This paragraph indicates that more nature/trees will make the rest of Athas worship her like the people of Gulg worship her, not that she is plotting to restore nature just so she can defile it. The idea that more trees/nature will make people worship Lalali-Puy doesn’t really make sense at all when you think about it.
I assert that Lalali-Puy cannot do what Bill Slavicsek proposes that she is doing in the Revised Campaign Setting. Look at the prolific forestation spell (I did a 3.5e conversion here). Avangions can do it because they are able to generate more life energy than they draw. They are like a magical free energy device. A defiler like Lalali-Puy would have to power the prolific forestation spells with her own XP, through sacrifice of living creatures (either animal or sentient), or a combination of both to gather the energy to create the forests.
It would be interesting to find out exactly how many people use Free Year 10 as the starting point for their Dark Sun campaigns. For the people that do not, what is the point of referencing the Revised Campaign Setting, which is based on the metaplot of the Prism Pentad (and arguably botched or retconned what happened in the PP)?