CD ■ c /
Division of Agricultural Scie

UNIVERSITY OF CALIFORNIA

' or &**• f

The Infi.

uence

of Modern Man
on the Vegetation
of Yosemite Valley

ROBERT P. GIBBENS ' HAROLD F. HEADY

CALIFORNIA AGRICULTURAL
Experiment Station
Extension Service

MANUAL 36

KE ARr ,E / HCRT.C ULTU3AL
FIELD STATION

PRICE: $1.25

Robert P. Gibbens and Harold F. Heady

The Influence of Modern Man on the Vegetation of Yosemite Valley

This publication compares the present vegetation of Yosemite Valley with that
existing in 1851 as depicted by early writings and photographs, and discusses the
changes — both man-made and natural — which have occurred since then.

UNIVERSITY OF CALIFORNIA • DIVISION OF AGRICULTURAL SCIENCES

i

Contents

INTRODUCTION 1

EVENTS AFFECTING THE VEGETATION 2

VEGETATION AT THE TIME OF DISCOVERY 6

TREE INCREASE 10

CAUSES OF TREE INCREASE 15

EFFECT OF CUTTING, CLEARING, AND PLANTING ON THE

FORESTS 17

CHANGES IN THE MEADOWS 21

INTRODUCTION OF PLANTS 25

RE-ESTABLISHMENT OF PLANTS ON DENUDED AREAS .... 26

WILDLIFE INFLUENCES 28

INFLUENCE OF FLOODS AND ROCKSLIDES 30

INFLUENCE OF VISITORS 31

DISCUSSION 33

ACKNOWLEDGMENTS 34

LITERATURE CITED 35

BIBLIOGRAPHY 37

APPENDIX 38

The Authors / Robert P. Gibbens is Assistant Specialist, School of Forestry,
University of California, Berkeley; Harold F. Heady is Professor of Forestry,
School of Forestry, University of California, Berkeley.

JULY, 19 64

This manual is one of a series published by the University of California Division of Agri-
cultural Sciences and is sold for a charge which is based upon returning only a portion of
the production cost. By this means it is possible to make available publications which,
due to relatively high cost of production, or limited audience, would otherwise be beyond
the scope of the Division's publishing program.

Introduction

Recreation in wildland areas is a major land use which is rapidly
gaining in extent and intensity. Because of this, recreationists may
possibly destroy their favorite wildland areas through sheer numbers
and overuse. To preserve the recreational values of such areas their
natural conditions must be understood and the changes caused by
recreational use determined. Because its spectacular scenery has
attracted so many visitors, Yosemite Valley has a well-documented
history as a recreation area, and thus offers a unique opportunity
for study of changes caused by recreationists.

Yosemite Valley is young geologically, although its age is great
when compared with its short historical period. Man is a newcomer
to the Valley, but in his short tenure he has exerted a great influence
on its vegetation. Aboriginal man manipulated the Valley's vegeta-
tion to supply his basic needs, but modern man has been more of an
exploiter. Fortunately, exploitation of the Valley was tempered by
the early realization that its scenic values were unique and should
be preserved.

Since 1864, when Yosemite Valley was set aside as a public trust,
two objectives have guided its management: perpetuating natural
conditions for continued enjoyment and, secondly, encouraging
public use. But attempts to attain both objectives inevitably result in
conflict as more and more disturbance of natural conditions is caused
by the ever-increasing influx of visitors. How much disturbance of

natural conditions has occurred? How much can be allowed? Before
these questions can be answered, an understanding of natural and
man-caused vegetational changes in the valley is needed.

Non-biological forces — such as rainfall, wind, fire, and climate —
fluctuate, and thus influence biological communities. Additionally,
the development of a biological community often so alters its own
conditions that some other community replaces it. This constant
interplay of physical and biological forces unhindered by man also
results in continual, though often unrecognized, changes of the
natural state. Man can, and often does, cause additional change, as
did the Indians inhabiting Yosemite Valley before 1851. Their
influence on the vegetation is recognized but not examined in detail
in these pages, as major emphasis is given to man's influence on the
natural scene since 1851.

The objectives of this study, which was conducted in 1961, were

( 1 ) to define natural conditions existing in the Valley in 1851, and

(2) to determine the role of historical events in changes which have
led to the Valley's present patterns of forest and meadow. With
such information, more accurate predictions of landscape-manage-
ment results are possible, and as a result the biologist is better
prepared to furnish his share of the information needed to strike a
balance between the natural scene and the vegetational changes
caused by recreational use of the Valley.

1

Events affecting the vegetation

Chronologies of historical events in Yosemite Valley have been
prepared by Russell (1959) and by Paden and Schlichtmann
(1955). Accounts of the Valley's early history were also recorded
by Hutchings (1886) and Bunnell (1911). The year 1851 marks
the first recorded entry of modern man into the Valley. Prior to
this the Valley had been part of the territory occupied by the
Awanichi, a small tribe of Miwok Indians. This tribe left the Valley
in the late 1700's or early 1800's, but a Miwok group re-entered
the Valley at least one generation before 1851. Considerable evi-
dence indicates that the Indians used fire and hand-eradication
methods to control brush and tree growth in the Valley (Ernst,
1943; Reynolds, 1959).

By 1854 the tribe was drastically reduced in numbers and their
culture, as a major influence on the vegetation, had largely ended.
This disruption of the Indian culture was, indirectly, the first influ-
ence of white man on the vegetation. If we credit the Indians with
slowing down the ecological succession of plants in the Valley,
the period of change thus began in about 1854. Thomas Ayres
made the first published sketches of the Valley in 1855 and these,
plus written descriptions, brought publicity that greatly accelerated
the Valley's occupation.

Events now happened swiftly. The first trail to the Valley was
completed in 1856. The first permanent structure, the "Lower
Hotel," was erected in 1856 near the base of Sentinel Rock, and
the "Upper Hotel" was built near the present Sentinel Bridge in
1858; these sites were focal points of activity for many years. The
first settler, James C. Lamon, located a preemption claim in the
upper end of the Valley in 1859, built a log cabin, planted an
orchard, and cultivated a garden. With the arrival of J. M. Hutchings
and his family in 1864, year-round occupation was firmly estab-
lished. Hutchings also planted an orchard and cultivated a garden;
hay was harvested, fields were plowed to provide grain, and build-
ings were constructed. Thus, some of the meadowlands and
woodlands began to be affected.

The year 1864 saw Yosemite Valley and the Mariposa Big
Tree Grove granted to the state of California as a public trust. A

Figure 1 A. Yosemite Valley from Glacier Point, 1866, showing the Hutchings'
home, corral, and several split-rail fences. Photograph by C. E. Watkins.

survey to establish the boundaries of the grant, which extended
back from the cliffs an average distance of one mile, was made in
the same year. Commissioners to manage the grant were organized
in 1866, when legal acceptance of the grant by the State was

completed.

Between 1870 and 1880 tourist facilities rapidly expanded and
trails were constructed to Glacier Point, Nevada Falls, and other
areas. In 1874 the Coulterville and Big Oak Flat stage roads made
entry to the Valley. During the 23 years when access was by horse
trail only, over 12,000 persons visited the Valley and by 1878
the influx of visitors necessitated the establishment of the first
public campground. The Commissioners did not attain full control
of the Valley until 1875 when claims of the early settlers were
finally extinguished. However, leases were still granted and few
land-use restrictions were placed on lessees.

The following statements, from the 1880 Commissioners' Re-
port, indicate that conditions in the Valley were causing concern:

1 . Most of the available land is under lease for pasture and
garden purposes.

2. The enclosed fields are being invaded by willows, wild
roses, and other growth, to the damage of their value and of the
beauty of the Valley.

3. The upper portion of the Valley, which has been set apart
for the convenience of campers, is largely overgrown with
willows and young pines. The views are obstructed, the pastur-
age destroyed, and the appearance injured.

4. There is no practicable and unobstructed carriage road
around the Valley, near the base of the cliffs. At present all who
attempt to make the circuit of the floor of the Valley, must pass
through gates and fields, lose some of the finest views, and be
subjected to annoyance and loss of time.

Figure IB. View from Glacier Point, 1943. National Park Service photograph.

Figure 1C. Yosemite Valley from Glacier Point, 1961. Photograph by R. P. Gibbens.

Encroachment of trees into the meadows now aroused increasing
comment. The Commissioners' Report for 1887-1888 mentions
clearing of undergrowth and pruning of trees in front of the Stone-
man House (a hotel constructed by the State) and other areas
in the upper end of the Valley. The same report contains one of
the few accounts of fires in the Valley since 1851:

Several times during the period of my labors on your behalf, it
required suddenly almost the entire force of twenty or thirty
men to divert the all consuming course of forest fires on the
floor of the valley. Since the annual practice of the Indians in
burning off the dried grasses and leaves has been discontinued,
and even forbidden by law, the accumulation of vegetable
matter beneath the trees has been practically undisturbed, until
a growth of young pines has sprung up all over the valley, and
destroyed much fine meadow land. A campfire carelessly left,
or a match thrown among the leaves, has caused several fires
within the past two or three years that could not be extin-
guished. They burned until the walls, the roadway, and streams
defined and determined their course.

Such fires would have an effect on existing and subsequent

vegetation.

In 1881 W. H. Hall, then the State Engineer, visited the Valley
and recommended extension of the grant to control the entire
watershed of the Valley, regulation of grazing, clearing of brush
and trees, and "perhaps" the plowing and reseeding of meadow
lands. He also suggested clearing and irrigating non-meadow lands
to increase the forage supply (Hall, 1882). These recommendations
may have influenced land use. "Farming" activities had reached
such proportions by the late 1880's that public opposition to the
management of the Valley was aroused. Complaints centered around
the presence of fences throughout the Valley, the use of meadows
for pasturage and hay by operators who charged the public high
prices, and the cutting of trees. This led to an investigation by the
State Senate in 1889; in 1890 a new board of commissioners was
appointed and a few corrective measures instigated.

Manipulation of vegetation to alleviate fire hazard was carried
out during the 1890's,.but not without criticism. The report of a

Figure 2A. Lower Yosemite Valley from Union Point, 1866. The "arboriferous
belt" described by Whitney (1868) is clearly evident at the base of talus slopes
on valley sides. Photograph by C. E. Watkins.

special land investigator detailed to examine the Valley is included
in the Report of the Secretary of Interior for 1892:

A good deal of underbrushing has been done near the Stone-
man House in Yosemite Valley and around the stables of the
Transportation Company by direction of the State commission,

under the supervision of Galen Clark, the guardian He

[Galen Clark] took me around to the places where the clearing
had been done for the purpose of lessening the danger of fires,
and which, it is true, at times partook of the nature of a mutila-
tion of natural beauty.

California's administration of the Valley ended with cession of

Figure 2B. Lower Yosemite Valley from Union Point, 1943. The original view was
blocked by trees which had grown in the foreground. This vantage point is a short
distance to the left of the one in 1866. The old Sewer Farm, a man-made clearing,
appears at the top of the foreground tree. National Park Service photograph.

