ROME (AP) " Rome's official Christmas tree is losing so many needles so fast it has become a jolly joke for city residents.

The 21-meter (70-foot) high tree, which was lit up on Dec. 8, started shedding needles badly as soon as it was hoisted in place in the middle of bustling Rome's main square, Piazza Venezia.

Romans have dubbed the tree The Mangy One. They're also needling Rome's mayor about the tree, which costs 48,000 euros ($57,000) to transport from South Tyrol, an Italian Alpine region.

The city said Tuesday it is investigating why the tree is ailing.

Despite the tree's 600 silver-colored decorative balls, the half-bare branches lend the square a forlorn rather than festive look.

Critics note that across town, the Vatican's Christmas tree, from Poland, looks healthy.