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PLANTS FOR REVEGETATION OF RIPARIAN SITES
WITHIN THE INTERMOUNTAIN REGION
Stephen B. Monsen
habitats benefit from the additional water
provided by the stream and, thus, the composition and growth of the vegetation differs from
that found on adjacent uplands. A greater
variety of plants is encountered within the
riparian zone than on adjacent drier sites.
This normally includes a mixture of woody and
herbaceous species. Abundant succulent herbage
is produced throughout most of the growing
season. Grazing animals are attracted to the
water, shade, and forage provided by these
sites, particularly during mid- and late summer
when other vegetation is dry. The sites not
only furnish forage and water but also concealment and protection. Fish and aquatic life are
dependent upon the vegetation to provide site
stability and food.
ABSTRACT: Revegetating riparian zones is
frequently difficult because many sites have
been seriously altered and reconstruction of
the entire plant community may be required.
Seedbed preparation and planting are frequently
delayed by spring flooding. Techniques must be
employed to minimize streambank erosion.
Species recommended for planting riparian
habitats are discussed.
INTRODUCTION
Restoration of riparian sites is a major
concern in the management of range and wildlife
habitats throughout the Intermountain region.
Many riparian zones have been seriously
degraded resulting in the loss of habitat for
aquatic and terrestrial animals (Boussu 1954;
Johnson and others 1977). Although improvement
of many western rangelands has occurred through
management and revegetation programs, many
riparian habitats have responded slowly to such
treatments (Meehan and Platts 1978).
Planting Conditions in Riparian Habitats
Within the Intermountain region, most riparian
zones requiring revegetation have been seriously
altered. Appropriate revegetation practices
must be used to stabilize and improve the sites.
The most obvious conditions that influence
restoration measures are:
Grazing by livestock has had the most
destructive effect upon riparian vegetation
(Behnke 1977). Removal of streamside
vegetation has resulted in destabilization of
the stream channel and streambanks. Stabilization and improvement of riparian habitats is
essential to the overall management of adjacent
rangeland and associated watersheds. Sites
that are not totally degraded usually can be
restored through livestock management and
natural or artificial revegetation. Platts
(1981) reports that improvement in density and
vigor of riparian vegetation occurs as livestock grazing is regulated. Carlson (1976),
Edminister (1919), and Fowler and Hammer (1976)
found that plantings of adapted species have
been successful in improving certain riparian
areas.
1. Vegetative protection is required to control
soil erosion and streambank deterioration.
Often entire watersheds have been seriously
altered and the entire area must be restored to
reduce serious flooding and sedimentation of the
riparian zone. Restoration along the stream
normally requires the reestablishment of woody
and herbaceous plants. Shrubs and trees often
are the most important part of the plant
community. Woody vegetation provides stability
to the sites but usually requires a number of
years to develop.
2. Sites requiring restoration are often
inaccessible to mechanical equipment. The
route of many streams extends along narrow,
steep, and rough terrain. Only small areas may
be level enough to accommodate vehicles or
planting machinery. Equipment designed to
treat small areas is not always available nor
adequate. Consequently, in many situations it
is impractical to mechanically prepare or plant
the disturbed areas.
Values of Riparian Habitats
Within the Intermountain region, riparian
vegetation is most often found along meandering
streams in narrow strips that may be only a few
feet wide. Wet and semiwet meadows also
intermix through the flood plain. Riparian
3. Most riparian zones requiring treatment
traverse a number of different plant communities
and site conditions. The riparian vegetation
may change abruptly and frequently. Restoration
of the vegetation may require reestablishment
of many species of adapted plants. Plantings
Stephen B. Monsen is a Botanist/Biologist at
the Forestry Sciences Laboratory, USDA Forest
Service, Intermountain Forest and Range
Experiment Station, Boise, Idaho.
83
can become quite complex. Variation in planting
sites can normally be accommodated by seeding
mixtures. However, if transplant stock is used,
areas must be correctly categorized and planted
with adapted species.
reduce existing competition. These practices
can seriously diminish the stability of the
streambank, permitting excessive erosion, and
should be avoided if alternative treatments are
possible. Seedbed preparation practices and
weed control treatments that do not destroy or
seriously decrease streambank stability must be
selected. Unstable areas should be mulched or
protected using control structures or grading.
Sites supporting a residual number of desirable
plants should be protected and allowed to
recover. Interseeding or seeding of small
disturbed areas intermixed throughout such
sites should be considered.
