Evening star., 1938-02-03
STARS, MEN AND ATOMS
Notebook of Science Progress in Field.
Laboratory and Study.
BY THOMAS r. HENRY
BY THOMAS r. HENRY.

American forests are marching north
ward. They have been on the move for
many centuries. but even with relatively
recent times they have made note
worthy progress.
There have been q number Of recent
reports that the northern fringes are
extending poleward in Alaska. Drs.
John E. Potzger and Ray G. Frisner Of
Butler University, Indianapolis, hnd that
their southern fringes in the Middle West
are moving in the same direction.
They gathered fossil pollen from six
bogs within the southern limits of the
last great glaciation of the United States.
This pollen they identified as from trees
which now are found far to the north
ward, although they once must have con-
stituted the predominant vegetation Of
Southern Indiana. They also found q
few isolated stands Of plants whose pres
ent habitat is considerably to the north
and which are making a last stand
against unfavorable climatic conditions.
At the end of the Ice Age, they found.
the present southern fringe was covered
with great spruce-fir forests. Some
time before the white settlement Of
America, these had given away to pine,
oak and hickory. Then the pine began
to drop out and be replaced by beeches
and naples. Probably the next move
northward, will be the oaks and hickory,
while more southern trees establish
themselves among the oaks and hickories.
The northward retreat of the forests
furnishes definite evidence of the grad
ual warming of the Northern Hemis-
phere, perhaps only as an interlude in
the last Ice Age which has continued
for about ten thousand years and per-
haps as definitely marking its end.
Millions of years ago the great northern
forest stretched very close to the pole
itself and Arctic lands now ice-covered
were thickly wooded.
Migratory birds that winter in South
America reach the northern shore OF
that continent almost completely ex-
hausted from their long sea flight.
DR.. Alexander Wetmore, assistant Sec
retary of the Smithsonian Institution,
reports seeing these migrants from the
United States and Canada coming in
over the Caribbean Sea to the coast of
Venezuela, some of them 50 weak and
weary that they barely could make the
last long mile. This northern coastal area
and the inland mountains, DR.. Wetmore
says, seem to constitute q natural rest
camp for North American birds, where
they can get plenty Of food and re-
plenish their energies for the long
flights which are ahead Of them. Some
winter as far south as Patagonia.
DR.. Wetmore has just returned from
Venezuela. where he made q collection
of birds native to that country for the
National Museum. He spent much Of
his time observing bird behavior in a
great national park set aside for the
preservation of tropical wild life by the
Venezuelan government. His chief in
terest was in watching the arrival Of the
migrants after the northern summer.
Through October and November they
-sandpipers from the Arctic, blue
winged teals, yellow warblers, and yel-
low-billed cuckoos from the Eastern
United States.
Such migrations must be terrible or
deals, he says. Even with good flying
weather many Of tho migrants must ex-
tend themselves to the utmost to get over
the broad stretches Of water between
them and their winter homes.
t+ Il
DR.. William j. Humphreys Weather
Bureau meteorologist, wants to add q
new verb to the English language-"to
laurence"
It Is . word, he says, used by West
Virginia farmers to describe the "shim-
mering" over the hot surface Of . stub
BILE f1e1d On Q hot day-a familiar spec.
taele due to unequal Light refraetions q