MASON CITY | North Iowa's ash and bur oak trees are at risk the most when it come to invasive species and diseases, according to Paul Tauke, a state forester with the Iowa Department of Natural Resources.
Tauke spoke about the state of Iowa's rural and urban woodlands and emerald ash borer during a Mason City Noon Rotary Club meeting on Monday.
"These forest threats are kind of like a slow-moving ice storm," he said. "We can mitigate the cost of the pest."
Tauke said the effects of the emerald ash borer would have been lessened had Iowans started planning seven or eight years ago, but said there is still time to act.
So far emerald ash borer has been confirmed in Des Moines, Cedar, Allamakee and Jefferson counties. While the Iowa Department of Natural Resources is working to prevent it from spreading, it will likely spread to the rest of the state, killing ash trees, he said.
Over the next 20 years it is expected to cost Iowa $27 million in wood products, $2.5 billion for urban removal and $1 billion in benefits, such as energy savings and property values, Tauke said.
"Once it gets in your community you have a limited time to do anything about it," he said.
Tauke said the best thing communities can do to prepare is to have inventory of their trees and to take care of them.
"A good healthy forest ... is the best defense against exotic and native pests," he said.
Diversity is also important to help lessen the impact of future threats, he said. Tauke noted that maple trees make up a large portion of Iowa's urban forests, which would be at risk if the Asian longhorned beetle comes to Iowa.
Such measures would also help Iowa address other diseases such as bur oak blight, which has been seen throughout Iowa, including in Mason City.
"It starts off with a few brown leaves and then it progresses year after year" until the tree dies, Tauke said.
He said bur oak blight and emerald ash borer are showing up particularly bad this year because of last year's drought.
"With this dry weather the tree isn't able to defend itself," Tauke said.
Forests make up 8 percent of Iowa's landscape and 87 percent of forest land is privately owned. Last year, the state's forest acres decreased by about 40,000 acres for the first time since 1974.
Tauke said the decrease is partially due to Iowa's aging trees, poor management and diseases, but an even bigger part is wooded areas being cut down for farming corn and soybeans.
Tauke said Iowa's forests are important because they create 18,000 wood-product jobs and $4 billion in wood products, and help support a $3 million tourism industry. They also support wildlife.