***Tamarix ramosissima; Tamarix chinensis***

**Salt cedar; tamarisk**

The following description of *Tamarix* *ramosissima* is adapted from
Munz and Keck (1973). *Tamarix* *ramosissima* is a deciduous member of
the Tamarisk Family (Tamaricaceae). It is a glabrous, loosely branched
shrub or small tree 1-3 m tall. The branchlets are slender with minute
appressed scaly leaves. The leaves are rhombic to ovate, sharply pointed
to gradually tapering, and 0.5-3.5 mm long. They are sometimes
auriculate but not vaginate or amplexicaul. The margins of the leaves
are thin, dry and membranaceous.

The white or pinkish flowers are borne on slender racemes (2-5 cm long)
on the current year\'s branches and are grouped together in terminal
panicles. The pedicels are short. The deciduous petals are obovate and
1.5-2 mm long. The bract is ovate. The 5 stamens have the filaments
(1.5-2.5 mm long) attached between the lobes of the disc and the anthers
blunt to mucronate. The flowers are most abundant in the Northern
Hemisphere from April to August but may be found most of the year.
Petals are usually retained on the fruits.

The seeds, borne in a lanceovoid capsule 3-4 mm long, are approximately
0.45 mm in length and 0.17 mm in diameter and have unicellular hairs
about 2 mm long at the apical end. The seeds have no endosperm and weigh
about 0.00001 gram (Wilgus and Hamilton 1962).

There are seven species of *Tamarix* listed as occurring in California
(Munz and Keck 1973). The characteristics which distinguish this species
from other deciduous species in its genus are its obovate petals, which
widen distally, and ovate to subobtuse bracts. Also, it is found in more
saline habitats than other *Tamarix* species.

The name *Tamarix* *pentandra* has apparently also been used for *T.
ramosissima* (Munz and Keck 1973), but T. *pentandra* may actually be a
synonym of *T. chinensis* (Kartesz and Kartesz 1980). None of the
members of this family are native to California and are distinctive in
having juniper-like leaves, white or pink flowers, and ovoid seed
capsules.

Another species that presents a problem in southwest deserts is *T.
chinensis*. *T. ramosissima* and *T. chinensis* are often confused with
each other. Each has leaves that are sometimes auriculate but not
vaginate or amplexicaul and staminate flowers with filaments that are
inserted below the disc. The basic difference in flower morphology is
that, while *T. ramosissima* has obovate flower petals which widen
distally, *T. chinensis* has oblong-ovate flower petals that are
narrowed distally.

Habitat preference also distinguishes the two species. *T. ramosissima*
is found invading areas of higher salinity than *T. chinensis*. *T.
ramosissima* is more common in standing water such as marshes, oases and
lakes or salty river banks and salty steppes. *T. chinensis*, however,
establishes most readily along major river drainages.

T. *aphylla* is also an escaped exotic in the Southwest. It is most
commonly found among stands of *T. ramosissima* along riverbanks. It is
an evergreen tree that flowers during the winter months. Its leaves are
vaginate, but its bracts are not. It does not reproduce by seed in
California and therefore is not as widespread as *T. ramosissima*. It
propagates from root and branch stock (Neill 1985).

*Tamarix* *ramosissima* is native from southeastern Europe to central
Asia. It was introduced into the eastern U.S. in the 1820s. By the early
1900s, tamarisk had escaped cultivation and had become widespread
throughout the southwestern U.S. along riparian areas and springs.

> \"On the California desert, tamarisk is well established along parts
> of the Colorado and Mojave rivers and at places around and near the
> Salton Sea \... At many smaller, isolated water sources that are
> scattered about the desert, the infestation is either fairly recent or
> is restricted in size by limited water supply or inhospitable
>
> growing conditions\" (Neill 1983 .

The list of desert water sources in California that have been invaded
include Amargosa Canyon, Big Morongo Canyon, Com Spring, Darwin Falls,
Piute Creek, Saline Valley, and San Sebastian Marsh (Neill 1983).

*Tamarix* is widely cultivated as an ornamental. In many places these
plants have also been used for windbreaks and erosion control.
Beekeepers regard it highly in the production of honey. In some areas
*Tamarix* thickets are valued nesting habitat for white-winged doves.

Tamarisk prefers the moist sand along river margins. It grows rapidly on
river floodplains in arid and semi-arid climates. In the southwestern
United States, it initially naturalized along most major river drainages
at lower elevations (Schopmeyer 1974). Now, however, its habitat
includes pastures, irrigation ditches, moist lowlands and streambanks.
It occupies the niche usually associated with willow and cottonwood.

The plants usually grow where the depth to the water table does not
exceed 25 feet, and normally where it is less than 15 feet. Tamarisk has
a wide range of tolerance to saline or alkaline soil and water. It has
been found growing in Death Valley, CA, where the groundwater contains
as much as 5 percent (50,000 ppm) dissolved solids. However, it grows
best where the groundwater is little to moderately mineralized (Robinson
1965).

