Q: The recent thunderstorm winds blew many small dead branches off of my soft maple. Should the tree be pruned? I did not think the tree was dying, but now I am wondering how healthy it is.

A: Silver maples, honey locusts and many other trees lost a lot of small branches during the storm. These are mainly the small interior branches that stopped getting enough sunlight over the years; the tree cut them off from access to the sap. Their death is a normal part of a tree's life. Many stay on the tree for several years, until a storm blows them off.

If any of the branches were bigger than an inch or so in diameter, it would be good to have the remaining stubs trimmed to avoid letting water into the trunk. Large branches can leave large wounds, which cause the trunk to rot. Then the tree falls over in high winds.

Large branch pruning should be done this winter. If only small branches fell, then look at the tree next spring — you will see more small dead branches. Anytime of the year is a good opportunity to remove dead wood from a tree. Losing a large number of branches may mean the tree needs to be thinned out, allowing more light to hit the inside.

Q: One of the three large trunks on our Bradford pear split off during the storm. How do we fix the remainder of the trunk?

A: It may not be possible to save the tree. Some trees have narrow branch angles, and they are difficult to save when a large piece tears off the main trunk.

The first task is to clean the wound — see how much trunk is left in good condition. Use a knife or saw to trim the ragged edges of the wound. Remove only small amounts of the good quality wood. Do not coat the wound with any black stuff or paint; research shows that all of these coverings slow the healing process as well as protect decay organisms and insects.

The remaining trunks may need to be bolted together for support. This will require drilling a hole through the trunks: A threaded rod needs to run through the holes, and nuts and washers at each end hold the trunks together. Higher cables with adjustable nuts also offer support for narrow trunks.

The bolts and cables are useful to prevent trunks from splitting. An arborist should be hired to install these devices. Putting them in the wrong location could crack the trunks.

Q: The storms didn't damage our big trees, but we see that several big branches should be removed. In the past, other branches with large decaying stubs have been cut from this tree. What do we do with them?

A: It is difficult and time-consuming for any tree to heal across the whole width of a large cut. If possible, it is much better to plan ahead and remove branches when they are much smaller in diameter. As the tree grows, it will become obvious which branches are going to overhang the house, walks, driveway, street or other location where they don't belong. They should be removed as soon as possible, while they are still small.

Trees heal from wounds and cuts in two directions. On the outside of the trunk or branch, they create a healing tissue that looks like it is rolling across the wound. This tissue will eventually develop across the wound and seal it off from the outside. At the same time, the tissue that makes up the wood of the trunk or branch is being compartmentalized from within the tree. Inside the tree, it is growing a scar tissue around the wood, which is exposed by the cut, to seal it from the rest of the tree's healthy wood.

If the ants, insects, bacteria and fungi breach the defenses around the compartmentalized tissue, they can move within the tree and hollow it out.

The best way to help the tree is to make proper cuts. The cut should not be allowed to tear off bark along the remaining branch or trunk, since that is an additional wound that must be healed. Large branches need to be removed near the trunk or a side branch, while leaving the base collar of tissue. Look at where a branch meets the trunk; you will see that it has a raised portion of supporting tissue. This collar of tissue will heal across the wound much faster than a larger flush cut against the trunk, which requires trunk tissue to develop across the wound.

After a cut has been made, the healthy tissue may die and leave a wooden stub sticking out with a ring of healing tissue growing around it. Remove the stub so the ring of growth can grow straight across to seal the wound.

Try not to create a cavity of your own - it usually prevents the healing tissue from continuing to grow across the wound. This is especially bad if the new cavity can hold water. You may need to drill a drain hole in order to keep water from accumulating in the cavity. Insecticide and fungal treatments painted or soaked into the wood of the cavity may be necessary to keep these organisms from further damaging the tree. Leaving the trunk cavity open will help it stay dry and allow an inspection. Filling it with foam or cement can trap moisture in the wound, which helps decay organisms survive and prevents an observation.

To summarize; keep the cuts as small as you can, keep them dry or exposed to the air, treat them if necessary for insects and disease organisms, and let the tree heal across the wound on its own. Continue with your other tree health-care treatments to maintain the tree's good health; it should be fine.

E-mail questions to Jeff Rugg, Kendall County unit educator, University of Illinois Extension at jrugg@uiuc.edu. To find out more about Jeff Rugg and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

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