Eastern White Pine provides a straight trunk, clear of branches for many feet up when growing in a forest environment. It is the largest conifer of the northern forests. The old growth pines still found in Itasca State Park are upwards of 130 feet high and over 45 inches in diameter and in the park was found the Minnesota record white pine which was considerably larger. Maximum height was around 225 feet with a 10 foot diameter in the old growth. Most modern forest trees top out around 100 feet. Branches grow in whorls, a new set each year from the leader.
Bark: The bark is thin, smooth and greenish-gray on young trees becoming grayish-brown and deeply furrowed on old trees.
Twigs are gray-green to orange-brown in color with long reddish brown slightly resinous buds.
Leaves: The needles are 3 to 5 inches long, bluish green on top and whitish under and are unique for Minnesota conifers in that they grow in bundles (fascicles) of 5. They are pointed, soft and very flexible, as are the younger branches. New growth needles may be much shorter and appressed to the twig. Needles last for only 2 years before turning brown and falling off.
Flowers: The tree is monoecious, that is, male and female flowers are separate. Male flowers are yellow in cylindrical clusters, up to 2 inches long, near the ends of branches behind the new growth. The female flowers are located there also but are light green, tinged with red and in smaller size clusters.
Seed: The cones are cylindrical, 4 to 6 inches long on average (and some may be much longer), one inch thick, on stalks up to one inch long, with thin and very gummy scales that lack prickles. Each scale can have two reddish-brown winged seeds. Each cone matures in its second growing season, taking 13 months for fertilization, and seeds disperse by wind. Cones usually drop after seed dispersion. Trees begin to produce cones when 5 and 10 years of age.
Habitat: White pine has a shallow spreading root system, without a taproot, preferring loamy well drained soils in full sun. It is long-lived and can be the dominant tree in certain areas. Trees are damaged by the white pine weevil, the pine cone beetle and by white pine blister rust whose alternate plant host is the Ribes genus (see notes below). White pine grows in a variety of soils but does best if not too dry. Spring growth begins when the terminal bud becomes what is called a "candle". This is a new shoot and at this stage it is extremely brittle. If the candle on the "leader" at the top of the tree is broken off, then the main trunk will no longer grow from that point and an auxiliary branch will attempt to become the new leader. When successful, the new leader will become the main trunk. When you see a pine with the trunk making an offset near the top, that is a sure sign that the original shoot was damaged. Sometimes several branches will compete to become the leader and occasionally you may see a pine with has several leaders from this process. When the terminal candle is finished growing for the year, it will have developed a terminal cluster of buds that will become the next whorl of branches the following year. The more buds, the better the tree was in storing energy this season.
Names: The genus Pinus is the Latin name for the pine tree. The species strobus is applied to an entire subgroup of pines whose cone scales lack sealing bands and the scales have a small projection at the tip. White Pine is the type tree of this subgroup. The author name for the plant classification - 'L.' is for Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Diseases: - see notes below.
Above: A stand of old White Pines in Theodore Wirth Park, Minneapolis, near the Garden entrance. Drawing from North Ameican Sylva by Francois Michaux and Thomas Nuttall.
Above: The bark of White Pine is initially smooth (1st photo) on younger trees like that pictured in the 3rd photo. It becomes grayish-brown and deeply furrowed (2nd photo) on old trees such as those shown below.
Below: 1st photo - The old stand of White Pines near the front gate of the Eloise Butler Wildflower Garden. 2nd photo - Twigs are gray-green to orange-brown in color with long reddish brown slightly resinous buds. 3rd photo - Needles are pointed, soft and very flexible and grow in bundles (fascicles) of 5.
Below: The cones are cylindrical, 4 to 6 inches long on average, one inch thick, on stalks up to one inch long, with thin and very gummy scales that lack prickles. 3rd photo - A cluster of forming male flowers, not at the pollen release stage.
Henry David Thoreau wrote in The Dispersion of Seeds: "As for the White Pine, you have all observed its clusters of sickle-shaped green cones at the top chiefly of the tallest trees, well nigh inaccessible to man. About the middle of September these turn brown and open in the sun and wind, and as in the case of the pitch pine, away go the seeds of future forests flying far and wide. How little observed are the fruits which we do not use! How few attend to the ripening and dispersion of the white pine seed! In the latter part of September in a fruitful year, the tops of high trees for six or ten feet are quite browned with the cones, hanging with their points downward and just opened. They make a great show even sixty rods off, and it is worth the while to look down from some favorable height over such a forest -- to observe such evidence of fertility in this which commonly we do not regard as a fruit-bearing tree. I occasionally go to the white pine woods merely to look a their crop of cones, just as a farmer visits his orchards in October."
Below: 1st photo - The leader with the prior years whorl of branches. 2nd photo - The developing "candles" at the twig tips.
Notes: Eastern White Pine is not indigenous to the Garden. Eloise Butler first recorded planting Eastern White Pine on May 19, 1909 with plants obtained from the Park Board nursery. Again on Sept. 11, 1911, and 11 on May 28, 1914, more in 1917 and '20, all same source. Another in 1920 from Milaca. Martha Crone planted it in 1937. The Common name of 'Eastern' White Pine is appropriate as the range of this species is the eastern half of North America, excluding the Gulf of Mexico states. In Minnesota it is native to the eastern 2/3rds of the state north of Sherburne County, then south along the St. Croix valley and along the Mississippi valley to the Iowa border. It is widely available in the nursery trade and can probably be found in many other locations as a planted landscape species. Hennepin County is a case in point, it is not native to the county but can be found in numerous landscape plantings. White pine was introduced into England in 1605 by British Naval Captain George Weymouth and in England the tree bears his name.
A grouping of these trees from Eloise Butler's time is near the front gate of the Garden (photo far above). Former gardener Cary George wrote in 2002 "Their wonderful, soft needles and the irregular form they take on after years of storms, lightening strikes and heavy snow damage give them a rugged, venerable character. While these trees are a significant part of the historic landscape they do present a major horticultural dilemma: Understory trees and wildflowers do not thrive under their tightly woven canopy. The soil is acidic and very dry. While many visitors like the open, unimposing feel, it is a compromise to devote such a vast area to so few plant species." Fringed Gentian™, Vol. 50 #1.
There are three species of Pine native to Minnesota: P. banksiana, Jack Pine; P resinosa, Red (or Norway) Pine; and P. strobus, White Pine. The Scotch Pine, P. sylvestris, native to Europe has been introduced for landscape planting and for Christmas trees.
Uses: Eastern White Pine was the most important softwood species for construction lumber during the development of Minnesota and remains an important timber tree. The wood is soft, of medium strength, easily worked and finishes nicely.
Diseases: Years ago when wild gooseberries and blueberries (the Ribes genus) were prevalent, mature stands of White Pine suffered 50 to 80% mortality from a fungus that uses the Ribes plants as an alternate host. This fungus, the White Pine Blister Rust (Cronartium ribicola) was put into check by the removal of the wild Ribes plants near many large stands of White Pine. Today there are far fewer wild Ribes near stands of the pine due to development and habitat changes. Losses to the blister rust are thought to be around 3% now. The fungus attacks pines that have 5 needles per bundle and mostly affects young pines via the needles and when it reaches the stem it is fatal. Older pines usually show top loss. The Ribes plants host the fungus only for a few weeks on their leaves before the spores are released to find the pine host. It is not treatable.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"