The emerald ash borer, a beetle, and thousand cankers disease, spread by another insect, threaten the trees, the Nashville Tennessean reported Sunday.
The beetle has already destroyed millions of trees in other states, and it recently showed up on a log at a Tennessee truck stop; thousand cankers disease was recently discovered for the first time in the state.
"We will be working closely with federal officials and other stakeholders to determine the extent of the infestation and to take steps to limit its spread," Tennessee Agriculture Commissioner Ken Givens said a prepared statement.
Ash is commonly used to make hardwood flooring, and about 10 million urban ash trees valued at $2 billion are potentially at risk, the Tennessee Department of Agriculture Division of Forestry said, but an estimated 261 million ash trees valued up to $9 billion are growing on state and private timber lands.
There are about 1.4 million black walnut trees valued at $1.37 billion in Tennessee's urban areas and an additional 26 million black walnut trees grow statewide.
Officials urged people not to move firewood from place to place, and not to buy or move firewood purchased outside the state.
Copyright 2010 United Press International, Inc. (UPI).