Evening star., 1950-09-25
Chino Birch May Prove
Resistant to Fatal Blight
Trees Near Roanoke
Show Much VitoIity
By Thomos R. Henry

Three or four remarkable white
birches now are growing in the George
Washington National Forest near Roa-
noke. Va.
They may make possible the extension
southwark to the Gulf Of one Of the
most picturesque and romantic Of north
ern trees. OF more Importance, they may
save North Americas birch forests, nov
threatened with one Of the most mys-
teriouS plant diseases known to forest
pathologists.
This is the "birch die-back." It appar-
emily started few years ago in Nova
Scotia and has moved slowly southwark
through Quebec, New Brunswick and
most of New England. The birches sim
ply stop growing and die. There is no
fungus, such as cause most fatal tree
diseases. The malady may be caused by
a virus, as would be suggested by its
progressive extension. Department Of
Agriculture workers have tried to dem
onstrate this by injecting healthy birches
with material from sick trees. They have
obtained some curious changes, but
nothing which fits the "die-back" pic.
ture.
Brought From China.
The new birch was brought In from
western China about 20 years ago. It
was quite close relative Of the Ameri-
can white birch species, but seemed to
have no particular virtues. A few speci-
mems, however, were distributed about
the country with the thought that it
might have more southerly range than
the native birch. This Is rather strictly
a northern tree, except that it extends
along Appalachian ridges as far south
as South Carolina. The altitude, how
ever. gives 1t essentially northern cn-
mate. The issue was not pressing, 80
little was done about 1t. Fortunately.
however, some specimens were planted
in the George Washington National
Forest.
The fact that it can stand q more
southerly latitude now has been demon
Strated. It also can Withstand far north
ern winters and there is good reason
to believe that it will be resistant to
"die-back." This now Is causing much
concern through parts of New England
and northern New York where consid-
cradle industries have been developed
around brentwood. Birch also Is one Of
the most famous ornamental trees, and
much of the charm of the northern
forests would disappear with the extinc-
ton Of the tree.
Superf1cially the Chinese birch is in
distinguishable from the native birch,
except that its bark does not appear
to be quite so white. Its most remark
able property is it's rapid growth. It
grows third again as fast as North
American birches and tends to have q
larger, Straighter trunk. OF major inn
portance is the fact that it grows cas-
lily from seed. A dead birch forest could
be replaced with little labor.
Disease Is Limited.
Birches are confined to the northern
hemisphere. There is great belt Of
them extending around the world across
northern North America, Europe and
Asia. So far as known, the die-back
has not been found in the last two con-
tinentS. although no systematic search
has been made. At least. the malady
has not been prominent enough to at
tract attention.
Department Of Agriculture specialists
have done lot of specializing on the
possible cause. since the customary in
fectious agents seem to be ruled out,
widely held theory is that it may be
due to warmer winters, on the general
assumption that the climate may be get.
ting uncomfortably warm for a tree &C.
customed for countless milleniums to ice
age cold. 1t cannot be demonstrated.
however, that the climate actually is
getting warmer-and even so the same
conditions obtain in Europe and Asia.
The Chinese birch, which at first at
tracted no attention, has been given
no special nursing by the George Wash
ington National Forest staff. It was an
orphan of the plantation which showed
native rapidity of growth greater than
that OF any other tree in the planting.
Seeds now are being distributed widely
over the natural birch area and through
the Southern States where, it is be.
heved, the Chinese tree may have con.
siderable vogue as an ornamental.
Its wood has been found equally a.
good as that Of the northern birch.