There were an estimated 601 million live trees in South Dakota forests last year, which was a 7.1% increase from five years earlier, according to a new report from the U.S. Department of Agriculture.

The annually published report is titled Forests of South Dakota, and the 2018 edition was published in July. It is based on inventory estimates conducted by the U.S. Forest Service in cooperation with the South Dakota Department of Agriculture, utilizing aerial photographs, satellite imagery and analysis of on-the-ground plots.

The report says South Dakota is home to 1.95 million acres of forest land, mostly in the Black Hills, which is up slightly from 2013.

Ponderosa pine is the dominant forest species in the state, according to the report, which said there are an estimated 352.9 million live ponderosa pine trees in South Dakota. That number is up from previous years, largely due to the estimated increase of 41 million in the number of ponderosa pines measuring smaller than 5 inches in diameter since 2013.

But while younger, smaller trees have proliferated, many larger, older trees have been dying. In fact, so many larger trees have died that the volume of ponderosa pines in South Dakota is estimated to be declining, even as the number of the trees increases. The report says mortality estimates for ponderosa pines are higher than any previous year.

“However,” the report says, “this trend will likely reverse because mountain pine beetle activity decreased to endemic levels in 2016, which should result in less mortality and greater net growth in the future.”

Other trees populating South Dakota forests, according to the report, include an estimated 39.7 million bur oaks, 35 million white spruces, 29.5 million Rocky Mountain junipers, 26.7 million green ashes, and 19.1 million eastern redcedars, among other species.