I think it tries to tell a good story, but it's bogged down by a couple things, namely its writer/adapter. Diana Young wrote the original FernGully stories, which seem to be tough finds; I suspect them to be pulps fiction, and they were only abridged into one book to tie into the film(s) and TV show. These stories were adapted for the film by none other than Jim Cox, who also wrote the Rescuers: Down Under. Some of the nonsenical aspects of that film seem to have coincidentally bled over to this one. For example, young blond boy allegedly from Australia sounds just like an American. I'm sure there's a detailed explanation to this conventional artifact, but I'm not sure how much digging I want to do to try to figure it out. Could have been the industry not thinking it was an error. Could have been Cox being completely ignorant of regional accents, which is more common than some may think. Another common element would be nonsensical antagonists. Now, I think the major antagonist fits perfectly into the worldbuilding, it's the minor antagonists in the form of the workers that seem obtuse. People have reasons for doing what they do, they don't just HAHA LET'S KILL TREE! Moreover, the cartoonishly large behemoth of a tree-killing machine speaks volumes to the creator's beliefs on human ingenuity and capacity for evil. I have a suspicion that the loggers in Young's original story didn't use a machine like this, and Cox's pathological leanings encouraged him to create a behemoth. The basis for this suspicion is that Cox's other film has a similarly obtuse machine whose purpose is also to target nature, only in that case it was via poaching. That villain doesn't speak like an Australian either, but I don't remember if he was actually American. Moving on.

The psychological read on these behemoth machines is that they embody the synthesis of two concepts: the human capacity for evil, and the human capacity for technological endeavors. It seems to be a conflation of the two; an oversimplification in error. Evil without technology is practically harmless, and someone who is practically harmless will likely become evil. Technology without evil is a fantastic, if perhaps theoretical, benefit for all creatures. The fact Cox put evil machines in two of his most well-known screenplays seems indicative of him thinking technology is evil, and perhaps, that humans are evil. I don't think we should be naive on the human capacity for evil, on the contrary, some of the imagery directed towards humans in this film are quite necessary to acknowledge. But if we dumb it down to "humans bad nature good" we will absolutely become hopeless and lose our purpose, individually and at large. Machines and technology are not inherently evil. On a biological level, my supposition is that multicellular, intelligent organisms such as ourselves only exist due to a collaboration to use adaptations to the greatest good possible, which is why our bodies are desgined and function similar to machines. If we are machines of a kind, and technology is an adaptation we use in order to more efficiently tackle the problems of life, then machines are simply an extension of us. And that's valuable. The machine is only as evil as the one who designed it, the one who operates it. The only technology in this film that isn't framed as evil, is Zak's walkman, and it's framed neutral-positive. I think this is because it's not seen as technology in the same way that the behemoth is seen as technology, even though categorically, they both meet the definition. The size, scope, and most importantly, purpose of each technology differs, but they are still both technology. I think Cox forgets this when he creates such behemoths. Again, it's not to say that the symbolic significance of them isn't lost on me, I just think it serves us better to be realistic in how these machines can be used for good, too, otherwise we risk reverting to a less morally advanced, paganistic, nature-worshipping people. Nature isn't separate from us, and nature isn't benevolent. It exists to kill you. Now, that doesn't mean we should go crazy on deforestation, it means we don't need to go too crazy in the other direction either. Conservation is important. Human life is more. It's not one or the other, there's a balance to be had in everything. The implicit ideology of this film is not balanced.

Crysta and Zak agreeing that Zak must go back to humans to prevent them from continuing efforts of deforestation doesn't sit quite right with me. This aspect of the film is naive. The only way I think this plan could possibly work, is if they could document what happened to the machine. I think most people would see the machine being enveloped by nature as some sort of poetic justice, however religious this conclusion is. Many people saw covid's effect on human behavior, and the resultant effect on nature, as more proof that "the real virus is us!" and this is, of course, silly. But it's enough, perhaps, to encourage people there are forces that are outside of our control. At the same time, humans exist to make order out of chaos, so naturally, chaos makes them quite curious, and they'd flock to see what forces, magical or otherwise, could have caused such an unnatural thing to happen. So I'm not sure what the best possible solution is, but I know it's not simply "Zak becomes a tree-hugging activist who writes ludicrous stories about fairies and magic to own the greedy corporate lumberjacks". That is naive as hell in both positive and negative directions; it believes people to be "better" than they are, and people to be worse than they are in reality.

Also, Batty is a character that creates massive tonal inconsistency. He seems anachronistic in many ways. Speaking of which, I think this film would have been FAR more tonally consistent if the songs sang by the FernGullians were classical, orchestral, choral compositions, rather than weird 90s hip-hop. It actually damages the worldbuilding; Crysta's father reacts to Zak's rock music with "that's not music that's just noise" when the songs sang by the animals are from the exact same, human society. It's anachronistic in a spacial, cultural sense. So perhaps Batty's anachronism comes from the fact that he was a lab bat, and he apparently has some sort of antenna that tunes in to TV frequencies that leak human elements into his psyche. Zak shouldn't have known how this worked functionally, by the way. He flicks the antenna to short it, saying "wrong channel," but that's the only line that we get to explain how his cybermetric component works. Batty probably should have said something more about it; in the beginning he seems to just be having electroconvulsive seizures that make him pretend to be different characters.

Apologies for the ramble, this isn't as coherent as I usually prefer to be. Worldbuilding is okay, characters are okay, plot isn't so good. If you want your kids to have valid concern for the environment, and an understanding that technology can be used for evil, but can't be thrown out, and thus must be used for good, don't show 'em this. The Lorax suffices perfectly for this moral lesson, in practically all its iterations. In any case, I don't think you can go wrong with Seuss' original book, whereas I think the conclusions to be drawn from this film are morally complex at best, misleading at worst. Tell the truth, or at least don't lie. This film seems to implicitly fail at both. Doesn't mean it's worthless, but it does mean that it's not the best. I prefer to prioritize the best.