Jessica wants to hang a divorced couple from a limb of our Christmas tree.

"I think that's kind of insensitive," I say.

"How is it insensitive?" she replies.

"She's remarried, he's remarried. Let it be."

"You are making too big a deal out of this," she says.

"I think you're not making a big enough deal!"

I should say for the record that we are not discussing just any divorced couple. Our focus is a particular couple, longtime friends of ours.

Jessica and I, after all, are not the sort of people to hang just anybody from a limb of our Christmas tree. We do have to know them, at least a little.

"I'm doing it," she says.

"Fine," I say. "Go ahead. But when things go badly, it's your responsibility."

She reaches up into the top branches and hangs their Polaroid picture.

YEARS AGO, a good pal of mine named Chuck was visiting from out of state. Jessica snapped a picture of the two of us together. Somebody - I like to think it was me - had the idea to poke a hole in its corner, thread a paper clip through it, and hang it on the tree so that even after he left for home a few days before Christmas, Chuck would be with us throughout the holidays.

We decided to do it the next year, and then the year after that, and the taking and hanging of pictures grew into a tradition.

Now we have a box packed with photos. Rummaging through them, I come across the first Christmastime Polar­oid of Sam. He is maybe three weeks old, the size of a peanut, and dressed in a red jumper, and he's cradled, a little stiffly, in Peggy's arms. Peggy has known Jessica since they were peanuts themselves. The two are among a group of six women­ who have known each other since before kindergarten. Seeing our newborn in the arms of such a dear friend is to stand on the banks and watch as the river of life flows by. Either that, or to wonder if Sam will ever forgive us for putting him in that jumpsuit.

Going through the photos is like going through a version of the old TV show This Is Your Life, except that, as often as not, it is someone else's life. Here is one of a buddy of mine sitting on the couch, grinning, his arm around his first ex-wife. A few photos later, here he is again, this time with his second ex-wife.

Some photos measure loss. Here is a picture of one of the best-hearted people I've ever known. He is standing with his mother in front of the tree, smiling his trademark broad, warm smile. He was one of the first people to visit the hospital when Sam was born. Thick as thieves we were back then. We've since drifted apart. Nothing caused it, really. Nothing I recall. Just, life. Here is another guy whom I haven't seen in years, but that was by mutual agreement. He's smart, funny, a tremendous gastronome, and, like me, argumentative. We just butted heads one too many times to want to butt heads anymore.

There is Sam's first rock band, Three Hours Sleep; the boys are 12 years old, each holding his instrument, like some early photograph of the Beatles. And Sam, around three years old, clowning in the bathtub with his pals. And those pals' mother, a beloved friend who moved away but now lives only an hour from us because we moved away, too. And another beloved friend who moved away but now lives only 10 minutes from us. And her first husband (yes, also beloved), who moved away as well and now lives across town from us. How did we all end up here?

And there is my mom and her husband, who, after the deaths of their spouses, met and married one another and have been together 25 years, my mother beaming, her husband with a Cheshire cat smile, their expressions epitomizing their hot and cool personalities and their ease with each other.

And Jessica's mother, several different pictures through the years, looking as she has always looked, serene and beautiful - and, of course, well dressed.

Oh, and here is Sam, last year at 15, with his arm around his girlfriend.

The tree has changed over the years. What started as a lark is now laden with meaning. There are families, grown. There are friends, deceased. There are couples, remarried. There are loved ones and liked ones, and those who are both. There are windows into souls and windows into nothing more, really, than the passing scene. And there are others, many others.

Its branches sag with memories.

Jessica, I expect, would disagree. Those Polaroids, messy as life itself, don’t “sag,” she’d say. They shine.