Another beauty from coniferjoy...and this cultivar is of a species I've never heard of!
What more can you tell us about about this species in general (growth habit, native range); it appears similar to P. strobus?

Barbara

More like Pinus monticola or P. lambertiana than P. strobus. Cones impressive, 17-35cm (rarely to 45cm) long, produced abundantly. Native to southern Mexico, Guatemala, Honduras, at high altitudes, but surprisingly hardy (zone 6; hardier than e.g. P. wallichiana) for its tropical origins. In the wild, a tree to 50m tall, but few (if any) in cultivation have exceeded 25-30m tall.

Resin

No other witches'brooms from Pinus ayacahuite are found in Mexico or in U.S. conifercollections?
This is very strange that this (only) one is found far away from it's native enviroment...

Not too surprising - it isn't very common in cultivation (its susceptibility to white pine blister rust doesn't help), and I doubt many people are looking in Mexico. The species is also not overly common in the wild due to the value of its wood and consequent over-harvesting.

Resin

This is the first I've seen.

Dax