MISSISSIPPI STATE -- Battling nature and people, trees that endure are genetically strong and environmentally lucky.

"Fire, lightning, construction projects, disease and insects are some of the main obstacles a tree must overcome to achieve a long life," said Dr. Andy Ezell, extension forestry specialist at Mississippi State University.

Recent storms packing high wind gusts have taken their toll on long-standing trees across the state.

In a state where forestry is a major economic and environmental resource, Mississippians appreciate majestic trees that demand attention as outstanding examples of longevity.

"Big trees are not necessarily old trees, and old trees are not necessarily big trees," Ezell said. "Trees don't die of old age; they die because something or someone kills them."

Trees are threatened by biotic and abiotic factors. Biotic factors are diseases and insects. Abiotic factors are physical forces such as wind, lightning, fire and people.

"Biotic factors are more likely to attack a tree when it is very young or very old," Ezell said. "During peak growing years, trees are stronger and more resistant to diseases and insects."

Large trees may be stronger, but they are also a bigger target for lightning and wind damage. While these forces alone will not usually kill a tree, they will allow insects and disease easy access through the open wounds on the tree. Ezell said special treatments to seal off these wounds have not been proven effective.

"Prolonged rain during the growing season can be detrimental especially during the peak growing months. Saturated soils deprive the tree's root system of its oxygen requirements," Ezell said. "But during dry spells, a steady flow from a low-volume water hose is one of the best protections for a tree.

"Most of the time, it's not a question of doing something more for the tree to help it live, it's not doing anything negative," Ezell said.

The forestry specialist said a death blow can come to trees in the form of "bulldozer blight." Construction work such as pouring concrete or rolling heavy equipment over a tree's root system usually will result in the loss of the tree.

"The construction is not damaging the tree above ground as much as it is damaging its root system," Ezell said. "It could take a couple of years for the tree to die, but the cause will have been the construction project."

When a long-standing tree dies, replanting the same type of tree in its place is a good idea, assuming the microenvironment -- especially the drainage -- hasn't changed since the days when the tree thrived on that spot.