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Garden Guru: Some trees can't be saved

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By John Porter

CHARLESTON, W.Va. - As I drove down the alley behind the house, I realized I had seen the tree before.

Five years ago, I answered a call from the McGraths, an elderly couple in Nitro, about some dead limbs in the maple tree in their back yard. There were no other symptoms, so chalking limbs up to storm damage, I told them to have them removed and monitor the tree for any other symptoms.

Now, five years later, the tree is obviously in distress. On closer inspection, bark is peeling away from parts of the trunk, revealing dead wood beneath, riddled with insects boring through the dead wood.

Up above, the stubs of poorly pruned limbs remain, along with a cap placed over the trunk where an uninformed pruner took over half of the tree out with a cut to the main trunk.

But the thing that catches my eye the most is at the base of the tree.

Radiating upward along the trunk from the ground, the bark is covered with small, whitish shelf mushrooms. This is the final nail in the coffin. The tree must go.

It is a problem that I have seen a few times this year. This tree is infected with a rot fungus.

There are several different ones that can infect trees. This one happens to be called a sap rot, meaning that it infects the living tissue of a tree, causing it to decline in health and eventually die (if it doesn't fall over first).

It is bad news. In fact, I saw a similar maple last week with the same disease. That tree was already dead.

Most people are familiar with what is called heart rot, which is a fungus that infects the interior of a tree and rots the center out. The center of a large tree is actually dead, and this fungus only decays dead fungus.

While it has really no effect on the overall health of the tree, a tree without its center will be much easier to blow over. Just ask my neighbors in Kanawha City who had the tall, 100-year-old pin oak trees lining the streets crush their homes during the summer of the derecho (interestingly, it was a storm the week after the derecho that affected us in Kanawha City).

Afterward, the city and the Municipal Tree Board had all of the trees inspected and began removing those found with heart rot.

Fungi that affect the outer, living tissue of the tree often lie hidden within the tree. The fungi still weaken the tree as they spread, and could even kill it without an outward sign. When conditions are right, though, the fungi will reproduce by forming reproductive mushroom structures on the exterior of the trees.

If you've been in a forest, you may have seen those yellowish-orange shelf fungus on trees. That is an infection, as well. This is a similar infection with a different fungus.

One thing that I think contributes to the spread of these diseases and the development of the mushrooms on the trees is the increase in rains we have had in early summer. Fungus requires water to both grow and to reproduce.

Here in Charleston, we've seen rains almost every day for weeks. It has happened for the last few years that we have a wet period at the beginning of summer. At this point, I think we need to start having an official monsoon season.

Unfortunately, once a tree has one of these infections, there is really no cure. The tree will slowly decline until it dies. One concern is that the weaker trees are more likely to fall and to be blown over by storms in the weakened state.

If a large tree is close enough to a house to cause damage if it falls, I generally recommend cutting it before the tree dies to avoid potential damage to property.

I certainly don't want to come across as a Debbie Downer. Trees are wonderful and we should be planting more of them. The good news is that while these diseases are not curable, they are preventable.

Most times, these diseases infect trees that are stressed. It's not like you have to send your tree away to a resort for a relaxing vacation and massage, but there are things you can do to reduce stress in your trees.

Some stresses are unavoidable, weather being one of them. Too much rain can cause root damage and allow diseases to enter. Storms can break limbs. And as we have seen this year with the ill-fated Leyland cypress, winter damage can allow for diseases to take hold.

But many of the stresses trees face are caused directly by homeowners. The tree I visited in Nitro had been very severely and improperly pruned. This weakens the tree and creates wounds where infection can enter (think of it as a wound on your skin allowing infection in).

People who have their trees overpruned on a regular basis (and you know who you are) open their trees up to all sorts of maladies. Once you top or severely prune a tree, it is the beginning of the end.

Another mode of disease entry is through damage around the trunk from being hit. In the business, we call this kind of damage weed-whackeritis - or sometimes its related malady, lawn-moweritis. Just a little bump can open a wound that will allow a fungus to infect the tree.

Keeping the tree healthy, through fertilizing and watering when the weather is dry, can help. Many times trees can live with these infections for a long time without it presenting a problem. But once branches start to die or the mushrooms start to appear on the trunk, the end is coming close. So keep those trees healthy.

If you do lose a tree, if you can have the fungi positively identified you may be able to find a tree that is resistant to that specific fungus to plant nearby. Upon this recommendation to the McGraths, all I received in return was a hearty chuckle.

"At this point," said Mrs. McGrath, "we only have a few years left! We wouldn't get to enjoy it."

Let's hope that their story of tree misfortune can influence others who enjoy trees in their yards. Be sure to keep them healthy. And stop pruning the life out of them.

n Plant late tomatoes and peppers.

n Add nonseed-bearing weeds to compost.

n Seed late cabbage, cauliflower, kale, corn, beans, Brussels sprouts and broccoli.

n Control cabbage worms with a Bt product such as DiPel.

n Seed or plant endive.

n Enjoy fresh tomatoes and corn on Independence Day.

n Visit the Garden Guru at the Mountain State Art & Craft Fair in Ripley, Thursday through Saturday. Here is my lecture schedule at the fair:

Thursday:

10 a.m.: "Growing Fruits in Containers"

1 p.m.: "Avoiding Common Garden Myths"

Friday:

Noon: "Gardening for Pollinators"

3 p.m.: "Garlic 101"

Saturday:

11 a.m.: "Growing Fruits in Containers"

2 p.m.: "Avoiding Common Garden Myths"

John Porter is the WVU Extension Service agent for agriculture and natural resources in Kanawha County. Follow him on Facebook, Twitter at @WVgardenguru and online at wvgardenguru.com. Contact him at john.porter@mail.wvu.edu or 304-720-9573.


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