A tamarisk plant may produce many thousand seeds in a single season
(Wilgus and Hamilton 1962). These seeds are dispersed by the wind. The
pappus hairs on the apex of the seed form a column when moistened.

> \"In 5-8 hours after moistening the embryo has usually swollen enough
> to break the seed coat, the hypocotyl has turned downward and a corona
> of root hairs has developed around the radicle to anchor the seedling.
> As the stem straightens the cotyledons separate\" (Horton et al.
> 1960).

Horton et al. (1960) did extensive research on seed germination and
seedling establishment of phreatophyte species for the United States
Forest Service (USFS). The results of their work are as follows:

> \"Tamarisk produces seed abundantly over a long period (April to
> October). Seeds remain viable for only a few weeks, especially at high
> temperatures characteristic of Arizona deserts. Fresh seed germinates
> rapidly, generally in less than 24 hours. Germination is dependent
> upon saturated soils. Receding spring and summer flows are ideal for
> germination and seedling establishment. Seedlings grow slowly and are
> sensitive to drying. In fact, survival is dependent upon saturated
> soils during the first 2-4 weeks of growth. Seedlings can be submerged
> several weeks or more, but when small they will be detached from the
> soil and float away
>
> if there is any appreciable current.\"

Light was found to have no effect on their germination.

> \"Early growth is very slow. Top height averages about 2.5 cm at
> thirty days after emergence and seedlings average only 11 cm tall
> after sixty days. At this time roots are about 15 cm long. After
> seedlings become established they can withstand severe drought. When
> mature, roots occupy the capillary zone above the water table with
> some roots in the zone of saturation (Schopmeyer 1974).
>
> \"Seedlings mature rapidly and produce small, pink flowers often by
> the end of the first year. Under optimum conditions, a desert riparian
> area containing only a few tamarisk trees can be converted to an
> impenetrable thicket in less than a decade\" (Neill 1983). Tamarisk
> grows so rapidly, up to one foot per month, and so densely, that
> native trees are crowded and shaded from direct sunlight and cannot
> thrive (Neill 1983).
>
> \"Historically, the area and the density of plant growth have
> increased wherever the species has become established. This effect may
> be expected to continue wherever area and density of growth have not
> reached their optimum and wherever new areas become established
> (Robinson 1965).\"

Vegetative surveys of the Bernardo Bridge-San Marcial Reach in the Rio
Grande Valley (Texas) were made by the Bureau of Reclamation in 1947 and
again in 1955. As part of these two surveys determinations were made, by
species, of the cover density and of the height component of the
foliage. \"In the 1947 survey, cover densities ranged from 1 to 81
percent and averaged 19.1 percent, while in the 1955 survey, cover
densities ranged from 2 to 100 percent and averaged 39.3 percent, an
increase of more than 100 percent. At the same time the increase of the
volume of foliage was over 75 percent\" (Robinson 1965).

Horton (1957) made detailed observations of the life history of
*Tamarix* *ramosissima* along the Salt River, east of Tempe, Arizona. He
found that the earliest flowers appeared as lateral racemes on old wood
of the previous year.

> \"Several weeks later the same shrubs began producing terminal
> panicles on shoots developed since the beginning of the growing
> season. These shoots often formed on the same branches that produced
> the spring racemes. A still further stage of flowering occurred as the
> central stem of the panicle often elongated to develop a secondary
> panicle after the first one had produced seed.\"
>
> \"Tamarisk stem tissue (including root crown material) will sprout
> vigorously and form new plants if buried or partially buried in warm
> moist soil. In the active growing season nearly all undried stem
> cuttings of all sizes and from any location in the crown of the
> original shrub produced roots and formed new plants under
>
> greenhouse conditions." (Gary and Horton 1965).

Sprouts, however, do not form from severed root tips (Horton 1960).

> \"Sprouting was delayed during the winter period. In some instances,
> cuttings planted during the late fall and winter months did not sprout
> for 3 or 4 months. (The drying of cuttings reduced sprouting
> ability.)\" (Gary and Horton 1965).

*Tamarix* is commonly known as salt cedar because the minute and
scale-like leaves are often coated with a salty white bloom.

> \"During periods of high humidity, twigs often become laden with
> droplets of salty fluid. These drops are a result of deliquescence of
> previously secreted salty bloom rather than from current guttation.
> The salt is secreted by salt glands imbedded in epidermal pits. The
> glands are dome shaped and consist of at least two cells which are
> non-vacuolate and densely filled with granular material\" (Decker
> 1961).
>
> \"It appears that active salt glands are highly turgid and force salt
> solutions out of their pores under pressure. The glands are primarily
> desalting organs capable of reducing the salt in the mesophyll cells
> of the leaves\" (Campbell and Strong 1964).

