BOSTON (AP) — Arborists in the Boston area are stumped by the theft of burls, those giant knots on the trunks of most tree species prized by woodworkers for their intricate grain.

Greg Mosman, the city of Boston’s arborist, noticed burls cut from trees during routine inspections at Franklin Park last spring. He’s since noticed them missing from trees in other city parks, and has heard they have been cut from trees in Brookline and Watertown.

He tells The Boston Globe (http://b.globe.com/RAh9fJ ) in most cases the burls are cut with chain saws. Cutting off a burl can shorten a tree’s life.

Dave Eaton, president of Central New England Woodturners, says a burl could fetch anywhere from $50 to $500 depending on size and quality.

Mosman urges anyone with knowledge of the thefts to contact police.

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