The falling level of Lake Lanier is not the only visible sign of tightening drought conditions in North Georgia.

Particularly with the approach of winter, trees are also feeling the effects of the hot, dry summer and fall.

Forsyth County arborist Greg Wallace said the prolonged drought, currently rated abnormally dry to moderate in Hall, has dried out the soil.

Winter officially arrives this week, and precipitation in the winter months, which are typically wetter, can loosen the area around a tree's roots, making it more susceptible to falling.

"Because that soil's been dry and shrunk, so to speak, and it gets wet and loose, it makes those trees easier to topple over," Wallace said.

A tree's top branches are also vulnerable to winter weather.

"If snow accumulates in the branches of the tree - or ice does - then it adds a lot of weight to the tree. It makes it more top heavy," Wallace said. "When you've got winds, too, in conjunction with that, it makes it more susceptible to blow over."

The drought has also left trees more prone to disease or insect attacks, he added, which in turn has led to more dead trees this season.

It's difficult to tell when a tree might be susceptible to falling, Wallace said.

Potential warning signs include decay or hollow cavities and mushrooms near its base.

A tree whose neighboring trees have recently fallen might also be in danger.

If residents see a possible problem tree near a road, they can contact county or state government.

For Hall County roads, residents can contact the Road Maintenance Division at 770-531-6824, said Johnny Hightower, division supervisor. Hightower said the county fields calls year round for decaying trees near roads.

Once the county gets the information, staff is sent out to determine if the tree is in danger of falling on a roadway and determine who is responsible for removing it.

Trees that are on state roads are handled by the Georgia Department of Transportation.

Times staff writer Aaron Hale contributed to this report.