(this post has been largely rewritten from the original -- altho my larger point about presents and trees was correct, I was wrong on about every single detail, including the name of the song)
I noticed, while listening to Xmas music, that in earlier versions of "I'll Be Home for Christmas" there's a line that goes "...and presents on the tree" but later takes on the song tend to change it to "...and presents under the tree." The later version makes sense, of course, since under the tree is where presents are put these days. But the custom of presents on the tree is much earlier (I was trying just now to track down when that was the norm, with no luck) than the 1940s when the song was written (1943, when it was a big hit for Bing Crosby). I've noticed that lots of the Xmas songs from the 40s tend to be explicitly nostalgic. Which had more than a little to do with the war, I'm sure. Also, since it was written a year after the fiercely nostalgic "White Christmas" it may be that was an influence on songwriters of the time.
House of Dioxin
Now Appearing Nightly in the Exotic Mondo Mundo Lounge
Way back in the day, like early 20th century and before, things in general--stuff, the crap we all have way too much of--were incredibly expensive. So gifts were likely to be things like ribbons and combs and tiny stuffthe recipients. These little things were a lot easier to tie to a tree than a PS3.