DS2:Alien vegetation

I am putting together some bases of alien vegetation using large tree
seeds
that I have found in my local park.  They resemble giant pods at 1/300
scale
and should look suitably alien as well provide cover for troops.  Has
anyone
put together some house rules for alien plants.  Am thinking on lines of
these being exotic ancient pods that take hundreds of years to grow
(hence
the massive size). They also on occasion emit noxious gases that while
not
deadly to PA or vehicles, could be fatal to un-armoured troops.  Maybe
if
any infantty base comes to within an inch of the pods, you have to throw
to
see if they are emitting such toxins (on D6 if you throw a 1, then you
have
been unlucky enough to enter a cloud of the stuff).  Then you draw one
or
two chits.  Troops would probably have some kind of gas mask equipment
so
you would have to be unlucky to throw a 1.  While the remote risk
remains,
the pods will provide excellent cover and cover LOS.  Blasting them with
a
heavy weapon would not help release the gas as it comes from deep below
in
the root system.  Just an idea.

dave t