The Salt Lake tribune. [volume] (Salt Lake City, Utah) 1890-current, 1913-04-05
FORESTS AND RAINFALL.

| DY lne det0rcStation or the country.
and that it we could have plenty OF
trees all over that region there would
be no more floods and no more danger
from disastrous storms. When we re-
member the accounts of the first ex-
plorers of all that region, however,
and especially the account OF the cx-
petition OF George Rogers Clark across
the State of Illinois, the expedition
| which resulted in his capture of Vim
comes, Indiana. where he says that
his command marched for days over
flooded regions, wading from knee to
waist deep in water, the fallacy OF
that sort of opinion is evident. 1t ap-
pears from this New Yorker 8 idea
that if there were abundant forests IN
all that region there would be no dis
astrous storms and floods. On the other
hand, there is a sort Of popular notion
that forests bring abundant rain, ana
that it is necessary in order to pre-
serve the rainfall of the country, tnar
there should be plenty of forests. And
vet, as Professor Willis Moore, of the
L. s. Weather Bureau, argues. forests
arc not proved to have any established
relations to rainfall, and the popular
notion as to such effect is notion
merely.
We note in the current Popular
Science Monthly an exhaustive article
by Professor Robert Dec. Ward, "The
Influence of Forests unon Climate.
al. ,1l bo fup pi
with regard TO the influence of forests
upon climatic conditions, and comes
TO the conclusion that climatic condi-
tions have more to do with forests
than forests have TO do with climatic
conditions. He states that opinions
are SO uncertain that one expert writer
on the subject holds that "no definite
and unassailable result can ever be OBJ
tanned by means Of such forest meteoro'
logical observations as those now made
in Europe" and that "there Will be
little to be gained by further study
of the question: Mr.. Ward admits
the present uncertainty Of the whole
matter, but concludes that 'we are
surely within the bounds Of reason
when we say that there is no hope that
we can increase our rainfall really ap-
preciably or effectively by any amount
of planting. A whole ocean OF
water cannot give rainfall if the gen
eral pressure and temperatures ana
winds are hostile TO precipitation.
His discussion is very conservative,
very clear, and his conclusion is that
if the statements of the chmatologist
care often disappointingly broad and
gencralizing. it is because he has not
the needed scientific basis for making
them otherwise. y He in fact leaves
the matter about as he found 1t, with
the clear expression as quoted above,
that climatic conditions, and not Cor
ests, govern rainfall, and that no
amount Of tree-planting will avail
where those conditions are adverse.
Mr.. Ward, however, does not entirely
ignore the question Of the influence
Of forests upon water supply, erosion,
and floods He devotcs page to that,
most of il quotation, the quotation be-
ing, as he calls it. the "last word
in the discussion. the final report Of
the National Highways Commission
(Senate Doc. No. 400, 62d Congress,
second session, 1879. The conclusions
expressed in this report are quite in
line with the climatic observations
made by Mr. Ward himself, the sum
ming up of it reading AS follows;
Whatever influence forests may exert
upon precipitation run-olf and crosion,
1t is evidently greatest In the noun
heaviest, slopes steepest and run of
most rapid Here also the land is less
useful for other purposes. The extent
| of the influence of forests upon these
| three factors varies greatly, according
| to circumstances involved in each case.
| Under one set of conditions, forests may
| benefit stream flow and mitigate Hoods.
while under other conditions they may
| have the opposite effect. In no case can
| they be relied upon TO prevent either
] floods or low-water conditions. There
| is substantial agreement on This point.
Nor is their influence extensive enough
| 10 warrant their use as the only means
| of securing the uniformity OF stream
| flow which is desirable for navigation or
| the development of water power. For
| this purpose storage reservoirs would he
much more effective. The prevention OF
erosion undoubtedly outweighs all other
| benefits OF forestation and constitutes
L
| servatiou. The commission faVorS the
prevention OF deforestation of mountain
slopes wherever the land is unsuitable
for agricultural purposes. and urges the
| reforestatioD of those tracts which have
already been deruded. not only when To-
Gated at the headwaters OF naviSable
streams. but wherever this would be the
| most valuable use OF the land. The in
! creasinG pressure OF population upon SUD-
| sstcncc VIII make 1t necessary to use
for agricultural purposes all land suit
| able for cultivation. The influence OF
forests upon stream flow and erosion is
not sufficient TO warrant their retention
except where the land is unsuited for
other purposes Furthermore. IL is pos
sIblc: IL correct methods Of agriculture
are employed, TO retain for cultivation
areas located on steep hlllsides. This has
been successfully accomplished in other
countries By terracing and by other
means. 1t must be remembered. how
ever that reforcsta,ion alone can accom-
plish little toward preventing erosion
The prevention of forest fires. the regu-
latlon OF hillside farming, and the pro-
hibition Of complete denudation Of noun
tain tracts. where the soil cover is thir
and the land unsuited for agriculture
purposes. are also necessary. Forests