Figure 2C. Lower Yosemite Valley from Union Point, 1961. The rock slide ap-
pearing at the base of Cathedral Spires (upper left) in 1866 has been nearly
obliterated by vegetation. Photograph by R. P. Gibbens.

the Valley and the Mariposa Grove to the Federal Government in
1905. The Commissioners were replaced by the U. S. Army, which
administered Yosemite National Park for the Department of In-
terior. Reports of the military commanders indicate that grazing,
mowing, and cultivation continued. There was considerable com-
ment on the necessity of clearing thickets but apparently no action
was taken until 1911, when some undergrowth was removed.

Automobiles were admitted into the park in 1913 and the number
of visitors increased sharply; by 1915, motor stages had replaced
horse-drawn stages in the Valley. Although grazing and hay growing
declined with the advent of cars, most of the meadows were grazed

until 1924 when the last dairy herd and most of the fences were
removed. These early fences delimited grazed areas and served
as boundaries for clearing operations, and their removal opened
the meadows to tourists who picnicked, camped, and drove over
them. Ditches were constructed to halt this use in 1929, but the
ditches may have had more far-reaching consequences by affecting

drainage.

Army administration of the Valley ended with the formation of
the National Park Service in 1916. By 1920 policies of this agency
were well established, and one idea emphasized was the "vista-
clearing' concept (Punchard, 1919). Vista-clearing and general

improvement activities reached unprecedented levels when abun-
dant labor was made available during the 1930's: ditches were
constructed, campgrounds delimited, screening trees planted, dead
trees removed, thickets thinned, insect-infested trees cut and burned,
young trees cut from meadows, meadows drained for mosquito
control, river and creek channels cleared, banks sloped and covered
to halt erosion, low areas filled, ground squirrels eradicated, and
deer trapped and removed. According to the Superintendent's
Monthly Reports for the 1930's, there were few areas in the Valley
which did not receive a face-lifting of some sort. These landscap-
ing activities ended with the start of World War II.

After the war, activities affecting vegetation were largely confined
to maintenance-type work: thistle control in the meadows, removal
of dead and dangerous trees, limited vista-clearing, relocation of
the Old Village and other structures. In post-war years, the dom-
inant factor affecting vegetation has been the increase in the number
of visitors, now (1963) numbering over 1,200,000 persons yearly.

Vegetation at the time of discovery

Unfortunately, we have only meager descriptions of the vegeta-
tion of the Valley at the time of its discovery by white man. Plants
and vegetation were weak rivals for attention compared with cliffs

Figure 3 A. Lower end of Yosemite Valley in 1866 from Old Inspiration Point. The
large open area in the lower left part of picture is Bridalveil Meadow. Note the open
character of the forest on north (left) side of river. Photograph by C. E. Watkins.

Figure 3B. View from Old Inspiration Point, 1961. The old Big Oak Flat road can
be seen on the talus slope north of the river. Photograph by R. P. Gibbens.

and waterfalls when early descriptions were written, and this is
true today. Even such naturalists as John Muir, who spent much
time in Yosemite and wrote of it extensively, recorded little specific
information on its flora; statements like "Verdant banks of new
leaves, and groves of half-open ferns, and thick settlements of con-
fident flowers . . ." (Muir, 1915) are of little scientific value.
Fortunately, a few sources containing other observations were
found. A brief comment on vegetation by a member of the Mariposa
Battalion which entered the Valley in 1851 was included in the
Commissioners' report for 1889-1890:

The valley at the time of discovery presented the appearance of
a well kept park. . . . There was then little undergrowth in the
park-like valley, and a half day's work in lopping off branches
along the course enabled us to speed our horses uninterrupted
through the groves.

Galen Clark, in a letter to the Commissioners dated August 30,
1894, said, in part:

My first visit to Yosemite was in the summer of 1855. At that
time there was no undergrowth of young trees to obstruct clear
open views in any part of the valley from one side of the Merced
River across to the base of the opposite wall. The area of clear
open meadow ground, with abundance of luxuriant native
grasses and flowering plants, was at least four times as large as
at the present time.

Sketches by Thomas Ayres, the artist who visited the Valley with
J. M. Hutchings in 1855, also suggest that trees were widely spaced
on the Valley floor.

In 1866 the State Geographical Survey party under direction of
J. D. Whitney made a detailed geographical and geological survey
of the Yosemite Valley region. This survey, published in 1868 as
The Yosemite Book, contains the first detailed descriptions of veg-
etation. It seems unlikely that extensive changes had occurred
during the 15 years since 1851. The few Indians occasionally
inhabiting the Valley continued the burning which was credited
with maintaining the park-like appearance of the Valley. Baxley

(1865) described his arrival at the Valley in the fall of 1861 as
follows:

A fire-glow in the distance, and then the wavy line of burning
grass, gave notice that the Indians were in the valley clearing the
ground, the more readily to obtain their winter supply of acorns
and wild sweet potatoe [sic] root — 'huckhau.'

Whitney (1868) included a lengthy description of the vegetation
in 1866 (currently-used names are in brackets):

Along the banks of the river and over the adjacent rather
swampy meadows, we find a somewhat varied vegetation, ac-
cording to the locality, the narrow portions of the Valley dif-
fering considerably from the broader ones. In the former, near
the falls, there is a dense growth of alder (Almis viridis), [A.
rhombifolia] . . . associated with this are small trees of Rhamnus
Menziesii, [??]. ... A few willows [Sali.x spp.], the Douglas
spruce (Abies Douglasii), [Douglas-fir, Pseudotsuga menziesii]
and, in the upper part of the Valley, an occasional sugar pine
[Pinus lambertiana], are also found in this position. Where the
Valley widens out, and the river banks become lower, so that
sloughs and swamps are formed, the Balm of Gilead popular
(Populus balsamifera) [black cottonwood, P. trichocarpa]
comes in; this is a common tree in the Valley, . . . with this
occur large willows and abundance of the Douglas spruce, and

also the Azalea occidentalis, The meadows are swampy,

with a deep peaty soil; their vegetation consists chiefly of
carices or sedges and a few coarse grasses ....

The sandy region of the Valley proper forms a connecting
strip along the edge of the rocky talus, on both sides of the
river. . . . This is peculiarly the arboriferous belt of the Valley,
and various portions of its area exhibit different characters of
vegetation to correspond with the differences of soil. On the
drier and looser portions, the pitch (or yellow) pine {P. pon-
derosa) and the bastard cedar [incense-cedar] (Libocedrus
decurrens) are the most abundant and characteristic trees; both
these species occur of considerable size and of fine proportions,
the pines being usually from 125 to 150 feet high. Below the
Bridal Veil Fall, near the debris, the fir (Picea grandis) [white
fir, Abies concolor], a noble tree, comes in; near the swampy
land, the black oak ((?. Sonomensis) [Quercus kelloggii] is

abundant. The sandy regions also bears a great number and
variety of shrubs and undergrowth; ....

The most characteristic tree of the debris piles is, perhaps,
the mountain live-oak [canyon oak] (Q. chrysolepis, Liebm.)

The spectacular scenery attracted early photographers, arid their
photographs provide the best means of determining vegetational
changes. The first pictures were taken in 1859 by C. L. Weed,
who took additional photographs in 1863. Examination of some
of these show few changes between the above dates and 1866, when
C. E. Watkins took an extensive series. The Watkins photographs
(figs. 1A, 2 A, and 3A) depict original conditions on the Valley
floor.

Although white man had altered conditions to some extent by
1866 it seems reasonable that the vegetation was not greatly differ-
ent from that of 1851. Whitney's description fits the conditions
shown by the photographs — for example, the "arboriferous belt"
is plainly visible in figures 1A and 2 A.

Whitney (1868) also gives the extent of vegetational types.
"There are, altogether 1,141 acres of land in the Valley proper,
of which 745 are meadow, and the remainder, a sandy soil, a little
more elevated, partly covered with a sparse growth of forest trees
and partly with pertinacious ferns." The acreage figures were evi-
dently based on a stylized plat prepared by a member of the survey
party (fig. 4) . Whitney evidently restricted his definition of meadows
and "land in the Valley proper" to low-lying areas which were
periodically flooded. Based on planimeter readings from the 1961
U. S. Geological Survey map of Yosemite Valley there are, from
Pohono Bridge to the eastern end of the Valley, over 2,200 acres
enclosed by the 4,000 foot contour line which roughly coincides
with the base of the talus slopes. Vegetation in 1866 thus seems to
have consisted of extensive wet meadows bordering the river and
of open forests along the sides of the Valley.

In 1851 the tree population in the Valley was composed of two
distinct age groups. One group consisted of old-growth stands,

primarily black oak and scattered individuals of ponderosa pine,
incense-cedar, white fir, and Douglas-fir; counts of growth rings
indicate the age of this group to be largely in excess of 250 years.
Reynolds (1959), besides noting the old-growth stands, observed
a "stand of intermediate age" consisting of ponderosa pine and
incense-cedar. On the basis of growth-ring counts, he placed the
age of this group of trees at about 150 years, with the date of
origin being 1800 plus or minus 10 years. According to Bunnell
( 1 9 1 1 ) , the Indians fled the Valley temporarily because of disease,
and Reynolds speculates that the period when the Valley was empty
might well have been about the year 1800; the trees were able to
become established then because the Indians were not present to
carry out their usual practice of burning.

The presence of the other group, intermediate-aged stands, is
significant because it indicates that a trend toward the development
of a forest cover existed before 1851. One wonders what preceded
the old-growth stands? Plant succession only to a black oak stage
in the 10,000 years since the filling of ancient Lake Yosemite seems
highly unlikely. Plant succession probably did not pass through
marsh, bog, and meadow stages because the lake was filled by delta
formation which would allow colonization by trees on a well-drained
substrata. The hypothesis that woody plants appeared at an early
date is supported by Matthes (1930) :

It is probable, . . . , that like the [present] deltas at Merced Lake
and Washburn Lake, the delta at the head of Lake Yosemite
was largely covered with vegetation. Its more stable portions
bore forest trees, and its shore was fringed with willows. That
the climatic conditions permitted vegetation thus to establish
itself can scarcely be doubted, for there are indications in
various parts of the Sierra Nevada that even during glacial time
extensive forests of pine and sequoia flourished on its lower
slope and well up on the ridges between the canyons.

Evidence of former forests in Yosemite is found in old soil pro-
files in the talus slopes (Matthes, 1930) . If forests developed enough

8

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Figure 4. Plat of Yosemite Valley made by C. F. Hoffmann, a member of the State Geological Survey party, in 1866 or 1867. According to the legend there were 745.63
acres of meadowland and 395.93 acres of "fern and high lands" on the Valley floor.

on talus slopes to form soil profiles, it is likely that they also ap-
peared on the Valley floor. Destruction of these ancient forests
could be accounted for by rockslides or by fire. The probable estab-
lishment and destruction of past forests suggests that aboriginals

arrived following, or took advantage of, such a destruction — and
then arrested plant succession toward another forest cover at the
stage best suited to their needs. As will be seen, the arrival of modern
man brought other influences into play.

