What is specifically Christian about a Christmas Tree? (other than the
name.)  Like so much we celebrate, it's simply another seasonal festival,
linked to the mid-Winter (or in our case mid-Summer solstice).  It's not in
the same category as a crib, and its primary symbolic meaning celebrates the
return of light and life after the darkness and bareness of Winter.
 Perfectly appropriate for a science museum (if you do anything with
astronomy and/or  biology) and rather nice in a foyer.  Just call it a
solstice tree, and try for a solar powered lighting system, or you may end
up celebrating the high fibre diet, like the Christmas episode of South
Park!

In an age of environmental degradation and urban loss of a sense of season,
anything promoting renewal is fine in my book!  (But please, not plastic!)

Heleanor Feltham
Powerhouse Museum