Root rot can kill a tree before you even know it's infected, and there is little you can do to stop the process. Rot is typically caused by a combination of factors, including overly wet soil and a fungal or bacterial infection. Once it spreads to the majority of the root system, the only choice is to have the tree removed before it fully dies and becomes a falling hazard.

1. Canopy Die Back

As the roots suffocate and rot, nutrient flow to the canopy is blocked. Often, you will notice dieback beginning at the furthest branch tips and slowly moving inward toward the trunk. Depending on the extent of the rot, only a section of the canopy may suffer dieback or the entire canopy may dieback evenly. Dieback can be caused by many things, so a tree service will need to verify that root rot is the cause.

2. Yellowing Leaves

Yellowing or browning leaves out of season — when they should still be green — is a major sign of rot. Sometimes the leaves will first become speckled with black or brown spots due to fungal infestations that are causing the rot. Often, the leaves on an affected tree will yellow or brown but they won't fall off in large numbers as they would for other health issues.

3. Trunk Fungus

Fungus growing along the trunk, around the base of the trunk, or from the soil directly above the root system means that the rot is quite extensive. Visible fungus means that there is an entire network of fungal mycelium already breaking down the roots and trunk of the tree, and it is now sending out the reproductive fruiting bodies which you can see. The fungus may also appear as mushrooms or shelf fungi on the trunk.

4. Trunk Cankers

A trunk canker is a wound on the side of the trunk that is wet or weeping sap. The cankers are a result of part of the trunk dying, possibly due to a lack of oxygen because of root rot. Fungus and bacteria then infest the dead spot and cause the nearby living tissues to weep sap in an effort to seal off the wound.

5. Leaning

A tree that suddenly begins to lean is a major danger on your property. This happens when the rotted roots begin to give out and can no longer support the weight of trunk and canopy. Sometimes a tree may not lean immediately, but you may notice that the soil around the base of the trunk looks churned up after a windy day. This churning is caused by the tree moving in the ground because the roots are no longer anchoring it in place.

Contact a tree removal service if you suspect a tree is suffering from root rot.