Tree increase

The 1943 and 1961 photographs of areas covered by the 1866
photographs show a striking increase in the number of trees in the
Valley, and most of this increase occurred before 1943 (see all
photographs in figures 1, 2, and 3). The 1866 photographs do not
show young trees, but trees younger than 4 or 5 years would prob-
ably not be visible; this is evidence that widespread establishment
of trees took place after 1860.

Growth-ring counts were made of trees at various points through-
out the Valley. The oldest trees on former open areas are about 90
years old (appendix fig. 1). Emil Ernst, a park forester for many
years, made hundreds of ring counts on trees and found few older
than 70 years (Ernst, 1943), and Reynolds (1959) placed the
age of most trees in the Valley as post- 1851. Thus, the oldest trees

Figure 5A. Yosemite Valley from Eagle Peak, probably in the late 1870's. The
Cosmopolitan Walk (constructed in 1870 — the straight white line in lower right),
the Four Mile Trail to Glacier Point (1871), and the Sentinel Hotel (1876) are
visible. Black oak predominates in upper end of Valley. Photographer unknown.

Figure 5B. View from Eagle Peak, 1943. National Park Service photograph.

in the young forest which predominates in the Valley today must
have appeared about 1870.

Contemporary reports, such as the following statement in the
Commissioners' Report of 1882, confirm that the spread of trees
took place between 1866 and 1880:

In our brief report of 1880, we called attention to the rapidly
increasing breadth of underbrush and second growth pines, and
need not restate our convictions with respect to the importance
of counterworking this spreading infestment. While the Indians
held possession, the annual fires kept the whole floor of the
valley free from underbrush, leaving only the majestic oaks
and pines to adorn the most beautiful of parks.

Although 1880 is 10 years later than the date established by
growth-ring counts, the time lag necessary for trees and shrubs to

Figure 5C. View from Eagle Peak, 1961. Some of the trees formerly present on
the Ahwahnee Meadow have been removed. Photograph by R. P. Gibbens.

attain sufficient stature and density to attract attention is about
what one would expect.

Further evidence of the widespread invasion of trees and their
rapid growth is furnished by photographs (figs. 5A, 6A) showing
that establishment of trees occurred throughout the Valley on talus
slopes, sandy delta remnants, dry meadows, and wet meadows.
Although Ernst (1961) states that the area of wet meadow has
remained about the same, photographic evidence indicates that very
wet sites were invaded at an early date. Whitney (1868) refers
to the meadows as "swampy." The dark color in area A on figure 1 A
suggests wet meadow. The early building of a board walk across
this meadow is a further indication that inundation by overflow
was common, and that swampy conditions prevailed during at least
part of the year.

Another example of invasion of a wet habitat is Black Spring
(see all photographs in figure 7). This area was an open spring-fed
drainageway in 1866, and Hutchings (1882) described road-
building activities across the area:

From the Phono Bridge we followed up our work on the north-,
ern side of the Valley to Black Springs. This is a wet and
swampy place, which required ditching on both sides for nearly
two hundred feet, and three rock-covered culverts for drainage.

The road may have altered the drainage and created drier con-
ditions but some of the trees now growing in the area became
established before the road was built. Other examples of forest
encroachment on what must have been wet sites are found through-
out the Valley.

Dry habitats were also readily invaded by trees. In figure 1A,
area B shows a bare, sandy site which is now covered by a stand of
trees. The increase in number of trees along the base of the talus
slopes is evident in figure 2. But increase in density is not confined
to the Valley floor; canyon oak has increased in number and size
on the talus slopes (see all photographs in figures 1, 2, and 3).

Ponderosa pine and incense-cedar were the primary but not the
only woody plants which increased on the Valley floor. Young

11

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Figure 6B. View from Columbia Point, 1943. National Park Service photograph. Figure 6C. View from Columbia Point, 1961. Photograph by R. P. Gibbens.

stands of white fir are found in certain areas, and willows and wild
roses (Rosa spp.) are listed as invaders of open fields in the Com-
missioners' Report for 1880. Galen Clark (1894) noted that young
willows and cottonwoods were becoming so thick on the meadows
that little clear ground was left. Today, only a few of these plants

survive.

The rapid growth of conifers has greatly changed the appearance
of extensive woodland areas formerly dominated by black oak (see

Left, Figure 6A. View of upper end of Yosemite Valley from Columbia Point, 1899. Pre- 1851
conifers are plainly visible above the stands of black oak and young trees. Photograph by
H. G. Peabody.

all photographs in figure 8 ) . Black oaks are still present, but they
have been overtopped by conifers and are no longer dominant.
Ponderosa pine and incense-cedar are now the most abundant trees
and dominate most of the forested areas on the Valley floor (appen-
dix tables 1 and 2) . Small areas are dominated by white fir, Douglas-
fir, black oak, black cottonwood, and alder. Canyon oak is dominant
on most of the talus slopes.

In the forest stands outside the Valley's campgrounds the increase
in tree density has been a continuing process, and there is often a
continuous range of tree ages and sizes from seedlings to the pre-
1851 trees (figs. 9, 10). Growth of the understory trees is slow,
as can be seen by the ages of trees with a small diameter (appendix
fig. 1 ) . Recent tree establishment has not been confined to forest

13

Figure 7A. Right, top. The Black Spring area, 1866.
Photograph by C. E. Watkins.

Figure 7B. Right, center. The Black Spring area, 1943.
A small rock has rolled against the larger one since the
1866 photograph was taken. National Park Service photo-
graph.

Figure 1C. Right, bottom. The Black Spring area, 1961.
Tree in left foreground is about 73 years old; small
incense-cedars in center are 65 to 70 years old. Flowering
dogwood has become established since 1943. Photograph
by H. F. Heady.

stands, however, as young trees are found on meadows and other
open areas (figs. 11, 12).

The development of a dense tree canopy has created conditions
favorable for the establishment of shade-loving plants within the
forest. The high shade tolerance of incense-cedar accounts for its
abundance as an understory in dense stands. Young trees and seed-
lings of two other shade-tolerant species, white fir and Douglas-fir,
have appeared in the dense stands of ponderosa pine and incense-
cedar. It is possible that white fir will in time become a co-dominant
with ponderosa pine and incense-cedar. Plants other than trees now
occupy sites formerly unfavorable for them — flowering dogwood
(Cornus nuttallii), for example, has become established at Black
Spring since 1943 (fig. 7C).

Sampling of several forested sites showed that the herbaceous
understory is varied, both in species and density (appendix table 3 ) .
Although the tree cover is often essentially the same, there is a great
deal of difference in understory plants on wet and dry sites
(figs. 13, 14).

14

Causes of tree increase

\

The increase in woody plants was often attributed to the ceasing
of burning by the Indians, but another hypothesis to explain the
increase was postulated by W. H. Hall after his visit to the Valley
in 1881 (Hall, 1882):

The use of the valley itself by the constant travel and the grazing
of animals upon it, is beginning to tell upon the character and
extent of its vegetable productions. The finer forage grasses
are being thinned out; the coarser and more robust or hardy
grasses and weeds, able to withstand the trampling and crop-
ping, are taking their places; and the area of meadow is decreas-
ing, while young thickets of forest or shrub growth are spring-
ing up instead. . . . The cause is alleged to be the abolition of the
old practice of burning off the thickets, which practice formerly
made new clearings almost every year for grass growth. Doubt-
less this clearing had its effect in this way, but another cause,
and perhaps a more potent one, is to be found in the continued
cropping of the grass and trampling of the ground by horses.
The finer grasses are cropped off. pulled up, trampled under
foot into soft meadow ground, while coarser growths are
avoided by browsing animals and permitted to flourish. The soil
and the subsoil of the meadows is becoming compacted, and
percolation of waters therein is arrested, so that they dry out
earlier each year; the change in character of their forage vegeta-
tion results, and the thicket growths encroach upon their
borders.

Hall was not the only person to note the impact of grazing on
vegetation during this period. The Commissioners' Report for 1 885—
1 886 states in part:

During the season now closing — with its list of visitors largely
in excess of former years — the utmost resources of the valley
were drawn upon and exhausted for pasturage. Any increase of
demand must be met by a timely increase of meadow land area,
and the Commission has no choice but to appeal to the State on
this behalf. The truth is that, under the strain of over-pasturage,
the best meadow lands are being injured, while all of them show
narrowing lines from the encroachment of brambles and
thickets of young pines, willows, and cottonwoods, and some
of them are so entirely overgrown as to have passed out of a
pasturage classification into that of woodland.

It seems safe to assume that overgrazing was a factor in 1870
when trees began to increase in number. In 1868 there were only
623 visitors, but in 1869 visitors numbered 1,122, and this increase
meant that the meadows, already grazed by residents' livestock,
were grazed by many additional animals. 1870 is only the approxi-
mate beginning of widespread increase in trees; many became
established in the late 1870,s and early 1880's when grazing was
severe.

Hall (1882) made an accurate analysis of grazing factors which
contributed to the spread of trees: Heavy grazing allows seedlings
to become established by reducing the competition from sedges,
grasses, and broad-leaved plants. Trampling creates drier conditions
by compacting the soil and, in very wet areas, by forming a rough,
ridged surface which increases evaporation and drying. Exposure
of mineral soil provides an excellent seedbed. With conditions favor-
ing seedling establishment, the absence of fire allows trees and
shrubs to develop. Even if occasional fires do occur their effective-
ness as a killing agent is greatly lessened because herbaceous fuel

is scarce.

There is no evidence that the early spread of trees in meadows
was facilitated by a lowering of the water table, and it is unlikely
that deposition raised land levels significantly between 1851 and
1870. Blasting of the rocks in the river channel at Bridalveil in

15

Figure 8A.The upper end of Yosemite Valley as it appeared between 1887 and
1896; the Stoneman House is visible on right. Young conifers are visible among
the black oaks. Photograph by George Fiske; exact date unknown.

Figure 8B. Upper end of Yosemite Valley, 1943. The black oaks have been over-
topped by ponderosa pine and incense-cedar. National Park Service photograph.

1879 was the first recorded event which might have caused an
appreciable lowering of the water table, but this was 10 years
after the start of tree invasion. Ernst (1961) has suggested the
possibility of a lowering of the water table by natural processes
coincident with early settlement of the Valley, but this cannot be
substantiated. Evidence already presented indicates that tree inva-

sion occurred in wet habitats; in addition, willows and cottonwoods
(adapted to very wet conditions) were not abundant when white
man arrived but increased after his arrival. Only the marshes appear
to be too wet for establishment of a coniferous cover, and no soil
habitat in the Valley is too dry.

Since trees have become established in meadow areas after grazing

16

Figure 8C. View of same area in figures 8A and 8B but taken from a ledge above
the original point to avoid screening trees. Photograph by R. P. Gibbens, 1961.

ceased (fig. 11), it seems most probable that fire was the major
factor in suppressing them before 1851. Heavy grazing, which
coincided with the first widespread establishment of trees, was more
an accelerating than an initiating factor. The drying influence of
trees, and possible lowering of the water table, did not influence
early tree increase because these factors became operative only later.