In one experiment, concentrations of all soluble salts averaged 5200 ppm
in the upper 20 cm of soil supporting salt cedar. The range of salt
concentration was 700-15,000 ppm which is relatively high (low to medium
concentrations of soluble salts in soil average in the range of 100-3500
ppm).

> \"Tamarisk is a virulent pest in desert riparian areas because it
> aggressively displaces native trees and shrubs, it withdraws and
> transpires water from the ground at a high rate, and it is a poor
> source of food and shelter for desert wildlife\" (Neill 1985).
>
> \"Invasion of a floodplain by *Tamarix* usually leads to depletion of
> streamflow, an increase in the area inundated by floods, and an
> increase in sediment deposition. Salt cedar clogs channels by invading
> stream banks and sand bars close to the stream. During a flood, the
> restriction and increased channel roughness cause inundation of areas
> that normally are not flooded. The damming and ponding effect of dense
> salt cedar reduces stream velocity and, consequently, its power to
> carry sediment. Sedimentation is thus accelerated\" (Blackburn et al.
> 1982). On the Brazos River in Texas, for example, some sections have
> been reduced in width by 71% between 1941 and 1979. Sediment deposits
> (caused by tamarisk invasion) ranged from 1.2 to 5.5 m deep, average
> sediment depth was 3.0 m (Blackburn et al. 1982).
>
> \"Continued and widespread expansion of tamarisk in stream systems not
> only increases river sedimentation and causes higher peak flows but
> consumes large quantities of water. It is estimated that about 2 acre
> feet of water per acre of phreatophytic vegetation could be saved
> annually by removing riparian vegetation from floodplains in the
> southwest U.S.\" (Blackburn et al. 1982). This is because *Tamarix*
> has an extremely high rate of evapotranspiration. \"Evapotranspiration
> rates of salt cedar are among the highest of any phreatophyte
> evaluated in southwestern North America. Denser stands of salt cedar
> occur where water tables are close to the surface. Annual water losses
> may total as much as 2.1 cubic meters/square meter\" (Carmen and
> Brotherson 1982).

Tamarisk is a successful competitor with native riparian species, often
replacing willow and cottonwood (Neill 1985).

> \"It often forms extensive and nearly impenetrable stands along banks
> and flood plains of streams\" (Decker 1961). In 1960 in a quantitative
> study of vegetation of Glen Canyon in Colorado, a team from the
> University of Utah wrote: \"There are many areas of heavy cover of
> willow in which the tamarisk has not so far established a foothold,
> but there are many other areas in which the willow cover has been
> broken and the tamarisk has occupied sites that are normal habitat of
> the willow\" (Horton et al. 1960).
>
> \"Where the two grow together, the willows usually occupy the muddier
> parts, and the tamarisk the sandy areas \... Tamarisk seedlings are
> sometimes abundant on wet sand, but willow seedlings are not with
> them. There is no evidence to indicate that willows will displace
> *Tamarix* on sandy soil. It is probable that
>
> competition between the two will tend to restrict the willows more and
> more to the muddy parts and yield sandy areas to *Tamarix*, although
> without competition either one alone might spread more widely into
> both types of soil\" (Christensen 1962).

One example of how quickly tamarisk can establish itself as a dominant
riparian species can be seen from records kept on the vegetation of the
delta area of Lake McMillan on the Pecos River in New Mexico.

> \"There are no records or reports of salt cedar in this area prior to
> 1912. By 1915 the plants had spread over an area of about 600 acres of
> delta land. In the next 10 years the plants continued to spread over
> the delta area until by 1925 they covered 12,300 acres\" (Robinson
> 1965).
>
> \"The same rapidity of infestation was observed in central Utah and
> the Rio Grande and Pecos river valleys of New Mexico and Texas. By
> 1961, according to the only comprehensive inventory yet published,
> tamarisk occupied an estimated 1400 square miles of flood plain land
> in the western United States (Neill 1983).

Along with crowding out the native riparian flora and increasing the
salinity of the soil, *Tamarix* is also a threat to forage production
for cattle. Between 1920 and 1960 it was estimated that tamarisk acreage
increased in extent from 10,000 to 90,000 acres (Robinson 1965).

Anderson and Ohmart (1976) found that fewer species of birds nest in
*Tamarix* than in native riparian vegetation. The average number of bird
species found in the tamarisk community from December 1975 to November
1976 was 21. The number of bird species in the cottonwood-willow
community averaged 36 during the same time period.

In summary, tamarisk has a major effect on stream sedimentation, bed
roughness, water consumption, and native species richness of both plants
and animals.

