To be confirmed but I remember hearing about 1 month / cm
Kelly, It depends on different things
If it’s a fresh wood cut (best is in winter time) it could take time. Proffesionals usually wait 2 years to get a fully dry and stable wood. The wood should reach 15%-18% of humidity.
Because we remove the heart to make a hollow tube, we don’t need to wait so long but 8 to 12 months seems to be a minimum.
It’s not the same story if the wood is already dead when you pick it up. It could be there for a year or maybe more and you can use it immediately after only few weeks of drying.