A 20-year-old horse trail guide at southern Indiana’s Brown County State Park was killed Sunday, authorities say, when she was hit by a falling tree limb. State conservation officers say Chelsea Lovett of Granger in northern Indiana was on horseback leading a ride about 12:30 p.m. when a dead tree fell, catching the limb of another tree that struck her. Lovett died at the scene. Police say a second rider was thrown from a horse and suffered minor injuries. Lovett was a wildlife management major at Purdue University and Penn High School graduate who had taken the spring semester off to work at the state park’s horse stables.