Case History:

> \"One tamarisk removal project has been completed, with dramatic
> success, at Eagle Borax Spring in Death Valley National Monument.
> Deciduous tamarisk probably was present at this large marsh on the
> west side of the valley floor in the 1940s or before, but due to
> grazing by horses it did not proliferate until the mid 1950s. It then
> spread and grew rapidly during the next decade. By the late 1960s the
> surface water in the marsh had disappeared, the native grasses and
> reeds were being replaced by tamarisk, and mesquite trees adjacent to
> the marsh were slowly losing vigor owing to the competition for ground
> water.
>
> \"After burning the tamarisk cover in 1972 to restore the water level
> in the marsh, the Park Service began permanent removal by cutting with
> chain saws and applying systemic herbicide to the stumps. The program
> was continued intermittently by Park Service employees over the next
> 10 years and then was completed in 1982 with volunteer assistance.
> With the tamarisk gone, the recovery of the marsh has been rapid and
> impressive. The surface water has returned. Use by migratory birds has
> returned to former levels. The grass and reeds are flourishing, and
> the grove of mesquite trees is again healthy\" (Neill 1983).

Biological monitoring is needed to determine the effectiveness of
management practices.

Detailed observations focused on the vegetational changes of the
affected area over time will help to determine what method of control
would be the most efficient.

Biological monitoring of *Tamarix* *ramosissima* was begun at Anza
Borrego State Park in the spring of 1985. In Coyote Canyon three
different plots encompassing 10 square meters will be delineated. The
three treatments will be: (1) no *Tamarix*, (2) all *Tamarix*, and (3) a
mixed stand of *Tamarix* and natives. The rate of tamarisk infestation
will be determined from the plot initially devoid of *Tamarix*. The
pioneering characteristics of natives in the area will be assessed from
the plot with initially 100 percent cover of *Tamarix*, after the stand
has been cut and treated with a systemic herbicide. The changes in the
percent cover of natives and their composition will be calculated from
the plot initially mixed with *Tamarix* and natives, after the *Tamarix*
is selectively removed from the area.

While treating *Tamarix* stands in June and July 1985, M. Jorgenson,
State Park Naturalist at Anza Borrego State Park, began another
monitoring program to determine the death rate and effectiveness of
current control procedures. Monitoring will consist of counting the
trees in a site as they are cut and treated with Garlon 34 (a systemic
herbicide which breaks down in three days), tagging the perimeter of a
stand of 100 stumps, and visiting every six months to count regenerating
individuals.

The following are specific areas of research that need study to improve
control efforts:

1\. Basic research on morphological and physiological features of the
plant as they relate to burning and spraying.

2\. An evaluation of early-midsummer burning and spraying as means of
controlling tamarisk to determine when the plant is most susceptible.

3\. Evaluation of potential for biological control of tamarisk.

4\. Would revegetation enhance eradication efforts of *T. ramosissima*
in California?

This weed does require active management. Researched methods of control
are listed below.

Tamarisk is probably the most suitable of \"ecological weeds\" for
investigation of biocontrol. It belongs to a family not native to North
America and has only marginal economic use. Its costs, in terms of
floodplain management and water consumption, are high, and as will be
discussed below, biocontrol agents may be available. However, the U.S.
Department of Agriculture must be lobbied to undertake the long and
expensive task to developing a biocontrol strategy. Since tamarisk is
not an agricultural pest, THE USDA

must be specifically encouraged to commit resources.

In an unpublished annual report on biocontrol of *Tamarix* 1969- 1970,
researchers reported that

> \"the most significant contribution of this research is the
> demonstration of a significant reduction in *Tamarix* growth by a
> natural field population of the host specific leafhopper, OPSIUS
> STACTAGALLUS. This constitutes the first positive evidence of a
> building block toward an eventual biological control of salt cedar.
> This evidence, combined with the report of several host specific
> insects on *Tamarix* in Morocco, offers encouragement to the idea that
> a combination of several biological agents may be brought into focus
> to reduce the salt cedar population below the economic level. Because
> the Tamaricaceae is a small family and the genus *Tamarix* is unique
> in many physiological characteristics and does not include species of
> great economic importance to man, it is possible to choose the best
> combination of biological control agents from the range available and
> to achieve desired degree of control ranging from slight suppression
> to stand destruction.\"

The following is a list of some insect species that feed upon tamarisk
with an evaluation of their damaging potential (Gerling and Rugler
1976):

> \(1\) Destroys fruiting bodies: *Corimalia* spp. (Coleoptera:
> Cureulionidae); *Crastina linnruouri* (Homoptera: Psyllidae).
>
> \(2\) Causes moderate and long-range damage: *Tuponia* spp.
> (Heteroptera: Mirdidae); *Opsuis* spp. *Tamaricella* spp. (Homoptera:
> (Cicadellidae); *Ornativalva* spp. (Lepidoptera: Gelechiidae);
> *Agelistis* spp.; *Lepidognea tamaricalis* (Lepidoptera: Dryalidae).
>
> \(3\) Highly damaging insects: Psiloptera spp.; *Steraspis squamosa*
> (Coleoptera: Buprestidae); *Cryptocephalus* spp.; *Coniatus* spp.;
> (Coleoptera: Curulionidae); *Opsuis* spp. (Homoptera: Pseudococcidae);
> *Semiothisa aestimaria* (Lepidoptera: Geometridae).

