Tropical zone
The tropical zone was a region on planets and moons.

On the heavily glaciated planet Sigma Draconis VI, this zone was ice-free. ()

On the planet Risa, this zone contained jungles. While working for the Ministry of Security in 2135, T'Pol tracked Menos and Jossen, two rogue Vulcan operatives, to the Tropical Zone, where she killed Jossen. ()

External link 
 
Geography