Evening star., 1935-08-18
Natures Power
Plant Busy
BY Frederic J. Haskin.

Ol
the forest. To the Iroquois or the Choc-
taw| nothing quite so thoroughly en-
phasized incalculable quantity as til,
foliage under which, over much of the
land, he was constantly embowered. The
Indian had no science, in the modern
acceptation of the term, but his realiza-
tion of the mightiness of power of
forest leaves must have been instructive,
for now it is known that these innumer-
able leaves are power plants for the
storing up Of energy which can be used
by man.
In the time of Theodore Roosevelt a
wave of interest and apprehension swept
the country in response to that Pres
idents crusade for the conservation of
natural resources. 1t was foretold that
the vast riches in American natural re-
sources would sooner or later, become
exhausted. Particular stress was laid
upon the necessity for conserving the
forests.
The forests of the land have, indeed.
been reduced. The pioneer was eager
to get rid Of the trees for combination
Of reasons. He wanted the timber to
build his house and provide fuel, he
wanted it removed TO make room for
titled crops. and it was imperative that
the forest be felled to destroy the In
dams ambush his natural fortress
Millions Of acres Of land were speedily
denuded.
But there is marked difference be-
tween using up coal, petroleum. gold or
iron and using the forests Nature is
far more deliberate and leisurely in pro-
duclng the minerals than in producing
the forests. All around us. while We talk
about it, Nature is replacing the forests
with a rapidity which, in historical
terms, is rapid.
Researches of the scientists Of the
United States Forest Service. conducted
in the Boyce Thompson Institute at
Yonkers, N. Y; at the Forest Expert
ment Station at st. Paul. Mimi, and in
the forests Of Northern Minnesota and
Northern Wisconsin. point the way out
Of cold and impotence into heat and
power in the distant future when coal
and petroleum supplies run low. These
experiments illustrate how nature is
still, through the medium of trees, con-
verting sunshine into stored-up heat and
poWer-just as she has been doing for
millions of years. ever since leaves
learned how to imprison sunlight.
Enormous Storage of Energy.
Actually. DR.. Hardy L. Shirley Of the
Lake States Forest Experiment Station,
who has been in charge of the Forest
Service delving into this subject. de-
clares that the forests are today chain
ing two and one-half times as much
energy as is annually released by the
burning of coal. Wood. for equal
weight, has heat of combustion of ap-
proximately rs per cent that of coal,
SO that we may say that an acre of pine
forests may produce the equivalent Of
1888 pounds of coal each year. II we
consider the entire forest area of the
United States, which amounts to &c.
100000 acres, and assume that it could
all produce wood as efficiently as an
acre OF white pine, the annual produc-
ton OF wood in usable form would be
equivalent to $1,000 900 tons of coal, or
approximately one and one-half times
the amount OF coal mined in the United
States in 1890"
In addition to the wood DR.. Shirley
points out there is the litter Of the
forest floor, which annually accumu-
lates at the rate of 2,122 pounds to the
acre. Taking this into consideration,
the total energy stored each year by the
forests of America would be equivalent
to l,403, 100000 tons of coal-over two
and one-half times the amount ordi-
nar1ly mined in this country.
Nevertheless. DR.. Shirley indicts the
trees on the charge of ineficiency. The
heating value, of the $50 cubic feet of
pine annually produced on an acre is
only about OFT per cent Of the solar
energy which falls on that acre in the
course of year
DR.. Shirley points out that in passing
through forest canopy. solar energy
is modified in both intensity and quality.
Hardwood leaves modify the light to a
greater extent than conifers, since a
large percentage of incident energy ac-
tually passes through them. The forest
canopy also changes the proportion Of
direct sunlight to sky light.
The intensity of light which penetrates
the canopy varies somewhat with the
age and density of the stand and also
the species which compose it. Though
chlorophyll has its greatest absorption
bands in the red and blue regions of the
spectrum. recent experiments indicate
that the efficiency of photosynthesis per
unit energy actually absorbed by the leaf
is about equal in the different spectral
regions.
Benefits Of Experiments.
The greatest differences were between
plants in the blue house and those in
the red house. Those developed in the
former reSembled somewhat plants
grown in daylight at equal intensity.
except that they appeared to be dwarfed.
The ones in red, on the other hand, were
greatly elongated and somewhat reSem-
bled twining plants. Such changes in
the quality of light as occur in passing
through the forest canopy could not
produce such astounding effects. but the
changes in intensity Of light do have a
very marked influence on the growth Of
plants in the forests Photosynthesis in
creases in almost direct proportion to the
light factor over considerable range,
provided that other factors are favorable.
Practical benefits from these expert
mentS will result from regulation of the
forest cover by thinning so as to get
maximum intensity of light down to the
under-story of new growth near the
forest floor. While an enormous quantity
of wood is still used for fuel, the
photosynthetic deposition of wood which
ceaSeleSSly goes on is now far more
important as source of industrial ma
terial than of heat and power DR.. Shir-
ley'S researches emphasize the fact that
on its timber lands the United States
has perpetual supply of building ma
, terial and of raw material for the plastic
and fiber industries. AS the fixed min
erol S,,pplieS hacome den1eted the ever-