NSMBA site is great for construction techniques as is the IMBA site. The Filthy Trails do look solid with some nice lines, they hold momentum well. Thier use of wood could be largely determined by the climate and wood availability, Belgium has a fairly temperate clim so untreated pine or hemlock will last for a good few years but the temperate rain forest with a s**tload of rain needs a hardier wood. First growth cedar has a natural oil to combat the huge moisture onslaught however, 2nd growth hasn't had enough time to mature to develop this substance but it is still the best to use with fir a close second (apparently). If we have it, I think we should use it and build it to last. The technique of cribs and layered rock has lasted thousands of years in Europe as the Romans used this way of roadbuilding. The Welsh laid flat stones on edge, rather than flat, to lift the roadway for good drainage and although this all takes longer, land managers will respond more favourably to well constructed trails than mediocre ones which means more trails for us!!