One of Many Firsts: Lewis and Clark Nature Trail

By editor

Great Falls, Cascade County, Montana

On a clear morning of June 12, 1805, Meriwether Lewis stood amid the cottonwood groves near what we now call Great Falls, Montana, and recorded a discovery that quietly marked the Corps of Discovery’s detailed encounter with the natural world of the Upper Missouri. He described the narrowleaf cottonwood (Populus angustifolia) as "a tree with a leaf like that of the wild cherry." This simple observation was part of a larger catalogue of species that Lewis and Clark documented in this region, many for the first time by European science. The cutthroat trout (Oncorhynchus clarkii), western meadowlark (Sturnella neglecta), swift fox (Vulpes velox), thirteen-lined ground squirrel (Ictidomys tridecemlineatus), and Brewer’s blackbird (Euphagus cyanocephalus) were among the many creatures noted as new to the explorers’ journals.

The narrowleaf cottonwood, a tall and slender tree adapted to the floodplains of the Missouri River, played a far greater role in the lives of both indigenous peoples and the expedition than a mere botanical curiosity. Its presence was woven tightly into the survival of the native tribes of the Plains and the passage of the Corps itself.

Lewis’s words on June 12 also noted the close relationship between beavers and cottonwoods: "The beaver appear to be extremely fond of this tree." Indeed, the beaver (Castor canadensis) has long shaped riverine landscapes by selectively feeding on cottonwoods, promoting the dynamic processes of floodplain ecology. The cottonwood’s role in these ecosystems cannot be overstated. Its seeds, released in the spring, ride on the swollen waters of snowmelt floods, lodging in freshly deposited silt along riverbanks. This natural cycle allows young saplings to establish themselves above rising waters and winter ice, perpetuating the groves that fringe the Missouri River.

For the Plains tribes such as the Blackfeet, Crow, and Salish, the cottonwood was almost as vital as the bison. Nearly every part of the tree found practical use. Leaves served as poultices to treat wounds and swellings. Buds yielded a bright yellow dye, a rare and valuable pigment in their crafts. The inner bark, soft and fibrous, was consumed by horses and people alike during times when other food was scarce. Branches supplied firewood, while roots and inner bark could be employed as tinder and firestarters. Medicinal teas brewed from the bark were used to alleviate various ailments. Even twigs were gathered as supplemental fodder for horses during harsh winters. These uses demonstrate an intimate knowledge of the cottonwood’s properties and an economy of resourcefulness born of necessity.

The Corps of Discovery relied heavily on cottonwoods as well. In their journey to ascend the Upper Missouri, the expedition built dugout canoes and paddles from these trees. The cottonwood’s light, workable wood made it suitable for crafting vessels that could navigate the river’s currents. When the explorers reached the Great Falls, a series of five waterfalls spanning nearly ten miles, they faced a formidable obstacle. To bypass these falls, the men portaged their boats and gear overland. The cottonwood’s pliable wood was fashioned into cartwheels, enabling the transport of the dugouts and supplies around the falls. This ingenuity underscored the intimate relationship between the expedition and the natural materials of the land.

Lewis and Clark’s journals reveal a keen eye for detail and a scientist’s curiosity. Beyond mere survival, their observations contributed to expanding the knowledge of North American flora and fauna. Lewis’s note about the cottonwood’s leaf shape might seem modest, yet it was the first formal description of the species. His words, "a tree with a leaf like that of the wild cherry," link the new world to familiar forms of the old, bridging continents through botanical analogy.

Yet despite the cottonwood’s historical significance, the groves that once lined the Missouri River are vanishing. The steamboats that began to navigate the Missouri in the 19th century consumed vast quantities of cottonwood fuel. This demand, coupled with the clearing of riverbanks for agriculture and settlement, diminished the extent of these forests. Today, threats persist. Beaver populations, although beneficial for river ecology, can severely damage young cottonwoods by gnawing on their trunks. Grazing cattle strip bark and trample saplings, further reducing regeneration. Additionally, the construction of dams along the Missouri has altered the natural flooding regime vital for seed dispersal and growth of cottonwood saplings. Without the spring floods depositing silt and seeds above the high-water line, cottonwoods lose their foothold.

The plight of the cottonwood groves carries broader ecological implications. Approximately three out of four Montana wildlife species depend on riverside habitats for food, shelter, and breeding grounds. The loss of cottonwood forests threatens the integrity of these riparian zones, affecting songbirds, mammals, and fish alike. The western meadowlark, a species first documented by Lewis near Great Falls, nests in these habitats. Similarly, the cutthroat trout relies on the cool, shaded waters that the cottonwoods help maintain.

As I reflect upon the land the Corps of Discovery traversed, I am reminded of the intricate relationships between species and their environments. The narrowleaf cottonwood is not just a tree; it is a linchpin in the web of life along the Missouri River. The explorers’ journals offer a snapshot of a landscape in flux, one that has changed dramatically in the centuries since that June day in 1805. Yet the lessons remain clear. To understand this place, we must attend to the details -- the shape of a leaf, the habits of a beaver, the lifecycle of a floodplain tree. In these particulars, the story of Montana’s natural heritage unfolds.

See also

• One of Many Firsts at Great Falls, Cascade County
• Lewis and Clark Portage Route at Great Falls, Cascade County
• Lewis and Clark Passed Here at Great Falls, Cascade County