The slats or decking as I call it is dimensional lumber from the hardware store. By far the quickest most economical method in my mind. I don't have time to slab trees all day. 2x4's are cheaper to use than 2x6's, 8's or 10's because there's more air space per foot of decking with the 2x4's. 2x4's are also light enought to carry into the trail 4 at a time. A 2 x4 costs about 2 bucks for an 8 footer and one 8 foot 2x4 cut into 2' long pieces covers 20 linear inches of decking, so if you have a 10 foot long deck 2 feet wide you only need six 2x4's which will cost you 12 bucks. I space the boards 1 1/2 inches apart which works good so that you can't put a tire through it or your foot which is important for safety. I used to slab a trees to make decking but it's too time consuming? By the time you factor in time, wear on your saw, gas, oil etc I bet it's the same or cheaper to buy 2x4's and it's a heck of a lot faster.

 Ha ha, thanks man. I love to build them but I also like that other people enjoy them too. I'll extend the invitation to you that I do to everyone, if you're ever up in the Fernie area I'll give you a tour.