Station
Paper
No.
October
38
HALF A CENTURY OF RESEARCH FORT VALLEY EXPERIMENTAL FOREST
1908 - 1958
ROCKY MOUNTAIN FOREST AND RANGE EXPERIMENT STATION
Raymond Price, Director
FOREST
SERVICE,
U.
Fort Collins, Colorado
S. DEPARTMENT OF AGRICULTURE
1958
This file was created by scanning the printed publication.
Errors identified by the software have been corrected;
however, some errors may remain.
R E F L E C T I O N S
It was
a
sultry
Raphael Zon,
Forest
to
chief
had
of
Silvics
come
location
a
i n August 1908.
for
to
in the
Flagstaff
what
was
first forest experiment station
United
I
then
Service,
select
the
afternoon
States.
were
Zon,
urging
our
stable
cayuses
over
Valley
to
visor
of
by
the
the
Drake,
road
site
Frank
Coconino.
livery
Fort
had been
Pooler,
Two
the
and
to
that
be
in
phlegmatic
a
examine
recommended
Willard
to
super
miles
-
short
of o u r d e s t i n a t i o n a t h u n d e r s t o r m c r a s h e d
upon u s in t r u e Arizona style.
pour was more
violent
than
The down-
usual,
s o we
t o o k s h e l t e r i n a l a r g e b a r n of t h e o l d A-1
Cattle
Company.
hour later,
the
was
a
fluid
running
whose
plainly
dogs
that
even
crossing
mile
a
to
tree
of
hundred
yards
and
in
that
area
said
we
stand
Zon,
wide
going
early
day.
it was
only
had
of
an
with
consistency
country was
"river",
emerged
d r y Rio de Flag
the
beautiful
"Here,"
we
normally
color
the
the
When
come
to
told
to
shall
the
After
half
see
ponderosa
"we
a
plant
a
--
pine.
the
research."
---
G.
A. P e a r s o n
April 1936
HALF A
FORT
CENTURY
VALLEY
O F RESEARCH
EXPERIMENTAL
-
FOREST
by
Edward M. Gaines and E l m e r W. shawl
Fifty y e a r s ago in 1908, the U. S. F o r e s t S e r v i c e launched
i t s r e s e a r c h p r o g r a m in f o r e s t management on the F o r t Valley
E x p e r i m e n t a l F o r e s t n e a r Flagstaff, Arizona. This was the
f i r s t scientific venture of its kind in A m e r i c a - now the oldest.
-
F r o m the beginning the chief a i m of r e s e a r c h h e r e h a s
been to work out b e t t e r ways of managing ponderosa pine in the
Southwest. Already, we have l e a r n e d much. But to keep pace
with the advance of s c i e n c e and industry, we need to know m o r e .
F o r example, in 1953 the pulp industry c a m e to Flagstaff, bringing new opportunities f o r m o r e intensive f o r e s t management. In
the b r o a d e r picture, r e c e n t f o r e c a s t s p r e s e n t e d in "Timber
R e s o u r c e s f o r A m e r i c a ' s F u t u r e " indicate t h a t the Nation will
need a l l the wood we c a n grow. To h e l p m e e t this r i s i n g demand,
we m u s t intensify o u r r e s e a r c h and improve our management
practices.
The h i s t o r i c a l background of F o r t Valley, highlights of the
r e s e a r c h r e s u l t s , and the c u r r e n t p r o g r a m a r e p r e s e n t e d in this
Golden A n n i v e r s a r y publication.
Rocky Mountain F o r e s t and Range E x p e r i m e n t Station,
F o r e s t Service, U. S . Department of Agriculture, with c e n t r a l
h e a d q u a r t e r s at Colorado State University in F o r t Collins.
Mr. Gaines i s l e a d e r of the station's r e s e a r c h c e n t e r with
h e a d q u a r t e r s at Arizona State College in Flagstaff. Mr. Shaw
is station editor.
