Will pruning plants or getting rid of some plants reduce humidity levels??

Defoliation, and having less plants will reduce your RH in the grow room. When I have my vegetation tent full it will stay at 60% RH no matter what. But when I remove 1 to place in my dark room my humidity drops to 50% If I move a second one it will drop to 40%. So defoliation wont really help lower RH but it helps get light exposure to blocked nodes and gives you better air circulation to pull humidity out of the room if you have an exhaust. Also a small fan blowing in the door at the bottom of the tent for a few minutes will clear humidity out pretty quickly if your willing to do that a few times a day.