Regardless of wood species, wood air dries at a rate of one inch thickness per year. So a stave of 2" thick (and unlimited width) will take one year to dry (it dries from both sides). A stave of 3" thickness will take about 1½ year.
The best way to speed up the drying process, is to remove as much wood as possible early in the stage. You can go to near-floortillered stage. Make sure to leave some extra width though, just in case the wood warps a little upon drying. The wood is now significantly thinner, and it will dry much faster. It may take 3 months if left outside, but to speed up the drying even further, you can place the wood indoors. In a dry room (so not the garage (too cold), bathroom (too humid) or kitchen (too moist)) it will take around 4 weeks to fully dry. The best way to check when the wood is dry, is to weigh it accurately. If it stops losing weight (water) for a few days on end (or gets even heavier), that means the wood is as EMC (equilibrium moisture content). Then it's time to bend it!
I dislike the heat box for drying wood; it often dries out the wood too quickly, resulting in cracks. Or it may dry out the wood too much, resulting in a too low EMC making the wood weaker. It also costs a lot of energy...