FACTS ABOUT F O R T VALLEY
San F r a n c i s c o P e a k s
A 1 2 , 670 f e e t
Location. --Headquarters for the F o r t Valley
Experimental F o r e s t i s right in the thick of
the ponderosa pine about 9 m i l e s northwest
of Flagstaff. Locations of the 5 units of the
f o r e s t a r e shown in figure 1.
lI
\
Area. --4,700 a c r e s ,
Elevation.
I
- - 6,700
to 8, 000 feet.
F o r e s t type. - - P u r e ponder osa pine. The
experimental fore s t i s located within the
m o s t extensive pure stand in the United
States
.
N
I
Climate. -- Cool and r a t h e r d r y but favorable
for t r e e growth. Annual precipitation
averages 2 3 inches. Mean annual t e m p e r a t u r e i s 43°F. In s u m m e r , t e m p e r a t u r e s
usually r e a c h 90"; in the average winter,
they d r o p to 15 " below zero.
Physical environment. - -Topography i s
n e a r l y level to rolling. Soils a r e mostly
residual, very stony, sandy loams. Some
soils have high cinder content, Geologically,
the a r e a contains t e r t i a r y volcanics ( b a s a l t s ,
cinders, and other m a t e r i a l s 1.
,
2
3
1
5
SCALE - MILES
UNIT
F i g u r e 1. - - L o c a t i o n of F o r t Valley E x p e r i m e n t a l F o r e s t .
PERSONNEL AND HISTORY
The n a m e of G. A. "Gus" P e a r s o n i s indelibly s t a m p e d
on f o r e s t management r e s e a r c h a t the F o r t Valley E x p e r i m e n t a l F o r e s t . P e a r s o n s t a r t e d the work in 1908 and guided
it until h i s r e t i r e m e n t in 1945. Up to h i s d e a t h January 31,
1949, he continued working on h i s now-famous monograph,
"Management of P o n d e r o s a P i n e in the Southwest. "
Yet P e a r s o n was the f i r s t to acknowledge the c o n t r i bution of m a n y a s s o c i a t e s who helped a t one t i m e o r another
to c a r r y on the r e s e a r c h p r o g r a m a t F o r t Valley. The l i s t
includes many who would be prominent in a "Who's Who"
in A m e r i c a n f o r e s t r y . Raphael Zon and S T. Dana, chief
and a s s i s t a n t chief of s i l v i c a l investigations in the F o r e s t
S e r v i c e , and T. S. Woolsey, J r . , a s s i s t a n t regional f o r e s t e r ( t i m b e r management) in Region 3, took active p a r t s in
e a r l y planning. O t h e r s who have p a r t i c i p a t e d actively in
the work, m o r e o r l e s s in chronological o r d e r , include :
.
H a r r i s o n D. B u r r a l l
J. S. Boyce
M a x H. F o e r s t e r
Harold H. G r e e n a m y r e
Alexander J. Jaenicke
Norman W. S c h e r e r
Enoch W. Nelson
C l a r e n c e F. Kor s t i a n
He r m a n n Kr auch
Harold S. Betts
S. S. Van Boskirk
J o s e p h C. K i r c h e r
Emanuel F r i t z
Lenthall Wyman
F e r d i n a n d W. H a a s i s
B e r t Lexen
E . M. Hornibrook
E l b e r t H. Little
Edward C. Martin
F r a n k W. Wadsworth
Geraldine P e t e r s on
George S. Meagher
F r a n c i s R. H e r m a n
E d w a r d M. Gaines
M. M. L a r s o n
L. P. Heidmann
This l i s t m a y not be complete; e a r l y r e c o r d s a r e
not always c l e a r a s to who worked in v a r i o u s capacities.
Nor i s the r e c o r d c l e a r a s to the contributions made by
F o r e s t S e r v i c e Region 3 personnel. Most of the a s s i s t a n t
regional f o r e s t e r s in t i m b e r management have been helpful,
a s have been Coconino National F o r e s t s u p e r v i s o r s and
many of t h e i r staffmen and r a n g e r s .
The f o r e s t w a s f i r s t c a l l e d the "Coconino E x p e r i m e n t
Station, I ' then in 19 11 was r e n a m e d the F o r t Valley " E x p e r i ment Station.
