Things that increase a tree's chances of blow over:

• Trees on lots of homes that have been built in the last five years or so. Many of these trees will have root damage from lot clearing and home construction.

• Newly cleared areas with scattered trees remaining. The trees have not adjusted to the newly open grown conditions and higher winds. (new road construction)

• Areas with loose, gravelly soil.

Characteristics that increase a tree's susceptibility to storm damage:

• Included bark where large stems meet (maple and ash).

• Rot in the roots, stem or branches

• Lopsided tree tops (previous storm damage - Bradford pears)

• Trees with numerous small branches and twigs that create a sail effect (topping/poor pruning often causes this). Never top trees!

• Mechanical damage and poor maintenance (soil compaction, damaged tree)

Homeowners should examine their trees before the storm:

• Remove trees with large cracks or splits or severe root damage

• Remove tree branches with rot in them

• Advise power company of trees with branches interfering with power lines

• Contact a competent, certified arborist

• Good branch angles are 10 o'clock and 2 o'clock, closer together causes weaker branches

• Remove rubbing and broken branches

• Prune properly (do not flush cut to stem, but do not leave big stubs that will rot either)

• Some trees (silver maple, willow, cherry) have more brittle wood.

Some trees that do not have as many storm-related problems: white oak, sweet gum, black gum, bald cypress.

Prevention Measures that can make trees stronger and more resistant to storm damage:

• Prune to encourage good branch angles. Narrow branch angles are weak. They are weak because neither has sufficient space to add wood needed for strength. This can be prevented by removing one branch when it is young. The strongest angle is 10 o'clock and 2 o'clock.

• Encourage strong branch/trunk size relationships. Ideally lateral branches should be no more than 1/2 to 3/4 the diameter of the trunk. Branches larger than that often can not be supported.

• Eliminate lopsided crowns and maintain a stable center of gravity. Reposition a tree's center of gravity by selectively removing branches on the leaning side and encouraging branches on the opposite sided.

• Remove rubbing branches, suckers, watersprouts and temporary branches. Branches that rub make wounds and allow decay. One of the branches should be removed. Suckers and sprouts are rapidly growing and weakly attached. They often use more energy than they produce. Temporary branches low on a tree when it is young and protect young base from injury by the sun. After a tree is 3-4 years old, these should be removed. Never remove more than 1/3 of a tree's leafy crown when pruning. Remove problem branches before they are 1" in diameter when possible

• Don't cut branches back to stubs. People often think long branches will break, so they shorten them. When a branch is left with a stub end, the new branches are weakly attached at that point.

Consider the following suggestions when hiring individuals or companies for tree care work:

• Beware of people knocking on doors offering to work on trees. Established arborists do not go door to door.

• Make sure they have insurance for personal and property damage and worker's compensation. Ask them to show you paperwork.

• Ask for references.

• If time permits, obtain cost estimates from several arborists. Get written estimates.

• Don't pay for anything until EVERYTHING agreed upon is completed.

• Be prepared to wait for many weeks for the work to be done.

• Make sure you know whether the work includes removal of the tree/branch or just the felling.

• Does the price include stump removal?

Don't be pressured into making a decision. Taking the time to select a qualified professional can safeguard your trees and save you from the long-term consequences of wrong decisions about what to do about them after a storm.


Source info: http://www.dof.virginia.gov