During this holiday season, more than 35 million Americans will buy natural Christmas trees. If you are among them, David Robson, University of Illinois Extension horticulture educator, offers these tips for keeping the tree fresh as long as possible.

Pulling and bending needles, bouncing the butt of the tree on the ground to see if needles fall off or snapping small branches are not always good ways to tell if the tree is fresh. In fact, these practices can destroy the appearance of the tree for others who may visit the lot after you do.

If you buy your tree "off the lot," Robson says it is best to buy it early in the season. Trees on many retail lots were cut in October or early November. The sooner you can get your tree home to a constant source of water, the fresher it will stay. Cutting a tree from a "choose and cut" plantation will ensure a fresh tree.

Once you have chosen your tree, you need to protect it during the drive home. Wind rushing through the tree can cause it to lose valuable moisture. For long trips, cover the tree if it is tied on top of the car or in an open trunk.

If you will not be putting the tree in its stand right away, store it in a place that is out of the wind and where it will not freeze. Make a fresh cut on the butt by removing 1 inch of the trunk; then, place the tree in a bucket of water. Be sure the tree has a constant source of water.

When you are ready to put the tree up in the house, remove another inch of the stump. A flat cut is best; there is no advantage to an angled cut.

Immediately place the tree into a stand that holds at least 1/2 gallon of water. A fresh tree may soak up a quart or more of water per day. Avoid the tiny stands that hold only a cup or two of water. Keep the water level well above the base of the cut at all times. If the cut base dries out, the sap will harden, and the tree will not take up any more water.

No water additives such as aspirin, sugar or flame retardant are necessary. All a fresh tree needs is continued watering.

"Many families like to put their tree up in front of a large picture window or patio door, but that is about the worst place to put it," says Robson. "Avoid standing the tree in front of large glass surfaces that expose it to the sun and heat. Furnace register vents and fireplaces also expose the tree to heat, which leads to rapid moisture loss."

Expect a fresh tree to use 1/2 to 2 gallons of water the first day it is brought inside. A fresh tree will continue to use water, but at a reduced rate throughout the holiday season.

A truly fresh tree is not a fire hazard. It will not burn. But if the tree has been allowed to dry out, fire is a real threat. If you have made a fresh cut on the base and the tree no longer takes up water, it has lost moisture below a critical level and will never regain its freshness. A tree in this condition will burn and should be removed from the house.