Regularity: Regularly occurring
Global Range: Known from the Sierra Nevada from Mt. Rose (Nev.) north nearly to Oregon, and perhaps also in eastern Oregon as well.
Great Basin in northeastern California and northwestern Nevada [3,4,17].
It occupies a few square miles on the east slopes of Mount Rose, Nevada,
and can be found in small stands in the southern Warner Mountains and in
the Bald Mountain range of northeastern California [3,4]. Isolated
stands have been reported in Oregon and British Columbia [4,16].
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):
4 Sierra Mountains
5 Columbia Plateau
Occurrence in North America
and 5 feet (1.5 m) in diameter. It has a conic or flat-topped crown
. The short, stout needles occur in bundles of three and are 4 to 6
inches (10-15 cm) long . The seed cones are 2 to 3.2 inches (5-8 cm)
long and have short-winged seeds . The bark is shallowly furrowed
. The oldest Washoe pine is on Mount Rose, Nevada. Its estimated
age in 1962 exceeded 300 years. Several other trees in the area have
estimated ages of 100 to 250 years .
Catalog Number: US 2301121
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): H. L. Mason
Year Collected: 1940
Locality: E side of Mount Rose, Sierra Nevada., Washoe, Nevada, United States, North America
Elevation (m): 2591 to 2591
- Isotype: Mason, H. L. & Stockwell, W. P. 1945. Madrono. 8: 62.
Comments: Mountain slopes (1980-2440 m elevation) with western white pine (P. monticola), lodgepole pine (P. contorta), ponderosa pine (P. ponderosa), and California red fir (Abies magnifica).
Key Plant Community Associations
Washoe pine typically occurs in pure stands at higher elevations along
the eastern slope of the Sierra Nevada. In the northern Sierra Nevada
and into the southern Cascade Range, it forms mixed stands with Jeffrey
pine, Pacific ponderosa pine, incense cedar (Libocedrus decurrens),
white fir (Abies concolor), California red fir (A. magnifica), and
western juniper (Juniperus occidentalis) [4,10,14,16,21]. Other common
tree associates include sugar pine (Pinus lambertiana) and quaking aspen
(Populus tremuloides var. aurea). Other associates include mountain
sweetroot (Osmorhiza chilensis), white hawkweed (Hieracium albiflorum),
greenleaf manzanita (Arctostaphylos patula), mountain big sagebrush
(Artemesia tridentata ssp. vaseyana), antelope bitterbrush (Purshia
tridentata), snowbrush ceanothus (Ceanothus velutinus), wooly wyethia
(Wyethia mollis), snowberry (Symphoricarpos vaccinioides), Idaho fescue
(Festuca idahoensis), Wheeler bluegrass (Poa nervosa), and Orcutt brome
(Bromus orcuttianus) [1,10,14,18,20,21].
Publications listing Washoe pine as a dominant species are:
Preliminary descriptions of the terrestrial natural communities of
Symposium Proceedings--plant communities of southern California 
Forest habitat types of the South Warner Mountains, Modoc County,
Montane and subalpine vegetation of the Sierra Nevada and Cascade Ranges
[18,20]. It may occur on other aspects; on volcanic ridges south of the
Warner Wilderness area, it comprises 50 to 75 percent of total stocking
on gentle west- and southwest-facing slopes . Best growth occurs on
well-drained soils . Washoe pine occurs from 5,500 to 8,500 feet
(1,650-2,550 m) elevation [4,9,10]. An isolated population in British
Columbia, Canada, occurs at 4,818 feet elevation (1,460 m) .
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):
FRES21 Ponderosa pine
FRES23 Fir - spruce
FRES26 Lodgepole pine
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
207 Red fir
208 Whitebark pine
211 White fir
218 Lodgepole pine
237 Interior ponderosa pine
238 Western juniper
243 Sierra Nevada mixed conifer
247 Jeffrey pine
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K005 Mixed conifer forest
K007 Red fir forest
K008 Lodgepole pine - subalpine forest
Habitat & Distribution
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 6 - 20
Fire Management Considerations
Fire suppression in white fir habitat types in northeastern California
leads to an increase in white fir, with a corresponding decrease in pine
species (including Washoe pine) reproduction .
A yellow pine-fir forest in the eastern Sierra Nevada near Truckee,
California, burned in a 1960 wildfire. In 1965, the burned plot had
greater cover of shrubs, herbs, and grasses than an adjacent unburned
plot. From 1966 to 1985 shrub cover increased while herbaceous cover
decreased. In postfire year 15 yellow pines were the dominant trees,
although white and California red fir were present. Yellow pines
codominated with the firs in nearby unburned stands. Data are shown
postfire year 15
density/ha basal area (sq.m/ha)
yellow pine complex 97.4 3.1
white and California red fir 4.5 1.7
yellow pine complex 335.5 24.2
white and California red fir 448.8 15.1
The responses of small birds to succession after this wildfire
demonstrates the potential effectiveness of increasing habitat
diversity, spatially and temporally, on breeding bird populations .
