WEEDY ANNUALS AND ESTABLISHMENT OF SEEDED SPECIES ON A
CHAINED JUNIPER-PINYON
WOODLAND IN CENTRAL UTAH
James N. Davis
Kimball T. Harper
ABSTRACT
United States is grazed. Heavy grazing in this type results
in greater than average juniper-pinyon tree densities and
invasion of this vegetational type onto a<ljacent plant communities (Aro 1971; Woodbury 1947). Loss of vegetation
in the understory due to grazing appears also to have decreased the incidence of wildfires in these woodlands and
allowed an increase in tree density (Arnold and Schroeder
1955; Johnsen 1962). An example of the problem that depletion of understory species can cause on many of Utah's
juniper-pinyon winter ranges is evidenced by large proportions (up to 50 percent) of some deer herds that were lost
during the severe winter of 1949-50. In contrast and during
this· same time, juniper-pinyon winter ranges in good condition experienced deer losses that were only slightly higher
than those expected in moderate winters (Plummer and
others 1968). The severe winter of 1949-50 was not an isolated event; there have been many winters since (including
1964-65, 1972-73, 1978-79, 1979-80, 1983-84, and 1988-89)
in which there have been heavy deer losses in many different geographic areas of the State (Jense 1989).
In an effort to remedy damage on some pinyon-juniper
critical winter ranges, cooperative work between two agencies, the Intermountain Forest and Range Experiment
Station (now the Intermountain Research Station), Forest
Service, U.S. Department of Agriculture, and the Utah
State Department of Fish and Game (now the Utah State
Division of Wildlife Resources, hereafter referred to as the
Division) was initiated. The objective of the effort was to
find plant materials and revegetation methods for artificially restoring forage production on depleted juniper-pinyon
winter ranges. Such efforts were considered to have value
for watershed protection and for improved livestock grazing
and big-game habitat (Plummer and others 1968).
Anchor chaining has proven to be the most effective and
economical of several techniques tested for tree removal,
seedbed preparation, and seeding success (Plummer and
others 1964). The anchor chain is particularly effective
on juniper-pinyon sites that are undulating, rocky, and
sometimes steep. Such sites characteristically have shallow, poorly developed soils that make establishment of
seeded species more difficult.
Since the beginning of our rehabilitation efforts, the
Division has treated more than 50 areas statewide, a total
of over 24,000 ha (60,000 acres) on State-owned lands, and
has cooperated with the Forest Service, Bureau of Land
Management, U.S. Department of the Interior, and private
landowners on chaining projects involving an additional
Bur buttercup (Ranunculus testiculatus) and cheatgrass
brome (Bromus tectorum) occurred in very large numbers
on a juniper-pinyon (Juniperus spp.-Pinus spp.)-treated
site. Of the herbaceous species planted (nine grasses and
seven {orbs), only nine appeared in large enough numbers
to occur in any of the 520 sample quadrats. Significant
plot-to-plot variation in density of seven ofthe seeded species was explained by the initial densities of either bur
buttercup or cheatgrass. Precipitation probably was not
responsible for the poor establishment of seeded species,
because it was 160 percent ofnormal in that year. Almost
without exception, the native and seeded perennial grass
species increased over the period of observation. The data
suggest that, although annual weeds interfered with initial establishment of the seeded perennials, these species
gradually became highly competitive with and strongly
reduced the density of both bur buttercup and cheatgrass.
INTRODUCTION
Juniper-pinyon woodlands dominate almost 30 percent
of Utah's land area (West and others 1975), and are estimated to cover from 17.5 to 32.5 million ha (43 to 80.2
million acres) of the western United States (Kuchler 1964;
West and others 1975). In Utah, this type occurs primarily between 1,500 and 2,100 m (5,000 and 7,000 ft) elevation, but it is not uncommon for these limits to be transgressed (Woodbury 1947). For example, the woodlands
occur as low as 980 m (3,200 ft) near St. George and as
high as 2,560 m (8,400 ft) on south-facing slopes on the
Book Cliffs in Carbon County.
The current low carrying capacity (understory productivity) of this vegetative-type appears to be a consequence
of many years of excessive grazing by domestic animals
(Forest-Ra:nge Task Force 1972). Clary (1975) estimated
that 80 percent of the juniper-pinyon type in the western
Paper presented at the Symposium on CheatgTass Invasion, Shrub DieOff, and Other Aspects of Shrub Biology and Management, Las Vegas, NV,
April 5-7, 1989.
