Lots of information on the web, a simple search will provide hours of reading. Try starting here :
And yes, there are cob, straw, rammed earth, tire, bottle and all kinds of other building material, but what would be the effect on the earth if all that material was used to build the millions of houses required for people. There just isn't enough of it, and it will always remain a very small percentage of houses built for those who like to live outside the box. I have even considered building with one of these other materials (timber framed bottle house). In the end they all still use wood, be it for the timber frame, window frames, trim, floors, etc.
A thrifty stand of young trees takes up carbon dioxide at a much higher rate that a mature stand (sometimes called old growth). As a tree matures its growth rate declines rapidly. Eventually a mature stand reaches an equilibrium where it takes up very little carbon and releases more due to breakage and decomposition. Trees converted to lumber do not release their carbon until they rot or are burned. The slash left behind from logging is an issue especially up here with dry pine stands, but there are several benefits to the slash. As it decomposes it releases nutrients back to the soil to help the future stands grow. It provides food for millions of organisms, provides cover for small mammals, and many others. In terms of slash use, there are several areas where roadside slash is processed and hauled to facilities to be used as pellets for wood heat, burned in power plants, used to create heavy diesel, and so on. Again, we are just in the infancy of using this source of fibre, and the economics aren't quite there yet. If they took the billions they waste on protecting oil and gas interests and invested in research on alternative fuels (all kinds) then perhaps there would be a change.
I am as open to change as the next person, if the forest industry were to go away tomorrow I'm smart enough to get another job. I've protested logging in the past, then I decided to learn more about forestry so I could talk with some insight on forest practices. As it turns out, in Canada does a pretty good job of managing our forests and it beats the hell out of sending wood production to countries with few standards.
Sorry to get off topic, but until everyone stops reading papers, living in wood houses, and wiping their bums, the forest industry in Canada will be around to provide wood for consumers.