Smith Falls
Encyclopedia
Smith Falls, at 63 feet (19 m), is the highest waterfall
Waterfall
A waterfall is a place where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.-Formation:Waterfalls are commonly formed when a river is young. At these times the channel is often narrow and deep. When the river courses over resistant bedrock, erosion happens...

 in the state of Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

. Located 18 miles (29 km) east of Valentine
Valentine, Nebraska
-Demographics:As of the census of 2000, there were 2,820 people, 1,209 households, and 733 families residing in the city. The population density was 1,401.1 people per square mile . There were 1,373 housing units at an average density of 682.2 per square mile...

, the falls is part of Smith Falls State Park and is adjacent to the Niobrara National Scenic River
Niobrara National Scenic River
The Niobrara National Scenic River is located in north-central Nebraska, United States, approximately 300 miles northwest of Omaha. In 1991, Congress set aside 76 miles along two stretches of the Niobrara River for preservation under the management of the National Park Service with assistance...

. The state park was established by the Nebraska Game and Parks Commission
Nebraska Game and Parks Commission
The Nebraska Game and Parks Commission is a public agency of the government of the State of Nebraska in the United States. The commission is charged with stewardship of the state's fish, wildlife, state park, and outdoor recreation resources. The commission is also charged with issuing of state...

 in 1992; in 1996, a footbridge
Footbridge
A footbridge or pedestrian bridge is a bridge designed for pedestrians and in some cases cyclists, animal traffic and horse riders, rather than vehicular traffic. Footbridges complement the landscape and can be used decoratively to visually link two distinct areas or to signal a transaction...

 was built across the Niobrara River
Niobrara River
The Niobrara River is a tributary of the Missouri River, approximately long, running through the U.S. states of Wyoming and Nebraska. The river drains one of the most arid sections of the Great Plains, and has a low flow for a river of its length...

 to provide more convenient public access.

The falls are on a short spring-fed stream that plunges into a small canyon on the south side of the Niobrara. As the canyon is narrow and sheltered from direct sunlight, it is much cooler than the surrounding landscape; this allows a unique set of flora to grow that is atypical for the Sand Hills
Sand Hills (Nebraska)
The Sand Hills, often written Sandhills, is a region of mixed-grass prairie on grass-stabilized sand dunes in north-central Nebraska, covering just over one quarter of the state...

 of Nebraska. The canyon is home to Paper Birch
Paper Birch
Betula papyrifera is a species of birch native to northern North America.-Description:...

 and an endemic hybrid grove of quaking aspen
Populus tremuloides
Populus tremuloides is a deciduous tree native to cooler areas of North America, commonly called quaking aspen, trembling aspen, American aspen, and Quakies,. The trees have tall trunks, up to 25 metres, with smooth pale bark, scarred with black. The glossy green leaves, dull beneath, become golden...

 (Populus tremuloides) and bigtooth aspen (P. grandidentata).

During the Wisconsin glaciation
Wisconsin glaciation
The last glacial period was the most recent glacial period within the current ice age occurring during the last years of the Pleistocene, from approximately 110,000 to 10,000 years ago....

, which ended around 10,000 years ago, north-central Nebraska was much cooler than it is today. The ice age
Ice age
An ice age or, more precisely, glacial age, is a generic geological period of long-term reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental ice sheets, polar ice sheets and alpine glaciers...

 climate supported boreal forest
Taiga
Taiga , also known as the boreal forest, is a biome characterized by coniferous forests.Taiga is the world's largest terrestrial biome. In North America it covers most of inland Canada and Alaska as well as parts of the extreme northern continental United States and is known as the Northwoods...

 trees like birches, spruces
White Spruce
Picea glauca is a species of spruce native to boreal forests in the north of North America, from central Alaska east to Newfoundland, and south to northern Montana, Minnesota, Wisconsin, Michigan, upstate New York, Vermont, New Hampshire, and Maine; there is also an isolated population in the...

, and aspens, all of which currently predominate in Canada. As the glaciers retreated, so did the boreal forest, which is ill-suited for hot, dry summers. However, the cool canyons along the Niobrara sheltered some of these trees. The spruce trees did not survive in Nebraska; the nearest extant population is in the Black Hills
Black Hills
The Black Hills are a small, isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, USA. Set off from the main body of the Rocky Mountains, the region is something of a geological anomaly—accurately described as an "island of...

 of South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...

. Protected by the cool microclimate
Microclimate
A microclimate is a local atmospheric zone where the climate differs from the surrounding area. The term may refer to areas as small as a few square feet or as large as many square miles...

s of the small canyons that feed into the Niobrara River, a small population of paper birches and aspens survive. The continued survival of these trees is threatened by warming temperatures. The paper birch population around Smith Falls is not currently reproducing, and may soon die out.

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