How Landsat Helps Tennessee: Crops, Clean Water and Pine Forests

From the flat, rich soil of western Tennessee to the Appalachian Mountains in the east, with rolling hills between, "the Volunteer State" has a wealth of natural resources.

• The Tennessee, Cumberland and Mississippi Rivers carry economically crucial navigation and offer recreation.
• 14 million acres of hardwood and softwood forest cover roughly half the state, contributing an estimated $24 billion and nearly 100,000 jobs.
• Across more than 400 miles, farms produce cotton, corn, soybeans, poultry, horses, cattle, goats, hay, vegetables, nursery crops and tobacco.
• Power comes from coal, nuclear and hydroelectric sources.
• Tourism balances music attractions and historic sites with natural ones such as Great Smoky Mountains National Park, which had 14.1 million visits in 2021, the second most of any National Park Service site.

Landsat's broad view and long archive have made it useful to land managers and state agencies monitoring these resources. Three examples follow.

Estimating crops

Landsat data are a crucial part of the U.S. Department of Agriculture's Cropland Data Layer, which maps crop type, acreage and yield in Tennessee and other states. Each year it shows what is planted, how much, where, and how land use is changing — helping farmers and the industry make sound decisions. University researchers have also used Landsat greenness and wetness indices to predict cotton yield in an irrigated field in western Tennessee.

The 2021 Cropland Data Layer for Tennessee: cotton (red) in the west, corn (gold), soybeans (dark green), grass and pasture (light yellow-green) and forest (medium green); grey is developed land and dark blue water. Image: U.S. Department of Agriculture.

Watching water quality

Satellite data can also support public safety — for example by helping identify harmful algal blooms. Researchers at the University of Tennessee at Chattanooga and the Hamilton County Geospatial Technology Department used Landsat surface reflectance data to estimate turbidity, an indicator of water clarity and quality, in the Tennessee River, a key water supply for cities such as Chattanooga. Stormwater can carry excess nutrients and chemicals from the city into the river, and a turbidity model can help officials monitor water quality continually.

Chattanooga and the Tennessee River on August 15, 2019, one of three dates used in the turbidity study. Image: U.S. Geological Survey.

Tracking pine forests

With 30-meter resolution and 50 years of images, Landsat is well suited to following landscape change. Tennessee State University researchers analyzed Landsat data from 1988, 1999 and 2016 to track southern yellow pine forests in east-central Tennessee — loblolly (Pinus taeda), shortleaf (P. echinata) and Virginia (P. virginiana) pine — showing the gains and losses that can guide management of these commonly harvested species.

Forest in south-central Tennessee. Photo: National Park Service.

Landsat for the nation

• The USGS National Land Imaging Program supplies satellite and other remotely sensed data to government, commercial, academic and public users; Landsat data are available worldwide through the USGS Earth Resources Observation and Science (EROS) Center.
• Landsat is the most widely used land remote sensing source among federal civilian agencies, and local, state and Tribal agencies use it too — for decisions on land, water and resources that protect life and property, the environment, science and the economy.
• Businesses build customer applications on it, and commercial imaging firms use it to refine their products.
• A 2017 USGS study put Landsat's annual economic benefit in the United States at $2.06 billion, far more than it costs to build and run.
• Landsat 8 and 9 image Earth's land every 8 days. NASA and the USGS were reviewing an architecture study to shape Landsat Next, extending a 50-year record — the world's longest of Earth's land surface.
• Consistent data and a no-cost policy let users study long-term change over large areas, and new cloud computing tools put Landsat into decision-support tools every day, much like global positioning systems and weather data.

Sources

Based on "Tennessee and Landsat," U.S. Geological Survey Fact Sheet 2022–3063, U.S. Geological Survey; a work of the United States government in the public domain.