Cedar trees, like most trees, must be watered deeply and maintained well. Keeping the trees pruned, watered and healthy will reduce the risks of fungal infections, insect infestations and mineral and nutrient deficiencies.
Cedar trees may die due to lack of water, sunlight or infection. Cedar trees need direct sunlight, so cut back or remove any light blocking growth or vegetation. Water the tree regularly and deeply, 1- to 3-inches per week during the summer months. A well watered and well-lit tree fights off disease and pests.
Inspect your tree for bark damage, especially near the root collar. The root collar is the area between the roots and the trunk. Lawn mowers and lawn equipment can damage the bark in this sensitive area allowing moisture and insects to infect and rot the tree. Protect this area by placing mulch around undamaged trees or fencing around damaged trees.
Needle blight, nematodes, rust and bark beetles are all common diseases found on and in cedar trees. If your tree is infected, you should contact a licensed arborist who will remove dead limbs, diagnose the problem and provide treatment.