One way I have to keep both the furkin as well as the felines away from
my tree is to cover pieces of cardboard with tape sticky side up.  They
don't like the feel and will normally stay away.  If that doesn't detour
them then just don't put expensive breakable decorations on the lower
branches.
 
As for all this talk about ferret porn ..... here is one for the break
the rule books.  What the discovery channel never wanted you to see:
 
http://pg.photos.yahoo.com/ph/ladyhawk_76/detail?.dir=2aa7&.dnm=252d.jpg
[Posted in FML issue 4665]