TECHNICAL
Gross Energy Value
of Aboveground Parts
of Alpine Plants
DIXIE
R. SMITH
Plant
Ecologist,
Rocky
Principal
Mountain Forest and Range Experiment Station,1 Laramie, Wyoming.
Highlight
Gross energy of aboveground parts
of alpine plants averaged 4.16 kcal/g
during the summer months. This is
below the average values reported
by oiher authors.
In energy flow studies, ecologists
must frequently
convert biomass to
energy by using caloric equivalents
found in the literature.
Equivalents
for Rocky Mountain alpine flora are
rare in the literature. Caloric values
are presented here to aid and perhaps stimulate the study of energy
dynamics in alpine ecosystems.
Golley (1961) found that caloric
values varied among species, plant
1 Forest Service, U.S. Department of
Agriculture,
with headquarters
at
Fort Collins, in cooperation
with
Colorado
State
University.
Research reported here was conducted at Laramie, in cooperation with
the University of Wyoming.
Table 1. Gross energy value (kcal/g
Species
Grasses
Tufted hairgrass
(Deschampsia
caespitosa (L.)
Beauv.)
Cusick bluegrass
(Pea cusickii Vasey)
Patterson bluegrass
(Pea pattersoni Vasey)
Timberline
bluegrass
(Pea rupicola Nash)
Sedges
Ebony sedge
(Carex ebenea Rydb.)
Short-stemmed
sedge
(Carex brevipes W. Boott)
Forbs
Pale agoseris
(Agoseris glauca
Parry clover
(Trifolium
parryi
D. Dietr.)
Gray)
179
NOTES
parts, seasons, and plant communities. He also demonstrated
that
average energy values were higher
in tundra vegetation than in vegetation of lower elevation and latitudes.
Bliss (1962) presented data on 40 alpine flowering plants in New Hampshire. Bliss’s data also showed alpine
plants to be relatively high in energy
value, but he did not find a significant seasonal variation
in caloric
value of aboveground parts.
Methods
Biweekly samples of several species
(Table 1) were collected in 1962 at
three stations between
10,200 and
10,600 ft in the Snowy Range, Wyoming. Each sample was a composite
of the living aboveground portion of
several individual plants. Subsamples of 0.7 g of air-dry material were
burned in an oxygen bomb calorimeter by the Division of Agricultural
Biochemistry,
University
of Wyoming. Procedures of the Parr Manual
(1948) were followed. Caloric values
were not corrected for ash content,
and are expressed
as kcal/gram
oven-dry wt.
The three stations-Headquarters
Park, Libby Flat, and Sand Lakesupported vegetation representative
of the upper limits of the subalpine
sedge-hairgrass
and of the transition
to the alpine sedge-hairgrass
comdry weight) of aboveground
--__-___-
are
Results
Caloric values showed no consistent seasonal trends. The expected
due to fruiting
(Golley,
increase
1961; Bliss, 1962) may have been
obscured by the limited weight of
the flowering structure in relation to
the aboveground parts.
Energy values, averaged over all
collection periods, ranged from 3.71
kcal/g of Parry clover (Trifolium
parryi Gray) at Libby Flat to 4.35
kcal/g for pale agoseries (Agoseris
at Libby
Flat
glauca D. Dietr.)
(Table
1). Average
energy value
was highest for the two sedges, intermediate for the four grasses, and
lowest for the two forbs-4.30,
4.19,
and 4.02 kcal/g, respectively.
The
was frequently
range
of values
greater among species within classes,
however, than between classes.
The average caloric value of all
collections
was 4.16 kcal/g - considerably below the average of five
alpine species (4.915 kcal/g ash-free
wt) reported by Bliss. It is also below the 4.711 kcal/g dry wt value
reported
by Golley
for dominant
vegetation
of the alpine meadow
community. Golley’s values, however,
were for total vegetation
(roots,
Station
July
12-13
by species, dates, and station.
___
_
Date
-___
Aug.
Aug.
Aug. July
July
13-15 27-29
16-19
23
l-2
Libby Flat
Sand Lake
4.15
4.25
4.18
4.10
-
-
-
-
4.22
4.14
4.28
4.28
4.03
4.25
3.98
4.35
Headquarters
vegetation
munity. The two communities
similar (Johnson, 1962).
Park
Sand Lake
4.08
4.14
-
4.23
4.35
4.02
Libby Flat
4.38
3.98
-
-
-
4.33
4.41
4.41
4.23
4.20
4.24
-
4.30
-
4.38
4.32
4.28
4.32
4.22
4.18
4.45
4.14
4.42
-
3.88
4.12
4.31
-
4.38
4.29
3.57
4.21
4.26
4.40
4.31
3.55
3.68
4.48
4.16
3.43
3.80
Headquarters
Sand Lake
Libby Flat
Park
Headquarters
Libby Flat
Sand Lake
Libby Flat
Sand Lake
Park
4.12
3.57
4.10
-
180
TECHNICAL
leaves, and stems). The comparisons
are also confounded by the fact that
the alpine climate and vegetation of
New Hampshire,
from which both
Galley’s and Bliss’s data were obtained, are more closely related to
that of the arctic and alpine communities of Scandinavia and central
Europe than to the western United
States (Bliss, 1963).
NOTES
LITERATURE
CITED
BLISS, L. C. 1962. Caloric and lipid
content in alpine tundra plants.
Ecology 43: 753-757.