Campbell (1966) in a paper written for the USFS-United States Department
of Agriculture (USDA) entitled \"Periodic mowings suppress tamarisk
growth increase forage for browsing\" found:

> \"In many areas of the Southwest, complete eradication of tamarisk is
> probably not economically feasible. Initial treatment with herbicides
> or mechanical clearing is costly and retreatment is always necessary.
> Estimates of benefits in water savings following such treatments on a
> reach or reservoir delta are not always reliable. Tamarisk, however,
> can be suppressed on flood- plains and reservoir deltas by periodic
> mowing. In central Arizona, mowings in May, July and September are
> necessary to keep foliage succulent and within reach of browsing
> cattle. It is estimated that Bermuda grass and tamarisk resprouts
> would produce hundreds of pounds of available forage per acre per year
> on what would otherwise be relatively low-yield sites.
>
> \"Tamarisk was killed by frequent foliage removal, although mortality
> rates varied between treatment years. Mortality increased when
> tamarisk plants were completely defoliated at frequent intervals.
> Plants were not killed by one season of mowing. Evapotranspiration was
> decreased by approximately 50% following mowing treatments. Total
> hydrolyzable carbohydrate root contents decreased with severity of
> treatments,\" an important factor when considering herbicide
> application.

Horton (1960) researched the feasibility of using a root plow to clear
tamarisk stands. His contention was that if shrubs are cut below the
surface of the ground when the soil is dry, the stems and branches die
before new plants develop from sprouting. This method appeared to be
effective, although costly.

> \"Some management recommendations to prevent reestablishment of
> tamarisk by sprouting of several stem portions are: (1) control
> operations should be done during the growing period when the soil is
> dry and weather warm; and (2) stems should be left on the surface of
> the ground and never buried in moist soil\" (Gary and Horton 1965).

Uprooting tamarisk stands with a backhoe or tractor and chain has been
successful at Chuckwalla Well and Darwin Dry Lake in California. This
mechanical means of removal is suitable in marshy areas where the
tamarisk will have shallow roots and chemical means of treatment are
prohibited. This task is best undertaken during April and May when the
plants are flowering and therefore more visible.

Horton et al. (1960) mention that

> \"construction of levees to reduce the area flooded during highflows,
> and regulation of releases from reservoirs to avoid slowly decreasing
> flow during the seed production season, may also prevent tamarisk
> invasion of many areas.\"

In heavily infested areas, control practices will have to extend beyond
the initial treatment. Seedlings may continue to sprout for years to
come. In combination with the other means of control, removal of
saplings by hand is suggested. Until the stem diameter exceeds 3 cm,
tamarisk can be pulled up with relative ease while the soil is moist.

***Tamarix chinensis***

Although *T. chinensis* and *T. ramosissima* occupy two different
niches, there has been work done on wildlife enhancement in areas
occupied by *T. chinensis* (Anderson and Ohmart 1982) that is worthy of
consideration in developing *T. ramosissima* management plans. The site
chosen for study was located on the Cibola National Wildlife Refuge, 40
km south of Blythe, California. The area covered 20 ha and supported a
mean of 345 trees per ha. When the study began (1973) the site was
vegetated with *T*. *chinensis* and a few widely scattered clumps of
willow trees.

The area was initially cleared of *T. chinensis* with bulldozers which
pushed the debris into piles. The clearing was done selectively so that
the willow stands were left intact. The slash was then burned and the
area root-ripped approximately 30 cm below the soil surface. It was
subsequently leveled. This activity took place in the spring of 1978.

> \"Immediately after this treatment in March 1979, there was no sign of
> any living salt cedar trees. By October 1979, there were 59 salt cedar
> trees per ha, these having regenerated from rootstock which had not
> been killed. These trees were chopped off below ground level the
> following winter. At the same time the area as seeded with *Atriplex
> lentiformis* (quailbush). This shrub was planted with the intent of
> enhancing wildlife and to provide competition for any *Tamarix* which
> might redevelop. *A. lentiformis* germinates in the winter when
> *Tamarix* is dormant. Treatment in this manner for two consecutive
> winters resulted in an additional 9 percent reduction in the number of
> *Tamarix* per ha (see Table 1 below).

TABLE 1: Number of salt cedar trees before clearing and percent
reduction in salt cedar at various times after clearing and root-ripping
on an experimental plot along the lower Colorado River (from Anderson
and Ohmart 1982).

