For years I have only been using the pre made trees. Just recently I discovered that there are trees that my sims can decorate themself.
Ever since
@ModHunter posted that, I kept meaning to try that out when Winterfest rolled around. And I kept forgetting. Until today, finally, I remembered to look for the bare tree.
So, yes, your sims can decorate it themselves. And they can do this as a group activity-- I have a lot of fond memories of doing this IRL. And when you're all done, you can put the presents under it!
And your household will gather around the tree, rather than a separate present pile.