Effect of cutting, clearing, and
planting on the forests

Besides being instrumental in increasing the extent of the forests,
man has affected the character of the forest cover in many other
ways. Pre- 1 85 1 forests and woodlands were thinned by early settlers

Figure 9. A dense understory of incense-cedar is often found in forested areas on
the Valley floor. The trees grow very slowly and may take over 20 years to reach
a height of 6 feet. Photograph by R. P. Gibbens, 1962.

Figure 10. Young ponderosa pines often occur in great abundance in small open-
ings in the forests at the foot of talus slopes. A "young" black oak tree (probably
40 to 50 years old) is also shown. Photograph by R. P. Gibbens. 1961.

seeking cabin logs and firewood. With the creation of the Yosemite
Grant it was unlawful to "cut down or carry off any wood, under-
wood, tree, or timber, or girdle or otherwise injure any tree or
timber, . . ." without permission of the Commissioners. But this
rule was not rigorously enforced, and permission was easy to obtain
if logs were needed for building or firewood.

John Muir, among others, operated a sawmill in the Valley for
J. M. Hutchings about 1870. Logs were obtained from a large
windfall and it is doubtful if much standing timber was cut for the
mill although mature trees were cut for other purposes. In the
Guardians Report for 1880, J. M. Hutchings stated: "Growing
trees, of great size and beauty, have been felled, contrary to law
and the order of your honorable Board. " Evidently no action was
taken and the cutting of trees continued. An article in the San Fran-
cisco Examiner (Hutchings, 1888) brought the "timber slaughter"

18

to public attention. According to the article, a 3-acre grove of cotton-
woods, a number of large oaks, and assorted other "noble" trees
had fallen to the axe in 1887. Further evidence of tree cutting,
primarily around the Stoneman House, was contained in an article
in the San Francisco Examiner for November 29, 1888. These
cutting operations were concentrated in the upper part of the Valley
and probably significantly reduced the number of pre-1851 trees.

After 1870 the spread of trees and shrubs was increasingly influ-
enced by the activities of man. Cultivated areas were kept free of
young trees, and loss of valuable grazing land led to more clearing
efforts. During the seasons of 1891 and 1892, men were employed
to thin some of the thickets of young pines and cedars and clean
up combustible material; about 150 acres were partially reclaimed.
More clearing was done during 1897 or 1898, and practically
every annual report during the early years of the Army adminis-
tration mentions the need for clearing in the Valley, although little
seems to have been done until 1911 when some undergrowth was
removed.

The 1914 Report of the Acting Superintendent states, in part:

The clearing of thickets is a very important part of the work on
the floor of the valley and becomes necessary to safeguard the

Figure 11. Young ponderosa pines (4 to 6 years old) in Stoneman Meadow. This
is an example of the invasion of meadow areas which has been going on for many
years. Photograph by R. P. Gibbens, 1961.

.. ;

.* '"-, - -• V' ' ■ ■V,rv.V:>& fl£*"* ■"?/■:.*.

M V ,

Figure 12. Young ponderosa pines at edge of a torrent channel between Cathedral
Rocks and Sentinel Rock. Establishment of trees in open areas such as this has led
to the dense stands now found in the Valley. Photograph by R. P. Gibbens, 1961.

growing trees both from fires and natural destruction of its own,
caused by rapid and dense growth.

There were approximately 150 acres cleared this season on
the floor of the valley, and the work continues in connection
with wood-cutting, . . .

The objective of the clearing and thinning operations was set
for the National Park Service in 1919, and the report of the land-
scape engineer (Punchard, 1919) appointed to study landscaping
problems says:

Generally it was concluded that the present growth was greatly

Figure 13. Understory of bracken fern {Pteridium aquilinum var. lanuginosum)
and western raspberry (Rubus leucodermis) characteristic of forests on low, wet
sites on the Valley floor. Photograph by R. P. Gibbens, 1961.

in need of attention and that thinning on the floor of the valley
should be undertaken for two reasons — first, to preserve the
health of the larger trees and as a protection against serious
fires, and, second, that thinning and clearing of the meadows
would tend to open up and develop very interesting open spaces
and vistas on the valley floor. It is not the intention to do this
work in a drastic manner and reclaim the floor of the valley
entirely and thus reproduce the conditions which existed at the
time of the Indians, but to confine the work to such lines as will
make the woodlands safer from the standpoint of fires and also
produce a pleasing landscape effect.

-*<ffiflk.

Figure 14 Forested area at base of talus slopes, where tree canopy is open and
ground cover is usually sparse. Pine bluegrass (Poa scabrella) and lupine (Lupinus
greyii) are the principal herbaceous plants. Photograph by R. P. Gibbens, 1961.

The vista-clearing concept was not new to the Valley — in the 1 800's
J. M. Hutchings had cut a lane through the trees so his guests would
have a clear view of Yosemite Falls.

During the 1920's, wood and pole cutting was used to open
vistas and thin trees in campground areas; cutting of insect-infested
trees (which had begun in 1915) was also continued and some
idea of the extent of tree-removal for all purposes is indicated by
the 1,000 stumps blasted out along the roads in 1930. Oyster-shell
scale also took a heavy toll of cottonwoods and willows during the
1920's. Thinning of trees and cleanup of dead brush and timber
reached a peak during the Civilian Conservation Corps (CCC)
days, and most of the Valley floor was affected. Such activities have

20

been continued to a lesser degree to the present day. In addition to
vista-clearing, snags and unsound trees are pruned or removed for
public protection. Generally, such activities have had little effect
on the extent of the forests, but constant thinning has influenced
the relative abundance of species, particularly in campgrounds.

From about 1914 to 1924 some meadows were intentionally
burned, killing many small trees and brush plants. In 1930, 9,170
small trees were cut from El Capitan meadow. In 1943, trees were
again removed from El Capitan and other meadows (figs. 15 A,
15B), but clearing did not end the problem of tree invasion in
those meadows, as indicated by a 1961 photograph (fig. 15C).

Despite natural abundance, trees have also been planted at
various times. Sequoia {Sequoia gigantea) and sugar pine were
unsuccessfully planted along several roads in 1913, but in the CCC
days, local species (primarily incense-cedar) were transplanted in
order to screen barrow pits, campgrounds and comfort stations, and
many of these trees still survive.

Figure 15A. Woodland in El Capitan Meadow, 1943. Young ponderosa pines are
abundant. National Park Service photograph.

(1-4

1 ■'

l|iP^ '■■ '' ' ■ '

' • M

Changes in the meadows

Meadowland in the Valley is divided into several more or less dis-
tinct areas which have had names loosely applied to them (fig. 16).
Grazing, long a major meadow use, began when the Mariposa Bat-
talion camped on Bridalveil Meadow in March, 1851, and increased
with the appearance of settlers and tourists. Fences were erected

around meadows at an early date (figs. 1A, 6A), and by 1888
there were 700 acres of land, presumably mostly meadowland, under
fence. Various transportation operators used El Capitan Meadow
for pasture in the 1870's and 1880's. Until 1892, Slaughter House
Meadow was reserved for the pasturage of fat stock brought in for
slaughter; army troops quartered in the Valley grazed their horses
and pack stock on Sentinel and other meadows.

Grazing declined as automobiles increased, but dairy herds con-
tinued to use the meadows (fig.( 17). The Slaughter House and
Lamon Meadows were still fenced in 1919 and were used for pas-
turing pack stock. Widespread grazing ended in 1924 when most
fences were removed, and all grazing was discontinued in 1933
when the tule elk penned in Cook's Meadow were removed. Only
a very small part of Lamon Meadow remains in the present stable
complex.

Meadows were also widely used for growing hay. An Army
Engineers Map, made from data collected in 1878-79, shows a hay

Figure 15B. El Capitan meadow after young trees were removed by Civilian Con
servation Corps personnel. National Park Service photograph taken in 1944.

Figure 15C. View of El Capitan meadow in 1961. Young ponderosa pines are once
again present in large numbers. Photograph by R. P. Gibbens.

EAGLE PK

Scole l« 24000

Pohono

Br idge
/

Figure 16. Map of Yosemite Valley showing the location of meadows and sampling sites.

shed in El Capitan Meadow; at least 20 acres of El Capitan Meadow
was plowed and sown to timothy in the 1 87CTs in an unsuccessful hay
growing project, and Leidig Meadow was plowed in 1885 and 1887
to raise hay, and again in 1888 when wheat was sown. Part of the
Ahwahnee Meadow was plowed during the late 1800's, and from
1910 to 1914 it was plowed and sown to hay by government em-
ployees. According to testimony at the Investigation of the Yosemite
Valley Commissioners (California Legislature, 1889), Stoneman
Meadow was cleared and plowed in 1887; the investigation placed
the acreage under cultivation at that time at about 150 acres. Galen

Clark testified at the hearing that cultivation was considered a
means of "reclaiming" meadowlands.

Portions of the Lamon, Stoneman, and Schoolhouse meadows
were planted to orchards which still exist. The Schoolhouse Meadow
was the site of gardening activities by J. M. Hutchings, and by
Valley residents during the two World Wars; hay barns and the
Yosemite Park and Curry Co. warehouses were formerly located
on this meadow. In 1941, small plots in El Capitan meadow were
cultivated and sown to native plants in an unsuccessful attempt to
re-establish wildflowers. Some of the meadows were drained for

22

mosquito control. Ditching of unspecified meadow areas was done
in 1932, and drainage tiles still exist in Royal Arch Meadow.

The old Sewer Farm is a man-made meadow (fig. 2B, 2C). In
1866 the area was covered by brush and probably developed a tree
cover during the 70's and 80's. In 1921 it was cleared to provide
space for settling basins of the first centralized sewage system, but
with the completion of the present sewer plant in 1931 operations
ceased and the dikes and tanks were leveled in 1932. Today the veg-
etation is essentially meadow-like in character, although some trees
have become established.

Ahwahnee, Cook's and Bridalveil meadows were burned inten-
tionally in 1919, 1920, 1921, and 1930. The Ahwahnee meadow
was accidentally burned in 1929, and other meadows probably have
been burned by accident.

The problem created by tourists' use of the meadows (fig. 18)
is mentioned in the Superintendent's Monthly Report for June, 1929:

Ditches constructed around the meadows on the floor of the
Valley have aided materially in protecting these spaces from
encroachment by tourists. With autos traversing them con-
stantly, and with daily picnics being held in these meadows, the
native flowers and grasses were rapidly becoming a thing of the
past.

Figure 17. Dairy herd in Leidig Meadow, 1918. Until 1924, several meadows were
grazed by dairy herds during summer months. National Park Service photograph

..«*/■ .'■ v

Figure 18. Stoneman Meadow as it appeared in May, 1927. Use of meadows for
picnics and camping was common in the early 1900's. Construction of ditches
along roadways in 1929 brought a halt to such use. National Park Service photo-
graph.