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

\# *T. chinensis* Percent

trees/hectare reduction

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Before clearing

March 1978 345 0.0

After clearing

July 1970 0 100.0

October 1979 59 82.9

October 1980 45 87.0

December 1981 29 91.6

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

In the southwest deserts, root ripping and augering (tillage) are
essential in site preparation for revegetation following tamarisk
removal (Anderson and Ohmart 1982). A drip irrigation system was also
found to be directly correlated with the successful re-establishment of
native riparian species. The cost of this project came to a total of
\$189,634 or \$99 per tree, rendering the economics of this method
somewhat prohibitive.

This Element Stewardship Abstract would not be complete as a literature
and research review without including information on chemical means of
*Tamarix* control. However, due to their potentially far-reaching
harmful effects on biological systems, chemical procedures should be
used only as a last resort, and only after other appropriate methods
have been attempted with negative results.

Howard et al. (1983) made the following conclusions from a research
project designed to evaluate the effects of fire and 2,4-D as control
methods:

> "1. Fire in late July effectively combatted salt cedar the initial
> year following the burn. Burning in September and October did not
> control saltcedar.
>
> 2\. Spraying one month after the July burn increased mortality from
> 64% to 99%.
>
> 3\. Spraying after the September or October fire was ineffective."
>
> \"Triclopyr ester (\[(3,5,6-trichloro-2-pyridinyl)oxyl\] acetic acid)
> shows promise as a basal and stump application. \"Triclopyr amine was
> ineffective in controlling salt cedar for all three application
> techniques, especially the basal bark application. This probably
> indicates poor penetration and/or translocation of this formulation of
> triclopyr.
>
> \"The basal bark application requires the most spray solution (95
> ul/stump) when compared to the cut stump and modified cut stump
> applications (38 and 86 ul/stump, respectively). The most expensive
> application, however, is the cut stump due to the high concentration
> of triclopyr included in the spray solution.\"

Another combination method of control is mowing and spraying. In 1963
and 1964 a study was conducted near Bernardo, New Mexico, comparing
single and combination mowing and spraying with the propylene glycol
butyl ether (PGBE) ester of 2-(2,4,5 tricholorophenoxy) propionic acid
(Silvex), repeated spray applications of Silvex and single applications
of mixtures of Silvex and 4-amino-3,5,6 trichloropicolinic acid
(picloram) (Hughes 1966).

> \"None of the mow spray combinations initiated in 1963 reduced the
> stand of salt cedar more than 8%, and there were no significant
> differences between treatments. A follow-up spray treatment of 4
> pounds per acre of Silvex in 1964 increased the plant kill up to 60%.
> Spraying undisturbed salt cedar in June 1964 and respraying in August
> with 2 pounds per acre of Silvex reduced the salt cedar approximately
> 40% as did a single application of a mixture of 2 pounds per acre of
> Silvex and 2 pounds per acre of picloram in June\" (Hughes 1966).

Bill Neill, a tamarisk expert in California, explained that the most
effective means of tamarisk control is to cut the individuals at ground
level with chain saws, hatchets or hand saws and spray the stump
immediately with Tordon.

(Silvex has been banned by the EPA because it carries the caustic
element 2,4,5-T, also known as Agent Orange. Tordon is banned on federal
land due to a lawsuit in Oregon over aerial spraying. The active
ingredient in Tordon is 2,4-D.)

Experimentation on the effectiveness of chemical control of salt cedar
is extensive. In Arizona, basal and stump treatments with isopropyl
ester of 2,4-D at 0.25, 0.5 and 1.0 percent concentration in diesel oil
were monitored.

> \"Stump treatments at the two higher concentrations have given high
> percentages of kill, with no difference for the year of age of tree.
> Basal spray treatments were somewhat less effective.
>
> \"In Wyoming, dormant basal spray applications of a mixture of esters
> of 2,4-D and 2,4,5-T (50:50) to salt cedar trees in November or April
> reduced the stand 79% and 93% for a 2% and 8% concentration,
> respectively.
>
> \"Work in New Mexico by Whitworth indicated that the propylene glycol
> butyl ether (PGBE) ester of 2,4-D was effective as a basal spray at 20
> ml of herbicide per tree in 0.5 pint of diesel oil per tree.
> Subsequently higher kills were obtained from treatments with the
> butoxyethanol (BE) ester of 2-(2,4,5-trichlorophenoxy)
>
> propionic acid Silvex as compared to the same esters of 2,4-D and
> 2,4,5-T\" (Hughes 1965).

From 1961-1964 Hughes\' studies in New Mexico showed basal and stump
applications of ester and oil soluble amine formulations of
2-(2,4,5-trichlorophenoxy) propionic acid (Silvex) to be effective means
for controlling tamarisk.

> \"Trees with trunks 2 inches or larger in diameter were harder to kill
> than smaller trees and retreatment was often needed. Spraying the
> lower 2 feet was no more effective than spraying the lower foot.
> Cutting the larger trees and spraying the stump increased
> effectiveness\" (Hughes 1965).

