Officials plan to announce some great news Monday morning in the Arnold Arboretum —- the tree-killing Asian Longhorned Beetle has been eradicated from the Boston area. Jamaica Plain has been a quarantine area since 2010, when six infected trees were found near Faulkner Hospital. No firewood was to be brought in or out of JP. The beetle, which eats maples, birches and elms, can decimate whole forests or vast stretches of urban trees. That's what it did in Worcester, where thousands of trees had to be destroyed.