Have you been seeing dead leaves on trees in your backyard or in parks throughout Cincinnati?Scenes like that are common now, according to officials with Cincinnati Parks.So why are there so many dead leaves? Cicadas are to blame, park officials say.Female periodical cicadas have cut into twigs all over Greater Cincinnati. They do this so they're able to inject their eggs inside. RELATED VIDEO ABOVE: 2038 Brood X cicadas make their first appearance in CincinnatiFemale cicadas usually lay 20 to 30 eggs in each slit of a twig. A female can lay 400 to 600 eggs in a lifetime.Some twigs on trees are killed when cicadas do this. Park officials say that's "too bad" because more cicada eggs actually hatch in live twigs instead of dead twigs."Cicadas' favorite egg-laying trees are healthy ones surrounded by grass," Cincinnati Parks wrote on Facebook Tuesday.