Induce Lower Nighttime Temps?

[voyager]

I have a Den. Mousmee [D. amabile X D. thyrsiflorum] X Den. frameri, had it for 5 years or more.
It is tree mounted, grows well, but has never bloomed.
The plant's ancestors are all callista section species.
D.'s farmeri and thyrsiflorum are the coolest growing.

The Baker's tome shows the habitat for amabile as having the warmest Jan/Feb nighttime temp of 50/51°F.
While D.s farmeri and thyrsiflorum have habitat temps below 50°F down as low as 45°F for the same period.

I do not want to remove it from the tree, moving it to a raft type mount.
Although, I could possibly put a raft into a refrigerator during the night for a few weeks possibly initiating blooming.
But, it would inconveniently take up a lot of room.

I'm not very hot on the idea of farming it out to someone up in Volcano at 4 to 5k' elevation that might get cool enough temps for it.
I'd rather keep it on the tree and figure a way to cool it while outside here.
In 7 years, the coolest winter morning temps I've ever seen here have only been about 65° +/- 1 or 2°.

So, my question:
Is there any practical way to lower an outdoor tree mounted plant's nighttime temp 5 to 10°F or more?

EDIT:
I also have a D. chrysotoxum, another callista.
The Bakers tome also shows it as having 50°/51°F winter habitat nighttime temps.
I threw it outdoors and told it to fly.
It blooms nicely for me every year.
Go figure.