Regularity: Regularly occurring
Occurrence in North America
[16,31,43,88]. A few populations occur in southeastern California near
the Colorado River in the Whipple Mountains [3,10,26]. The range of
yellow paloverde extends southward through Sonora and Baja California,
Regional Distribution in the Western United States
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
7 Lower Basin and Range
Yellow paloverde is a native, monoecious, spiny shrub or small tree that
may grow to 26 feet (8 m) tall [3,37,52,88]. The trunk may be 1 foot
(0.3 m) in diameter; it branches about 8 inches (20 cm) from the ground
into four to six major stems . The crown spreads 12 to 18 feet
(3.7-5.5 m) . The bark is thin and photosynthetic . Yellow
paloverde has numerous flowers in 1 inch (2.5 cm) long clusters [16,37].
It has pinnately compound leaves about 1 inch (2.5 cm) long with minute
leaflets and is drought-deciduous [37,100]. Fruits are 2 to 3 inches
(4-8 cm) long and have one to five seeds with constrictions between the
Yellow paloverde lives longer than 72 years .
Yellow paloverde is susceptible to freezing .
Yellow paloverde occurs in arid to semiarid climates with mild winters
and hot summers; precipitation is bimodal, occurring in summer and fall [15,54].
Yellow paloverde is found on lower mountain slopes and alluvial outwash
plains [54,97]. In the most arid parts of its range, yellow paloverde
occasionally occurs in small washes or arroyos [24,59,64,91,97].
Yellow paloverde occurs from 1,000 to 4,000 feet (305-1,219 m) in
elevation throughout its range [19,23,54,97,99]. It grows on very
gradual to steep slopes that may face south or north, but it has been
reported on all aspects [19,24,28,36,60,101].
The sites on which yellow paloverde occurs are well-drained .
Surface soils may be 1.6 to 2.8 inches (4-7 cm) thick and subsoils may
be 20 inches (50 cm) thick over caliche [91,101]. The soil temperature
regime is thermic (that is, average soil temperatures are between 59 and
72 degrees Fahrenheit [15-22 deg C]) . Soil textures range from
sand to sandy loam to loam . They may be underlain by clay loam and
clays [23,89]. Parent materials may be basaltic, rhyolitic, granitic,
mixed alluvium, and metamorphic [22,49,59,60,91].
The distribution of yellow paloverde is influenced by the continuum of
soil textures that occurs from upper to lower bajada . It is found
primarily on the upper bajadas [6,7,93,97]. Coarse soil of the upper
bajada has one-half the wilting coefficient (which is an estimate of
plant stress) of the finer soil of the lower bajada . Yellow
paloverde grows infrequently on the middle and lower bajada .
Key Plant Community Associations
Yellow paloverde is an indicator species of the Sonoran Desert floristic
region . It is a dominant species in the Arizona upland subdivision
of the Sonoran Desert [9,41,43,93]. Codominant species include
creosotebush (Larrea tridentata), triangle bursage (Ambrosia deltoidea),
brittle brush (Encelia farinosa), ocotillo (Fouqueria splendens), and
Berlandier wolfberry (Lycium belandieri) . This assemblage is also
called the paloverde, bursage (Ambrosia spp.) desert scrub community
type. It grades into spinose suffrutescent desert scrub .
A major climax association found on bajadas and rocky slopes throughout
the Sonoran Desert is the paloverde/saguaro (Carnegiea gigantea)
association [5,9,42,89,102]. This association grades into adjacent
semidesert grasslands and interior chaparral [53,54].
Yellow paloverde is the principal species in the paloverde series
[51,61]. This is also called the paloverde-cacti-mixed scrub series and
paloverde woodland and succulents association [93,103].
Yellow paloverde is a facultative riparian species. It may move into
riparian areas from surrounding desert and upland positions [1,74,83].
Where precipitation is less than 3 inches (7.6 cm) per year, yellow
paloverde is confined to washes and is an obligate riparian species .
Yellow paloverde is listed as a dominant or indicator species in the
(1) A series vegetation classification for Region 3 
(2) A vegetation classification system applied to southern California
(3) Vegetation of the Santa Catalina Mountains, Arizona: a gradient
analysis of the south slope .
Species associated with yellow paloverde but not previously mentioned in
DISTRIBUTION AND OCCURRENCE include white burrobrush (Hymenoclea
salsola), white ratany (Krameria grayi), organpipe cactus
(Lemaireocereus schottii), MacDougal ocotillo (Fouqueria macdougalii),
and heart leatherstem (Jatropha cordata) [25,78,97].
