I actually have this aerosol spray that I bought a couple years back for our fake tree. You pretty much just spray the tree down with it and it holds the 'christmas tree' scent. I recall it being a bit over-powering at first but the tree still smells as good as ever these years later .. but so does the attic where it lives most of the year. I will see if I can find what I used.
"I have always thought of Christmas time, when it has come round, as a good time; a kind, forgiving, charitable time; the only time I know of, in the long calendar of the year, when men and women seem by one consent to open their shut-up hearts freely, and to think of people below them as if they really were fellow passengers to the grave, and not another race of creatures bound on other journeys." ~Charles Dickens