My red maple

Asked August 1, 2017, 8:27 PM EDT

black streaks up trunk,scaring on two sides leaves seem small and limpy.use to big and full

Washington County Minnesota

1 Response

Thank you for the question. Maple trees are susceptible to insect, disease, or cultural problems. The photos do not allow for accurate diagnosis but the tree trunk may be suffering from a canker fungal infection or if liquid is oozing from the affected area, a bacterial wetwood or slime flux may be occurring.

Cankers can be cut out when present on other tree limbs but not the trunk. A certified arborist should be hired to evaluate the the tree. Cankers can cause structural integrity problems making the tree more likely to fall over in high winds.

Bacterial flux doesn't usually weaken the tree but if the tree is under stress for other reasons, the bacteria can invade the rest of the tree and cause die back.

Both of these conditions can be avoided to a certain degree by avoiding damage to the tree. I see a zip tie encircling a branch and a plant hanger possibly hanging from the tree. Both could cause wounds that allow entry of bacteria and fungus, or in the case of the zip tie, eventually a strangled limb.

Use our self diagnostic program "What's wrong with my plant" to read about different cankers and other problems with maple trees:

How to hire a certified arborist:

Thank you for contacting Extension.