Playing CT too fast

I was going through Crono Trigger for the 7th or 8th time (New Game+) to level everyone up to 99 (I know you don't need to and I have beaten the game on level 50 or so) when I got to the subquest portion of the game. For not the first time I have noticed that the sunken desert and pit does not appear (Rebuilding the forest quest). I have done EVERYTHING else besides the Black Omen, Gaspar still says the thing about "In the past a woman's devotion brings back the forest..." and still the sinkhole isn't there. Is there some trigger that happens to actually make the hole appear? Have I missed something that I thought I did? Or perhaps the hole doesn't appear after only 6 hours or gameplay. The other times I have played this file, Evenually it appears, but I have no idea what triggers it. Thanks for the help.

After Zeal crashes down in 12000 BC there is a person at the camp standing next to a plant seedling. If you talk to them they will ask you whether to plant it or burn it. The sunken desert will not appear unless you tell them to plant it.

You can do the same thing before the fall of Zeal. The lady's in the Queen's palace.

As I recall, she's standing in the main palace place.