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Pinus strobus

L.

Eastern White Pine

Pinaceae

Pinus strobus is a large coniferous tree species in the family Pinaceae. It is endemic to eastern North America, and is widely grown for ornament and for lumber, being cut down extensively in the past. It is the state tree of Maine and Michigan, and the provincial tree of Ontario (eFloras).

Description

Pinus strobus is a tall evergreen tree that grows up to 67 m tall, straight, conical in outline with numerous large branches in whorls. Needles are thin, 6 to 10 cm long in bundles of 5. They are deep- or blue- green with a white band (which are stomata) on the inside, and persist on the tree for 2 to 3 years. They are straight, very finely toothed and end in a sharp point. The sheaths are 1 to 1.5 cm long and are not persistent. The bark is gray-brown, vertically furrowed, a bit scaly. Male cones are small, yellow, 1.0 to 1.5 cm and round. Seed cones are 8 to 20 cm long, cylindrical or tapering and slightly curved. Cones are found in clusters hanging on 2 to 3 cm long stalk. They are pale brown and have numerous scales that are thin, curved, and smooth (i.e. without prickles). They often have splotches of white resin on the tips of scales. These cones mature after 2 years in the fall, then release their seeds and fall from the tree (FNAEC 1993; Kershner et al. 2008).

Pinus strobus is the only species of white pine (subgenus Strobus) native to the eastern North America. The most similar species, the western white pine (Pinus monticola), is native to western North America and has longer cones (Kershner et al. 2008). It easily hybridizes with that species (Eckenwalder 2009).

The variety chiapensis, formerly classified as a separate species, is found in a disjunct population in Central America. It differs from the main species in having slightly longer needles (10 cm on average compared to 8 cm for var. strobus) with more finer teeth (about 25 per centimeter along the edge, compared to 12 for var. strobus). Its seed cones have about 4.5 cm long stalks compared to strobus’s 3 cm long stalks, averaging 90 scales with the most basal ones not curled back. The main variety has about 70 scales with the most basal ones curled back towards the cone stalk (Eckenwalder 2009).

Uses

Note: Please see the disclaimer regarding any information about medical or edible uses.

Pinus strobus is often cultivated in parks, large gardens, or other spacious areas as a specimen tree. It may also be grown as a hedge. It grows in USDA zones 3 to 8, and it prefers full sun, medium moisture, and fertile soils, although it grows well in many other soil conditions (MBG).

Pinus strobus was once the most important timber tree in the United States. The supply of wood from this species reached a peak at around 1890, when 10 billion board-feet were produced; the original old-growth forests have now been cut down and are mostly gone. The wood is light brown, light in weight, and relatively soft and weak. The lumber had for a huge variety of uses, such as building houses, but has since been used for many things, such as boxes, furniture, patterns, etc. (Betts 1954).

Distribution

Pinus strobus is widespread and common in dry to medium soils, growing at elevations of up to 1500 m. It is native to northeastern North America, from Ontario east to Newfoundland, to the southern end of the Appalachian Mountains, and around the Great Lakes (FNAEC 1993). Pinus strobus var. chiapensis is found in mixed broadleaf and coniferous forests, often cloud forests, at an altitude of 500 to 2200 m. It is native to the Mexican states of Puebla, Guerrero, Veracruz, Oaxaca, and Chiapas, as well as the Guatemalan departments of Quiché and Huehuetenango (Thomas and Farjon 2013).

Status

The main variety of Pinus strobus is listed on the IUCN Red List as "Least Concern". The species suffered through extensive logging by the 1800s, but has since recovered. The species is susceptible to white pine blister rust (Cronartium ribicola) but the species is still extremely common (Farjon 2013). However, variety chiapensis is considered “Endangered” because it is being cut down for timber, and its habitat is being deforested for ranching (Thomas and Farjon 2013).

References

Betts, H. S. 1954. Eastern white pine (Pinus strobus). U.S. Forest Service. [accessed 2018 Nov 09]. http://www.fs.usda.gov/treesearch/pubs/32213

Farjon, A. 2013. Pinus strobus. The IUCN Red List of Threatened Species. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T42417A2978687.en.

FNAEC (Flora of North America Editorial Committee), editor. 1993. Flora of North America, north of Mexico. Volume 2: Pteridophytes and Gymnosperms. New York: Oxford University Press.

Kershner, B., Tufts, C., Nelson, G., Spellenberg, R., Purinton, T., Block, R., Moore, G., and Thieret, J. W. 2008. National Wildlife Federation: Field Guide to Trees of North America. New York: Sterling Publishing Company.

MBG (Missouri Botanical Garden), Pinus strobus. Plant Finder. [accessed 2018 Nov 09]. http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=e710

Thomas, P., and Farjon, A. 2013. Pinus strobus var. chiapensis. The IUCN Red List of Threatened Species. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T32499A2820834.en

Description
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