This old guy in PA, while ranting, may be on to something. And if you give him $5 he'll send you three cuttings, from which he claims you can get 30k tree starts propagated in two years. Since you only need 600 for his scheme, I'd reckon you could start your acre's worth of coppice the first year (a 25x25 grid is 625 trees, 8' spacing gets you to 40k sq ft, 3,560 sqft shy of an acre). Continuing with his assumptions, 5 years later you have 12x[0-5] 6" diameter trees about 40' tall. Because of taper, we'll assume you average 6" of mass if you fold the tree in half. So now you have a pile of logs 20' long and 30 [120trees/4trees per sqft] sqft on the end, volume 600 cuft. A cord is 128cuft, so you have slightly more than 4.5 cords of wood. In my temperate climate, this should last one to two years, allowing you to coppice the same number of trees on a longer rotation, resulting in larger logs, or to coppice fewer trees. His claims are only valid with hybrid poplar. Yay caveats.