Construction of these ditches ended the last general use of
meadow areas; deer and other wildlife use the meadows today. Foot
traffic is not extensive except in Stoneman Meadow and along the
river banks. The remaining meadow areas are largely the product
of man's activities. Plowing, mowing, burning, and probably in some
cases severe overgrazing, served to keep out encroaching trees; in
addition, clearing activities of the 1890's, 1930's and 1940's have
prevented the establishment of woody growth. Boundaries of the
present meadows could probably be correlated with the location
of fences which delimited activities.

A major change in the meadows has been their decrease in size
due to forest encroachment. Whitney (1868) classified 745 acres
as meadowland. Russell (1927) using 1922 U. S. Geological Survey
maps of Yosemite Valley placed the meadow acreage at 430 acres.

23

Ernst ( 1949) measured the meadow area on an unpublished vegeta-
tion-type map prepared in 1937 and found 327 acres of meadow;
planimeter readings from aerial photographs taken in 1960 show
approximately 334 acres of meadow. Recent invasions by trees (figs.
11, 15C) indicate that only continued tree removal will maintain
the meadows as open areas.

Today, the meadow vegetation only partially fits Whitney's
(1868) description: "consists chiefly of carices or sedges and a few
coarse grasses . . ." For the present study, all of the major meadow
areas (except the Schoolhouse Meadow) were sampled to determine
the kinds of plants present (appendix table 4). Sedges {Car ex spp.)
are still very abundant and it seems safe to assume the species (not
given by Whitney) are essentially the same today, although their
relative abundance may be different. The "coarse grasses" listed as
characteristic of the meadows by Whitney are all adapted to very
wet habitats. The present rarity of these grasses indicates that the
meadows are much drier now.

Next to sedges, Kentucky bluegrass (Poa pratensis) is the most
abundant plant in the meadows. Undoubtedly, Kentucky bluegrass

was introduced, as was redtop {Agrostis alba), another grass prom-
inent in the meadows today. Annual grasses, also introductions, are
abundant in sandy or disturbed sites. Only one native grass, wild-
rye (Elymus spp.), is probably much more abundant today. While
sedges typically predominate in the lower, wetter portions of the
meadows, the abundance of plants (such as Kentucky bluegrass)
adapted to relatively dry sites further substantiates the deduction
that the meadows are, in general, drier than when seen by Whitney.
Aside from the shift to plants adapted to a drier habitat, there is
little remaining evidence of the plowing and heavy grazing of the
past. On meadows which were plowed sedges have re-established
themselves wherever moisture conditions permit. The Elk Paddock
has completely recovered from the relatively recent heavy grazing
(see both photographs in figure 19 ) . If the Elk Paddock and the ad-
jacent Superintendents part of Cook's Meadow, which was not
grazed during the same period, are compared (appendix table 4),
it is evident that differences in kind and abundance of species are
minor. In Lamon Meadow, another area of recent heavy grazing,
sedges are least abundant. This may be due to the compacting and

(

Figure 19A. Elk Paddock portion of Cook's Meadow between 1921 and 1933;
note heavily grazed condition inside the fence. National Park Service photograph.

Figure 19B. Elk Paddock site, 1961. Photograph by R. P. Gibbens.

drying action of trampling, but there are few low areas which are
favorable for sedges. Soil factors may also play a part in species
distribution.

Broad-leaved plants are not abundant on the meadows. There are
many references through the years to the decreasing numbers of wild-
flowers in the meadows. Michael (1929) stated: "June of the year
1920 witnessed the last great bloom on the floor of the Valley. "; she
attributed the comparatively small numbers of flowers present in
1927 to the influence of mowing, burning, deer, and people, although
these factors were also operative prior to 1920. The same author
also noted that after being absent or nearly so from 1923 to 1935,
various lilies appeared in great abundance, even on meadows which
had been plowed (Michael, 1935). Obviously, it is difficult to deter-
mine if wildflowers are now more, or less, abundant than in 1851.

Abundant production of fruiting stalks by a wide variety of plants
common to the lower Sierra Nevada is assumed to be climatically
controlled. The optimum combination of moisture and temperature
needed for such production in many species occurs only in widely-
spaced years, and this helps account for the fact that myriads of
flowers may be seen one year and only a few in another year. To
blame the decline on grazing or some other factor is especially haz-
ardous; valid comparisons should be based on the actual number
of plants and not on the number of flower stalks.

Plowing, mowing, and grazing has undoubtedly reduced the popu-
lation of certain wildflowers, while populations of some rare but at-
tractive species have been decimated by picking and trampling.
Perhaps the re-establishment of sod-forming sedges and grasses and
the accumulation of a heavy mulch layer prevented the return of
wildflowers after disturbance had ceased: It is also possible that lack
of disturbance could decrease the wildflower populations; grazing,
for example, would reduce mulch and weaken the sod-formers. Cer-
tainly, any species favored by burning is less likely to be found
today than in 1851. The great variety of wildflower species means
that there will be some which will increase with disturbance and
some which will decrease, some which will increase with protection
and some which will decrease.

Introduction of plants

numerous plant species were brought to California by the Spaniards
as early as the 16th century and many others have arrived since.
Some of these scattered rapidly and by the middle of the 19th cen-
tury were widespread and abundant in California (Burcham, 1957).
Although the Spaniards rarely penetrated into the Sierra Nevada,
the wanderings of Indians and natural dissemination by wind and
animals could have introduced non-indigenous plants to the Valley

before 1851.

With the entry of early visitors a great importation of plants began,
and conditions favorable for the establishment of introduced species
were created. Plowing and heavy grazing broke up or weakened
the cover of native plants, creating space readily occupied by the
well-adapted introductions, many of which were brought in with the
hay, grain, and seed imported for feed and cultivation. Seeds were
widely disseminated over the Valley floor by grazing animals and by
man, and disturbed areas were often deliberately seeded with plants
foreign to the Valley. Out of 470 known species of plants on the
Valley floor and lower portions of the talus slopes, 1 8 per cent are
non-indigenous (appendix table 5).

Introduced trees and shrubs are not a significant part of the vege-
tation outside the orchards planted by the early settlers, although
apple trees have naturalized to some extent. Introduced grasses
which have become naturalized are very abundant. Kentucky blue-

25

grass is a major meadow plant, redtop was undoubtedly introduced
as a hay plant and has spread throughout the Valley, other hay
grasses are found scattered in the meadows, and velvet grass (Holcus
lanatus) has become widely established in wet habitats. Most of the
annual grasses are introduced species, and are now major constit-
uents of the herbaceous vegetation throughout the Valley.

Generally, introduced broad-leaved plants are weeds found in
small numbers on disturbed areas. Some of these, such as thistle (Cir-
sium vulgare) and Klamath weed (Hypericum perforatum) , suc-
cessfully compete with established vegetation and have been the
object of control measures because they detract from the natural
appearance of the meadows. Control of all weedy species in the
Valley is not necessary; some may become temporarily abundant due
to favorable climatic conditions, but they are unlikely to displace
the more desirable perennials. Since weeds flourish on disturbed
areas, the best control is to keep disturbance at a minimum. Because
of their long-lived seeds, many weeds will remain a potential, if not
active, part of the vegetation.

Re-establishment of plants
on denuded areas

man's activities, and natural events such as floods and rockslides,
have caused much denudation — although little evidence of such
events remains because of rapid re-establishment of plants. The

Figure 20A. Gravel road skirting the north side of Elk Paddock in the late 1920's
or early 1930's. Photographer and date unknown.

Figure 20B. North side of Elk Paddock site, 1943. (Paddock fence was removed
in 1933.) National Park Service photograph.

Figure 20C. North side of Elk Paddock site, 1961. Old road was torn up in 1953. Photograph by R. P. Gibbens.

27

present distribution of species on such disturbed areas reflects mois-
ture gradients and soil differences, and not the type of disturbance.
The old Sewer Farm, for example, is now completely revegetated;
where remnants of the old dikes impede drainage there is a dense
cover of sedges, surrounded by wild-rye. Part of this area lies on the
Eagle Creek outwash fan where rapid drainage and occasional de-
position of material creates conditions ideal for abundant annual
grasses. A few trees and shrubs have become established and,
barring further disturbance, others are likely to appear.

In the spring of 1959 the Old Village store was removed, and in
1961 its site was sampled to determine the extent of recovery and
the kinds of plants found on recently disturbed areas. Red fescue
{Festuca rubra) had been sown on the site and was the most abun-
dant plant, but annual weeds — characteristically the first invaders
of denuded areas — were abundant (appendix table 6). Sedges and
perennial grasses from the bordering meadow had gained a strong
foothold on the site by 1961. Young trees were not present at this
time, but may appear while herbaceous cover is sparse.

Development of rhizomes by the dominant meadow plants enables
them to move into disturbed areas very quickly, and perennials,
when firmly established, crowd out annual species (see fig. 20C).
Such disturbed areas may be identified for a long time, not because of
species differences, but because of differences in plant size or color.
On sandy or other dry sites introduced annual grasses, which are
better adapted to less moisture than are perennials, may become the
dominant plants.

Well-adapted native and introduced herbaceous species are the
best choices for artificial revegetation of denuded areas. "Foreign"
species* such as red fescue, may be successful temporarily but will
usually be replaced by the natives. Trees may become established on
denuded sites along with herbaceous plants, and may develop con-
currently; when this happens the trees become dominant. Woody
plants are often the primary invaders on rock slides; shrubs and
young ponderosa pine trees were well established 9 years after a
large rock slide at Rocky Point, but few herbaceous plants were
present (Carlson, 1932).

Wildlife Influences

Deer and rodents are the animals most likely to significantly affect
vegetation in Yosemite Valley. Although wildlife was protected in
the Valley after 1864, deer did not increase greatly until they were
protected throughout Yosemite National Park, and by effective game
laws outside the Park. The Acting Superintendent's Report of 1912
contains the first mention of an increased deer population; since
then the population has fluctuated, with excess resident animals
being removed when necessary.

Herbaceous plants constitute a major part of deer's diet, as browse
plants are not abundant in the Valley. Some deer-relished plants,
such as evening primrose {Oenothera hookeri), have apparently
been reduced in abundance by the animals. Young white fir trees and
favored shrubs are often hedged by browsing, thus greatly slowing
their growth, and the limited reproduction of black oak (particularly
in the grove surrounding Yosemite Village) has been attributed to
deer browsing. A survey of the relatively deer-proof Ahwahnee
Hotel grounds reveal a few small black oaks less than 1-foot tall,
with one tree found outside the fence. As the grounds have been
fenced since 1929, more young oaks and a number of different age
groups would be expected if deer were the only limiting factor
involved.