In the y e a r s following, a distinction developed
between the "Experiment Station" -- the group of m e n conducting r e s e a r c h and the " E x p e r i m e n t a l F o r e s t " - - the
a r e a on which p a r t of the r e s e a r c h was done. In 1927,
f o r e s t and range r e s e a r c h throughout the Southwest w a s
consolidated a d m i n i s t r a t i v e l y a s the Southwestern F o r e s t and
Range E x p e r i m e n t Station, with F o r t Valley a s a b r a n c h
station. P e a r son w a s d i r e c t o r of the new station f r o m i t s
beginning until 1935, when he gave up the position in o r d e r
to devote all h i s t i m e t o ponderosa pine r e s e a r c h . G e n e r a l
supervision and direction of r e s e a r c h a t F o r t Valley h a s
r e s t e d with subsequent d i r e c t o r s of the Southwestern Station:
Arthur Upson (1935-42) and Raymond P r i c e (1942-53). The
Southwestern Station w a s combined with the Rocky Mountain
F o r e s t and Range E x p e r i m e n t Station in 1953, and P r i c e h a s
continued a s d i r e c t o r of the e n l a r g e d Rocky Mountain Station.
The p r e s e n t r e s e a r c h p r o g r a m a t F o r t Valley i s conducted by Rocky Mountain Station p e r s o n n e l stationed on the
campus of Arizona State College a t Flagstaff.
A s t h i s h i s t o r y shows, an i m p r e s s i v e r o s t e r of f o r e s t e r s
have worked at F o r t Valley o v e r the y e a r s . S e v e r a l have come
and gone in r a p i d succession. L a c k of funds, equipment, and
personnel h a s always l i m i t e d the F o r t Valley r e s e a r c h p r o g r a m .
But in spite of these limitations, a g r e a t deal h a s been a c c o m plished and much h a s b e e n l e a r n e d about ponderosa pine
silviculture znd management.
THE RESEARCH PICTURE
The accumulated r e s u l t s of 50 y e a r s of f o r e s t r e s e a r c h a t
F o r t Valley a r e too n u m e r o u s to include h e r e in any detail. Most
of t h e s e findings have been s u m m a r i z e d in P e a r s o n ' s monograph:
"Management of P o n d e r o s a P i n e in the Southwest."
Ecology and Silvics
Many of the s i l v i c a l c h a r a c t e r i s t i c s of southwestern ponderosa
pine have been p a r t i a l l y worked out a t F o r t Valley. F o r example,
it h a s been found t h a t :
O c c u r r e n c e of ponderosa pine i s l i m i t e d by r a i n f a l l a t
lower elevations but by t e m p e r a t u r e a t higher altitudes.
In v i r g i n stands, ponderosa pine t e n d s to g r o w i n
s m a l l , even-aged groups.
P o n d e r o s a pine i s not exacting in i t s s o i l r e q u i r e m e n t s ,
but it m a k e s b e s t growth on s o i l s whose physical p r o p e r t i e s provide the b e s t m o i s t u r e conditions.
S u m m e r r a i n is i m p o r t a n t for germination and s u r v i v a l
of seedlings, but s ~ im
l o i s t u r e f r o m winter s t o r m s
s u s t a i n s growth of o l d e r t r e e s .
Sunlight influences growth; b e s t t r e e f o r m i s developed
in p a r t i a l side shade (fig. 2). Moisture i s i m p o r t a n t i n
determining t o t a l growth, e s p e c i a l l y a s t r e e s grow
o l d e r and l a r g e r .
Growth of a n individual i m m a t u r e t r e e i s d e t e r m i n e d
m o r e by i t s position r e l a t i v e to competing t r e e s than
by i t s a p p a r e n t vigor c l a s s . I m m a t u r e t r e e s of a l l
vigor c l a s s e s r e s p o n d well to r e l e a s e f r o m competition.
Height growth i s p r a c t i c a l l y complete by m i d - July each
y e a r . D i a m e t e r growth usually continues through
August (depending on s u m m e r r a i n s ) and n e e d l e s
continue growth into e a r l y fall.
Mature t r e e s i n virgin stands a r e mostly l e s s than
300 y e a r s old.
