A Wild River
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Growing Old
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Cotton

A Wild River, also, Growing Old, also, Cotton. . , A Wild River , The undammed Little Missouri River floods often, eroding areas of floodplain and depositing new land. This new land next to the river offers plenty of water and sunlight. It is the only place cottonwood seedlings can survive. As the river changes course slowly from year to year, new generations of cottonwood trees grow in its wake. , This natural cycle of flooding and tree growth is disappearing across the Great Plains where most rivers are tamed by dams and do not flood. Without natural flooding, new generations of cottonwoods fail to thrive. Other Species, some of which are invasive, replace old generations of cottonwoods when they die. , , The Next Generation , Plains cottonwoods grow in curved, same-age bands on new land deposited by the river. These generational bands show the river's changing course and history of flooding., Growing Old , In 2010, researchers working in the valley below discovered the oldest known living plains cottonwood. The tree, believed to have sprouted in 1641, and other old cottonwoods are keys to unlocking the history of the region's rivers and climate. , The image below, taken through a microscope, shows a core sample from a cottonwood tree in the park. Narrow annual growth rings indicate drought years during the 1930s Dust Bowl. Growth rings also indicate a more severe drought from 1816 to 1823., Cotton , Cottonwoods are water-loving trees with heart-shaped leaves. Their seeds are well adapted to the wet areas in which they grow. The fluffy, white "cotton" helps the seeds float on the surface of the water and cling to he soil where the water deposits them.