Marc Fallow has faithfully watered and mulched the 60 oak trees in Logan Circle for 24 years. So when he discovered large portions of bark missing from about 15 of the smaller trees on Feb. 7, he “was heartbroken.” Fallow says at least three of the trees won’t survive. The damage could have taken place anytime after Feb. 4, says Lt. Keith Horton of the federal Park Police, which has jurisdiction over the park. In the aftermath, an all-points bulletin went to community e-mail lists: “[R]emember, this is someone running around with a knife….Don’t let him continue to kill the trees,” resident Mary Brown wrote. But the e-mail was premature, Horton says—Park Service arborists doubt the damage was caused by a knife. Or a human, for that matter: “It was caused by an animal,” Horton says. “It could be some kind of dog.” —Mike DeBonis