Populus deltoides Bartr. ex Marsh. ssp.
monilifera (Ait.) Eckenw.
Plains cottonwood
The expedition needed trees on numerous occasions
as sources of lumber, firewood, and shade. In spite of
Lewis’ low esteem for its qualities, the cottonwood
was often the only timber at hand to fulfill their
lumber requirements, including building the winter
quarters at Fort Mandan and constructing canoes.
More than once, in the barren landscape of the high plains, the Lewis and
Clark expedition would welcome a small grove of cottonwoods to protect
them from sun or rain during a respite or an overnight stay, and to provide
firewood for cooking or warmth. Cottonwoods require moist soils, and
their natural habitat, along the edges of streams and rivers on islands
above the flood plain, made them easily accessible for the Corps.
Populus balsamifera L. ssp. trichocarpa (Torr. & Gray ex Hook.) Brayshaw
black cottonwood - Susan McDougall @ USDA-NRCS PLANTS Database
In an early comment, Lewis found the cottonwood “so abundant as to be
troublesome to the traveler.” Not a bad-looking tree, Lewis compared it to
the “beautiful and celebrated Lombardy poplar”, but he saw it as useless
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except for some of the pirogues the Indians made with the trunks of the
larger trees (Lewis journal, May 25, 1804). His main complaint was that
the wood was not durable; indeed Sgt Gass described it as “a light soft
wood” (Gass journal, November 28, 1804).
Nevertheless, cottonwoods happened to be a crucial resource in several
instances. The plains cottonwood provided the lumber for the construction
of the party’s winter lodge at Fort Mandan. Eight huts, each 14 feet square,
were built on the east bank of the Missouri taking advantage of the
availability and size of the trees. Overall, as Sgt Ordway wrote, “we find
the cottonwood Timber will Split Tollorable well, and as their is no other
building timber in this bottom we expect to Split punchin to cover the huts
with” (Ordway journal, November 2nd, 1805). This was done a few weeks
later, according to Sgt Gass’s journal (November 28, 1804).
Canoes from Clark’s
journal February 1st, 1806
Reproduced in Thwaites
1959 vol.4
Photo Smithsonian
Institution
Before leaving Fort Mandan in May 1805, and probably following the Indian
method, Lewis had his men hollow out large cottonwood trunks to make six
sturdy canoes. Though the journals say nothing about the sort they built, later
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in the trip Lewis and Clark sketched several of the fine canoes they saw with
Indians from the Pacific coast.
To his own surprise, Lewis found that the horses he had bought from Indians
would prefer the bark of the cottonwood to the meals he had prepared for
them. He realized that, in the winter, the Mandans would cut down trees and
fed their horses with the tender branches and cut pieces of the scrapped bark
(Lewis journal, February 12, 1805; Cutright 1969:86).
A few months later, the larger size of some of the local cottonwoods helped
them portage around the Great Falls. At Fort Mandan they had used trees
18 inches in diameter (Gass journal, November 28, 1805). At the Great
Falls, Sgt. Gass was in charge of the construction of two wagons to
transport the heavy dugout canoes and all the expedition equipment
around the falls. He found a tree 22 inches in diameter, big enough that
the men could cut cross sections to serve as wheels (Lewis journal, June
17, 1806).
Cottonwoods are less abundant today, although big trees survive thanks to
a root system able to seek water as deep as 30-40 feet below ground
(Cutright 1969:139). The Missouri River course has changed during the
last 200 years and dramatically reduced the habitat for these large trees of
the prairie. Interest in navigable waters has deepened and narrowed the
channel in many places, eliminating the shallow riverbeds where the trees
used to grow. Likewise, several dams have been built across the Missouri
River to control flooding and to provide electricity. These dams created
large lakes in the place of the meandering river and, consequently, the
cottonwood habitat has disappeared.
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Two other types of cottonwoods
Although the Plains cottonwood was
already known to science, Lewis
reported and collected two other
types previously unknown: Populus
angustifolia James, narrow-leaved
cottonwood, and Populus
balsamifera ssp. trichocarpa, black
cottonwood.
Populus angustifolia in Nuttall’s Sylva
Photo Smithsonian Institution
They differ from the plains cottonwood by the shape of their leaves and
their location along the trail. The party found the narrow-leaved
cottonwood near Great Falls. All three cottonwood species are found in
Montana and Wyoming, but the plains cottonwood is not found beyond
lower elevations of the eastern slope of the Rockies and their foothills,
while the narrow-leaved cottonwood, the dominant species in the Rocky
Mountains, does not extend beyond the western slopes of the Rockies and
Bitterroots, leaving the black cottonwood as the predominant species
along the Columbia River and its tributaries (Earle and Reveal 2003:206207). On July 26, 1806, Lewis found the three species growing together
along the Two Medicine River, in modern Montana (Reveal and al. 1999:
n. 152).
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Bibliography
Cutright, Paul Russell. 1969 . Lewis and Clark: Pioneering
Naturalists. University of Nebraska Press, Lincoln and London.
For cottonwoods, see pp. 86, 107, 123, 131, 139, and 159.
Earle, Scott A. and Revea, James L. 2003 . Lewis and Clark’s
Green World, The Expedition and its Plants. Farcountry Press,
Helena, MT.
Nuttall, Thomas. 1849 . The North American Sylva. Smith & Wistar,
Philadalphia. 3 volumes.
Reveal, James L., Moulton, Gary E., Schuyler, Alfred E. 1999 . The
Lewis and Clark collection of vascular plants: Names , Types, and
comments. Proceedings of the Academy of Natural Sciences of
Philadelphia 149: 1-64, 29 January 1999
Thwaites, Reuben Gold . 1959 . Original Journals of
Lewis and Clark expedition 1804-1806. Antiquarian
Press LTD, New-York (First Published 1904-1905).
Volume 4.
Internet Resources
Fact sheet page on cottonwoods, Great Plains Nature Center
website - http://www.gpnc.org/cottonwood.htm
United States Department of Agriculture (USDA) Plant Database,
http://plants.usda.gov/index.html
The text of the University of Nebraska edition of the
Lewis and Clark journals edited by Gary Moulton [The
Definitive Journals of Lewis and Clark - By Meriwether
Lewis and William Clark, set of 13 volumes, 2002 ] is
available at “The Journals of the Lewis and Clark
Expedition Online Edition” http://lewisandclarkjournals.unl.edu/
Dominique Harre Rogers
Edited by Rusty Russell
“Lewis and Clark as Naturalists” website
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