Shade trees are a key part of a home's curb appeal. They help reduce energy bills, give families a pleasant place to relax, and provide habitat for songbirds. But these suburban fixtures are living things, and like all living things, they have enemies.

For homeowners with shade trees, the emerald ash borer is the insect equivalent of an unstoppable monster from a B-movie. In just a few years it has spread to cover two-thirds of the US, leaving empty spaces where ash trees once provided a welcoming canopy.

If there are trees in your yard, take these steps to protect your shade and your property value.

Identify. Find out whether you really have an ash tree. There are several trees that mimic ash, but are safe from the emerald ash borer.

Evaluate. Signs of infestation include dead or dying leaves near the crown of the tree, D-shaped holes in bark, and suckers growing near the base of the tree.

Decide. Not all trees can or should be saved. Good candidates are healthy, planted in the right spot, and add value to the land. Ash trees that are less than 20 inches in diameter can be treated by homeowners. Larger trees need professional attention. Even if you choose not to save the tree, something will have to be done if it dies. Deciding what to do before that happens lets you budget for treatment or removal.

Help Trees Stay Healthy

Give your tree the best chance possible to fight off invaders. Make sure it gets the right amount of water and fertilizer. Roots need to breathe, so don't pile mulch up against the base of the tree. Instead, leave a gap so air can circulate. Keep the tree pruned: Damaged branches are an invitation to insects and fungi.

Treatment Options

Emerald ash borer is treated with a soil drench around the trunk of the tree. Do-it-yourself treatments must be done between the start of April and the middle of May in order to interrupt the insect's life cycle. DIY methods are unlikely to work on larger diameter trees, which must be treated by a professional.

Professional tree care specialists have access to stronger pesticides and specialized equipment that can deliver chemicals more effectively than a simple drench can do.  In many cases, these treatments can also be done later in the year.

If All Else Fails

If your ash tree can't be saved, it may be possible to replace it with another species that will provide some shade in several years. Contact an arborist or your university extension to find out which fast-growing shade trees do well in your area. To learn more, speak with someone like Advanced Arbor Care.