What Causes Sugar Maple Trees to Suddenly Die?

Verticillium Wilt

• When a sugar maple suddenly dies, verticillium wilt is the first suspected culprit. A soil fungus causes the common disease that invades susceptible plants through the root system. Sugar maples are among the most susceptible of the more than 300 identified vulnerable species. Verticillium wilt symptoms can be slowly evolving and chronic, or acute and suddenly lethal. In cases of sudden death, early symptoms include curling, drying and abnormally red or yellow leaves, defoliation, wilting, and the death of individual branches or entire sections. This disease often occurs in July or August and might be more severe during or shortly after cool weather.

Sap Rot

• Sap or heart rot usually occurs slowly, but it can appear as though it suddenly kills a tree. This is because one or more fungi that decay a tree's wood from the inside out cause sap rot. It starts at the center of a trunk or branch and works its way toward the surface. By the time obvious signs of the disease appear, such as mushrooms or conks, the damage is extensive and death often follows. Sugar maples are susceptible to several of these wood-decaying fungi, including artist's conk, varnish fungus rot, sulfur fungus, oyster mushrooms, parchment fungus, turkey tail and hairy turkey tail.

Freezing Injury

• Freezing injury kills young maple shoots. This occurs when temperatures plummet in the winter or when frosts occur in late spring or early fall. Shoots are especially vulnerable to freezing injury and death when extreme cold trails shortly behind a prolonged period of unusual warmth. Although these cold snaps are a threat to maple shoots, they rarely kill healthy, well-established trees.

Transplant Injury

• Trees and shrubs dug out of their wild or landscaped settings may only have 25 percent of their roots still intact. This, combined with the stress of transplanting and improper care, can lead to the tree's sudden death. Transplant trees in spring after the thaw but before buds begin swelling, or in the autumn after the leaves drop but before the ground freezes. Water the maple two to three days before transplanting and when moving it, keep the roots moist by wrapping them in wet burlap. Replant maples immediately in moist, fertile, well-drained and slightly acidic soil in a hole two to three times wider than the rootball. Keep the soil moist while the tree establishes its roots and use mulch to conserve moisture, control weeds and moderate soil temperature.