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
More info for the term: cactus
K042 Creosotebush - bursage
K043 Paloverde - cactus shrub
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES30 Desert shrub
FRES40 Desert grasslands
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
Fire Management Implications
Desert fire temperatures are variable due to interactions of
microhabitats and fuel. This prescribed fire did not alter physical
site characteristics such as albedo, soil water repellency, and
long-term microsite temperatures. Perennial plant cover was
significantly (P=0.001) reduced which may lead to soil erosion. Yellow
paloverde is very susceptible to fire, but no mortality data were given.
The study site was located in a desert canyon at 1,477 feet (450 m)
elevation. Spring months are dry and warm in this semiarid climate. No
appreciable precipitation was reported from the April prefire
assessments to the June prescribed fire. No information was given on
specific topography, slope, or soils.
Fire Management Considerations
Introduced annuals in desert habitats may create sufficient fuel to
increase fire frequency and severity . Native annuals probably
provided less fuel [39,71].
In the soils on which yellow paloverde occurs, nutrients are quickly
translocated following fire. Two years after fire, soil nitrogen levels
can drop below prefire levels [13,101].
Plant Response to Fire
During May 1981 in the Tonto National Forest, Arizona, the prefire mean
density of yellow paloverde was 30 plants per acre (75 plants/ha).
Following a controlled fire of moderate severity during June 1981,
yellow paloverde mean density was 24.8 plants per acre (62 plants/ha).
Heat-damaged plants subsequently died. Nine months after the fire,
yellow paloverde mean density was 17.2 plants per acre (43 plants/ha)
Yellow paloverde was completely eliminated by fire at one site on the
Tonto National Forest, Arizona .
Yellow paloverde may require 20 years to return to prefire plant
densities and community species composition following fires in
paloverde-saguaro communities [13,39,72].
Wildfire during June 1979 in Arizona top-killed 83 percent of yellow
paloverde present. Twenty-five percent of top-killed plants sprouted
about 2 years following the fire. There was 63 percent mortality for
yellow paloverde after about 3 years .
Fire burned during June 1974 in two desert scrub communities of
south-central Arizona. Before the fires, yellow paloverde had not
sprouted; no seedlings were present on one site (Dead Man Wash Site),
and five seedlings were present at the other site (Saguaro Site).
Prefire data concerning yellow paloverde were not given. Fire killed 78
percent of the photosynthetic tissue on the Dead Man Wash Site and 92
percent on the Saguaro Site. For both sites, approximately 10 percent
of the yellow paloverde present after fire were not top-killed;
approximately 14 percent were top-killed and sprouted. Five seedlings
were found on the Saguaro Site in postfire year 1 [71,72].
Yellow paloverde occurred in two different communities that were
prescribed burned during different years, one in 1983 and the other in
1985. Control and prefire communities were similar in composition. No
information specific to yellow paloverde was given. The fires consumed
70 percent of the perennial vegetation. Plants were two-thirds less
dense immediately after than before the fire. In 1986, plant densities
were still below prefire levels .
Yellow paloverde was codominant with triange bursage and buckhorn cholla
(Opuntia acanthocarpa) on rocky slopes on the Tonto National Forest. A
prescribed fire during June 1985 burned 9.9 acres (4 ha). The fire
burned vigorously in washes and on lower slopes. But fire decreased on
the upper slopes due to a lack of fuel between the shrubs; vegetation
patches were ignited with flares. The spotty burning reduced shrub
cover by 49 percent. No specific effects on yellow paloverde response
to fire were given in the article .
The Research Project Summary Ibarra-F and others 1996 provides
information on mortality of yellow paloverde after prescribed fires
in buffelgrass (Pennisetum ciliare) pastures in Sonora, Mexico.
Immediate Effect of Fire
fire, they are top-killed or killed. Surviving yellow paloverde
rootstocks sprout following fire. Sprouting plants are susceptible to
death from repeated fires .
A fire on a southern Arizona rangeland during the 1900's burned for 2
days and killed paloverde species. Postfire recovery of the vegetation
was not mentioned in the article .
Tree with adventitious-bud root crown/soboliferous species root sucker
Tall shrub, adventitious-bud root crown
Secondary colonizer - off-site seed
The thin-barked photosynthetic stems of yellow paloverde are killed by
fire . Yellow paloverde may sprout from the root crown following
The temperatures of desert fires are variable due to fluctuations in
kinds and quantities of available fuel . Heavy grazing in some
upland sites has eliminated the grass understory beneath paloverde
species and saguaro. Grass species were replaced with bursage,
burroweed (Haplopappus tenuisectus), and snakeweed (Gutierrezia spp.).
