The lag in the animated forest has been reduced to playable levels (see 4418), but it is still significantly worse than it was in r64.
To get a quantifiable measure of this, I tested out using w5 in the animated forest with Recovery=500 (i.e. w5 waits for 500 turns). I waited until the number of trees on the level had maxed out (806).
r64 NotEye ASCII: 1.9 seconds
r69 ASCII-only: 57.6 seconds
r72 NotEye ASCII: 62.4 seconds
So for the most recent versions, there can be over a tenth of a second of lag per move in the animated forest. This is enough to be detectable, and is especially annoying given how tedious traversing the animated forest is.
In my local version the speed has been increased by 4x to 6x the old speed due to heavy internal optimizations. So far only tested with the pure ASCII version but it should have highly beneficial effects on the graphical version, too.