Tree Rot 101: What You Need to Know

You probably have a tree in your yard you regularly admire. Maybe it towers over your home, shading you in the summer or perhaps its stature is shorter and produces beautiful blooms each spring. It may be a tree you’ve tied a swing to or one you gaze upon each morning over a cup of tea.

But what if you awoke one day to realize your tree wasn’t quite right. You hoped the problem you eyed would resolve itself, but what if it continued to worsen? That’s when it’s time to call your local arborist for a diagnosis.

When your tree begins to deteriorate, it may be a result of tree rot – more commonly referred to as heart rot disease. This is a fungal disease that affects mature trees, literally rotting your tree from the inside out as it starts in the center of the trunk or branches.

In fact, unless you notice your tree is beginning to lean, this disease will remain invisible until fruiting bodied – which looks like mushrooms – appear on the outside of the tree.

While any hardwood tree is susceptible to this tree rot, if your tree is old, weak or experiencing other environmental stressors, the risk is increased.

The First Sign
In addition to unexpected tree leaning and the mushroom-like growth on the outside of the trunk, there are a few other clues to look out for. If you notice the leaves are wilting or the tree growth has slowed or stunted, these may also be signs of internal tree rot.

Additionally, if you can see inside the trunk from a previous cut or injury, you may be able to identify the rotting taking place.

A few more indicators of a problem include dead branches littering the ground, fine sawdust near the base of the tree, cracked sidewalks caused by uprooting, as well as multiple trunks splitting at what looks like a “V” rather than “U” shape.

Unfortunately, unless you can actually see the tree rot, the symptoms associated with heart rot disease are similar to other tree conditions. For this reasons, it’s advisable to contact an arborist. This specialist will be able to diagnose the problem with your tree, hopefully saving it before its disease progresses too far, with the only option as tree removal.

Types of Heart Rot
When you notice tree rot, then your tree has been attacked by a fungus. This can manifest in the following three ways.

Brown Rot – This is the most serious version. It causes your tree to decay, dry out, and crumble into pieces.

White Rot – This is still severe as it too causes tree decay, but the wood will feel moist and spongy instead.

Soft Rot – This can be caused by a fungal or bacterial infection. While it will still lead your tree to decay, the process is much slower and causes the least structural harm.

Prevention is Key
If your goal is to ensure your tree thrives, then the key to dealing with heart rot disease is prevention. Here are just a few tips to keep your trees healthy.

-Mulch should be used, but should not be added immediately adjacent to the base of the tree, so create a barrier between the root crown and the mulch to eliminate any excess moisture.

-Stressed trees are much more susceptible to tree rot. Use this knowledge to check for and resolve any stressors you can, like insect infestation or limited drainage.

-Choose a fertilizer packed with phosphorus to promote root growth. A fertilizer with the numbers 0-20-0 or 0-46-0 is often recommended, but check with a tree specialist to double check you are using the best one for your size and species.

-Prune away dead branches or those that have sustained injury. Also, cut away any offshoots – called suckers. Each of these is taking energy away from the tree that it needs to heal itself. If you are hesitant to take this on yourself, it’s best to leave this job to a tree professional. Any wrong cut can cause more harm.

Treating Heart Rot
Once your tree is rotting, it’s not likely to survive. If those mushroom-like growths are present, there is no recommended treatment. In fact, the best solution at that point is tree removal and preventing the spread to other trees.

Tree Removal is Often Required
Once fruiting bodies appear on the outside of the tree, the heart rot disease has progressed to a point where it’s unlikely your tree can be saved.

While it may take a few seasons to fully decompose, a rotting tree causes trunk and branch weakness, which can lead to dangerous situations. If the tree in question is near your home or another structure, power lines, or the like, it will create an emergency situation when it falls. In this instance, it’s often advised that your tree is removed.

It’s no hidden secret that tree removal can be a complex and potentially expensive undertaking, so your instinct may be to hold off. However, it’s essential to remove potentially dangerous problems from your property.

For this reason, you need to regularly check your tree for signs of uprooting. Pull back any ground covering from the base of your tree and look closely for cracked or raised soil. These are signs of uprooting.

Similarly, the tree growths mentioned above are also a clear indicator of trunk rot, and once this spreads to the roots, the tree is at great risk of falling over. At this stage, your tree is also at risk for the trunk to simply buckle or break.

If you notice any of the above, immediately call an arborist to assess the situation as the next gust of wind could cause your tree to come toppling down.