James N. Davis is research biologist for game range restoration studies
with the Utah Division of Wildlife Resources stationed at the Shrub Sciences Laboratory, Intermountain Research Station, Forest Service, U.S.
Department of Agriculture, Provo, UT 84606; Kimball T. Harper is professor of Botany and Range Sciences, Department of Botany and Range
Science, Brigham Young University, Provo, UT 84602.
72
This file was created by scanning the printed publication.
Errors identified by the software have been corrected;
however, some errors may remain.
The areas chained on this study site were not continuous,
but were small areas of varied shapes ~d topographical
relief along ridges, ravines, and in smallvalleys. Since
traditional wildlife management has considered "edge" an
important wildlife habitat variable, there was a conscious
effort in the chaining operation to increase edge effect. The
areas were chained and seeded in November of 1982. Elevation ranges from 1,740 m (5,700 ft) on the westerly edge
of Black Hill to 2,070 m (6,800 ft) in the mountain brush
zone at the head of Cane Valley.
The area has an average slope of 13 percent (ranging
from 7 to 26). Soils are shallow, 25 to 30 em (about 10 to
12 inches) deep over fractured parent material. Soils on
the lower portions of the site are an Am toft flaggy loam
series (loamy-skeletal, carbonatic, mesic, Lithic Xerollic
Calciorthids); the upper sites are an Atepic-Badland association series (loamy, carbonatic, mesic, shallow, Xerollic
Calciorthids) (SCS 1981). The shallow soils support scattered populations of black sagebrush (Artemisia nova),
Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis), and mountain low rabbitbrush (Chrysothamnus viscidiflorus ssp. lanceolatus ).
Sampling was done in midsummer along 10 permanently
marked lines, each 270 m (about 900 ft) in length. The
lines were located and read in 1982 before the area was
chained. Lines were relocated after chaining and remarked
for easier location and were read for the next 3 years. Each
line consisted of five transects 30m (almost 100ft) long,
except line 6, which had seven transects because of vegetational diversity along its length. Transects alternated
with 30-m segments that were not inventoried. Quadrats
(1.0 m 2 ) were placed at 3-m intervals along each transect
beginning at the 0 point and alternating from the right to
the left sides of the survey tape. This allowed placement
of at least 50 quadrats along each of the 10 lines distributed
throughout the chained area.
Cover was determined within each 1.0-m2 quadrat for
each species using a procedure slightly modified from that
described by Daubenmire (1959). The modification consisted of adding one extra cover class with limits ofO to 1
percent. The modification provided a more accurate estimate of cover for small or subordinate species. Plant densities for grasses and forbs were determined by counting
individuals rooted within the 1.0-m2 quadrats. Deer presence was determined before and after treatment with
each of the l.O-m2 quadrats that contained recent pellet
groups (Ferguson 1955; Neff 1968; Wallmo and others
1962). Shrub densities were estimated along a 0.005-ha
strip plot centered on the 30-m survey tape (1.67 m wide).
Frequencies for both forbs and grasses were based on species presence within any quadrat along each of the 52 transects. Frequencies for shrubs were based on occurrence
within each of the 52 0.005-ha strip plots on each transect.
Tree densities were determined with the quarter method
(Cottam and Curtis 1956). Points for the quarter method
were located at the beginning and end of each transect.
This gave 40 point-to-tree distances per line.
A soil penetrometer was used to estimate depth to obstructions in the soil at random points (Ostler and others
1982). Most obstructions were stones. Five depth measurements were taken at each end of each transect along
each line. This gave 50 measurements per line.
84,000 ha (207,000 acres) of big-game winter range
(Fairchild 1982). There are divergent views regarding
whether such woodlands should be chained and seeded
(Dalen and Snyder 1987; West 1984) or whether suitable
sites should be treated at all (Gifford 1987; Lanner 1981),
but these efforts have almost always enhanced soil stability, forage production, and habitat recovery.
