We have Franklin Pierce to thank (blame?) for one of the traditions that beset us this holiday season -- putting up and decorating the Christmas tree. In 1856, Pierce became the first U.S. president to have a Christmas tree in the White House. Because fashion, then as now, was given to imitating life at 1600 Pennsylvania Ave., it wasn't long before pine needles were dropping onto living room carpets throughout America.

If Pierce is remembered as the first president to hang colored balls on a pine tree, history is silent on the first hostess who managed to get someone else to do it for her. The tree-trimming party, with its Tom Sawyer overtones, is still cherished by people who wonder how in heaven's name they're going to fit everything into the holiday season.

Tree-trimming parties get the halls decked and the boughs filled with baubles while providing a chance to see friends. If you are very brave or have far too many friends, you can do it as an afternoon eggnog party.

If you haven't already got one, borrow or rent a large silver punch bowl, fill it with that rich and potent punch, set out platters of tea sandwiches and Christmas cookies and hope the tree gets trimmed. If you're risking an open house, make sure the boxes of ornaments are not left on chairs, or surely they will be sat upon.

The tree should be up and the lights wound 'round before the guests arrive. Trying to make sure the tree is straight while 16 people urge you to move it a bit more to the left or the right or twist it this way or that will make even the jolliest Christmas spirit begin to sound like Scrooge.

One reason to have a mob help at the tree trimming (aside from having too many friends and not enough time to see them) is to begin a collection of Christmas tree ornaments. The newly married or the newly divorced may find themselves bereft of baubles to deck the tree. When sending out invitations to the tree trimming, ask each guest to bring an ornament. Well, yes, you are asking for a present and that is not good manners, but you ought to be able to do it in a way that pleases instead of offending. You might say you want them to be part of your holidays forever; or that you want something of each of your friends on your Christmas tree. Couch your request in terms of sentiment, not of greed, and since turnabout is fair play, give each guest a small sprig of holly or rosemary, tied with a red ribbon, for them to hang on their own tree.

Inviting a few close friends to a small dinner party is another way to get the tree trimmed. When the party is small, you can afford to be extravagant: appetizers of caviar or smoked salmon, an oyster stew, a good champagne with dessert -- a proper payoff for friends generous enough to help you get ready for the holidays.

Even though the point of the party is to have your friends decorate the tree, there are things you can do before they arrive so that when they walk in the door they'll have no doubt as to what season it is:

If you don't want to go to the expense of having a special tablecloth or napkins, buy several yards of red plaid cotton cloth and green plaid ribbons. Cut the cloth into generous size napkins, pinking the edges to keep them from raveling (this assumes that you do not have time to sew a fine seam), roll them up like scrolls and tie them with the contrasting plaid ribbon.

Put out pots of poinsettias or cyclamen or gloxinia or narcissus. (Since the latter are heavily scented, keep them away from the dinner table.)

Hang mistletoe.

Buy one of those cones with spikes protruding -- it looks like a relic of the Inquisition but is actually the base upon which to build a pyramid of apples. (Cherishables Antiques, 1608 20th St. NW, has them for $14, as well as stocking Christmas crackers, brought over from England -- $7 apiece for the large ones, and $1 for the small.)

If you have an out-of-control fern or rubber plant or other household greenery, string it with tiny white lights.

Make placecards out of gingerbread -- appropriate animals or symbols with the guests' names in icing. If you are extremely creative, skip the names and do caricatures. See if the guests can recognize themselves.