When microwave drying wood you need to be careful that you don't "cook" the wood too long and ignite it. Yes, it will burn!
To dry your wood, wrap it in a paper towel and for a small block of wood (say 1x1x4) microwave it for about 20-30 seconds and remove it and let it cool for a few minutes and then nuke it again and so forth. The paper towel will absorb the moisture so that you will get an idea of how dry your wood is. Once you microwave your wood and get little-to-no moisture on your paper towel, your wood is ready to use. The key is not to rush the process.
Gene