Typically, the success of juniper-pinyon treatments has
been reported in terms of additional forage made available
by tree removal. For example, Phillips (1977) considered
59 such projects initiated in the Forest Service's Intermountain Region between 1954 and 1975. He reported
that on average, bare ground decreased by 11 percent
and forage production (air-dry weight) increased from
46 to 320 kglha (100 to 710 lbs/acre). Clary and Jameson
(1981) reported even greater increased production in
Arizona. Typically, the woodlands in New Mexico and
eastern Arizona receive more warm-season precipitation
than areas in Nevada and northwestern Utah and have
an inherently greater production potential. Other research has identified the species best adapted to specific
treatment areas (Johnsen and Gomm 1981; Jordan 1981;
Judd 1966; Monsen 1987; Plummer and others 1968;
Renney 1972; Springfield 1965).
Planting mixtures for seeding juniper-pinyon removal
areas produce artificial plant associations in which species
may not be fully compatible with each other or with resident native plants. Furthermore, it is difficult to produce
and maintain a stand of specified composition, because
each species responds differently to the natural and imposed environmental factors that affect seedling establishment and subsequent competitiveness. The species that
are best adapted to initial conditions favorable for germination tend to dominate rehabilitated plant communities;
seeds of species that are less adapted fail to germinate or
germinate late, and the seedlings are suppressed. Nevertheless, mixtures of species are almost universally seeded
on juniper-pinyon chained areas, because environmental
conditions in both space and time cannot be accurately
predicted. With several species in a mixture there is less
chance of failure. In this study, we evaluate initial establishment of seeded species on a chained juniper-pinyon
site in central Utah (Sanpete County) with high densities
of two weedy annuals: cheatgrass brome (Bromus tectorum) and bur buttercup (Ranunculus testiculatus).
LOCATION AND METHODS
The treated area 4s about 300 ha (750 acres) in size, and
is located about 4 km (2.5 mi) northeast of Ephraim, UT.
Most af the lower study area was privately owned before
purchase by the Division; the upper reaches of the treatment area included lands managed by the Forest Service.
Such lands are rehabilitated primarily for wildlife by the
Division, because they lie within geographic areas considered to be critical winter range or in areas experiencing
wildlife depredation problems. Many, if not most, of the
lands purchased for rehabilitation have had a long history
of overgrazing and therefore support communities with
dense populations of weedy species. The weeds are often
alien to the region and can interfere greatly with establishment of seeded species.
73
Statistics Analysis System (SAS 1985) was used for data
analysis. Multiple regression was used to determine how
seeding rate and density of naturally occurring plant species affected establishment of seeded species. Initially, the
power of various subsets of the independent variables for
predicting species response was evaluated by examination
of coefficients of multiple determination (R2) and magnitude
ofC(p) values (measure of total squared error). Intimately,
forward selection of independent variables for multipleregression models was used and vif (variance inflation factors) and eigenvalues were employed to evaluate the effectiveness of the predictive models. Plant nomenclature
follows Plummer and others (1977), except for Lewis flax
(Linum perenne ssp. lewisii), which follows Welsh and
others (1987).
RESULTS AND DISCUSSION
Chaining reduced Utah juniper (Juniperus osteosperma)
tree density on the site from 2,230 to 186 treeslha (902
to 75 trees/acre) 3 years after treatment (92 percent reduction). Pinyon (Pinus edulis) tree density declined from 627
to 62 per ha (254 to 25 per acre) for a decrease of about 90
percent. Average tree kill with cabling or chaining normally ranges from 40 to 80 percent (Arnold and others 1964;
Aro 1971, 1975). Thus, the anchor chain was unusually
effective in removing the trees from the ground at the beginning of this study because moisture conditions favored
uprooting of the trees and because trees were old and even
aged.
Precipitation near the study area during the first year
after seeding was unusually high. In the treatment and
establishment water year (October 1, 1982, to September
30, 1983), there was 437 mm (about 17.5 inches) of precipitation. Normal precipitation for the area is 272 mm (10.9
inches) a year. This above-normal precipitation pattern
continued through 1986 (1983-84, 454 mm or 17.9 inches;
1984-85, 372 mm or 14.6 inches) (NOAA 1983-86). In the
months of initial establishment (March-May 1983), temperatures were above normal for March, then abnormally
cool for April and May.
Total shrub density, irrespective of species, increased
steadily throughout the period 1983-85 rising from 9,570
to 11,880 plants per ha (table 1). Shrub decadence (plants
with ~25 percent of the crown dead) declined dramatically
from over 20 percent in the pretreatment period of 1982
to less than 2 percent in the summer of 1985. Shrub seedlings (surviving established plants ignored) were 77 percent more numerous after treatment than they had been
in the pretreatment sample. Grass and forb cover increased 26 and 40 percent respectively relative to pretreatment conditions by summer 1985.