In 1979, Hollingsworth et al. experimented with a modified root plow
that would place herbicides into the subsurface of the soil while
severing roots. It was found that

> \"one operation, preferably in the spring, which severed the tap root
> 35-60 cm below the soil surface and simultaneously applied any of
> several herbicides at the same depth increased salt cedar kill by more
> than 100% over that of root cutting alone. Residual herbicides,
> including uracils, substituted ureas, 2,3,6-TBA, picloram, dicamber,
> and karbutilate, applied with the root plow consistently controlled
> salt cedar with a single treatment. Phenoxy herbicides showed initial
> activity against salt cedar but did not persist long enough to
> satisfactorily kill late sprouting, previously quiescent buds."

Quimby et al. (1977) confirmed the effectiveness of root zone
applications of herbicides in a greenhouse evaluation. They found that
either soil layering or soil injection of herbicides resulted in a
higher mortality rate than stem or foliar applications.

Eradication efforts of *T. ramosissima* at Death Valley temporarily
lacks funding but will begin again in October of 1985. This management
program is funded for three years at \$9700/year. The plan is to cut the
tamarisk at ground level with loppers, chainsaws, and brushhooks and
treat the stumps with Tordon. This method will be employed with one
person sawing and another applying the herbicide to insure safety. They
will return to treated sites periodically to cut back resprouts and dig
up saplings (Mitchum 1985).

Mark Jorgensen, State Park Naturalist, has been administrating an active
management program for controlling *Tamarix* at Anza Borrego State Park.
In June 1985, hired seasonal help will cut *T. ramosissima* stands down
with loppers, chainsaws, and brushhooks. Immediately following cutting,
triclopyr will be applied in a 44.4 percent solution. Triclopyr 44.4
percent is sold by Dow Chemical under the trade name Garlon 3A. It is a
systemic herbicide and breaks down in three days. These procedures would
ideally be repeated three times during the summer, but lack of funding
will prohibit this follow-up work in 1985.

A variety of management methods for *T. ramosissima* have been
researched. Among mechanical methods, mowing can be successful,
especially if it is followed by the application of a systemic herbicide
to the freshly exposed cambium. The use of a root plow also appears to
be an effective, although costly, method. Fire as a form of control is
recommended in conjunction with herbicide application.

2,4-D (Tordon) and 2,4,5-T (Silvex) have been investigated as chemical
control agents and have been proven successful as a treatment applied to
freshly cut stumps. However, the use of Silvex or 2,4,5-T (the active
ingredient in Silvex) is completely banned by the EPA, and Tordon
(active ingredient 2,4-D) is prohibited on federal lands. Apparently,
health and safety are jeopardized by skin contact and/or inhalation of
these chemicals.

There is some progress in the field of biocontrol for *Tamarix*
population suppression by a host specific leafhopper, *Opsius
stactagallus*. More research is necessary to determine the feasibility
of large scale release of the agent.

**Cited References:**

Anderson, B.W. and R.D. Ohmart. 1976. A vegetation management study for
the enhancement of wildlife along the lower Colorado River, annual
report. In Fulfillment of Bureau of Reclamation Contract #7-07-30-V0D09.
Arizona State University, Tempe, AZ 85281.

Anderson, B.W. and R.D. Ohmart. 1982. Riparian revegetation for
mitigation and operational enhancement along the lower Colorado River.
Center for Environmental Studies, Arizona State University, Tempe, AZ.
Unpublished paper.

Blackburn, W., R.W. Knight, and J.L. Schuster. 1982. Saltcedar influence
of sedimentation in the Brazos River. Journal of Soil and Water
Conservation 37(5):298-301.

Campbell, C.J. 1966. Periodic mowings suppress tamarisk growth, increase
forage for browsing. U.S. Forest Service Research Note. RM 76. 4 pp.

Campbell, C.J. and J.E. Strong. 1964. Salt gland anatomy in *Tamarix*
*pentandra* (Tamaricaceae). Southwestern Naturalist 9(4):232-238.

Carmen, J.G. and J.D. Brotherson. 1982. Comparisons of sites infested
and not infested with salt cedar (*Tamarix* *pentandra*) and Russian
olive *Elaeagnus angustifolia*). Weed Science 30:360-364.

Christensen, E.M. 1962. The rate of naturalization of *Tamarix* in Utah.
The American Midland Naturalist 68(1):51-55.

Decker, J.P. 1961. Salt secretion by *Tamarix* *pentandra*. Forest
Science 7(3):214-217.

Gary, H.L. and J.S. Horton. 1965. Some sprouting characteristics of five
stamen tamarisk. U.S. Forest Service Research Note RM 39. 7 pp.

Gerling, D. and J. Rugler. 1976. Natural enemies and the prospects of
biological control of *Tamarix* sp. Proceedings of the IV International
Symposium on Biological Control of Weeds.