Black oak seedlings have appeared in large numbers at least once
in relatively recent times. Payne (1938), commenting on the ex-

28

ceptionally large crop of acorns produced in 1936, states: "With
the lapse of a year since the sprouting of the acorns, we find a great
host of these seedling oaks growing most vigorously." Reasons for
the present scarcity of black oak reproduction are not known. Con-
sumption of acorns may be a factor, but deer are not the only acorn
users present. Any one of a number of factors — disease, insects,
viability of acorns, competition from other plants, and climatic fac-
tors— may also be involved. Black oak grows very slowly and if
perpetuation of the grove is desired efforts should soon be made to
determine which factors are limiting reproduction.

Three exclosures were erected in 1935 to determine the effect
of deer browsing and grazing, but little was learned save that deer

seem to have had a minimum of influence on the vegetation. How-
ever, the exclosures are small and no record of vegetation on open
control plots was compiled.

Rodents may possibly have played a part in the early spread of
trees in the Valley. The bare soil of gopher-workings in meadows
would make excellent seedbeds, and seeds buried in animals' caches
would be a source of seedlings; however, during population peaks
rodents could reduce tree-establishment by eating seeds and girdling
young trees. Too little is known about the rodent populations to
evaluate their effect on the vegetation, but such effects have been
restricted by the rodent trapping and poisoning programs carried out
since 1912.

Figure 21. Camp 14. Note absence of small trees, herbaceous cover, and heavy litter normally found under similar stands of trees. Photograph by R. P. Gibbens, 1961.

Influence of floods and rockslides

Floods, rockslides, and avalanches have a catastrophic effect on
vegetation. Major floods occurred in 1867, 1890, 1919, 1937, 1950
and 1955.Hutchings (1886) described the flood of 1 867 as follows:

On December 23, 1867, after a snow fall of about three feet, a
heavy down-pour of rain set in, and incessantly continued for
ten successive days; when every little hollow had its own
particular water-fall, or cascade, throughout the entire circum-
ference of the Valley; each rivulet became a foaming torrent,
and every stream a thundering cataract. The whole meadow
land of the Valley was covered by a surging and impetuous
flood to an average depth of nine feet. Bridges were swept away,
and everything floatable was carried off.

Immense quantities of talus were washed down upon the
Valley during this storm, — more than at any time for scores, if
not hundreds, of years, judging from the low talus ridges, and
the timber growth upon them. After this rain-storm had ceased,
a wind sprung up and blew down over one hundred trees. In one
spot of less than seven acres twenty-three large pines and cedars
were piled, crosswise, upon. each other.

Such floods inundate areas normally not flooded by spring runoff.
The flood of 1950 covered 55 per cent of the nearly level floor of
the Valley, and one in 1 955 covered even more area. Floodwaters do
not stand long enough to cause wholesale drowning of plants, but
by erosion or deposition and changing of the river channel they can
influence the abundance and growth of plants; for example, bare

30

areas so created may be occupied by vegetation different from that
previously existing in the same area.

Since 1 879 there has been a continuing and not entirely successful
struggle to confine the Merced River to its channel and to halt the
cutting of banks, as both meadow areas and trees have been under-
mined and swept away by the river. Efforts to contain the river may
have caused a deepening of the channel, and with such deepening,
overflow is lessened, drainage is quicker, and the water table is
lowered. These facts indicate that the low-lying ground may now
be drier in summer than it was before 1851.

Rockslides shear off or bury plants in their path, and several have
occurred since 1851. The fall of Eagle Rock in the earthquake of
1872, which John Muir (1912) described so vividly, snapped off
huge fir trees and covered a large area with a rubble pile many feet
thick; much of this area is still bare of vegetation. Slides of lesser pro-
portions (such as the one at Rocky Point in 1923) are not so long-
lasting in their effect. Wildfires can also have a catastrophic effect
on vegetation, although most fires on the Valley floor have been
quickly controlled.

Figure 22. Denuded and trampled river bank at west end of Camp 14. The pile of
rocks is one of many efforts made to halt cutting of stream banks by the river. Photo-
graph by R. P. Gibbens. 1961.

Influence of visitors

The present boundaries of campgrounds in Yosemite Valley were
established in the 1930's and these areas have born the full impact
of increasing use. During the summer of 1958 there were 8,800 to
12,000 campers in the Valley's campgrounds each night (National
Park Service, 1958). Campgrounds in the Valley are all in forested
areas, yet, with so many people moving about, the ground is devoid
of herbaceous plants and young trees (fig. 21). Ernst (1947) lists
only two plants, miner's lettuce (Montia perjoliata) and false Solo-
mon's seal (Smilacina ample xicaulis), which appeared year after year
in campground areas. Miner's lettuce produces seed before the peak
of camping activity, and false Solomon's seal produces stems from
underground rootstalks. Even adapted plants such as these can sur-
vive for only a short period each year.

Vehicular and foot traffic compacts soil, and this influences vege-
tation. Soil compaction in campgrounds was found to be significantly
higher than in immediately adjacent areas' (appendix table 7 ) . Com-
paction dropped off sharply at campground boundaries, even though
adjacent areas are subject to foot traffic. Compacted soils have less
air space, lowered water infiltration rate, and increased runoff —
conditions which are unfavorable to plant growth.

The litter and duff layers characteristic of forest floors are reduced
by campers. Pine needles, the principal constituents of litter and duff
layers in the Valley's forests, make excellent kindling for fires and
as a result are removed each year. In Camp 14 the litter collected in

September from 25 random square foot quadrats was equivalent to
2.5 tons of oven-dry material per acre. Under a similar stand of trees
where camping was not an influence, litter and duff from 25 square
foot quadrats was equivalent to 17.4 tons per acre. Of this amount
9.8 tons were duff, or largely decomposed organic matter, a layer
that was non-existent in the campground. Larger debris has been
removed for fuel from campgrounds and from the upper end of
the Valley in general.

Constant removal of litter results in a loss of nutrients normally
returned to the soil by the breakdown of organic matter. While
leaching of campfire ashes and addition of material through spilled
foodstuffs may partially offset this loss in nutrients, organic matter —
important in maintaining soil structure — and nitrogen are not re-
placed.

Because the Merced River bisects the campground area and is a
focal point of activity, its banks are trampled bare (fig. 22). Before
campgrounds were established the river banks supported a thick
cover of shrubs and herbaceous plants; today, herbaceous plants are
gone and the remaining azalea clumps have been broken by people
(see all photographs in figure 23). River banks at favored bathing
beaches and picnic areas also show the effects of trampling, but
outside the areas of high human concentration trampling is largely
confined to paths along the river.

An indication of what would happen in the present campgrounds
if people were excluded was furnished by the temporary closing of
campgrounds 7 and 15 during 1943, 1944, and 1945 (Ernst, 1947).
Tree seedlings appeared and herbaceous plants recovered rapidly,
especially near protected spots and guard rails at camp boundaries
where the seed source was located. Several campgrounds, abandoned
for sanitary reasons soon after 1906 and still not in use as camp-
grounds, now show no evidence of past trampling.

Buildings and roads continue to influence the vegetation. Build-
ings serve as focal points of human activity, and trampling often
creates disturbed areas around them. Extensive walks and paved
areas have reduced trampling, but the runoff from such non-absorp-
tive surfaces influences vegetation on adjacent areas.

31

Figure 23A. Early photograph taken from below the present site of Stoneman
Bridge. (Washington Column in background.) Photographer and date unknown.

Figure 23 B. The river below Stoneman Bridge, 1943. River bank on the left borders
Camp 7; shrubs and herbaceous plants have been trampled out by campers. National
Park Service photograph.

32

With the exception of Lamon Meadow, all the Valley's meadows
are skirted or bisected by major roads. The fill and ditches of roads
have had considerable influence on drainage patterns and have
doubtless changed soil-moisture conditions. A small swamp support-
ing a stand of cattails (Thy pa latifolia) has been formed in the
Black Spring drainage by the damming action of the highway. The
influence of roads is seldom this marked, the shift usually being
from a wet to a dry meadow. The dry, frequently disturbed road
shoulders and embankments are often a haven for weedy annuals.

Opening of the forest canopy for power lines, installation of pipe-
lines, collection of gravel from the river bed and diversion of springs
for water supplies have also caused changes in plant cover.

Figure 23C. The river below Stoneman Bridge, 1961. Photograph by R. P. Gibbens.

Discussion

To preserve or enhance the beauty of the vegetative landscape of
Yosemite Valley it is essential that there be management of the
vegetation. This view was held by Frederick Law Olmsted, co-
designer of New York's Central Park and head of the first Yosemite
Commission, and was well stated by W. H. Hall in 1882:

If in the judgment of men who have studied such things, for
their love of the beautiful and the appropriate, who have striven
from professional motives and for professional distinction, in
the improvement of the great parks of the principal eastern
cities, large trees can be cut away with advantage, where it has
cost so much of time, money, and skill to raise them, certainly
you should be safe from censure if, in opening out the views,
caring for the full development of the timber, and clearing up
the more unsightly parts of the valley lands of the Yosemite,
you apply the axe right freely.

Today, ecological knowledge enables us to predict vegetation
changes under various kinds of management and we also have the
technical ability to produce almost any desired landscape. But, un-
happily, the aesthetic criteria for making decisions as to what vegeta-
tive landscape is desired appear to be lacking— and for Yosemite
Valley the decisions must be made soon.

On aesthetic grounds, a primitive state of tree density is frequently
deemed more desirable than the present one. Trees are now so nu-
merous in the Valley that any selected density and extent of forest

33

can be obtained by selective cutting, although it would probably be
impractical to thin the forests to their primitive low-density. How-
ever, some thinning must be done for other than aesthetic reasons:
a dense understory of young trees often forms a solid block of fuel
from the ground to the tallest tree tops, and this is a potentially catas-
trophic situation if fire occurs.

Although perhaps undesirable in some areas, dense stands of
trees are useful in screening the Valley's extensive campgrounds
from view. In the campgrounds a preponderance of sandy soils has
minimized the effect of trampling, but the soils have been altered and
the present tree cover may be adversely affected. Since there is a
lack of young trees in these areas, a time limit — the life span of the
existing trees — has been placed on the screening forest. Therefore,
steps to protect tree health and to provide replacements for dead
or dying trees should be taken. One solution might be to rotate camp-
ground use; during periods of closure an understory of herbaceous
species could be established by sowing, and replacement trees could
be planted.

To maintain the meadows in the Valley as open areas will require
continued removal of trees. Selective tree removal is expensive but
effective. Other methods, such as prescribed burning, might be less

costly or more long-lasting, but their effect on herbaceous vegetation
would have to be evaluated before they are used on a large scale.

The presence of the many introduced herbaceous plants in the
meadows must be accepted because they cannot be completely and
permanently eradicated. And indeed, many of these introductions
are desirable. On Stoneman Meadow, for example, Kentucky blue-
grass maintains a pleasing appearance despite trampling which would
cause more robust native sedges to become unsightly. Again, intro-
duced annual grasses provide cover on many areas too dry to support
a good cover of perennials. Only those introductions which detract
from scenic values need to be controlled. It is unlikely that the
sedges, which add much to the attractiveness of the meadows, will
be replaced by other plants as long as present moisture conditions
prevail. Creation of wetter conditions by changing drainage patterns
might be an effective method of increasing the numbers of sedges
and other moisture-loving plants.