Bare ground, which averaged 4 7 percent before treatment, decreased to 14 percent by the summer of 1985.
Percent rock cover showed essentially no change (8 to 9
percent) over the course of study. Litter was estimated
at 17 percent before treatment, increased to 26 percent
for 2 years following treatment, and then declined to 15
percent in 1985.
Twenty-six species were seeded onto the area. Species
of grasses (9), forbs (7), and shrubs (10) were included.
Of the species planted, only nine appeared as established
seedlings in any of the 520 1.0-m2 sample quadrats. This
was not expected since precipitation was well above normal
in the winter of 1982-83 and during the growing season of
1983 following the late fall seeding of the site.
Of the nine perennial grasses sown, only four established
in sufficient numbers to occur in the sampling quadrats
(fairway wheatgrass [Agropyron cristatum], intermediate
wheatgrass [Agropyron intermedium], bluebunch wheatgrass [Agropyron spicatum], and orchardgrass [Dactylis
glomerata]) (tables 2 and 3). These four species combined
were represented in 1983 (the year of establishment) with
an average of about 7.6 seedlings/m2 even though approximately 359 perennial grass seeds were sown per square
meter. The seed to seedling establishment rate in the
first year was 2.1 percent. Considering only the four species that did establish seedlings, the establishment rate
was 0.4, 12.4, 0.3, and 0.03 percent for fairway, intermediate, and bluebunch wheatgrasses and orchardgrass,
respectively.
Table 1-Average shrub density (plantslha) across the entire treated area for the 3 years following seeding. Densities are based on actual counts within strips 1.67 m wide by 30 m long centered on
the 30-m transect (0.005 ha)
Year
Plant species
Artemisia novel
A. tridentata ssp. wyomingensis2
A triplex canescens2
Ceratoides lanatcl
Chrysothamnus nauseosus2
ssp. albicaulis
C. viscidiflorus
ssp. lanceo/atus
Gutierrezia sarothrae
Leptodactylon pungens
Opuntia species
19821
1983
1984
1985
Black sagebrush
Wyoming big sagebrush
Fourwing saltbush
Common winterfat
White rubber rabbitbrush
320
220
50
660
60
230
130
100
870
70
240
140
100
810
100
470
130
90
860
210
Mountain low rabbitbrush
2,910
2,830
2,500
2,280
Broom snakeweed
Prickly phlox
Prickly pear
1,940
2,760
1,200
2,800
1,480
1,060
5,520
1,360
1,890
4,480
1,120
2,260
Common name
1Counts
2
done before treatment.
Seeded species.
74
Table 2-Average grass and forb plant density (plants/ha) across the entire treated area for the 3 years
following seeding in November 1982. Densities are based on actual counts in 520 permanently
marked 1.0-m 2 quadrats. The quadrats were read in mid-summer (about July)
Year
Species
1983
Common name
1984
1985
Grasses
Agropyron cristatum 1
Agropyron intermedium1
Agropyron spicatum1
Bromus tectorum
Dactylis glomerata1
Oryzopsis hymenoides
Poa secunda
Sitanion hystrix
Stipa comata
Fairway wheatgrass
Intermediate wheatgrass
Bearded bluebunch wheatgrass
Cheatgrass brome
Orchardg rass
Indian ricegrass
Sandberg bluegrass
Bottlebrush squirreltail
Needle-and-thread grass
780
74,570
160
1'130,420
0
9,080
1,090
12,420
10,450
690
110,090
90
229,560
650
11,830
1,310
7,320
10,410
1,660
71,420
660
140,720
300
17,740
5,260
17,700
14,070
Kings sandwort
Musk bristle thistle
Douglas chaenactis
Lambsquarters goosefoot
Cryptantha
Prickly lettuce
Lewis flax
Narrowleaf gromwell
Yellow sweetclover
Ladak alfalfa
Common sainfoin
Hoods phlox
Bur buttercup
Small burnet
Tumble mustard
Common dandelion
Yellow salsify
3,380
190
690
440
1,190
3,630
1,600
440
80
3,840
2,750
6,200
1,876,690
14,460
420
1,080
580
3,900
710
250
500
940
116,560
750
310
1,330
1,480
2,250
6,050
253,900
13,000
1,710
80
1,020
3,570
6,680
120
0
850
82,770
30
4,780
190
1,250
700
7,220
285,320
14,070
2,050
130
4,210
Forbs
Arenaria kingii
Carduus nutans
Chaenactis douglasii
Chenopodium album
Cryptantha humilis
Lactuca serriola
Unum perenne ssp. lewisii 1
Lithospermum incisum
Melilotus officinalis1
Medicago sativa1
Onobrychis viciifolia1
Phlox hoodii
Ranunculus testiculatus
Sanguisorba minor1
Sisymbrium altissimum
Taraxacum officinale
Tragopogon dubius
1Seeded
species.
