YELLOWSTONE ARBORETUM
" Stewards of the Natural Environment "
Billings, Montana @ ZooMontana
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The Plains Cottonwood
A Montana Keystone Species
Plains cottonwood trees are considered a keystone species because they play a disproportionately large role in the ecosystem of riparian areas, particularly along rivers and floodplains, by stabilizing stream banks with their root systems, providing crucial habitat and food sources for a wide variety of wildlife, and creating shade and shelter for other plants, all while being one of the first trees to colonize newly exposed riverbanks, essentially shaping the entire ecological community around them.
Cottonwoods can live to be over 100 years old. There are cottonwoods on the Great Plains today that were living when the great herds of bison still roamed the prairie. Cottonwoods are related to poplars and aspens, with which they share the same shaking, shimmering leaves.
The heartwood typically rots from the larger limbs and trunk of a cottonwood. If a windstorm breaks one of these hollow branches off, providing access to the interior, they can provide homes for squirrels, raccoons, and opossums or even a hive of honeybees.
These trees are facing various challenges due to the changing climate, including altered streamflows, seed dispersal, and riparian forest quality. As a result, the Yellowstone Arboretum has selected this tree for "Protected Status" and is in the process of propagating new seedlings to further the population.
The tree in front of you has been named "The Five Sisters" and is one of the original trees found on the property.
