Treebeard's fate
 

I can't recall what happens to Treebeard and the Ents at the end of the books, besides they just go about their everyday lives without orc rubbish. Presumably, they never find the Ent Wives, which is pretty sad...but let's not talk about the Ent Wives, that is a whole different can of worms, haha. What do you think happened to Treebeard and the Ents? Any official notes from Tolkien that anybody knows of?

may i say the great fangorn forest bush fire....

Maybe they wandered to the West and disappeared when all other legends did, possibly meeting the Entwines in the forests of the Blessed Realm...

Or maybe they all became, year by year, decade by decade, century by century, more treeish and faded away...

With Tolkien's style I think the latter is probably right Lommy. It's sad, but somehow more 'real'.

Great topic! Let me add a question (or two)... Are the Ents considered to be immortal (like the elves), or just extremely long-lived? As such, would they be welcome in Valinor?

As I recall from the Silmarillion, Eru had plans for the "souls" of elves and men (granted, his plan for men remained a mystery, but it is enough to know that there WAS a plan) and even the Dwarves were taken care of after Aulë's little coup d'etat... but is there anywhere in the works of Tolkien a mention of the afterlife of the Ents?

I'm not fluent with the Silmarillion, so unfortunetly I'm not sure! I would imagine so though, I mean that would just be bias if Eru didn't allow Ents to the Blessed Realm. We don't know that for sure, but say Eru did let the Ents in...that poses another question- how would Ents even get there?

From my guessings Ents were immortal, unless being cut down, burnt, and such. So maybe, like Thin said, time goes on, the world gets stale, and the Ents fade and become "treeish". Would the soul of that Ent then travel towards the Blessed Realm, its time on M-e being over?

Ents allowed in Valinor? Why, but what they were!
 

I think the point of all of this stands with the question: "Who the ents really were?" Because this is it. Let us take a peek in the Silmarillion, chapter 2. Here Yavanna comes to Manwë for advice, because she is worried about the fate of the trees when the Children of Eru Ilúvatar (the Men and the Elves) - and now also the Dwarves - come. Manwë in turn asks Eru for advice.
This is all about the beginning of the Ents. "Eru will summon spirits from afar" - I don't know if we are talking about ainur-like forms here, or if Eru "summons spirits from his sleeve", some totally new creation, but the point is, that they are spirits. "And they will go among the kelvar and olvar" - meaning Animalia and Plantae, respectively :D "and some will dwell therein" - this means, these spirits will "merge" with a living body (of a tree, or an animal). Note also that here, we are not informed just about Ents ("among olvar") but also about some spirits which, possibly, have come to dwell in animal bodies (in this case, the Eagles or, e.g. Huan). If we are to venture a little bit further, it is quite likely (and I am quite inclined to believe this) that there might be very much more of these "spirits" - whatever they were - and from here all the Dragons, Werewolves, Barrow-Wights (! ;) ) and all this stuff comes (be they just "some remaining spirits who did not find a body fast enough and were trapped by Melkor" or whomever Melkor has called in his early days, somehow being given the authority to do this, or be they Maiar who joined Melkor and Melkor trapped them in the wolf, dragon etc. bodies).

But I got a little bit off-topic. The point was, that Ents were not "fully valuable beings" in the same way as the Men or the Elves were, they were much more similar for example to the Wizards or the Eagles or whatever. Thus, I'd say there'd be nothing against them resting in Valinor, but since it seems their place was out there in Middle-Earth (as "the guardians", not in the Undying lands, where such things were not needed), and I can't imagine an Ent flowing across the Sea, it would seem, homm, hmm, they had to wait. Perhaps they became treeish (I find it quite likely), the "fire (if such a word is in place in case of an Ent) of the spirit" has faltered inside them, and so they are still here, around, but not distinguishable from other trees... only, maybe, older and more interesting at look... but until the drowned lands rise again, they won't awake and they won't be seen at dusk in the Men's realm.

Doesn't wood float? Drift-ents! <grins, ducks, and runs away>

I submit that the "log" that the Fellowship spied following them down the Anduin was not Smeagol at all, but rather an... ENTWIFE!