Both the original box set and the revised edition have Trees of Life detailed in the magic item chapters. Both state the trees were originally created by wizards who wanted to protect nature. The trees channel and store magic from the elemental planes. The only use wizardly magic actually gets from them is the super regen and defiling radius negation. Extra spells are only for priests.
I don’t remember them predating sorcery, but druids can more easily create them (if you ignore the caster level requirements). A wizard has to wait for Wish (9th level spell in 3e), a cleric uses Miracle (9th), but a druid is actually held up by Control Weather (7th). The odd spell out for a druid is Liveoak, a 6th level spell that substitutes for Wish and Miracle.
In 2e, a wizard (both defiler and preserver) could create a tree as an 8th level spell, priests at 6th (orig and revised).
Druids typically see all wizardly magic as something against nature, most don’t even like preservers and all actively hate defilers.
In my own campaigns the only druids who have created Trees of Life are grove masters (once they get high enough level) and the one Spirit Initiate who’s trying to restore all of Athas via an ever expanding forest (supported by Trees of Life). Trees of Life tend to attract defilers so having them isn’t always a good thing. Our druids aren’t typically trying to restore Athas to the Green Age, they are trying to preserve what’s already there (maybe improving their own little patch at most) and kill anyone who would harm it. Defilers destroy nature itself, at least deserts are nature.
Clerics are trying to change the world, they may be more inclined to create them but there aren’t that many of them and they don’t tend to stick around to guard them. Wizards typically would create them for their own use only (and in 3e defilers can’t create them, only preservers).