F i g u r e 2. - -A study of
shade effects on pond e r o s a pine seedlings
showed that p a r t i a l
s i d e shade h e i p s the
plant develop a b e t t e r
f o r m . F u l l sunlight
tends to produce
b r o a d crowns,
c o a r s e branches,
and thick, s h a r p l y
tapering bole s o
Much of the knowledge of s i l v i c s and ecology c o m e s f r o m
incidental observations and data f r o m studies in applied silvicultur.e. More detailed under standing of principles of silvic s and
ecology will be needed f o r intensified management.
Regeneration
Lack of advance reproduction in 1908 w a s the m a i n r e a s o n
f o r beginning r e s e a r c h at F o r t Valley. Although m u c h h a s been
l e a r n e d since then, techniques f o r i n s u r i n g adequate r e g e n e r a t i o n s
a t r e g u l a r i n t e r v a l s a r e s t i l l unavailable.
Only once since 1908 h a s a r e a l l y good stand of n a t u r a l r e p r o duction been established. That w a s in 1919 (fig. 3). All the b a s i c
r e q u i r e m e n t s f o r n a t u r a l r e g e n e r a t i o n w e r e m e t t h a t year:
(1) a bumper s e e d c r o p the f a l l b e f o r e ; ( 2 ) favorable weather
(especially r a i n f a l l ) f o r e a r l y germination and s u r v i v a l ;
(3) favorable seedbed a n d l i m i t e d competition f r o m g r a s s and
weeds, resulting f r o m heavy g r a z i n g i n preceding y e a r s .
Figure 3. --Above, View of F o r t Valley headquarters in 1916.
Note the open parklike stand of ponderosa pine.
Below, The same view 26 y e a r s later. Natural regeneration
almost obscures the headquarters buildings.
Studies now in p r o g r e s s a r e t e s t i n g methods of reducing
competition f r o m g r a s s and weeds and methods of controlling
s e e d e n e m i e s s o t h a t n a t u r a l seeding will have a b e t t e r chance
of producing new t r e e s .
Artificial r e g e n e r a t i o n (planting of nur s e r y - g r o w n t r e e s ,
o r sowing s e e d d i r e c t l y ) h a s been only p a r t i a l l y successful.
Basic r e q u i r e m e n t s , developed a t F o r t Valley, include:
Use only l o c a l seed, o r f i r s t - g r a d e seedlings grown f r o m
l o c a l seed.
P l a n t only on s i t e s w h e r e ponderosa pine h a s grown in
the past.
Avoid a r e a s of heavy competition f r o m g r a s s o r weeds, o r
control the competition.
P r o t e c t s e e d f r o m r o d e n t s and b i r d s , and seedlings f r o m
browsing a n i m a l s .
F u r t h e r r e s e a r c h will b e needed to develop t h e s e g e n e r a l
principles into s u c c e s s f u l techniques for r e e s t a b l i s h i n g a f o r e s t
on denuded a r e a s .
Growing the Young F o r e s t
As a young t i m b e r s t a n d m a t u r e s , i t s m a x i m u m value c a n b e
developed through s p e c i a l t r e a t m e n t s . Recommendations developed
f r o m F o r t Valley r e s e a r c h should b e applied to even-aged groups
of t r e e s a s follows:
When the young stand i s well established ( m o s t t r e e s 6 f e e t
o r m o r e tall), thin to 600 t r e e s p e r a c r e (8-112 foot a v e r a g e
spacing),
When the stand r e a c h e s pulpwood s i z e (average t r e e 7 inches
in d i a m e t e r , 4-112 f e e t above the ground) thin to a r e s e r v e
of 8 0 s q u a r e - f e e t of b a s a l a r e a p e r a c r e . B a s a l a r e a i s
the s u m of c r o s s - s e c t i o n a l a r e a s of the t r e e t r u n k s , m e a s u r e d
a t 4-112 f e e t above the ground.
P r u n e about 100 of the b e s t r e s e r v e t r e e s to the a c r e . Remove
a l l l i m b s to a height of 18 feet, cutting each c l o s e to t h e trunk.
