DNR Finds Last Year's Derecho Damaged Or Destroyed 7 Million Trees Across Iowa

The powerful derecho storm that blasted across Iowa on August 10, 2020 damaged or destroyed an estimated seven million trees statewide. A newly-released analysis from the Iowa Department of Natural Resources catalogues those impacts, which amount to millions of dollars a year in lost benefits.

For Iowans impacted by last year’s derecho, the images of what that storm did to the state’s trees will not be soon forgotten. Sentinel oaks shattered by 140 mph winds. Stately maples entirely uprooted. Snow plows driving the streets of Cedar Rapids in the middle of August, not to clear snowy slush, but to clear trees. And later, the gargantuan piles of woodchips that stretched on and on, enough to fill a skyscraper, a city worker said.

For Nick McGrath, the devastating impact to Iowa’s woodlands, urban forests, parks and yards was difficult to put into words.

“It's heartbreaking. I don't know how else to describe it,” McGrath told IPR in July, on a visit to Bever Park in Cedar Rapids to survey the damage there.

A community disaster recovery coordinator jointly hired by the DNR and the nonprofit Trees Forever, McGrath works with municipalities across the state to strategize best ways to replant in the wake of the derecho.

McGrath also oversaw the publishing of the DNR’s assessment of the impacts to the state’s urban tree canopy, which estimates that more than four million were lost in urban areas alone.

“I think this does provide a really, again, sad but unique opportunity to replant for resiliency. So taking a look at what is left after the storm and maybe those species are what we should be focusing on as a state,” McGrath said.

The analysis relied on data collected during an aerial flight survey of the impacted area, as well as urban forest statistics.

Quoting from the National Oceanic and Atmospheric Administration, the report notes that “[t]he strongest estimated wind speeds in the vicinity of Cedar Rapids, Iowa, were among the highest wind speeds ever recorded during a derecho event, peaking at about 140 mph.”

The derecho is considered “the costliest thunderstorm event in recorded history in the United States."

In terms of tree damage, the DNR analysis estimates that derecho impacts to the urban tree canopy alone amount to $90 million in lost carbon storage, and more than $20 million a year in total lost benefits.

Some residents say they can physically feel the absence of the trees, looking out over denuded landscapes. And some say they’re feeling the impact on their bank accounts as well, in the form of higher utility bills due to the lack of shade this summer.

McGrath says it will take sustained replanting efforts across the state for years to come, in order to replace what was lost that day. He’s hopeful that the children and grandchildren of Iowans who lived through the derecho will experience the wonder of a new generation of majestic trees.

“I think we could see some real results in 30 to 60 years. Maybe. If we start now,” McGrath said. “But the more we delay that, the longer it takes. If you think about the trees that we lost, if you want to regrow your 100 year old oak, it's gonna take 100 years.”

Overview of DNR’s assessment of derecho’s impacts to trees

• an estimated seven million trees damaged or destroyed across rural and urban Iowa
• 32,773 acres of urban tree canopy damaged
• 4,424,426 trees lost in urban areas alone, approximately 12.9% of the total canopy
• damage to urban tree canopy amounts to $90,294,408.12 in lost carbon storage
• total losses from damaged urban tree canopy amount to $20,238,846.62 a year
• an estimated 953,224 trees damaged in Linn County alone