There is, of course, an alternative to management of the vegeta-
tion, and that is the acceptance of the landscape which will develop
naturally. This alternative has been consistently rejected in the past,
and, if aesthetic criteria are used, continued rejection is likely in
the future.

Acknowledgments

this study was made possible by contract funds from region IV of the National Park Service during 1961-62. In addition, the interest
and cooperation of many individuals on the staff of Yosemite National Park allowed the study to progress rapidly. Their help is greatly ap-
preciated. Especially, we thank Keith Trexler, Coyt Hackett, and Douglas Hubbard for their many suggestions in locating source
materials, opening museum facilities, and improving the manuscript.

C. W. Sharsmith identified many of the plants mentioned; Mr. and Mrs. A. W. Hood allowed the use of their excellent collection of early
photographs and gave many tips on the location of historical information and field sites; A. M. Schultz made many suggestions for improving
the manuscript. Their help is gratefully acknowledged.

34

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Carlson, Reynold E.

1932. Plant succession at Rocky Point. Report for Yosemite Field School
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Clark, Galen

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DURANT, MARAFRED

1927. A comparison of the flora of the Ahwahnee meadow and the Royal
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Ernst, Emil F.

1943. Preliminary report on the study of the meadows of Yosemite Valley.
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1947. Results of retirement and rest during 1943-44-45 of campgrounds
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1949. Vanishing meadows in Yosemite Valley. Yosemite Nature Notes
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Goen, Alice

1932. Comparison of the vegetation on the north and south facing talus
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Hall, Wm. Ham.

1882. To preserve from defacement and promote the use of the Yosemite
Valley. Report of State Engineer. In Biennial Report of the Com-
missioners to Manage the Yosemite Valley and the Mariposa Big
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Hutchings, J. M.

1880. Guardians report. In Report of the Commissioners to Manage the

Yosemite Valley and the Mariposa Big Tree Grove. 1880. Calif.

State Printing Office, Sacramento.
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Lillard, Richard G.

1 948. Exotic plants in Yosemite Valley. Yosemite Nature Notes 27 : 1 00- 1 .

35

Matthes, Francois E.

1930. Geologic history of the Yosemite Valley. U. S. Geol. Survey, Prof.
Paper 160. U. S. Govt. Printing Office, Washington. 137 p.

McDonald, Louise O.

No date. A comparison of plants found in Royal Arches meadow and in
Kenneyville meadows. Report for Yosemite Field School of Natural
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National Park, Calif. Typewritten. 6 p.

Michael, Enid

1929. Brief survey of the plants of Yosemite National Park, p. 162-71.
In Yosemite Ranger-Naturalist Manual Vol. II, 2nd ed. National
Park Service. Processed.
1935. A good flower year. Yosemite Nature Notes 14:96-7.

Muir, John

1912. The Yosemite. The Century Co., New York. 284 p.

1915. Letters to a friend. Houghton Mifflin Co., New York. 194 p.

Munz, Philip A. and David A. Keck

1959. A California flora. Univ. of Calif. Press, Berkeley. Calif. 1681 p.

National Park Service

1958. Monthly travel reports, File No. A3015. Yosemite National Park,
Calif.
Paden, Irene D. and Margaret E. Schlichtmann

1955. The Big Oak Flat road. San Francisco, Calif. 356 p.

Payne, E. A.

1938. Natural wholesale planting of California black oak in Yosemite
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PUNCHARD, CHAS. P., JR.

1919. Report of the landscape engineer. In Report of the Director of the
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Reynolds, Richard Dwan

1959. Effect of natural fires and aboriginal burning upon the forests of the
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36

Bibliography

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1956. An appraisal of the archeological resources of Yosemite National
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Clark, Galen

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37

Appendix

METHODS OF STUDY

The quarter method (Cottam and Curtis, 1956) was used to
sample trees in seven forest stands on the Valley floor. A line of
march was selected, 100 feet paced off, and a plot center established
by means of a rod placed at the toe of the boot. With the line of march

as one axis and a line at right angles to it as another axis, four 90-
degree angles, or quarters, were established. The tree over 2 inches
d.b.h. (diameter breast high) nearest to the pin was measured and
recorded by tree species for each quarter. In each stand, 25 points
were sampled, giving 100 measured individuals. From these data
the relative abundance as based on number of individuals (appendix
table 1 ) and on basal area (appendix table 2) was calculated.

The relative abundance of herbaceous plants and trees on ten
forest sites was calculated from data collected by a modified step-
point method of sampling (appendix table 3). Three steps were
taken along a compass line and a pin placed at the toe of the front
boot. The closest rooted plant in front of the pin was recorded. The
rooted plant closest to the step-point was sometimes a tree, recorded
as mature, young (under 4 inches d.b.h.), or seedling (1 and 2
years old for conifers, under 1 foot for oaks). The seedling designa-
tion for oaks was used merely to distinguish recent reproduction.
This is not an ideal method to use in a forest because two different

Appendix Table 1

RELATIVE ABUNDANCE OF TREES WITH A D.B.H. OF 2 INCHES

OR MORE EXPRESSED AS PERCENTAGE OF TOTAL

NUMBER OF TREES CONTRIBUTED BY EACH SPECIES-

Site Numb

er

Species

1

2

3

4

5

6

7

per cent

Pinus ponderosa

40
53
4
3
0
0
0

45
39
11
4
1
0
0

54

29

14

1

2
0
0

56
37
2
5
0
0
0

26
56

16

1

0

1

0

59
28
8
5
0
0
0

12

Libocedrus decurrens

20

Quercus kelloggii

Abies concolor

Quercus chrysolepis

Pseudotsuga menziesii

Cornus nuitallii

7

54
2
4
1

* Calculated from 25 quarter-method samples taken on each of seven forest sites located
on the Valley floor (see figure 16 for site locations).

Appendix Table 2

RELATIVE BASAL AREA OF TREES WITH A D.B.H. OF 2 INCHES OR

MORE EXPRESSED AS PERCENTAGE OF TOTAL BASAL AREA

CONTRIBUTED BY EACH SPECIES*

Species

Pinus ponderosa

Libocedrus decurrens .

Quercus kelloggii

Abies concolor

Quercus chrysolepis . . .
Pseudotsuga menziesii
Cornus nuttallii

Site Number

1

2

3

4

5

6

7

per cent

64.2

68.0

54.2

62.3

54.4

86.5

33.3

29.1

20.0

29.3

29.9

35.4

10.7

17.7

6.5

9.4

16.3

3.1

8.9

1.6

9.4

0.2

2.5

0.1

4.7

0.9

1.2

31.4

0.0

0.1

0.1

0.0

0.0

0.0

1.1

0.0

0.0

0.0

0.0

0.4

0.0

7.0

0.0

0.0

0.0

0.0

0.0

0.0

0.1

* Calculated from 25 quarter-method samples taken on seven forest sites on the Valley
floor (see figure 16 for site locations).

38

260

240

220

200

80

160

to

cr

< 140

UJ

>-

uj 120
<

100

80

60

4 0-

20

407 r

• P0NDER0SA PINE
x INCENSE-CEDAR
o WHITE FIR

E

0.

©

- O * * • *

J» o •

°. * x

X

3®

X
. X'

sP

E

x •

tx

,1 X

X
• X

J *•

.•2

•22

.2 2

15

20 25 30

d.b.h. (inches)

35

40

45

50

life forms — trees and herbaceous plants — are intermixed,
but it was a rapid method and furnished a measure of
the relative abundance of the different species. The num-
ber of trees recorded indicates their relative proportion in
the total vegetation.

The relative abundance of species on the meadows was
calculated from rooted frequency as determined by the
modified step-point method described above (appendix
table 4 ) . Due to scarcity of fruiting bodies and lack of
distinctive vegetative differences the species of sedges
could not always be distinguished. However, the principal
species in approximate order of abundance were Carex
barbarae, C. vesicaria, C. feta, and C. kelloggii. Wild-rye
was not separated into species due to the intergradation of
forms. In general Elymus triticoides is found in open areas
and E. glauca in wooded areas. Species listed as "other
perennial grasses" in appendix table 4 include Stipa cali-
fornica, S. Columbiana, Muhlenbergia filiformis, M.
rigens, Panicum occidentale, and Calamagrostis cana-
densis; "other annual grasses" include Bromus commu-
tatus, Festuca reflexa, F. dertonensis, and Deschampsia
danthonoides. Only the most common forbs are listed in
appendix table 4. Nomenclature is based on Munz and
Keck (1959).

Appendix Figure 1.

Total ase of trees as estimated from growth ring counts in 1961. The
ranse of d.b.h. classes (diameter breast high— about 4.5 feet) was
sampled at several sites on the Valley floor. Symbols enclosed in a
square represent stumps whose diameter is larger than the d.b.h. Since
most of the samples were taken from trees on former meadow areas
the invasion of trees appears to have started approximately 90 years
ago. Diameter of the trees is closely correlated with age but this cor-
relation is influenced by site. For example, trees marked "1" are from
dry sites at the base of talus slopes and are much older than trees of
comparable diameters from level portions of the Valley floor. Trees on
very favorable sites (marked "2") have a large d.b.h. in relation to their
age. Understory trees, many of which are less than 10 inches d.b.h., are
quite old.

39

Appendix Table 3
RELATIVE ABUNDANCE OF SPECIES ON TEN FOREST SITES ON THE VALLEY FLOOR EXPRESSED AS PERCENTAGE OF

TOTAL NUMBER OF PLANTS CONTRIBUTED BY EACH SPECIES*

Site

Species

A

B

C

D

E

F

G

H

r

J

per cent

4.0
14.0
0.0
0.0
0.0
0.0
0.0
0.0
4.7

26.6
0.0

10.0
2.6
3.3
0.0
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0.7
0.0
0.0
2.1

0.0
0.7
0.0
0.0
0.0
0.0
0.7

0.0

11.3
0.0
4.7
0.0
0.0
0.0
1.3
2.1

18.0
10.6
8.7
2.0
4.7
0.7
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.0

12.6
0.0
0.0
0.0
0.0
0.0
1.3

10.0
48.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0

10.6
3.4
3.3
1.3
0.0
0.0
5.3
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
4.0

3.3
0.7
0.0
0.0
0.0
0.0
0.7

1.3
1.3
2.0
1.3
4.6
0.0
0.0
0.0
0.7

9.3
1.3
0.0
22.0
0.0
0.7
0.0
0.0
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
4.8

