Northern Prairie Wildlife Research Center
Smith Grove is an old-age stand of large cottonwood trees on the west side of the Missouri River approximately 25 miles north of Mandan. The land on which these trees live was owned by the George Smith family. The Smith family felt a strong sense of responsibility for the care and protection of the large cottonwoods, and in 1971, with substantial public support, sold this property to the North Dakota Game and Fish Department. The area, a 23.7-acre tract, is designated a state wildlife management area, and will forever be held in public trust by the Department.
| The most striking thing about the cottonwoods at Smith Grove is the
sheer size of some trees. They are old. They are large. They are impressive.
While humans are fascinated and impressed by things that are big, it is
not the size of the trees on which we should focus, but all that has happened
to the riverine system during the life of these trees. They are living
monuments to the changes in Missouri River ecology over the past 200 years.
When the large, old cottonwoods of Smith Grove were seeds, 250-300 years ago, the Missouri was a much different river. It ran unchecked as it passed through the state, flooding frequently, and continually recreating itself. Shifting channels and the scouring and redeposition of sandbars and shoreline made the Missouri River perfect habitat for cottonwood trees.
The release of seed from cottonwoods was in sync with reduced natural river flows in summer. Seeds found their way to newly-formed sand bars and exposed shorelines and, as a result, young cottonwood forests came to life. With perpetual renewal of habitat needed for new cottonwood growth, the forest component of that river system was viable and healthy. Uneven-aged stands of cottonwood, from seedlings to old-growth, and everything in between, thrived along the entire Missouri River corridor through the state.
Four-year-old Rachel Power, Bismarck give us some perspective on the size of this cottonwood at Smith Grove. It is estimated the tree is more than 250 years old.
Alteration of the Missouri River has significantly reduced the natural processes needed for cottonwood regeneration. Natural river flooding, shifting channels and sandbars are all needed to establish young cottonwoods like these.
| This forest component of the Missouri River System is largely gone
today, and that which remains is mostly old and dying. The majority
22,000 acres of what was the cottonwood forest of the Missouri
River in North Dakota is inundated by water held by Garrison and Oahe
dams. In addition, dams have eliminated natural river flooding, shifting
and meandering of channels, and have significantly reduced creation of
sandbar habitat all processes needed to establish young cottonwoods.
In areas where older and larger cottonwoods are found along the river, few young cottonwoods are present. The canopy and plant debris of older trees stops the full sunlight needed for successful germination and growth. Under the current flow regime of the Missouri River, we can only expect the cottonwood component of the river forest to continue its decline.
Why should we care? More than 100 plant species are associated with cottonwoods through the succession from seedlings to mature forest. Breeding bird densities and the number of species increase throughout the life of a cottonwood stand. The kind and number of plant and animal species associated with cottonwood forests continue to change throughout the forest's aging. The more varied the ages of cottonwoods in the forest, the more different combinations of plant and animal interactions that occur.
If any growth stage of the cottonwood component is removed, then some plant and animal species will not be able to meet their life requisites. The interrelationships are complex, and the effects of changing or eliminating these interrelationships are far reaching.
What may be even more significant is difficult to explain. We see trees. But if we look deeper, we should see the pure expression of something else that is living; something that has just found a way to live, to express itself in this particular environment at this particular time.
Cottonwoods have unique characteristics as living things that allowed them to contribute to the interactions of many other living and nonliving things. The environment that allowed that life to express itself has changed, and the expression of life that is a cottonwood probably will leave the Missouri River System. Simply put, few cottonwood seedlings are completing their life cycle to replace towering giants at Smith Grove.
We should think about that; and remember their long-standing role as part of the complicated mix of plant and animal life, natural processes, and non-living elements that make up the Missouri River System.
*Darren Bruning is the Game and Fish Department's assistant wildlife chief.