Thanks, L4 and Ulric! Work has been horrible to me as of lately. Hobby time is reduced to 15-minute sessions. I have at least managed to finish a Tyranid "brush". For my Tyranid terrain, I want two things, "living" terrain and traces of Tyranid activity. For my three upcoming Woods, that means lots of organic structures and capillary towers instead of trees. At "brush" level, I wanted to find a way to portray both cover save and visibility. I opted for small corals from my local pet shop and glued them to small movable bases, following the same design that I used for my swamp.
Base Area: just flock, sand and the odd rock or shell/coral stone. Enough to keep the terrain interesting without impeding placement of units. For flock, I used mainly green flock (to tie it to my battle mat) with dead grass in patches towards the centre. The general idea is that Tyranid terrain kills local terrain.

Five movable small pieces. Some use tyranid bitz to show tyranid activity. Tufts are added to add height. More dead grass than green grass. Corals and stones are used to portray Area terrain (blocking LOS).


and put together:

You can move around/take away parts as units enter the terrain.
For my woods, I experiment with Instant Mold to add numbers. Pictures of the progress will be posted when I'm back from a work-related journey. Thanks for watching,
Fredmans