After you've taken your freshly cut tree home, follow these recommendations to help keep it fresh and fragrant for about six weeks from the time it was cut:
Clean up the tree, removing any dry needles. The brown needles aren't necessarily a sign that the tree is dying. They're a part of a natural process, such as when a leaf dries up and falls to make way for new growth.
Hose the tree down, especially if it's a little dusty.
Cut about one-fourth inch off the bottom of the trunk. During the time it has taken you to get the tree home, the sap that builds up in the trunk has become self-sealant. So if you don't make a new cut, water can't get up into the tree.
Put the tree in water and store it in a cool place, such as a patio or garage, until you're ready to bring it into the house. It's not necessary to add anything to the water, although a preservative is available.