I've heated my house with slab wood for the last 25 years..... It is a PITA to cut with a chainsaw--yes--but it dries quickly and stack O-so-neat. The key to chainsaw cutting is to build a cradle....4 or 6 foot long, about 2ft wide. Two 2x12 work well. Then put 2x4 on edge every 16, 18, 24, 30 inches--what ever length wood you burn. If they stick out 4 inches on each side you can attach a vertical 2x4 in front and back to act as a holder and cutting guide. Stack the wood in the cradle and run the saw down, close, to the edge of the 2x4 "guide". Piles of slab wood mount up before you know it. It is way faster to do it this way, then to cut with a radial saw, although I have done quite a bit of that as well. It helps to have feed rolls on either end of the saw.
If I had a deal on white cedar slabs, I thing I would buy as much as I could handle, saw it all in 16" lengths, bundle it up and sell it for kindling. It's great for starting fires and burns hot, but only lasts a few minutes in the firebox even if you pack it. You also risk firing too quickly with such hot burning wood. I've used cedar edgings to fire a wood burning oven to super-heat the top of the masonry dome just before bread goes in, but it's tricky to get it just right because it is so volatile. Right now I've been milling mixed soft and hard woods. I sure try to sort out the hardwood & stack it separately so the pine, spruce & hemlock can just be for starting fires and in the wood cookstove in the kitchen where they burn hot and heat up the oven nicely. When I was living in WA on the coast nothing burnt better than pitchy fir--hot and long. And NOTHING burns better than fir bark! If you can collect piles of thick, chunky fir bark and keep them dry they burn just like coal and last forever in the stove.
