A trade association says new U.S. tariffs increased artificial Christmas tree prices by 10% to 15% this year as tree companies reduced their orders and raised prices to cover the higher import taxes.

Inflation has risen in three of the last four months and is slightly higher than it was a year ago.

If roughly 45,000 U.S. longshoremen make good on their threat to strike beginning Tuesday, they could shut down 36 ports from Maine to Texas that handle about half the goods shipped into and out of the United States.