4.
Re-thin the stand at about 20-year i n t e r v a l s , r e s e r v i n g
80 s q u a r e - f e e t of b a s a l a r e a p e r a c r e a t e a c h operation,
until the final stand i s m a t u r e and r e a d y for h a r v e s t .
5.
L a r g e w o r t h l e s s t r e e s m a y be poisoned with e i t h e r sodium
a r s e n i t e o r the s a f e r a m m o n i u m sulfamate (Arnmate).
This thinning r e g i m e w a s developed f r o m v e r y limited data.
F u r t h e r r e s e a r c h i s needed to r e f i n e and c o n f i r m the
r e c o m m e n d e d actions.
Management S v s t e m s
In the development of f o r e s t management, the techniques
of regenerating, growing, and finally h a r v e sting the stands a r e
i n t e g r a t e d into a s y s t e m of management. S e v e r a l such s y s t e m s
have been t e s t e d at F o r t Valley: g r o u p selection, light s e l e c tion, s c a t t e r e d s e e d t r e e , favoring dominants, and salvage.
,
F r o m a study of t h e s e s y s t e m s , another w a s developed,
which is now r e c o m m e n d e d f o r application in southwestern
ponderosa pine. It i s called "improvement selection. I ' The
objective i s t o place the s t a n d i n a vigorous growing condition
a n d to build u p a n effective growing s t o c k by improving spacing
i n all s a w t i m b e r - s i z e d g r o u p s ; retaining the b e s t quality s t e m s
f o r f u t u r e growth; and removing declining, p o o r - r i s k , d i s e a s e d ,
defective, o r poor-quality t r e e s .
The improvement-selection p r i n c i p l e s a r e being applied to
m o s t managed f o r e s t s in the Southwest. Marking r u l e s f o r the
f i r s t one o r two c u t s in virgin f o r e s t s , and f o r the f i r s t r e - c u t
i n old cutover f o r e s t s have been developed (figs. 4 and 5). The
c u r r e n t F o r t Valley r e s e a r c h p r o g r a m includes the developm e n t of additional technique s f o r sub sequent cutting, which
will be needed t o provide o r d e r l y h a r v e s t f o r c u r r e n t l y m a t u r e
t r e e s a n d the conversion of the f o r e s t s to b a l a n c e d age groups.
It is possible that even-aged m a n a g e m e n t m a y in the long
r u n b e m o r e productive than selection management. The theory
n e e d s to b e t e s t e d i n f u t u r e studies.
Growth and Development of Managed Stands
Management s y s t e m s a r e evaluated i n p a r t by the growth
and development of the s t a n d s left a f t e r cutting. At F o r t Valley
a l l t r e e s 8 inches in d i a m e t e r and l a r g e r have been tagged and
r e m e a s u r e d a t 5 - y e a r i n t e r v a l s on 11 l a r g e plots (72 to 320 a c r e s
e a c h ) t h a t w e r e c u t under v a r i o u s s y s t e m s , and on one virgin
plot. M e a s u r e m e n t s will be continued indefinitely a t I 0-year
i n t e r v a l s on 7 cutting plots and the virgin plot.
F r o m the p a s t m e a s u r e m e n t s , equations f o r estimating
growth and m o r t a l i t y following cutting have been derived.
Control of Damaging Agents
S e v e r a l of the e n e m i e s of ponderosa pine can be controlled
to s o m e extent through s p e c i a l management p r a c t i c e s . Among
those studied at F o r t Valley a r e :
Wind and lightning, which together account f o r about
7 0 p e r c e n t of the m o r t a l i t y i n both virgin and managed
stands. Young thrifty t r e e s a r e much m o r e r e s i s t a n t
than oid o v e r m a t u r e ones. Application of i m p r o v e m e n t
selection g r e a t l y r e d u c e s the l o s s through cutting the
m o s t susceptible (poor-risk) t r e e s .
B a r k b e e t l e s of v a r i o u s s p e c i e s a r e t h i r d i n causing
mortality. Improvement selection again r e d u c e s
l o s s e s b y cutting p o o r - r i s k t r e e s .