Five of the six seeded perennial forbs were included
in the sample of seedlings established in 1983 (tables 2
and 3). Cicer milkvetch (Astragalus cicer) failed to establish any seedlings despite an average seeding rate of
about 386 seeds/m2• It was only seeded on the four upper
lines (or sites) because it usually needs more moisture for
establishment and the lower sites were thought to be marginal for its establishment and growth. Establishment
rates (percent of seeds producing seedlings) for the other
five forbs were 0.02, 0.13, 0.06, 0.55, and 0.39 percent
for Lewis flax (Linum perenne ssp. lewisii), Ladak alfalfa
(Medicago sativa), yellow sweetclover (Melilotus officinalis), common sainfoin (Onobrychis viciifolia), and small
burnet (Sanguisorba minor), respectively.
Grass and forb species densities and frequencies are
summarized in tables 2 and 3 respectively for the 3 years
following seeding. Cheatgrass brome, the weedy species
generally considered to be the major competitor with
seeded species for space in see dings in the juniper-pinyon
zone (Krebs 1972), was represented by over 1.1 million
plantslha in 1983. Cheatgrass density had declined 88
percent by the summer of the third year. The density of
seeded species increased over the same period. This suggests, as did Stewart and Hull's (1949) work in southern
Idaho, that seeded perennial species were offering considerable competition to cheatgrass by the third growing
season and had forced a large reduction in its density,
but cheatgrass still persisted in low numbers on most
sites. All other grasses (both seeded and native perennials) except intermediate wheatgrass increased in density during the 1983-85 period. Despite the fact that intermediate wheatgrass density declined over the period
of record, it is still present in greater numbers than all
other perennial grasses combined (71,420 versus 57,400
plantslha). Three perennial grasses, bluebunch wheatgrass, orchardgrass, and Sandberg bluegrass (Poa secunda), had more than tripled their 1983 density by the
1985 growing season (table 2). Fairway wheatgrass and
Indian ricegrass (Oryzopsis hymenoides) densities had
increased by 112 and 95 percent respectively by the third
growing season. Needle-and-thread grass (Stipa comata)
and bottlebrush squirreltail (Sitanion hystrix) densities
increased 35 and 43 percent respectively in that interval.
By 1985, density of well-established perennial grass individuals averaged 131m2 across the entire treatment area.
Seeded species accounted for only about 57 percent of
the established individuals in the 1985 growing season.
N onseeded perennial grasses increased their density by
75
Table 3-Grass and forb frequency across the entire treated area for the 3 years following seeding.
Frequencies are based on actual presence within quadrats along each of the 52 transects
Species
1983
Year
1984
1985
Fairway wheatgrass
Intermediate wheatgrass
Bearded bluebunch wheatgrass
Cheatgrass brome
Orchardgrass
Indian ricegrass
Sandberg bluegrass
Bottlebrush squirreltail
Needle-and-thread grass
16
65
3
87
0
73
33
86
35
31
73
9
85
20
75
39
73
25
47
83
22
96
20
81
46
81
31
Kings sandwort
Musk bristle thistle
Douglas chaenactis
Lambsquarters goosefoot
Cryptantha
Prickly lettuce
Lewis flax
Narrowleaf gromwell
Yellow sweetclover
Ladak alfalfa
Common sainfoin
Hoods phlox
Bur buttercup
Small burnet
Tumble mustard
Common dandelion
Yellow salsify
40
10
25
21
17
73
50
13
4
39
60
31
98
71
15
29
37
33
17
10
19
15
87
22
12
35
27
30
23
87
63
25
8
42
25
23
8
0
12
87
3
23
4
19
25
37
92
62
33
10
50
Common name
Grasses
Agropyron cristatum1
Agropyron intermedium1
Agropyron spicatum1
Bromus tectorum
Dactylis glomerata1
Oryzopsis hymenoides
Poa secunda
Sitanion hystrix
Stipa comata
Forbs
Arenaria kingii
Carduus nutans
Chaenactis douglasii
Chenopodium album
Cryptantha humilis
Lactuca serriola
Linum perenne ssp. lewisii 1
Lithospermum incisum
Melilotus officinalis1
Medicago sativa1
Onobrychis viciifolia1
Phlox hoodii
Ranuncu/us testiculatus
Sanguisorba minor1
Sisymbrium a/tissimum
Taraxacum officinale
Tragopogon dubius
1Seeded
species.