0.7
0.7
0.0
0.0
0.0
0.0
0.0

4.0
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.7

26.0
0.7

14.6
0.7
0.0
0.0
0.0
1.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.1

4.0
0.0
0.0
0.7
0.0
0.0
0.0

3.3
15.3
1.3
3.3
4.0
2.6
0.0
24.0
0.7

0.0
2.0
0.0
0.0
0.0
0.0
0.7
0.7
1.3
0.0
0.7
0.0
2.0
0.7
0.0
0.0
6.1

0.0
0.0
0.0
0.0
0.0
0.0
0.0

13.3
5.3

0.0

0.7
4.7
8.6
4.7
8.0
0.7

0.0
5.3
0.0
0.0
0.0
0.0
0.0
0.0
1.3
0.7
1.3

21.3
6.7
0.0
0.0
0.0

10.7

0.0
0.0
0.0
0.7
0.0
0.0
0.0

0.0
4.7
1.3
0.0
9.3
0.7
0.7
0.0
2.7

7.3
2.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
6.0
0.0
0.0
0.0
0.0
4.8

0.0
9.3
1.3
0.0
0.0
7.3
0.0

0.0
6.0
0.0
0.0
0.0
22.0
0.0
7.3
1.4

0.7
4.6
0.0
0.0
0.0
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
7.3
0.7
0.0
5.3

0.0
0.0
2.7
0.7
4.0
0.0
0.0

0.0

4.0

0.7

0.0

0.7

14.6

0.0

7.3

2.0

Plpridiiiw anvilinuiJi var. lanuoinosuvi

0.7

2.7

0.0

0.0

1.3

0.0

0.0

0.7

1.3

12.0

0.0

0.0

0.0

6.6

5.3

0.7

0.0

0.0

0.7

0.7

0.7

0.0

Arctostaphylos mariposa

1.3

0.7

40

Appendix Table 3 — Continued

Species

Libocedrus decurrens

Mature

Young

Seedling

Finns ponderosa

Mature

Young

Seedling

Quercus kelloggii

Mature

Young

Seedling

Abies concolor

Young

Seedling

Quercus chrysolepis

Mature

Young

Seedling

Pseudotsuga menziesii. . .
Umbellularia calif ornica.

Acer macrophyllum

Alnus rhombifolia

B

Site

D

E

per cent

H

2.0

10.6

0.0

0.0
0.0
0.0

0.7
2.6
0.0

12.0

1.3

10.0

1.3

2.0

0.0

0.7

0.0

1.3

1.3

0.7

0.7

0.0

1.3

0.0

6.0

4.0

0.7

0.0

0.7

0.0

10.6

0.0

0.7

0.0

0.7

0.0

* Calculated from rooted frequency as determined by 150 step-point samples on each site (see figure 16 for site locations) .

41

Appendix Table 4
RELATIVE ABUNDANCE OF SPECIES ON THE MAJOR MEADOW AREAS IN YOSEMITE VALLEY EXPRESSED AS PERCENTAGE OF

TOTAL NUMBER OF PLANTS CONTRIBUTED BY EACH SPECIES-

Species

Meadow

Bridalveil

El Capitan

Open

Wood-
land

Slaughter
House

Leidig

Sentinel

Cook's

Superinten-
dents part

Elk
Paddock

Ah wah nee

Stoneman

La rnon

Royal
Arch

Old Sewer
Farm

per cent

Carex spp.f

Poa pratensis

Elymus spp.f

Agrostis alba

Other perennial grasses!

Bromus tectorum

Other annual grasses!

Total grasses and sedges

J uncus effusus

J. orthophyllus

Equisetum laevigaium

Scirpus aculus

Iris miss our iensis

Heleocharis spp

Solidago spp

Fragaria calif arnica

Asclepias cordifolia

Artemisia douglasiana

A . dr avunculus

Rudbeckia hiria

Hypericum formosum

Lotus oblongifolius

Rumex acetosella

Achillea lanulosa

Gayophytum nuttallii

Lessingia leptoclada

Other forbs

80.1
4.0
5.3
0.0
0.0
0.0
0.0

89.4

1.0
1.7
0.0
0.0
0.0
0.0
1.6
0.3
0.0
0.0
0.0
0.0
1.0
5.0
0.0
0.0
0.0
0.0
0.0

36.0
40.3
7.3
2.0
4.3
1.0
0.0

90.9

4.0
1.3
0.7
0.0
1.8
0.0
0.0
0.0
0.0
0.7
0.0
0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.3

17.6
35.9

10.7
7.0
7.0
0.0
0.0

78.2

5.0
0.0
2.3
0.0
2.3
0.0
3.0
1.0
0.3
1.7
0.3
0.0
0.3
0.3
0.0
1.0
0.3
0.0
4.0

21.0

21.3

25.3

3.3

1.3

7.0

12.1

91.3

0.7
0.7
0.0
0.0
1.7
0.0
1.3
0.0
0.0
0.7
0.0
0.0
0.0
0.3
2.4
0.0
0.0
0.0
0.9

29.4
51.0
15.0
0.0
1.0
0.3
1.7

98.4

1.0
0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.3
0.0
0.0
0.0
0.0

47.6
22.0
26.7
0.0
0.0
0.0
1.0

97.3

0.0
1.7
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.0

74.2
11.0
8.0
0.7
0.0
0.0
0.0

93.9

0.0
0.7
0.0
0.0
0.0
3.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.7
0.0
0.0
1.4

67.8
21.7
0.0
4.0
0.3
0.0
0.3

94.1

0.3
0.3
0.0
0.0
0.0
1.3
0.0
0.0
0.3
0.0
0.0
0.3
0.0
0.0
0.0
0.0
0.0
0.0
3.4

51.9
27.7
0.0
1.3
0.3
15.0
0.0

96.2

0.0
1.0
0.0
0.0
0.0
0.0
0.3
0.0
0.7
0.3
0.0
0.0
0.3
0.0
0.0
0.3
0.3
0.3
0.3

13.0
68.3
0.0
8.0
2.0
5.4
0.0

96.7

0.7
1.0
1.0
0.0
0.0
0.0
0.0
0.0
0.0
0.3
0.0
0.0
0.0
0.0
0.3
0.0
0.0
0.0
0.0

0.7
68.0
0.0
2.0
0.7
19.3
5.3

96.0

0.0
0.7
0.7
0.0
0.0
0.0
0.0
0.0
0.0
0,0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.0
0.6

78.1
10.2
0.0
0.5
0.0
0.0
2.7

91.5

0.5
0.0
0.0
6.2
0.0
0.0
0.5
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
1.3

26.6
1.7

38.4
0.0
0.0

19.4
1.7

87.8

0.3
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
2.7
0.0
0.0
0.0
0.0
0.3
5.3
3.6

* Calculated from rooted frequency as determined by 300 step-point samples in all meadows except Lamon (150) and Royal Arch (225) (see figure 16 for location of meadows).
t See appendix I for names of species.

42

Appendix Table 5
INTRODUCED PLANTS FOUND IN YOSEMITE VALLEY*

Trees and Shrubs

Acer saccharophorum
Cercis occidcntalis
Hedera helix
Mains sylvestris
Parthenocissus quinqiiefolia
Primus cerasus
Pyrus communis
Robinia pseudocacia
Rubus recurvans
Sequoia gigantea
Syringa vulgaris
Ulmus americana
Vitis spp.

Forbs

An the mis cotula

Brassica kaber var. pinnatifida

B. cam pest ris

Capsella bursa-pastoris

Card aria drab a

Cerastrium viscosum

C. vulgatum

Chenopodium album

C. botrys

Chrysanthemum leucanthemum

Cirsium vulgar e

Cnicus benedictus

Convolvulus arvensis

Conyza canadensis

Digitalis purpurea

Erigeron strigosus

Erodium botrys

E. cicutarium

Galium aparine

Glecoma he derate a

Humulus lupulus

Hypericum perforatum

Ilex aquifolium

Lactuca serriola

Malva parviflora

Mentha spicata

Mullugo verticillata

Pimpinella anisum

Plantago lanceolata

Plantago major

Polygonum aviculare

P. convolvulus

P. lapathifolium

P. persicaria

Portulaca oleracea

Prunella vulgaris

Rap ban us sativus

Rudbeckia hirta var. pulcherrima

Rumex acetosella

R. crisp us

Sisymbrium altissimum

S. officinale

Taraxacum vulgare

Thlaspi arvense

Tri folium repens

V erbascum thapsus

Veronica serpyllifolia

Grasses

Agrostis alba

A . alba var. palustris

A vena fatua

Bromus commutatus
B. inermis
B. mollis
B. rigid us
B. rubens
B. secalinus
B. tectorum
Dactylis glomerata
Digit aria ischaemum

D. sanguinalis
Eragrostis megastachya

E. pilosa
Festuca dertonensis

F. elatior
Holcus lanatus
Hordeum stebbinsi
Lolium perenne
Phleum prate use
Poa pratensis
Setaria lutescens
S. viridus

« List compiled from Durant (1927), McDonald (no date), Woodham (1927), Michael (1929, 1935), Carlson (1932), Goen (1932), Lillard (1948), Bryant (1951), and sheets in the
Yosemite Museum Herbarium. It is possible that many species have been brought in since the above collections and studies were made.

43

Appendix Table 6
RELATIVE ABUNDANCE OF SPECIES
ON THE SITE OF THE OLD VILLAGE
STORE EXPRESSED AS PERCENTAGE
OF TOTAL NUMBER OF PLANTS CON-
TRIBUTED BY EACH SPECIES. (DATA
GATHERED 2 YEARS AFTER RE-
MOVAL OF THE STORE.)*

Species

Per cent

Festuca rubra

Elymus spp

Poa pratensis

Agrostis alba

Sitanion hystrix

Carex spp

Bromus rigidus

B. tectorum

Sisymbrium altissimum

Lactuca serriola

Capsella bursa-pastoris ,
Chenopodium botrys . . .

C. album

Rumex acetosella

Artemesia douglasiana.
Unidentified

31.3
22.7
10.7
1.3
0.7
1.3
1.3
0.7
22.7
1.3
0.7
0.7
1.3
1.3
0.7
1.3

* Calculated from rooted frequency as deter-
mined by 150 step-point samples.

Appendix Table 7

DEGREE OF SOIL COMPACTION INSIDE AND OUTSIDE CAMPGROUNDS

AS MEASURED BY A SOIL PENETROMETER*

Location

Camp 14 east end.

Camp 14 central part

Camp 14 west end

Camp 11 west end

East of Yellow Pine Beach.
North of El Capitan Beach

Soil

sandy-loam

sandy-loam

sandy

sandy-loam

sandy

sandy to
sandy-loam

Area

inside
outside

inside
outside

inside
outside

inside
outside

forest

forest

Use

heavy
moderate

heavy
moderate

heavy
moderate

heavy
moderate

very light

very light

Number of
samples

39
10

40
38

50
50

50
50

50

50

Mean compac-
tion value*

2.82
1.16

2.34
1.40

1.35
0.48

2.78
1.24

0.55

0.60

* The larger the value of the means the greater the degree of compaction. Differences between the means of samples from inside
and outside the campgrounds were highly significant.

Co-operative Extension work in Agriculture ond Home Economics, College of Agriculture, University of California and United States Department of Agriculture co-operating. Distributed in
furtherance of the Acts of Congress of May 8, and June 30, 1914. George B. Alcorn, Director, California Agricultural Extension Serv.ce.

2m-7,'64(E5202L)V.L.

44

IS