4. Problem sites are often seriously disturbed
and altered. The riparian zone frequently has
lost much of the original vegetation and
serious cutting and erosion may have occurred.
Thus, the topsoil is lost, the water table
lowered, and active erosion continues, all
interfering with the establishment of small
plants. The sites no longer may be able to
support the original or desired vegetation.
Intensive treatment is required to prepare and
maintain a suitable seedbed, and introduced
species may be required.
Weed Control
Control of noxious weeds is often required
prior to planting. Sites supporting perennial
weeds such as Canada thistle (Cirsium arvense),
or whitetop (Cardaria draba), should be
mechanically or chemically treated. Herbicides
are effective but contamination of the stream
must be avoided. Many sites support little
vegetation and seeding can be accomplished
without weed control.
5. Noxious weeds and highly competitive
rhizomatous plants often invade and occupy
riparian zones and interfere with the
establishment of more desirable plants. Some
of the most serious weeds invade along
streambanks and can spread quickly, infesting
large areas. The weedy plants must be removed
prior to seeding or transplanting without
causing further destruction to the streambank.
Consequently, control by plowing or disking is
not always feasible. Many sites support a
desirable understory of herbs, yet may lack a
suitable overstory of shrubs and trees. To
establish woody plants, competition from the
herbs must be reduced.
Seeding
Areas not subjected to flooding should be fall
planted. Spring plantings are acceptable in
regions where spring or summer precipitation
could start germination and sustain new plants.
Where flooding occurs, planting should be done
as soon as possible after the water recedes.
Where possible, drill seeding or planting using
a cultipacker is recommended. Broadcast
seeding is acceptable if the planted areas can
then be harrowed or the seeds covered using a
drag or similar equipment. Seedbeds dry
quickly even in riparian communities. Although
the water table may occur close to the soil
surface, the moisture is not usually available
to newly germinated seedlings. Losses of the
young plants may often occur as the surface
dries.
6. Exclusion of grazing animals from the
treated areas is often difficult. Animals
naturally conc~ntrate along the riparian zone
and can seriously damage new plantings.
Without satisfactory control of livestock, new
seedlings and immature plants could be
vulnerable to grazing for a number of years.
7. Planting is often delayed past the optimum
season by flooding and high runoff. Appropriate
planting seasons cannot always be selected
because of fluctuating water levels. Certain
sites cannot be fall seeded because high runoff
and flooding in the spring washes away or
inundates seeds and new seedlings. If seeding
or transplanting is delayed until summer when
flooding has receded, the work must be completed quickly before the soils dry. Usually
the planting sites vary in regard to flooding
and availability of soil moisture. Some sites
become dry and ready for planting while adjacent areas remain under water.
Transplanting
Site Stability
Transplanting is the most practical means of
establishing shrubs and trees. Although most
riparian sites receive supplemental ground
water, not all areas remain wet enough to
assure the establishment of newly transplanted
stock. Establishment of the transplant is the
most critical hurdle to overcome in revegetation. Once plants become established, the
roots are usually able to grow into the wet
soil and growth is accelerated.
Stability of the streambank and the seedbed
must be considered as riparian sites are
prepared for planting. New seedlings cannot
become established amid a competitive stand of
weeds or perennial plants. Thus, sites are
often plowed, disked, or otherwise treated to
Planting unrooted cuttings is often attempted.
Success is variable, depending upon the
condition of the cutting and the planting site.
Rooted cuttings and nursery or container grown
stock are recommended. Cuttings can be rooted
in a nursery bed or under greenhouse conditions.
METHODS OF TREATMENT
84
Willow (Salix) or poplar (Populus) cuttings are
better able to establish if planted as rooted
stock. When planted, .all stock should be
dormant and in good condition.
Most species can also be grown as container
stock, but production and field planting costs
are increased. Species that are easily
propagated by stem or root cuttings can be
grown with little cost. When only a few plants
are required, cuttings are a quick and
satisfactory means of propagation. Small
seedlings or young plants can often be dug from
the area and used in restoration projects.
Regardless of the stock used, all materials
should be healthy and in good condition for
planting. Failure to use suitable stock cannot
be justified.
Transplant stock should not be planted directly
into established stands of understory competition. Weedy vegetation should be removed by
scalping or herbicide application. Using a
hand sprayer to treat a spot about 30 inches
(76 em) in diameter with a herbicide is
sufficient to eliminate competition and
facilitate transplanting. Adding an
agricultural dye to the herbicide solution
marks the spray area and aids in relocating the
planting spots. "Roundup" has been
successfully used to control grasses, sedges,
and broadleaf herbs. The herbicide must be
sprayed on actively growing vegetation. The
transplant should not be planted in the sprayed
area until the solution has dried.