Hollingsworth, E.B., P.L. Quimby, Jr., and D.L. Jaramillo. 1979. Control
of salt cedar by subsurface placement of herbicides. Journal of Range
Management 32(4):288-291.

Horton, J.S. 1957. Inflorescence development in *Tamarix* *pentandra* in
Arizona. The Southwestern Naturalist 7(1):23-28.

Horton, J.S. 1960. Use of a root plow in clearing tamarisk stands. U.S.
Forest Service Research Note. RM 50. 5 pp.

Horton, J.S. , F.C. Mounts, and J.M. Kraft. 1960. Seedy germination and
seedling establishment of phreatophyte species. U.S. Forest Service
Research paper #48. Rocky Mtn. Forest and Range Experiment Station.

Howard, S.W., A.E. Dirar, J.O. Evans, and F.D. Prorenza. 1983. The use
of herbicides and/or fire to control salt cedar (*Tamarix*). Proceedings
of the Western Society of Weed Science 36:65-72.

Hughes, E.E. 1965. Basal and stump sprays for control of salt cedar.
Weeds 13:338-340.

Hughes, E.E. 1966. Single and combination mowing and spraying treatments
for control of salt cedar (*Tamarix* *pentandra* Pall.) Weeds
14(3):276-278.

Kartesz, J.T. and R. Kartesz. 1980. A synonymized checklist of the
vascular flora of the United States, Canada, and Greenland. Vol. II. The
biota of North America. Univ. of North Carolina Press, Chapel Hill. pp.
461.

Mitchum, B. 1985. Resource Ecologist, Death Valley National Monument.
Personal communication.

Munz, P.A. and D.D. Keck. 1973. A California flora and supplement. Univ.
Calif. Press, Berkeley.

Neill, W. 1985. Personal communication.

Neill, W. 1983. The tamarisk invasion of desert riparian areas.
Education Bulletin #83-84. Publication of the Education Foundation of
the Desert Protective Council.

Quimby, P.L., Jr., E.B. Hollingsworth, and R.L. McDonald. 1977.
Techniques for greenhouse evaluation of herbicides on saltcedar. Weed
Science 25(1):1-4.

Robinson, T.W. 1965. Introduction, spread and areal extent of saltcedar
(*Tamarix*) in the western states. Geological Survey Professional Paper
491-A. U.S. Government Printing Office, Washington, D.C.

Schopmeyer, C.S., ed. 1974. Agricultural Handbook No. 450. USFS-USDA,
Washington, D.C.

Wilgus, F. and K.L. Hamilton. 1962. Germination of salt cedar seed.
Weeds 10(4):332-333.

**Other (Uncited) References:**

Anonymous. 1984. Special funding helps park wage war on tamarisk plants.
The Borrego Sun, June 14, 1984. P. 5.

Brotherson, J.D., J.G. Carmen, and L.A. Szyska. 1984. Stem diameter age
relationships of *Tamarix* *ramosissima* in central Utah. Journal of
Soil and Water Conservation 37(4):362-364.

Decker, J.P., W.G. Gaylor, and F.D. Cole. 1962. Measuring transpiration
of undisturbed tamarisk shrubs. Plant Physiology 1(37):393-397.

Freeman, T.E., ed. 1978. The Center For Environmental Programs Institute
of Food and Agricultural Sciences, University of Florida, Gainsville.

Gary, H.L. 1962. Removal of tamarisk reduces water-table fluctuations in
Central Arizona. U.S. Forest Service Research Note. RM 1. 6 pp.

Gary, H.L. 1960. Utilization of Five-Stamen Tamarisk by Cattle. U.S.
Forest Service Research Note. RM 51. 4 pp.

Gary, H.L. and C.J. Campbell. 1965. Water table characteristics under
tamarisk in Arizona. U.S. Forest Service Research Note RM 58. 7 pp.

Horton, J.S. 1964. Notes on the introduction of deciduous tamarisk. U.S.
Forest Service Research Note. RM 16. 7 pp.

Hughes, E.E. 1967. Influence of environment on shoot growth and total
carbohydrate reserves of salt cedar. Weed Science 15(1): 46-49.

Hughes, E.E. 1968. Hygroscopic additives to phenoxy herbicides for
control of salt cedar. Weed Science 16(4):486-488.

Reynolds, G.G. and R.R. Alexander. 1974. *Tamarix* *pentandra* Pall.,
five stamen tamarisk. In C.S. Schopmeyer (ed.), Seeds of woody plants in
the U.S. Agricultural Handbook #450. USFS- USDA, Washington, D.C.

Watts, J.G., D.R. Liesner, and D.L. Lindsey. 1977. Salt cedar - a
potential target for biological control. Bulletin of New Mexico State
University Agricultural Experiment Station \# 650. 28 pp.

Wilkinson, R.E. 1966. Vegetative response of saltcedar (*Tamarix*
*pentandra* Pall.) to photoperiod. Plant Physiology 41:271-276.

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