If the Douglas fir is freshly cut, you'd often find it with less then 40% - 50% moisture content and naturally after some time, it would drop considerably, usually between 15% - 20% in average, but out of weather condisions (under an open shed roof and properly stickered). This suggests you're picking up moisture, above it natural state (live and growing) or (my assumption) your meter isn't up to the task. Check various areas along the pieces, to see if you can localize increases in moisture content. This will help isolate and refine your leak search.
No hair drier, nor a bunch of them are going to do much, except dry the top 1 mm of previously painted or sealed stock. Even though the paint may be stripped, the pores are still likely partly or completely clogged up, which slows the process. You need to remove a fair bit of material to actually "unseal" the pores, which can make structural concerns.
Sealing the beam up and placing it in a modest vacuum (about 1/2 or less an atmosphere) will be much faster, though care needs to be taken to not crush things. Sealing the beam up with a properly vented dehumidifier works, though is slow, but no crushing concerns. Stripping the surrounding elements, like plywood sheathing, coverings and providing a generous path for moisture laden air to flow, helps too.
Find the leak(s), stop them or get her on the hard and under cover. This alone will promote the material to seek a moisture balance in the high teens, of course after quite a wait. The above will help expedite things, but if you can't wait, you'll have to force dry, which has its own concerns or consider removal of the offending areas and rebuilding them or finding another way (autoclave) to get them dry.
