As I ordered these and they gave me an especially awesome service and quick order turn around I thought I would show you all my tree bases. I followed Cait_Sidhe's advice annd used thinner cardboard for the bottom layer to reduce the profile and also give me some mdf bases for other terrain.
The bases can be found here: http://www.4ground.co.uk/bases-and-movement-trays
I bought three each of the small and the large tree bases for a bit of variety.
Beveling the edges.
Hot glue gunning the trees to their bases. Works a treat on those trees that don't come with the thicker trunks as seen on the left hand tree. I was even able to put in some root like lumps as well!
As usual on bases that I do, Poundlands "No More Nails" is my go to for smoothing areas out ready for basing to start properly. In this case to cover up the ugly hot glu round the base of this tree. I use it to hide integral bases on miniatures quite often now after RedZ once suggested it some time ago.
Basing the trees. PVA brushed onto the bases and then covered with chinchilla sand. Soldado first introduced chinchilla sand to me and it is fantastic, you want the un scented variety which you can get in most good pet shops for £2-£3 a bag. It's very fine and seems to stick a lot better than traditional sand.
Paint the bases with a cheap craft acrylic - Burnt Umber.
Dry brush the bases with a cream/ivory/bone colour.
I'll add a couple more shots with the next couple of stages as I get them done. Likely to be tomorrow or over the weekend.