RIGA, Latvia — In the Baltics, there may be no war on Christmas but there’s a pretty prickly one over the tree.

For six successive seasons, Riga and Tallinn — the capitals of Latvia and Estonia — have waged a feud over which was the site of the world’s first decorated Christmas tree. Riga says it was first, in 1510. Tallinn claims a much earlier event, in 1441.

More than civic pride is at stake. Christmas-themed travel has become extremely lucrative, especially in the ice-choked north, where there are no swaying palms to lure the winter-weary.

And this year, the rivalry has taken on both an added urgency and a darker tinge.

Simmering tensions between Russia and NATO and the faltering Russian economy have squeezed tourist traffic from what had been a prime source of vacationers. And the deadly attack on Berlin’s Christmas market this week has raised fears that holiday markets, in general, may see fewer customers for their hot spiced wine and sugary treats.