a total of 66 percent (3.3 to 5.5 plants/m2 ) during the observation period. Native grasses and other understory species
are usually assumed to decline in density after a chaining
treatment followed by seeding (Tausch and Tueller 1977),
but in this study the native grasses increased strongly.
The native grasses have become an important part of the
plant community now existing on the treatment area.
Frequency data show that two of the native, nonseeded
perennial grass species (squirreltail and needle-and-thread)
have not spread to new areas on the treated site, but two
other nonseeded perennial grasses (Indian ricegrass and
Sandberg bluegrass) appear to have colonized new sites
(they had higher frequency values in 1985 than in 1983).
By 1985, all of the seeded perennial grass species appeared
on sites not occupied in the 1983 growing season (table 3).
That apparent range expansion could represent dispersal
of seed into previously unoccupied quadrats, merely delayed germination, or slow development of seedlings that
were too small to be detected in 1983.
Forb densities and frequencies are also summarized in
tables 2 and 3. Almost all perennial native forbs increased
in density between 1983 and 1985. Two perennial native
forbs, cryptantha (Cryptantha humilis) and dandelion
(Taraxacum officinale) declined during this same interval.
Musk thistle (Carduus nutans), prickly lettuce (Lactuca
serriola), tumble mustard (Sisymbrium altissimum),
and yellow salsify (Tragopogon dubius ), all introduced
annuals or biennials, increased dramatically in density
and frequency during the 1983-85 interval.
Lambsquarters (Chenopodium album), and bur buttercup (Ranunculus testiculatus) both decreased in density
and frequency. Indications are that these species are not
able to compete with the species they are now forced to
associate with. It is often assumed that perennial species,
once established, will crowd out weedy annuals through
time and in the absence of heavy grazing (Stewart and
Hull 1949). Our data suggest that this is only partially
true, since some introduced annuals and biennials steadily
increased in the seeded area.
Prickly lettuce, whose life cycle varies from annual or biennial to a short-lived perennial in the study area, experienced a large increase in density between 1983 and 1985.
Density increased from 3,630 to 82,770 plantslha, while its
average frequency increased from 73 to 87. Prickly lettuce
was heavily grazed throughout its period of active growth.
The species appeared to function as a short-lived perennial
during the study period, a time of heavy animal use and
above normal precipitation. Harper (1977) noted that high
densities and severe competition cause Lactuca to function
in this way.
76
Table 4-The effect of several independent variables on establishment of seedlings of selected species. The analysis is based on seedlings observed in the first sampling (July 1983} after treatment. The density of competing species was taken concurrently with dependent variable species in the same period
lnde~endent varlable1
Seeded species
1
2
3
5
4
6
7
8
9
R2
Total
Prob>f
0.86
.66
.87
.97
0.14
.13
.13
.04
- - - - - - - - - - - - - - - Contribution to R 2 value - - - - - - - - - - - - - Agropyron cristatum
Agropyron intermedium
Agropyron spicatum
Dacty/is glomerata
Linum perenne ssp.
lewisii
Melilotus officina/is
Medicago sativa
Onobrychis viciifolia
Sanguisorba minor
2().38"
0.48"
0.19"
0.26"
0.23
0.24
0.61"
.97"
.91"
.41"
0.09
.32"
.25
.70
.04"
.20"
.19
.18
.54"
0.19
1.00
.77
.63
.89
.73
.002
.09
.15
.16
.14
1
1-Bur buttercup density, 2-Seed planted per square meter of the dependent variable species, 3-Total shrub density, 4-lntermediate wheatgrass density, 5-Mountain low rabbitbrush density, 6-Bottlebrush squirreltail density, 7-Cheatgrass brome density,
8-Total native grass density (includes: bottlebrush squirreltail, Indian ricegrass, and needle-and-thread grass), 9-lndian ricegrass
density.
