/gamerule randomTickSpeed doesn't seem to be working as advertised

while i'm playing on the server
I type in
/gamerule randomTickSpeed 2000

this i've been told should dramatically increase the speed at which the leaves decay

to prove it i set randomTickSpeed to 0 (which should mean that they no longer decay) but they are still decaying

tried typing these in on console as well as in chat in game , both tomes it responds that it has been changed