ST. PAUL — The unseasonably warm weather is gumming up Minnesota’s maple syrup season.

Maple trees produce sap only when the weather alternates between freezing and thawing temperatures. The sudden onset of warm weather has disrupted that cycle.

Stu Peterson, the president of the Minnesota Maple Syrup Producers Association, said he usually produces 250 gallons of syrup each spring on his farm near Fergus Falls. But he hasn’t collected any sap this year. And it takes about 40 gallons of sap to produce one gallon of syrup.

Peterson said he’s hearing similar stories from many parts of the state.

He said he could still have a crop if he gets a freeze cycle in the next several days. But once the tree buds bloom, the season is over.