This has lowered the fire frequency because there is insufficient fuel
to carry fires . However, introduced annuals in other areas may
have increased both the frequency and the severity of fire [71,72].
Fires in the Sonoran Desert are generally infrequent and are low
severity due to low fuel loads . However, fires can be relatively
common in the Sonoran Desert under appropriate conditions, especially
during the summer . Two consecutive wet winters are probably needed
to develop fuel loads adequate to sustain fire. Fire is frequent in
desert grasslands on the eastern edge of the Sonoran Desert .
The Sonoran savanna grasslands are subtropical, fire-climax grasslands.
Most of these communities were destroyed through grazing and other land
management practices by the 1940's. Yellow paloverde grows in remnants
of these communities at their northern limits .
More info for the term: climax
Facultative Seral Species
Yellow paloverde is a climax species in the Sonoran Desert flora [51,54,61].
Successional sequences have not been completely identified for the
desert scrub communities in which yellow paloverde occurs. Dominants
such as yellow paloverde are the first to reappear and replace
themselves following disturbance .
Yellow paloverde reproduces sexually and asexually. Yellow paloverde
has fair to poor ability to produce sprouts after top removal .
Photoperiod initiates fruit and flower production of yellow paloverde.
Subsequent local weather conditions determine whether flowering or seed
set occurs . A seed crop is produced when the spring is wet or very
Yellow paloverde is insect pollinated [44,82].
McAuliffe  stated that yellow paloverde pods rapidly abscise as a
mechanism to avoid seed predation by bruchid beetles. The constricted
fruits of yellow paloverde do not open before dispersing .
Seeds germinate during a rainy season after 1 year in the soil.
Seedlings are very susceptible to drought during the first 2 to 3 months
following germination. During a 9-year study in Arizona, 1.6 percent of
all seedlings that germinated survived .
Recruitment of yellow paloverde is very slow. Additions as low as two
individuals over 30 years or longer have been recorded [22,79].
Herbivory limits yellow paloverde distribution . Bruchid beetles
are seed predators of yellow paloverde . Heteromyid rodents rapidly
cache yellow paloverde seeds. The cached seeds occasionally germinate
Initial distributions of yellow paloverde seedlings are random.
However, after 1 year, a greater proportion of seedlings in open spaces
were consumed by rabbits and hares than seedlings beneath triangle
bursage. Recruitment patterns of yellow paloverde show significantly
(P less than 0.001) positive associations with mature triangle bursage and white
bursage (Ambrosia dumosa) [45,46]. Because yellow paloverde outlives
triangle bursage, large mature yellow paloverde have no association with
triangle bursage .
Unpredictable water availability causes low, erratic seedling
establishment . Mature yellow paloverde maintain deep root contact
with wet soil [73,105]. Yellow paloverde self prunes; large branches
die during drought [3,105]. Young plants usually survive drought once
they drop branches which occurs at variable ages [77,105]. Death of
mature yellow paloverde due to drought and subsequent desiccation is
uncommon [45,77,92]. Based on water requirement trials, the water-use
efficiency of yellow paloverde approaches that of perennial grasses
Growth Form (according to Raunkiær Life-form classification)
Life History and Behavior
Yellow paloverde may not flower every year, depending on adequate
moisture availability. It develops flowers from March to May
[24,31,80,91,100]. Leaf production is erratic . Yellow paloverde
grows drought-deciduous leaves two or more times during the year
following summer and winter rains [77,91].
Molecular Biology and Genetics
Barcode data: Parkinsonia microphylla
Statistics of barcoding coverage: Parkinsonia microphylla
Public Records: 1
Specimens with Barcodes: 1
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Dimensional analyses that relate fresh biomass to stem diameter and dry
matter content are available for yellow paloverde .
Yellow paloverde was evaluated as a potential energy-producing crop.
During 2 years of sampling, the stems, leaves, and fruits of yellow
paloverde yielded moderate amounts of oil and crude protein. It was not
considered a promising species for exploitation .
Yellow paloverde spread from residential plantings into surrounding
wildlands in Death Valley National Monument, California. Yellow
paloverde does not occur there naturally, and mechanical and herbicide
control methods have been proposed to eradicate it .
Yellow paloverde and other desert scrub species invade desert grasslands
following disturbances such as grazing [40,98].
Yellow paloverde up to 3 inches (7.6 cm) tall may be seriously injured
or killed by jackrabbit browsing. Larger trees are browsed to the
extent that a jackrabbit can reach, about 3 feet (1 m) .
