Use a 3kW electric fan heater (if you don't have one, the most powerful hair dryer you can find might work); put the cones in front of that until the scales crack open. When they have, turn off the heat, and put the cones in a bucket of cold water for a couple of hours. Then let them dry out, and they will open wide and shed the seeds.

Resin

Thats a nice cone! Good luck with this.

I tried the hair dryer with very little success as the cones has so much resin on the "knobby" side that it rehardened and the somewhat loosened scales were immediatedly locked down. The cone in the OP was cleaned with hand cleaner and a plastic bristle brush after considerable effort and would/should be more amenable to hot air method....."Less resin....More success" LOL

Also, the location/provenance should have read 'Jackson County Orgon'

Johnny

I'd suspect the hair dryer isn't powerful enough, you need a stronger source of hot air. A paint stripper gun would be better, if you have, or can borrow, one. Otherwise, any local politicians you can ask to deliver a speech at the cones? ;-)

If all else fails, put the cone on top of a small pile of dry hay, and set fire to the hay; stand by with a bucket of water to stop the fire as soon as you hear the scales crack open. Do all this outdoors, away from anything else inflammable, of course!

Resin

Lol Michael!

Wrap a cone in a hot-dog roll and put it in a microwave oven at a low setting. When the roll looks browned, take it out, throw away the roll, and eat the cone. Retrieve the seeds in a biologically obvious way.

Just put them on a dish on the heating system and the scales will crack open...

Is the cone ripe enough to produce viable seed?
Mike

"Is the cone ripe enough to produce viable seed?"

Looks to be, yes.

Resin

Attenuata can be a hard one, like coulteri - the resin is so thick that unless it is somehow wiped off it just reseals the cone when it hardens again. A surefire way which I've used to open both requires putting them on the dashboard of your car, in full sun, where the windshield meets the dash. If it is is not significantly hot outside (I.e. - the middle of winter) it will may not get hot enough. However it has worked like a charm for many of the closed cone conifers here in California when temperatures are no warmer than 70 degrees f - a car with all windows sealed up can get quite hot. It will take a few hours for the cones to open, perhaps a bit faster if on a black background. If you won't have warm temps for a while, just have a small fire in a stand alone metal barbecue and put the cones on the grill about eight to twelve inches above the fire. I'm serious - these things are not meant to open unless they really get HOT.