinger
and others for a relatively small and economical research
project (US$49,000) that will prove, once and for all, that
P. ramorum has been in forests all along. That
remains the critical unresolved question in this scientific
debate. The abundant production of certain spores by P.
ramorum and the general properties of such to survive in
soil provide an opportunity. Though their survival in soil
may be measured in years, these thick-walled structures are
likely to persist intact, especially in peat soils. If P.
ramorum were to be shown to occur in soils and/or
sediments older than 50 years, then the debate might be
settled.
Therefore, they propose to investigate carefully, buried
soils at three sites in northern California. At two sites
the soils have been buried (due to landslides which will be
confirmed using aerial photographs), or in peat bogs which
can be dated using radiocarbon analysis. Soils in all three
areas are nearby present rampant infections of P. ramorum
and have been totally undisturbed for 50 or more years. This
will determine whether or not the preserved materials
contain evidence of P. ramorum, especially the
spores. If they do reveal spores, then that evidence should
surely get the research onto the proper track. And, calcium
may become a valuable commodity for garden centres. If you
wish to know more about the $49,000 research project,
contact Ralph Zingaro at
nhcal@yahoo.com.
Another valuable resource on this topic is a new non-profit
organization--the Sudden Oak Life Task Force. It was created
this year to investigate, educate, and implement solutions
to Sudden Oak Death and other tree diseases. The Task Force
is open to anyone interested in healing the ancient trees.
You may check it out on the Web at
www.suddenoaklife.org.
Before SOD costs your business a lot more money, whether
wholesale growing, or garden centre, it would be worthwhile
for you to consider contributing even a token $200 to either
or both of the above ventures!
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Press
Release April 2005......
Etiology and
Evidence of Systemic Acidification in SOD-Affected Forests of
California
Etiology and Evidence of
Systemic Acidification in SOD-Affected Forests of California
Dr. Lee Klinger, Independent Scientist, 10 Elm Ct., San Anselmo, CA
94960; 415-457-2469; lee@luminousproject.org; Ralph Zingaro, White
Mt.Horticultural Consulting LLC Box 19, Harrisville, NH 03450; and
Michael D. Coffey 3206 Webber Hall UC Riverside, Riverside, CA
Pathologists investigating the widespread death of oak trees in the
forest ecosystems of northern California concluded, in 2000, that
the problem was due to a new plant disease, dubbed Sudden Oak Death
(SOD), which was caused by the fungal pathogen Phytophthora ramorum.
Since then this one organism
has been the focal point of notable
efforts to understand, monitor, and control SOD. While not disputing
that P. ramorum is involved in the final demise of many oaks, there
are a growing number of scientists and
arborists who do not agree
that this pathogen is the fundamental cause of the overall decline.
These experts point out that most of the dying oaks in SOD-affected
forests show no expression of P. ramorum. They further note that the
etiology of SOD closely resembles that seen in other aging forests
where the decline of the trees has been attributed to an increase in
acidity and mineral deficiency of the water and soils. In these
places, acidic conditions create mineral imbalances and deficiencies
in trees, especially calcium, which greatly weaken the trees,
raising their susceptibility to secondary pests and pathogens. Here
we present evidence that suggests systemic acidification of forests
can explain, quite well, the entire SOD phenomenon.
The etiology of SOD in California coincides closely with the
symptoms of systemic acidification in aging forest ecosystems.
Dieback starts with the upper and outer branches in the crown,
showing a pattern of wilting and browning of leaves along with dead
small branches and progressively spreading to the lower
parts of the
crown over several years. The decline affects nearly all kinds of
oaks, as well as bays,
buckeyes, pines, and so forth, hitting mainly
the larger trees in mixed-oak savannas and forests, most of which
have been under strict fire control for more than 50 years. Areas
near the coast and those
experiencing frequent seasonal fog are
especially hard hit by SOD. Affected trees tend to occur in mature
forests (greater than
100 years old) and are always found in
association with a heavy cover of mosses and lichens. Moss mats have
been shown in both laboratory and field studies to create conditions
acidic enough to kill the
underlying fine roots and mycorrhizae,
which leads to water and nutrient stress and reduced radial growth
in nearby trees. Mosses and lichens are also observed to degrade the
tree's protective bark layer, allowing for pests/pathogens to more
easily infest/infect the tree. In general, the etiology of SOD in
California is much
like that seen elsewhere in dying oaks (e.g.,
Texas, Missouri, Pennsylvania, Manitoba, and Europe), except that P. ramorum is not found to be involved in these other declines.
Data on pH from 34,700 soil samples taken from a wide range of
agricultural and forest soils in California indicate that between 14
and 21% of the soils are acidic (pH < 6.0) and 3 to 4% are strongly
acidic (pH < 5.0). However, a subset of samples taken from
SOD-affected sites indicates that 72% of these soils are acidic and
4% are strongly acidic (median pH = 5.7; n = 132). The soils from
these sites were also found to be consistently low in Ca and very
high in soluble Al and Fe. Spatial analysis reveals a strong coastal
gradient in soil pH with the lowest pH values found near the coast.
Strong coastal gradients are also
apparent in soil Ca, which is
lowest near the coast, and in soil Al, which is highest near the
coast. Precipitation chemistry data from this region also reveal a
coastal pH gradient much like that found in the soils. Similar
coastal gradients in precipitation pH have been reported from the
Olympic peninsula, from southeast Alaska, and from Scandinavia.
These results lend further support to the theory that systemic
acidification is adversely affecting the
health of the trees and
soils in SOD-affected forests. The situation described here in
California is not unlike that in other regions of the world where
aging forests are experiencing decline. From this and other work
(e.g., studies at Hubbard Brook), we strongly believe that the cause
(and the definition) of SOD is still an open question, and that the
scope of SOD research should be expanded to include studies of
acidification
by cryptogams in the context of forest and soil
ecology.
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