Yellow paloverde is an alternate host for seed-predating bruchid
beetles (Mimosestes spp.). Yellow paloverde responses are probably
similar to those of the beetles' primary host, mesquite (Prosopis spp.),
with reduced yields of viable seeds .
Yellow paloverde and community associates typical of the Arizona upland
subdivision of the Sonoran Desert occur in very few places in
southeastern California. This is a community type with one of the
highest priorities in California for rare plant inventories .
Yellow paloverde provides canopy cover that reduces maximum soil surface
temperatures. This is important for the establishment of other desert
species [20,78]. Yellow paloverde is the primary nurse plant for
Relevance to Humans and Ecosystems
Yellow paloverde that are taller than 6.6 feet (2 m) are used for
nesting . Verdin and black-tailed gnatcatchers nest in yellow
paloverde . Gambel's quail use them for roosts . Yellow
paloverde snags are important wildlife habitat because snags occur
infrequently in the Sonoran Desert. In Arizona, nine bird species used
one yellow paloverde snag daily .
White-throated woodrats use yellow paloverde for shelter or nests .
Other uses and values
Native Americans [37,66].
Yellow paloverde is planted as an ornamental .
Value for rehabilitation of disturbed sites
in Arizona. Yellow paloverde survived significantly (P less than 0.05) better on
the east slope (27 plants/244 sq m) than on the north slope (1 plant/244
sq m) .
Importance to Livestock and Wildlife
Bighorn sheep, mule deer, and feral burros browse yellow paloverde
[25,34,63,75,76]. It is important browse for jackrabbits, heteromyid
rodents, and other small mammals [16,25,67,96]. Collared peccary
consume yellow paloverde fruits from July to September . Yellow
paloverde was used significantly (P less than 0.01) more than other plant species
for foraging by birds .
Small mammals such as desert shrews and mice use the habitats where
yellow paloverde occurs .
leaves, flowers, and new growth had from 30 to 60 percent dry matter and
from 6 to 16 percent crude protein [34,63,76]. Yellow paloverde has
large seeds that weigh an average of 0.005 ounce (0.147 g) and contain
733.3 calories per seed .
|This article includes a list of references, related reading or external links, but its sources remain unclear because it lacks inline citations. (March 2013)|
It is native to the Southwestern United States in southeastern California and southern Arizona; and to Northwest Mexico in Sinaloa, Sonora, and Baja California. The plant is mostly found on slopes, and is one of the most common trees of the Sonoran Desert.
Parkinsonia microphylla is a bristling, upright-branching tree. The species is slow-growing, sometimes living for several hundred years. It typically grows to heights of around 5 metres (16 ft), although rarely it can reach 6–7 metres (20–23 ft) tall.
The leaves are yellowish green, and during extensively dry and hot periods the tree will shed them. It has the characteristic of performing photosynthesis in its bark (hence the green color), and this is what allows it to survive leafless in hotter periods.
The flowers are found on the end of a branch, small, pale yellow and occur in late spring. The tree may not flower every year, depending on the amount rainfall. If there is enough rainfall, seeds will also appear in 4–8 cm long, soft pods which dip in between each seed. They ripen in July, and stick to the branches. Rodents will often carry and store the seeds underground, where some of them will germinate after a rainy season.
The seedlings are very sensitive to drought for the first two to three months of their lives, and only about 1.6% will survive after germinating.
Buffelgrass is an exotic species of grass native to Africa, first introduced into the Sonoran Desert for livestock grazing, which spreads very quickly and can often kill seedlings by using available water, which could be a threat in the future.
The Seri people, a Native American group of northwestern Mexico, call this tree ziipxöl [ ʃiːpχʷɬ ]. They used to grind up the seeds for flour, boil the green pods with meat, and eat the sweet green seeds as well as the flowers. They also strung the seeds for necklaces.
Parkinsonia microphylla is cultivated as an ornamental tree for use in drought tolerant, modernist, and native plant gardens. It is also used as a small tree in parking lot plantings of commercial developments.
- Germplasm Resources Information Network: Parkinsonia microphylla
- Felger, Richard; Mary B. Moser. (1985). People of the desert and sea: ethnobotany of the Seri Indians. Tucson: University of Arizona Press.
|Wikimedia Commons has media related to Parkinsonia microphylla.|
Names and Taxonomy
microphylla Torr. [26,52,80,88,107]. Yellow paloverde occasionally forms
hybrids throughout its range with blue paloverde (P. floridum) . In
Mexico, yellow paloverde hybridizes with P. praecox to form Sonoran paloverde
(P. x sonorae) [43,93].
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