Carroll County officials say two children were injured, one of them seriously, when a tree fell on them at a county-run nature camp. County spokeswoman Vivian Laxton says a 9-year-old boy and a 10-year-old girl were taken by ambulance to a local hospital. The boy, who was seriously hurt, was then transferred to Johns Hopkins Children's Center. The girl was treated and released. Laxton says the tree fell shortly before 10 a.m. Tuesday at Hashawha Environmental Center north of Westminster as the campers were preparing to go on a hike. Adults on the scene called 911. The Carroll County Sheriff's Office is investigating. It's not clear why the tree fell, but Laxton says there were wind gusts of up to 35 mph in the area.