2 Superscript n shows the relationship is negative.
The annual, bur buttercup, occurred in very large
numbers in 1983 (1,876,690 plantslha or 190 plants/m2),
but decreased dramatically over the 3 years of record to
283,320 plants/ha or 28 plants/m2, a decrease of 85 percent
(table 2).
The seeded forbs were all in decline in both density
and frequency by the third growing season after seeding
(table 2). Lewis flax decreased more in relative terms than
any other seeded species during the first 3 years of study.
Its density decreased by 98 percent (1,600 to 30 plants/ha),
while its frequency decreased from 50 to 3 percent. Sainfoin also declined dramatically over the period 1983-85
(tables 2 and 3). Ladak alfalfa also declined, but its losses
were smaller than those experienced by Lewis flax and
sainfoin. Small burnet is the most persistent of the seeded
forbs in this study by a large margin; it declined only 3 percent (tables 2 and 3). Performance of yellow sweetclover,
a biennial, is more difficult to assess. Its numbers were
low the first year after seeding (80 plants/ha), but that
number increased to 1,330/ha in 1984 and then declined
again to 190 plants/ha in 1985. Frequency data for yellow
sweetclover reflected similar trends, from an initial value
of 4 percent, to an intermediate value of 35 percent, and a
1985 value of 4 percent again.
Precipitation is one of the most common factors blamed
for establishment failures (Vallentine 1980), yet there was
more than adequate precipitation during the establishment
period. With almost 7 inches of above-normal precipitation
in the year of establishment and above-normal precipitation
for the next 2 years, lack of water should not have been a
major limiting factor for establishment. Winter frost heaving also is not likely to have been an unusually serious
problem for establishing seedlings at the site because snow
cover was far above normal during that study period. Temperature conditions that may have destroyed new seedlings
were probably not the warmer temperatures for March,
which would have promoted germination, but the low temperatures in that same month. A minimum temperature
77
of -6.1 oc (21 °F) was recorded on March 20 and 23. That
tern perature could have been lethal for some seedlings.
The cold spell started in midmonth and continued with
minimum temperatures (Fahrenheit) in the low- and midtwenties for 12 days (NOAA 1983). Therefore, the late
March interval of severe cold could have had an important
effect on the mortality of some species' seedlings. This
would have in tum depended on how soon each species
germinated and how developed they were at the time of
the cold temperatures. It is possible also that the poor
initial establishment observed for seeded species (some
never became established) was related to interaction with
the weed species (table 4). Buchanan and others (1978)
reported that bur buttercup tissue exerted an allelopathic
effect in in vitro experiments on germination and seedling
development of many range grasses, such as tall wheatgrass (A elongatum), fairway wheatgrass, Russian wildrye (Elymusjunceus), and intermediate wheatgrass.
Average bur buttercup density on the chained area was
190 plants/m 2 during the year of establishment. Such
high densities of this weed appear to have adversely
affected the establishment of five of the seeded species
(table 4). This effect may well have been enhanced with
the elevated levels of precipitation during the year of
seeding. For example, since the allelopathic agent in bur
buttercup is water soluble (Buchanan and others 1978),
and it is known that the intensity and volume of rain influence the efficiency ofleaching, larger amounts of precipitation would have leached more allelopathic agents
into the soil, where they may have exerted an adverse
effect on germination and growth of seeded species
(Tukey 1971).
Normally, fairway wheatgrass is the dominant grass
in seeding efforts in areas comparable to that studied
(DePuit 1986; Rogier and Lorenz 1983). In this seeding,
fairway wheatgrass was unimportant even though an
average of over 42 seeds were sown per square meter.
Conditions for establishment also appeared to be unfavorable for many other seeded species, since only nine of 16
grass and forb species seeded established in the quadrats
inventoried. In only one case (common sainfoin) is there
any strong indication that increased seeding rates would
have improved establishment success (table 4).
Reservation. Station paper No. 18. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 35 p.
Aro, R. S. 1971. Evaluation of pinyon-juniper conversion to
grassland. Journal of Range Management. 24: 188-197.
Aro, R. S. 1975. Pinyon-juniper woodland manipulations
with mechanical methods. In: Gifford, G. F.; Busby, F. E.,
eds. The pinyon-juniper ecosystem. Logan, UT: Utah
State University: 67-76.
Bradley, B. 1989. [Personal communication]. Data on
file at: Utah Division of Wildlife Resources, Salt Lake
City, UT.