Dwarfmistletoe, the m o s t s e r i o u s d i s e a s e (fig. 6), k i l l s
s o m e t r e e s , badly d e f o r m s o t h e r s , and r e d u c e s growth
of s e v e r e l y infected t r e e s . Control through stand
management is being studied c u r r e n t l y with the a i d
of station pathologists.
Red r o t d e s t r o y s a s m u c h a s 20 p e r c e n t of t h e usable
wood in virgin stands. P r o p e r thinning and pruning
c a n p r a c t i c a l l y eliminate the l o s s i n managed f o r e s t s .
Limb r u s t i s a slow but c e r t a i n k i l l e r ; fortunately i t
a t t a c k s only o c c a s i o n a l t r e e s . Cutting c y c l e s of
20 y e a r s of l e s s under the improvement-selection
s y s t e m make it possible to salvage m o s t infected
t r e e s b e f o r e they die.
Fig.ure 6. - - A female dwarfmistletoe plant growing on a ponderosa
pine twig. This p a r a s i t e i s the m o s t s e r i o u s t r e e d i s e a s e in the
Southwe st.
6.
Live stock and d e e r kill o r damage seedlings (fig. 7). The need
to control domestic livestock i s obvious. Deer -repellent chemi c a l s a r e being studied a t F o r t Valley.
Most other enemies m u s t be m e t by special control m e a s u r e s .
The s e r i o u s n e s s of many of these h a s been established and n e c e s s a r y
r e s e a r c h i s being c a r r i e d out elsewhere by other r e s e a r c h groups.
F i r e i s the b e s t known f o r e s t enemy. Prevention, including
fuel-reduction m e a s u r e s , h a s been and i s being studied by other
F o r e s t Service r e s e a r c h e r s . Guides to salvage fire-damaged
f o r e s t s have been developed.
Porcupines and seed-eating rodents a r e under study by the
U, S . F i s h and Wildlife Service.
The s e r i o u s n e s s of c e r t a i n other e n e m i e s i s yet to be e s t a b lished, C u r r e n t studies a t F o r t Valley will shed light on the damage
done by A b e r t s q u i r r e l s and cone b e e t l e s . T i p moths should a l s o
be studied.
F i g u r e 7 . --New buds f o r m e d on this ponderosa pine a f t e r a
t e r m i n a l shoot h a d been b r o w s e d off by d e e r .
SELECTED LIST O F PUBLICATIONS
Some 100 a r t i c l e s have been published covering the work a t
F o r t Valley. By f a r the m o s t i m p o r t a n t i s :
P e a r s o n , G. A.
1950. Management of ponderosa pine in the Southwest.
U. S. Dept. Agr. Agr. Monog. 6, 218 pp., i l l u s .
This bulletin r e v i e w s m u c h of the work done a t F o r t Valley
f r o m 1908 through 1946. E a r l i e r publications of h i s t o r i c impor
tance, o r that p r e s e n t r e s u l t s not c o v e r e d in the monograph a r e :
-
Betts, H. S.
1912. P o s s i b i l i t i e s of w e s t e r n pines a s a s o u r c e of naval
s t o r e s . U. S. F o r e s t S e r v . Bul. 116, 23 pp.,
illu s
.
Haasis, Ferdinand W.
1923. F r o s t heaving of w e s t e r n yellow pine seedlings.
Ecol. 4: 378-390, illus.
Krauch, Hermann.
1926. The d e t e r m i n a t i o n of i n c r e m e n t in cut-over s t a n d s of
w e s t e r n yellow pine i n Arizona. Jour. Agr. Res.
32: 501-541, illus.
Lexen, B. R.
1935. Some f a c t o r s influencing the yield a n d m o r t a l i t y of
ponderosa pine in the Southwest. Jour. Agr. R e s .
50: 777-787, illus.
P e a r s o n , G. A.
1910. Reproduction of w e s t e r n yellow pine in the Southwest.
U. S. F o r e s t Serv. C i r . 174, 16 pp.
1923.
N a t u r a l reproduction of we s t e r n yellow pine i n the
Southwest. U. S . Dept. Agr. Bul. 1105, 144 pp.
illu s
.
