Usually, hosting a variety of birds in your trees is half the joy of having them. But some birds are considered unwelcomed guests, and woodpeckers are at the top of that list. As they peck through your trees’ bark to find sap, they leave behind rows and rows of drilled holes. While woodpeckers rarely kill trees, those holes leave the trees vulnerable to disease and burrowing insects. Follow these three tips to protect your tree trunks.