Plummer and others (1968) report the success of
certain species for inland saltgrass sites.
McGinnis and others (1963) and Eckert (1975)
describe plants for wet meadow situations.
Many plants that normally are easy to propagate
such as willow (Salix), Dogwood (Cornus), and
cottonwood (Popu~may not survive when
planted on disturbed areas. Even when adapted
species are used, considerable care is required
to assure planting success.
Most transplanting failures result from
improper handling of stock and planting
practices. Container stock should be hardened
before field planting. Plantings that are
delayed until late in the spring are not only
subjected to drying soil conditions, but
desiccation from high temperatures.
PUBLICATIONS CITED
Behnke, R. J. Fish faunal changes associated
with land-use and water development. Great
Plains-Rocky Mountain Geol. J. 6(2): 133-136;
1977.
Site Improvement by Management
Many riparian sites support a remnant of woody
and herbaceous plants. Although the plants may
be heavily browsed and weak, recovery can occur
if grazing is controlled. Reestablishment of
beaver and moderation of streamflow also benefit plant rec~very (Smith 1980). Not all sites
are capable of recovering in an acceptable
period even when protected; therefore, planting
may be required.
Boussu, M. F. Relationship between trout
populations and cover on a small stream. J.
Wildl. Manage. 18: 227-239; 1954.
Carlson, J. R. Purpleosier willow for stream
bank erosion control. Am. Nurseryman. 144(2):
12, 73; 1976.
Eckert, R. E., Jr. Improvement of mountain
meadows in Nevada. Reno, NV: U.S. Department
of the Interior, Bureau of Land Management;
1975 June. 45 p. Research report, filing code
4400.
Recommended Species
Plants recommended for riparian communities
normally consist of the native species
prevalent in the area. Many woody species that
are encountered in the riparian zones can be
propagated by stem or root cuttings. If not,
seeds can be collected and plants can be grown
in containers or as bareroot nursery stock.
Species recommended for planting riparian zones
in the major plant communities of the Intermountain region are listed in tables 1 and 2.
Edminister, F. C. Streambank plantings for
erosion control in the Northwest. U.S.
Department of Agriculture, Soil Conservation
Service; 1919. 8 p.
Fowler, D. K.; Hammer, D. A. Techniques for
establishing vegetation on reservoir
inundation zones. Soil Water Conserv. 31(3):
116-118; 1976.
Most planting stock should be of sufficient
size to survive the harsh conditions that often
occur. Usually large size plants, 2-0 nursery
stock or 18 to 20 inch (45 to 50 em) containergrown plants survive better than smaller stock.
Plants should have a satisfactory root system
to be able to grow quickly and become fully
established. Most transplant stock can be
nursery grown within one or two seasons, as
shown in table 3.
Johnson, R.; Haight, L. T.; Simpson, J. M.
Endangered species vs. endangered habitat: a
concept. In: Johnson, R. R.; Jones, D. A.,
tech. coord. Importance, preservation, and
management of riparian habitat; Symposium.
Tech. Rep. RM-43. Fort Collins, CO: U.S.
Department of Agriculture, Forest Service,
Rocky Mountain Forest and Range Experiment
Station; 1977: 68-79.
85
McGinnies, W. J.; Hervey, D. F.; Downs, J. A.;
Emerson, A. C. A summary of range grass seeding
trials in Colorado. Tech. Bull. 73. Fort
Collins, CO: ColoradD State University
Agricultural Experiment Station; 1963. 81 p.
Meehan, W. R.; Platts, W. S. Livestock grazing
and aquatic environment. J. Soil Water Conserv.
33(6): 274-278; 1978.
Platts~
W. S. Sheep and cattle grazing
strategies on riparian-stream environments.
In: Proceedings of the wildlife-livestock
relationship symposium; 1981 April 20-22;
Coeur d'Alene, ID. Moscow, ID: University of
Idaho, Forest, Wildlife and Range Experiment
Station; 1981: 251-270.
Plummer, A. P.; Christensen, D. R.; Monsen,
S. B. Restoring big game range in Utah.
Publ. 68-3. Salt Lake City, UT: Utah Division
of Fish and Game; 1968. 183 p.
