Saving the American Elm

BCarley978 bcarley978 at aol.com
Thu Dec 20 23:15:39 EST 2001


I have posted this article to call attention to a special project which
I have
been doing continually since 1994 and which I hope will be a source of
inspiration for many. Ever since some new disease-resistant varieties of purely
American elm were called to my attention, I have been hooked on raising these
trees for local distribution in my home town of Acton, Massachusetts,
and it
did not take me long to conceive of finding a way to have them planted on
various conservation lands, where they will always be safe from indifferent
landowners. I soon became acquainted with this towns conservation director,
who welcomed my idea wholeheartedly and gave me the necessary
permission. 

QUINTESSENTIAL MAIN STREET 

During their usual strolls along the main streets of their home towns, our
parents and grandparents gazed at the scenery around them and took for granted
a spectacular picture that is seldom observed nowadays and that few of
us can
hope to see during our lifetimes. The interweaving limbs of the stately trees
that lined the streets ascended into a towering canopy with a graceful, arching
beauty unmatched by any tree that is commonly seen today, spreading
horizontally at heights often greatly exceeding 100 feet (in rare cases
attaining 140 feet with even greater spreads and 11 foot trunk
diameters), and
drooping long, slender branches in abundance high above the street, blocking
all view of the sky. Along countless streets for many miles in cities
and towns
throughout the tree's extensive native range in the eastern half of North
America, even as late as the early 1960's, this scene abounded, the
effect of
the only species capable of giving us such majestic splendor. 

Veritably the standard against which the merits of other shade trees were
measured, the American elm provided the ultimate in stateliness and beauty,
making it the single most popular shade tree for lawns and city streets
in the
eastern United States, and earning it distinction as the state tree of
Massachusetts and North Dakota. Architects even designed buildings with elm
plantings inherent in their plans. The early citizens of Portland, Maine and
New Haven, Connecticut had such a passion for the American elm that they
created elm-lined streets on practically every block and earned each
city the
nickname, City of Elms. Once as naturally abundant as maple, oak, and pine,
the American elm was an essential part of our natural landscape and cultural
heritage throughout the first few centuries of our history, and it was
in fact
the first symbol of our national independence; for a fine example had
stood in
Boston as the famous Liberty Tree, an emblem of promise and a gathering site
for patriotic citizens intent on independence, until British soldiers destroyed
it as a final act of hostility during a hurried retreat from Boston in
1775. 

THE FALL FROM GRACE 

Many of us remember how painful it was for our communities to witness the
tragedy that recurred throughout the eastern states, mostly during the 1960's.
Many remember watching helplessly as countless main streets, parks, historic
sites, and neighborhoods that had been so handsomely graced with fine
elms were
transformed within a few years into barren, urban-looking landscapes
devoid of
trees, the result of a frighteningly efficient epidemic that had appeared
suddenly. We can imagine the profound dismay of the citizens of Portland and
New Haven as each City of Elms was quickly transformed into a City of
Firewood, necessitating almost phenomenal removal expenses. Some may recall
marveling at the futility of the cut and burn campaigns which were initiated
to halt the spread of an epidemic which was killing trees literally by the
millions each year. 

The cause of this pervasive syndrome of wilt and dieback was a parasitic
fungus. The spores of the fungus were being deposited into the vascular systems
of healthy elm trees through twig-crotch feeding wounds chewed by elm bark
beetles, the carriers of the disease. Once in contact with the inner
bark, the
spores germinated into rapidly growing fungal threads which invaded the entire
conducting systems, gumming them up and preventing the transport of
water and
nutrients to the hosts' crowns, thereby killing the trees in a manner not
unlike that of the chestnut blight. Unlike the chestnut blight, however, the
elm pathogen proved efficient at destroying the root systems of its hosts,
preventing them from sending up new shoots, and it even was observed to spread
to adjacent trees through natural grafts between their roots. 

A native of Asia, the fungus first had appeared in North America in 1930 in
Cleveland, Ohio, having found its way into the continent by the same
means as
the chestnut blight, namely, through the accidental import of infested logs
from a closely related species. The parasite was no stranger in Europe, where
it similarly had appeared early in the twentieth century, and where its
pervasive devastation of a number of European elm species, including the highly
esteemed Dutch elm hybrids which had lined many streets, had given rise
to its
now-familiar name, Dutch elm disease. 

The various elm species native to Asia, where the so-called Dutch elm disease
originated, are highly resistant to this disease, as healthy specimens
are able
to manufacture chemicals which prevent the spores from germinating or
gaining a
stronghold in the inner bark of the trees, and they consequently are
able to
thrive with little or no stress in the face of generations of exposure
to the
disease. In its native Asia, the disease actually serves the valuable function
of eliminating old or weakened elms to make way for new growth. The
Dutch elm
disease fungus, like purple loosestrife and water hyacinth, thus
provides us
with yet another classic illustration of the danger inherent in the
introduction of an organism into an ecosystem that is not its own. 

Nowadays we have to search rather painstakingly to find an occasional large
surviving American elm tree, as the pathogen's destruction of more than a
hundred million American elms during the last few decades has effectively
depleted the population throughout the tree's natural range in eastern North
America. Inevitably, the continuing pattern of destruction soon will threaten
the survival of the species, for although young saplings are still
common, the
current population consists primarily of immature specimens with little chance
of reaching a stately maturity, and the large, mature specimens that
still are
seen occasionally are being eliminated rapidly. Like the American chestnut,
which is now gone from the forest canopy, the American elm has been declining
slowly but surely ever since the introduction of a lethal fungal blight, and
although the threat of extinction is not immediate, we cannot realistically
avoid the conclusion that the last of the sizable, wild American elms likewise
will disappear within our lifetimes. 

THE SOLUTION 

The development of purely American elm varieties with adequate
resistance to
Dutch elm disease remains the only hope for ultimately saving the
species, as
systematic injection with elm fungicide is an expensive, cumbersome, and
unnatural process. It was fortunate, indeed, that such development proved
possible and eventually yielded the American elm varieties which now constitute
the essential ingredients of my project. In other words, we now have a
realistic means to ensure the ultimate survival of the American elm and to
bring about the imminent return to our landscapes of fine, stately specimens
that are likely to survive through the decades. That is the essence of my
endeavor, and it is my hope that this writing will help to sow the seeds of
this inspiration for others as well....

**** This article continues at the URL below, including detailed
information on
specific disease-tolerant American elm varieties, cultivation, propagation,
availability, many research links, and a gallery of young American elm
plantings.

http://www.elmpost.org




More information about the Plant-ed mailing list