Every few years the U.S. Geological Survey and its partners release an updated version of what is known as the “National Land Cover Database.”
In the database, the entire U.S. is broken into 30-by-30 meter squares, which are put into categories like “forested” or “agricultural” using satellite imagery. The resulting data ranges between71-97 percent accurate.
The latest version describes land cover in 2016 and was released this May.
Forests
“Forested” is the largest land cover category in Michigan -- which makes up about half of the state.
There were roughly 45,000 fewer acres of land classified as deciduous, conifer or mixed forest in 2016 than in 2013. But there was an almost equal gain in land classified as “shrub or scrubland.”
Bill Cook, a forester for the Michigan State University forest extension, thinks that land was probably harvested for timber and is now being regrown.
“I suspect much of the ‘shrub/scrub’ area is regenerating clearcuts,” says Cook.
Overall, the amount of land considered “forested” in Michigan has stayed relatively stable over the last few decades, even increasing a bit. And according to the U.S. Forest Service, Michigan’s forests are maturing.
Development
The amount of land considered “developed” has continued to increase in Michigan, although growth was slower from 2013-2016 than 2001-2013. An extra 12,000 acres of developed land were added between 2013-2016.
Within that, there was a loss of what is known as "open development," which is mostly lawns and green space, and gains in "higher-intensity development," which means more roofs and concrete.
Open water
Water areas can vary a lot from year to year. According to the data, Michigan gained more than 3,500 acres of open water between 2013 and 2016. One contributing factor could be that the Great Lakes saw record-breaking water level increases in the same time period.
Detailed land cover estimates for all categories, in thousands of acres, are below.
Land cover category (2001/2013/2016)
Open water, including Great Lakes to Michigan boundaries (25,526/25,533/25,536)
Developed - open (1,779/1,792/1,782)
Developed - low-intensity (1,210/1,224/1,231)
Developed - medium intensity (493/528/538)
Developed - high intensity (192/212/216)
Barren (178/174/165)
Forest - deciduous (8,086/8,052/8,015)
Forest - evergreen (2,006/1,903/1,891)
Forest - mixed (2,844/2,847/2,849)
Shrub/scrub (342/481/522)
Grassland/herbaceous (1,035/987/972)
Agricultural - pasture/hay (1,172/1,125/1,112)
Agricultural - crops (8,469/8,473/8,494)
Woody wetlands (8,070/8,114/8,112)
Emergent herbaceous wetlands (478/438/445)