Trees and Lightening

There are some storms brewing, so I thought I would enlighten folks on some recent discoveries about the effect of lightning on trees.

When lightning strikes a tree, the biological functions of a tree are interrupted--sap boils, steam is created, and at a cellular level, the tree suffers intense damage. However, trees are amazingly resilient. If the lightning only affects a portion of a tree, it may be able to survive and close any visible wounds. Here is some key advice for homeowners.

WAIT.

International experts suggest simply monitoring the tree for potential hazards for AT LEAST A YEAR OR MORE. Internal damage cannot be assessed immediately, and sometimes damage extends to the root system. (Of course, serious external damage, like broken branches hanging precariously over your house, should be dealt with immediately.) If you go ahead and start corrective pruning too soon, you risk stressing an already stressed tree; in the worst case, you waste time and money on a tree that might die the following year, and must be removed as a hazard. The International Society of Arboriculture recommends that after the initial waiting and watching, treatments to consider include restoration pruning, water management, pest attack prevention, and bark repair, if applicable. The injury may not immediately cause structural damage, although it might serve as an "open door" for borers, decay, and future structural degradation.

Finally, if you have a very special, vulnerably placed tree (in the open, or near water), you can set up a tree lightning protection system. Or, if you are like me, you depend on trees to act as a protection system for your house

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TREES AND VINES

I have colleagues in Virginia who take on contracts to prune trees covered in massive poison ivy vines, with diameters the size of my forearm and growing 50 feet in the air. These arborists cut the ivy during winter and leave it to die, and then remove them in the spring to access the tree. These are some additional tips to help homeowners prevent future growth of invasive vines.

  • Cut the vines at the base of the tree, and those attached to the tree at shoulder height with hand pruning shears. Cut larger vines with pruning saw.

  • Water the soil, approximately six feet around the tree, deeply and allow to soak overnight. This makes it easier to pull out vines by hand.

  • Dig up stubborn vine roots with a shovel, taking care not to damage tree roots close to the surface.

  • Allow the vines that are attached to the tree between the cuts to completely die. They will die off after a few days and will become more brittle.

  • Pry the vines from the tree bark gently, using a sharp edge wrapped with a cloth, taking care not to damage tree bark.

  • Allow overhead vines to die off and decay, or fall on their own. You risk pulling dead tree branches out of the tree if you tug on the vines.

  • Spread a 2 to 4-inch layer of mulch 6 feet in diameter around the base of the tree. Keep the mulch 3 inches from the trunk. Mulching prevents the vines from reestablishing.

  • Check around the base of the tree periodically after removing the vines and pull out any new vine growth. This may take a few seasons, but you'll eventually slow the growth rate.

  • While herbicides kill vines and other plants, they may also harm trees. Even selective herbicides are absorbed through vine roots into the soil and can cause significant harm  especially to young trees.