Smith, B. H. Not all beaver are bad; or, an
ecosystem approach to stream habitat management, with possible software applications.
In: Whaley, Roy, ed. Proceedings, 15th annual
meeting, American Fisheries Society, ColoradoWyoming Chapter; 1980 February 27-28; Fort
Collins, CO. American Fisheries Society. 1980:
32-37.
86
Table 1.--Grasses and broadleaf herbs recommended for riparian plantings within major plant communities
_SEecies
Wet
meadow
Forest
ty}2es
Areas of adaEtation
Mountain
brush
Sagebrush and
desert shrubs
Saltgrass
X
X
Grasses
Barley, meadow
Bluegrass, Kentucky
Bluegrass, Sandberg
Brame, meadow
Brame, mountain
Brame, smooth
Canarygrass, reed
Fescue, tall
Foxtail, meadow
Hairgrass, tufted
Orchardgrass
Redtop
Reedgrass, chee
Ryegrass, perennial
Sacaton, alkali
Squirreltail,
bottlebrush
Timothy
Wheatgrass, bluest em
Wheatgrass, slender
Wheatgrass, streambank
Wheatgrass, tall
Wildrye, creeping
Wildrye, Great Basin
Wildrye, mammoth
Wildrye, Russian
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Forbs
Alfalfa, creeping type
Aster, alpine leafybract
Aster, Pacific
Bassia, fivehook
Clover, alsike
Clover, strawberry
Cowparsnip, common
Crownvetch
Medick, black
Milkvetch, chickpea
Valerian, edible
Yarrow
Sagebrush, Louisiana
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
87
X
Table 2.--Trees and shrubs recommended for planting riparian sites within major plant communities
Species
Alder, thinleaf
Aspen, quaking
Birch, western river
Buckthorn
Buffaloberry, russet
Buffaloberry, silver
Ceanothus, redstem
Chokecherry, black
Cinquefoil, bush
Currant
Dogwood, redosier
Elaeagnus, autumn
Elder, blueberry
Elder, redberry
Greasewood, black
Hawthorn
Honeysuckle, Tatarian
Honeysuckle, Utah
Maple, bigtooth
Mountain-ash, Greenes
Ninebark, mallow
Pachistima, myrtle
Peachbrush, desert
Pine, lodgepole
Plum, American
Poplar, black
Poplar, narrowleaf
Raspberry
Rose, Woods
Russian-olive
Sagebrush, silver
Saltbush, Gardner
Snowberry, mourttain
Snowberry, western
Willow, purpleosier
Willow, Scouler
Wet
meadow
Areas of adaptation
Mountain
brush
Forest
types
X
X
X
X
X
X
X
X
X
X
X
X
Sagebrush and
desert shrubs
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Saltgrass
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
88
X
X
X
X
X
Table 3.--Size and type of planting stock recommended for field transplanting
Transplant material
Species
Alder, thinleaf
Aspen, quaking
Birch, Western river
Buckthorn
Buffaloberry, russet
Buffaloberry, silver
Chokecherry, black
Cinquefoil, bush
Currant
Dogwood, redosier
Elaeagnus, autumn
Elder, blueberry
Elder, redberry
Greasewood, black
Hawthorn
Honeysuckle, tatarian
Honeysuckle, Utah
Maple, bigtooth
Mountain-ash, Greenes
Ninebark
Pachistima, myrtle
Peachbrush, desert
Pine, lodgepole
Plum, American
Poplar, black
Poplar, narrowleaf
Raspberry
Rose, Woods
Russian-olive
Sagebrush, silver
Saltbush, Gardner
Snowberry, mountain
Snowberry, western
Willow, purpleosier
Willow, Scouler
Nursery
stock
1-0
2-0
1-0
1-0
1-0
2-0
2-0
1-0
2-0
1-0
2-0
1-0
1-0
2-0
1-0
1-0
1-0
2-0
2-0
2-0
2-0
2-0
2-0
1-0
1-0
1-0
1-0
1-0
1-0
2-0
1-0
1-0
Containers
Cuttings
Wildings
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
stem/roots
roots
stem
roots
roots
stem/roots
roots
stem/roots
stem/roots
stem/roots
roots
roots
stem/roots
stem
stem
stem
X
X
X
X
roots
stem/roots
roots
X
X
X
X
X
X
X
stem/roots
stem
stem
stem/roots
stem/roots
stem/roots
X
X
X
X
X
stem/roots
stem/roots
stem/roots
stem
stem
X
X
X