A couple of years ago I picked up a bag of model trees from Dobbies, our local garden centre [and craft shop]. They only have them in the run up to Christmas as they're for making your own Christmas scene with miniature revelers and holiday nik-naks.
Now I haven't had chance to go this year but I'm betting they're back in stock and just thought I'd remind folk about them. The set I got was 21 pieces from a company called Lemax for £13 which I think is good value. Clearly there's at least two that are just a bit too big, they're the same size as my 40k outpost that got bigger! but great line of sight blockers for a Trygon!
Of course they weren't going to fit with my table so I decided to paint them - undercoating them all in Red Oxide primer and then repainting them in shades of yellow.
And here's the finished result: