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Conservation status

Pinus washoensis

Mason et Stockwell 1945

Common names

Washoe pine (Kral 1993), 'North Plateau' Ponderosa pine.

Taxonomic notes

Pinus washoensis may be synonymous with P. ponderosa subsp. ponderosa, as detailed on that page. However, its cones are fairly distinctive and I am not fully persuaded that the described P. washoensis populations do not warrant distinction as a variety or even a subspecies of P. ponderosa. For now, this small-coned form of P. ponderosa is distinguishable in the field and certainly occurs at the type locality (Mount Rose, Nevada), even if it does not occur in all of the areas where collections have been described. It is also recognized as a good species by a variety of recent authoritative published sources and by many dendrologists familiar with these trees. This page is thus a representation of what has been published about the Washoe pine.

P. washoensis was described when California botanist Herbert Mason found what seemed to be a small-coned version of P. jeffreyi growing on the east slope of Mt. Rose in Nevada. Subsequent fieldwork delineated the extent of the Mt. Rose stand, most of which had regenerated after being logged in the 1860's (Lanner 1999), and in 1945 the trees were described as a new species (Mason and Stockwell 1945). Mason and Stockwell evidently did not consider their new pine to be a ponderosa, believing 'Pacific' ponderosa pine (here treated as P. ponderosa subsp. benthamiana) to be identical to the type collected by David Douglas in eastern Washington (P. ponderosa subsp. ponderosa). Noting that the Mt. Rose trees were distinct from those of western California (benthamiana), but failing to compare them with populations from eastern Washington, they described the Mt. Rose trees as a new species, Pinus washoensis. In the 1960s, similar populations were found in the Warner and Bald Mts of NE California and were also assigned to P. washoensis (Haller 1961, 1965; Critchfield and Allenbaugh 1965). Subsequent California investigators searching for 'P. washoensis' further north continued to make the same error, leading to reports of 'P. washoensis' from as far north as British Columbia (Critchfield 1984). The error was discovered during a review of the species by F. Lauria (1991, 1996).

Description

Trees to 60 m tall and 100 cm DBH (possibly much larger; see note below), with a straight cylindrical trunk and pyramidal crown. Bark yellow-brown to red-brown, fissured, plates scaly. Branches spreading-ascending; twigs stout, orange, aging gray, rough. Buds ovoid, red-brown, 1.5-2 cm, not resinous; scale margins fringed. Leaves (2)-3 per fascicle, spreading-ascending, persisting (2)4-6(7) years, 10-15 cm × ca. 1.5 mm, slightly twisted, gray-green, all surfaces with stomatal lines, margins finely serrulate, apex acuminate; sheath 1-2 cm, base persistent. Pollen cones cylindric, 10-20 mm, red-purple. Seed cones maturing in 2 years, shedding seeds soon thereafter, not persistent, spreading, slightly asymmetric, ovoid-conic before opening, broadly ovoid when open, 7-10 cm, tan or pale red-brown, sessile, abaxial surface of scales darker and sharply contrasting in color with adaxial surface; apophyses slightly raised, low pyramidal; umbo central, narrowly pyramidal, tapering to a short, incurved, fine prickle. Seeds ellipsoid; body ca. 0.8 cm, gray-brown; wing to 16 mm. 2n=24" (Kral 1993).

The species can really only be discriminated from P. jeffreyi or P. ponderosa subsp. ponderosa by inspection of the mature seed cones. The crown form and the distinctive vanilla odor are essentially identical to P. jeffreyi and P. ponderosa subsp. benthamiana, but the cones are less prickly than those of the ponderosa because most of the prickles on the cone scales do not point outward, and the cones are mostly 6-10 cm long, compared to 7-15 cm for the ponderosa. Jeffrey pine cones are also not prickly and are larger, typically 15-30 cm long (Lanner 1999 and my pers. obs. of material collected on Mt. Rose in 2009).

Distribution and Ecology

USA: NW Nevada and adjacent California at 2100-2500 m elevation in dry montane forests (Kral 1993). The largest population is in the southern Warner Mtns. of NE California, and it is also reported within the region from Lassen Volcanic National Park, the Bald Mountains, Last Chance Creek in Plumas County (all in California), the headwaters of Galena Creek on Mount Rose, and the Mosquito Mountains in extreme NW Nevada (Lanner 1999, Charlet 1996). I have also received a reliable report (Michael Taylor email 2009.08.26) of some very large trees in upper Hayfork Creek in the Trinity Mountains of California. These may not be pure P. washoensis but could have a hybrid origin, or may even be a new taxon; terpene and genetic studies may be needed to better understand this unique population.

Big tree

The "official" big tree has diameter 104 cm, height 27 m, crown spread 16 m, located in Thomas County, CA (American Forests 1996). Michael Taylor, however, reports that he knows of a tree 160 cm dbh and 50.6 m tall (Michael Taylor email 2009.09.09).

Oldest

Dendrochronology

Ethnobotany

Observations

Remarks

Named for the Washoe Indians, who formerly inhabited the Mt. Rose area (Lanner 1999).

Citations

See also

The FEIS database.

Lanner (1983).

Little (1980).

Niebling, C. R. and M. T. Conkle. 1990. Diversity of Washoe pine and comparison with allozymes of ponderosa pine races. Canadian Journal of Forest Research 20:298-308.

Last Modified 2012-11-23