Buchanan, B. A.; Harper, K T.; Frischknecht, N. C. 1978.
Allelopathic effects of bur buttercup tissue on germination and growth of various grasses and forbs in vitro and
in soil. Great Basin Naturalist. 38: 90-96.
Clary, W. P. 1975. Present and future multiple use demands on the pinyon-juniper type. In: Gifford, G. F.;
Busby, F. E., eds. The pinyon-juniper ecosystem.
Logan, UT: Utah state University: 19-24.
Clary, W. P.; Jameson, D. A. 1981. Herbage production
following tree and shrub removal in the pinyon-juniper
type of Arizona. Journal of Range Management. 34:
109-113.
Cottam, G.; Curtis, J. 1956. The use of distance measures
in phytosociological sampling. Ecology. 37: 451-460.
Dalen, R. S.; Snyder, W. R. 1987. Economic and social
aspects of pinyon-juniper treatment-then and now.
In: Everett, R. L., compiler. Proceedings, pinyon-juniper
conference, 1986 January 13-16; Reno, NV. Gen. Tech.
Rep. INT-215. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station:
343-350.
Daubenmire, R. 1959. A canopy-coverage method of vegetational analysis. Northwest Science. 33: 43-66.
DePuit, J. 1986. The role of crested wheatgrass in reclamation of drastically disturbed lands. In: Johnson, K. L., ed.
Crested wheatgrass: its values, problems and myths;
symposium proceedings. Logan, UT: Utah State University: 323-330.
Fairchild, J. 1982. Wildlife habitat management on pinyonjuniper chainings. In: Johnson, K. L., ed. Proceedings
of the second Utah shrub ecology workshop. Logan, UT:
Utah State University, College of Natural Resources:
19-20.
Ferguson, R. B. 1955. The weathering and persistency of
pellet groups as it affects the pellet group count method
of censusing mule deer. Utah Academy of Sciences, Arts
and Letters Proceedings. 32: 59-64.
Forest-Range Task Force. 1972. The nation's range resources, a forest-range environmental study. For. Resour.
Rep. 19. Washington, DC: U.S. Department of Agriculture, Forest Service. 147 p.
Gifford, G. F. 1987. Myths and fables and the pinyonjuniper-type. In: Everett, Richard L., compiler. Proceedings, pinyon-juniper conference; 1986 January 13-6;
Reno, NV. Gen. Tech. Rep. INT-215. Ogden, UT: U.S.
Department of Agriculture, Forest Service, Intermountain Research Station: 34-37.
Harper, J. L. 1977. Population biology of plants. New York:
Academic Press. 892 p.
MANAGEMENT IMPLICATIONS AND
CONCLUSIONS
On this site, had not the seeding mixture contained intermediate wheatgrass and small burnet, this treatment
may have been considered a failure. These two species
contributed 94 percent of the total seeded population of
grasses and forbs 3 years after treatment. Previous experience would not likely have enabled anyone to predict
which species would become dominant and which would
fail to establish significant numbers of seedlings even if
the unusually favorable moisture conditions could have
been predicted.
This site and the resulting seeded population also
prompt one to ponder the criteria one should use to rate
the success of a revegetation project. Usually production
of the seeded species is the only measure used. An alternative measure of success to be considered is increased
onsite use by wildlife and an accompanying reduction in
depredation of nearby agricultural lands, which in some
areas is a major problem.
Spring range ride transect counts in the vicinity of the
study area and before the chaining usually yielded more
than 100 dead deer for areas both to the north and south
of the chaining. No dead deer have been observed on or in
the immediate proximity of the chaining since treatment,
evert though deer pellet group distribution patterns have
~ot changed significantly since treatment. Deer depredation calls once numbered more than 200 per winter-spring
season; after treatment, they were reduced to two to five
calls a year for areas near the chaining (Bradley 1989).
In this respect, the chaining would have to be considered
very successful, even though many revegetation efforts
in similar ecological situations have resulted in far denser
populations and greater production from seeded species
(Aro 1971; Clary and Jameson 1981; Phillips 1977).
ACKNOWLEDGMENTS
Federal funds for wildlife restoration were provided
through Pittman-Robertson Project W-82-R, studies 2,
4, and 6. Work was done in cooperation with the Utah
State Division of Wildlife Resources and the Intermountain Research Station, Forest Service, U.S. Department
of Agriculture.
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79