BLISS, L. C. 1963. Alpine plant communities of the Presidential Range,
New Hampshire.
Ecology 44: 678697.
GOLLEY, F. B. 1961. Energy values
of ecological
materials.
Ecology
42: 581-584.
JOHNSON, W. M. 1962. Vegetation
of high-altitude
ranges in Wyoming as related to use by game and
domestic sheep. Wyo. Agr. Exp.
Sta. Bull. 387. 31 p.
PARR INSTRUMENT COMPANY. 1948.
Oxygen
bomb calorimetry
and
oxygen bomb combustion
methods. Manual No. 120. Moline, Ill.
80 p.
9
Seeding fourwing saltbush (AtripZex canescens
(Pursh)
Nutt.) for
range improvement
has become a
common practice in the Southwest.
Land-managing
agencies as well as
ranchers
are seeding this species,
either
alone or in mixture
with
grasses. Some seedings have resulted
in appreciable
improvement,
but
many have failed. The causes for
failure, though not always apparent,
have been traced to adverse weather
or damage from rabbits, rodents, insects, or premature grazing by wildlife and livestock.
Experience
indicates seeding too
deeply also could be a cause for failure. Seedings failed for two consecutive years at a site with coarse-textured soil in central New Mexico.
Few seedlings emerged, even with
favorable
precipitation.
In both
years, de-winged seeds? of fourwing
saltbush were sown in furrows 3 to 5
inches deep. The intent was to cover
the seeds with 1 inch of soil, but each
year the seeds became covered with
2 to 3 inches of soil that sloughed
off the sides of the furrows.
In earlier studies in New Mexico,
Wilson (1928), Cassady (1937), and
Bridges (1941) all found that seedling emergence dropped off rapidly
when seeds were planted more than
0.5 inch deep. Their studies, however, were all with winged seeds.
To evaluate this depth-of-seeding
factor with de-winged seeds, a study
was established
at Santa Fe, New
Mexico in 1965. Seeds were planted
at depths from 0.5 to 2.0 inches in
coarse- and fine-textured
soils from
a nearby range site representative
of the pinyon-juniper
type. The soils,
derived from the Santa Fe formation,
are described as follows:s
Al O-4 Brown (10 YR 5/3); sandy
inches loam; dark yellowish
brown (10 YR 3/4) when
moist; moderately coarse
platy structure breaking
to weak fine granules;
soft, friable,
non-sticky
and non-plastic, abundant
fine roots; few medium
pores; non-calcareous,
neutral (pH 7.2) abrupt
smooth boundary.
B2t 4-11 Reddish
brown
(5 YR
dark
inches 4/4); clay loam;
reddish brown (5 YR s/4)
when moist; strong fine
and medium
angular
blocky
structure;
hard,
slightly firm,
slightly
sticky and plastic; common moderately
thick
1 Central
headquarters
maintained
at Fort Collins in cooperation with
Colorado State University; research
reported
here was conducted
at
Albuquerque
in cooperation
with
the University of New Mexico.
2 The prevailing practice is to remove the wings from the seeds by
hammermilling
to facilitate seeding with mechanical equipment.
3 Prepared by Donald W. Meister,
Soil Scientist, Santa Fe National
Forest.
Depth
Fourwing
fo Seed
Salfbush
H. W. SPRINGFIELD
AND
DONALD G. BELL
Range Scientist
and Range Aid,
Rocky Mountain Forest and Range
Experiment
Station,1 Albuquerque,
New Mexico.
Highlighi
De-winged seeds of fourwing salfbush were sown at 0.5, 1.0, 1.5, and
2.0-inch depihs in two soils. Toial
seedling emergence af the end of 30
days was greater, and the raie of
emergence higher from fhe shallower
depths of seeding. Seeding depths of
0.5 fo 1.0 inch are suggesied for dewinged seeds.
clay films; plentiful fine
roots;
few fine pores;
mildly
non-calcareous,
alkaline (pH 7.6).
The B horizon soil was included because seeds are placed in that horizon when site preparation methods
such as deep furrows, pits, or basins
are used.
Methods
The sandy loam A horizon soil
was kept separate from the clay
loam B horizon soil. Basins 10 ft
long, 3 ft wide, and 5 inches deep
were dug and filled with either the
A or B soil. Two basins of each soil
horizon were prepared. These 10 x
3-ft strips of soil were divided into
3 plots approximately
3 ft square
(Fig. 1). Each plot was carefully
leveled with a hand level and trowel.
Rows 0.5, 1.0, 1.5, and 2.0 inches
deep were made by hand in each
plot (Fig. 2). One hundred de-winged
seeds were distributed evenly in each
3-ft row. Seeds were covered to the
prescribed depth. In half of the plots,
the soil over the seeds was firmed
by rolling a wheelbarrow
up and
back the full length of the rows to
obtain closer contact between the
seeds and the soil. The plots were
sprinkled daily to keep the soil moisture near field capacity.
The seeds, collected near Bernalillo, New Mexico in 1963, had been
de-winged in a hammermill.
They
averaged 3.0 mm in diameter and 5.7
mm in length. Cutting tests showed
75% of the seeds contained an embryo.
The seeds were planted July 19,
1965. Seedlings were counted at intervals from the 7th to the 30th day
after seeding. No emergence
was
found after the 24th day. Seedling
emergence percentages as of the 30th
day were analyzed by analysis of
variance.