1924.
,
Studies i n t r a n s p i r a t i o n of coniferous t r e e seedlings.
Ecol. 5: 340-347, illus.
1931.
F o r e s t t y p e s in t h e Southwest a s d e t e r m i n e d by
c l i m a t e and soil. U. S. Dept. Agr. Tech.
Bul. 247, 144 pp. , i l l u s .
1940.
T i m b e r s t a n d i m p r o v e m e n t i n the Southwe s t .
U. S. Fed. S e c u r i t y Agency, Civ. C o n s e r v .
C o r p s F o r e s t r y Pub. 6, 1 2 p p . , illus.
1940.
R e f o r e ~ ~ a t i oinn the Southwest by CCC c a m p s .
U. S. F e d . S e c u r i t y Agency, Civ. C o n s e r v .
C o r p s F o r e s t r y Pub. 7, 1 4 p p , , illus.
1942.
H e r b a c e o u s vegetation a f a c t o r in r e g e n e r a t i o n
of p o n d e r o s a pine. Ecol. Monog. 12: 315-338,
illu s
.
1942.
I m p r o v e m e n t s e l e c t i o n cutting i n ponder0 s a pine.
Jour. F o r e s t r y 40: 753-760, i l l u s .
1944.
Applied g e n e t i c s i n f o r e s t r y .
453, i l l u s .
Sci. Monthly 58: 444-
a n d McIntyre, A r t h u r C.
1935. S l a s h d i s p o s a l in the p o n d e r o s a pine f o r e s t s of the
Southwest. U. S . Dept. A g r . C i r . 357, 29 pp.,
illus.
a n d M a r s h , R. E.
1935. T i m b e r growing and logging p r a c t i c e in t h e Southwest
and i n the B l a c k Hills region. U. S. Dept. Agr.
Tech. Bul. 480, 8 0 p p . , illus.
M o s t of the e a r l i e r r e f e r e n c e s a r e out of print, b u t a r e
a v a i l a b l e in m a j o r f o r e s t r y l i b r a r i e s throughout the country.
Publications since Agriculture Monograph No. 6 include :
Gaines, Edward M . , and Kotok, E. S.
1954. Thinning ponderosa pine in the Southwest. U. S.
F o r e s t Serv. Rocky Mountain F o r e s t and Range
Expt. Sta. Sta. P a p e r 17, 20 pp., illus.
[ processed. ]
Herman, F. R.
1954. A guide for m a r k i n g f i r e - d a m a g e d ponderosa pine in
the Southwest. U. S. F o r e s t Serv. Rocky Mountain
F o r e s t and Range Expt. Sta. Res. Note 13, 4 pp.
[ processed. ]
1954.
Use of Arnmate c r y s t a l s for poisoning ponderosa pine
in stand improvement. U. S. F o r e s t Serv. Rocky
Mountain F o r e s t and Range Expt. Sta. Re s. Note 14,
5 pp. [ P r o c e s s e d . ]
Meagher, George.
1950. Reproduction of ponderosa pine.
48: 188-191.
Jour. F o r e s t r y
P e a r s o n , G. A.
1949. Management of cut-over land in the i n t e r i o r ponderosa
pine type. Jour. F o r e s t r y 47: 172-178, illus.
195 1.
A comparison of the c l i m a t e in four ponderosa pine
regions. Jour. F o r e s t r y 49: 256-258, illus.
LOOKING FORWARD
The work a t F o r t Valley i s n o t finished. True, many
s t u d i e s have b e e n completed.
O t h e r s a r e s t i l l in p r o g r e s s
and new ones a r e being added a s new v i s t a s unfold.
R e s e a r c h , like the f o r e s t itself, is a growing thing.
It m o v e s f o r w a r d with the t i m e s .
Or to p a r a p h r a s e Tennyson:
It looks to the future.
"All r e s e a r c h is a n a r c h wherethrough g l e a m s
that untraveled world, whose m a r g i n s fade
f o r e v e r and f o r e v e r a s we move.
"
Agriculture
--- CSU. Ft. Collins