In the eastside yellow pine forests of northeastern California, fuel
loading has increased over time. Early logging operations increased
slash and fire hazards. Invasion of eastside pine lands by cheatgrass
(Bromus tectorum) and increases of woody shrubs, dense thickets of young
trees, and accretion of woody debris have increased the probability of
stand-replacing fires .
Immediate Effect of Fire
However, many of the yellow pines harvested in northeastern California
during the early 1900's survived earlier fires. Stumps 16 to 36 inches
(40.6-81.4 m) tall usually remained after harvest. The lowest portions
of the trees were left because they were defective from fire scarring or
accumulation of pitch from low-intensity fires .
Before settlement, eastern-slope yellow pine communities of northeastern
California generally consisted of either monotypic stands or mixtures of
Washoe, ponderosa, and Jeffrey pines. Structurally, eastside pine
forests usually consisted of widely scattered, large trees.
Low-severity fires were frequent, but forests may have had occasional
stand-replacing fires [14,28]. Canopy closures probably ranged from
about 30 percent on dry sites to 80 percent in the most productive
areas. A 1917 report stated that yellow pines of the area were often
only four-log trees (a standard log was 16 feet long), suggesting that
mature trees were shorter than 100 feet (30 m) .
Susceptibility to fire in mid-elevation Washoe pine stands has increased
since 1850 because of fuel buildups and increased stocking of white fir.
Juniper and shrub cover have replaced the typical shrub/grass understory
at low elevations as a result of livestock grazing and fire suppression
More info for the term: cover
Facultative Seral Species
Washoe pine is a long-lived seral species in white fir communities .
It is plentiful in the community, with cover often equaling or exceeding
white fir. Fir reproduction usually exceeds that of Washoe pine,
however, unless fires are fairly frequent . Washoe pine is dominant
at higher elevations [14,20].
Growth Form (according to Raunkiær Life-form classification)
Rose population, Washoe pine exhibits low seed production and has low
reproductive capacity [4,17].
Plant Response to Fire
Life History and Behavior
More info for the term: natural
Washoe pine pollen is shed from June 24 to July 4 on Mount Rose .
Cones mature in August and September and open in September throughout
its range .
Natural seedling dormancy begins when soil temperature is below 50
degrees Fahrenheit (10 deg C) .
In the nursery, Washoe pine seedlings cease visible top growth by
mid-October and visible root growth by late November. In January top
growth is evident. The first traces of renewed root growth appear in
late February and bud swell begins in late March .
Persistence: PERENNIAL, Long-lived
Molecular Biology and Genetics
Barcode data: Pinus washoensis
Statistics of barcoding coverage: Pinus washoensis
Public Records: 3
Specimens with Barcodes: 3
Species With Barcodes: 1
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: G3 - Vulnerable
Reasons: A rare and local conifer of higher elevations in the Sierra Nevada of California and adjacent Washoe County, Nevada, and eastern Oregon.
Relevance to Humans and Ecosystems
Importance to Livestock and Wildlife
The avian species composition of stands containing Washoe pine depends
on the stage of succession. A fire burned 450,000 acres (18,000 ha) of
a yellow pine (Washoe, Jeffrey, and ponderosa pines)-fir forest near
Truckee, California, in 1960. At postfire years 6 to 8, nine species of
birds were unique to the burned areas, six to the unburned area, and 17
were found on both sites. Shrub cover on the burned plot increased from
about 20 percent to over 43 percent from postfire year 6 to 25, and
birds that nest and feed in shrubs increased by over 500 percent.
Throughout the study, bird numbers remained relatively stable in the
unburned forest. On the burned plot, however, primary-cavity nesting
birds declined over time. The decline probably resulted from a decrease
in standing dead trees. Snag density declined from about 65 per acre
(26/ha) in 1966 to less than 12.5 per acre ( less than 5/ha) in 1985 .
Names and Taxonomy
Comments: Maintained as an accepted species in most current works, including Kartesz (1994 checklist and FNA), but has also been classified as a variety of Pinus ponderosa.
The currently accepted scientific name of Washoe pine is Pinus
washoensis Mason and Stockw. [3,8,9]. There are no recognized
subspecies, varieties, or forms.
Washoe pine origins are uncertain. Haller  proposed that Washoe
pine resulted from hybridization between either Pacific ponderosa pine
(P. ponderosa var. ponderosa) and Jeffrey pine (P. jeffreyi) or Pacific
ponderosa pine and Rocky Mountain ponderosa pine (P. ponderosa var.
scopulorum). Mirov  dismissed Jeffrey pine as a possible ancestor
on chemical and morphological grounds, suggesting that Washoe pine is a
variety or mutant of ponderosa pine. Critchfield  stated that Washoe
pine is a Pleistocene derivative of Rocky Mountain ponderosa pine.
Washoe pine sets more sound seed per cone in artificial crosses with
Rocky Mountain ponderosa pine than in natural intraspecific crosses.
This rare instance of heterosis for seed set in interspecific conifer
hybrids establishes a strong and direct evolutionary relationship
between Washoe pine and the Rocky Mountain ponderosa pine .
Washoe pine hybridizes with Pacific ponderosa pine [17,26] and rarely
with Jeffrey pine .
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