If I were you... Fir for an ELB.
Fir- heavy, strong, durable. Like hardwoods. Good with a heavy bow like an ELB.
POC- light, not very strong, more like pine. Its good for a fast bow, but not a heavy bow.
Sitka Spruce- a bit heavier than POC, much stronger, but still light. Good for a fast bow. Sort of a stronger POC.
Fir or better yet hardwoods. Ash shafts aren't that costly.