How does it happen in the movie?
Merry and Pippin have run into Fangorn forest where they are saved by Treebeard, the Ent that appears to be a tree, from a pursuing Orc. Treebeard picks the hobbits up because he is in doubt whether they’re not small Orcs as well but still he talks to them about his allegiances and tells them a bit about himself. Merry tries to convince the old Ent that he and Pippin are hobbits, but Treebeard is still not convinced because he’s grown suspicious of the outside world because of the destructive, rampaging Orcs. He says he’ll wait and see what the White Wizard says. The hobbits, hearing this, are frightened for they fear that they are taken to Saruman.

When we see the three again Treebeard is singing while both Pippin and Merry are getting drowsy and eager to arrive at Treebeard’s home, but when they ask how much further it is he tells them not to be hasty. His home lies in the heart of the forest and he’ll bring them there to keep them safe, as Gandalf told him too. After this Treebeard continues singing again, though this time it is a song of his own composition.
While he sings the hobbit fall asleep and therefore, when they arrive to his home in the end, he put them on the ground and tells them to sleep without worries. Then Treebeard returns to business, there are people who need to be called and things that need to be attended to, of that his talk with Gandalf has convinced him. He now sees that the end of the woods is drawing near.

In the morning when Merry wakes up it is to a forest bathed in light, yet Merry is somewhat alert and calls for Treebeard and listens to the many sounds of the forest. Suddenly Pippin addresses him telling him of a dream he had about pipeweed and he goes on to say how much he’d give for a whiff of Old Toby’s. As Merry turns around to look at him Pippin sits near a spring with a water bowl in his hands, he relaxes – but then more treeish sounds are heard. At first Merry is in doubt from where they come but then he realises it’s Pippin making them when he stretches. Pippin denies it and rises from his seat and as he’s rising he stretches again and the sound is heard again. Pippin takes a sip from the water bowl and grins and suddenly Merry realises Pippin has grown taller than him.
This creates quite a discussion between them at first as to who is the taller, then to how Pippin has grown so much in such a short time and it ends up with Merry realising it’s the water doing it and taking it from Pippin, making the latter chase him to get it back while warning him that Treebeard said he couldn’t have any. The chase ends quickly though, because suddenly the roots of one of the trees grab Pippins foot and suspend him while others make Merry fall to the ground. Soon, after some desperate fighting done by the hobbits and cry-outs for help, they’re both covered completely by root and twig –and leaves.
At this moment luckily Treebeard comes back and he tells the tree to act treeish instead of catching hobbits. “Away now, go back to sleep” he says and soon after the hobbits are released.

After this the Treebeard picks them up again telling them they have to go because this place is no longer safe. As they’re walking Treebeard tells Merry and Pippin of the current conditions in Fangorn forest, how many of the trees have grown hateful, dangerous and aggressive because they’re not enough Ents to manage them. Pippin asks why they’re so few and if they haven’t got any Ent-children and Treebeard says they haven’t had any Entings for a long while because they’ve lost the Entwives. Pippin asks how they died but Treebeard says it isn’t that they’ve died but that the Ents have lost them and cannot find them again. He asks if they’ve seen any Entwives in the Shire and Pippin asks what they look like; Treebeard says he no longer remembers.

How did it happen in the book?
Merry and Pippin have fled into the forest of Fangorn where they go deeper and deeper until in the end, weary and tired, they stop to have a drink. While drinking their weariness departs but they do not notice it as they talk about where they are and what to do now. Both agree that there is a stuffed feeling in the forest which disables them to spend much time there, especially since their food supplies are also running low.
Then they see a gleam of sunlight further ahead and decide to follow it. As they follow it they come across a hill and they climb it to get a better view of the forest. Reaching the top they get a glimpse of Fangorn in sunlight but as the sky is already covered with clouds again, Pippin comments that it’s a pity because he almost felt he liked the forest. This remark causes some reaction from what appeared to be a tree standing beside them but in reality is Treebeard the Ent. He says it was lucky he heard their voices because otherwise he’d have thought them to be Orcs whereas now he’s only puzzled by what they then may be.
The hobbits however are also both shocked and curious as to who and what Treebeard is. He tells them the name that other calls him and says he is an Ent but that he’ll do the rest of the questioning. Then he starts mumbling lines from the Old Lists of the free peoples to figure out where the hobbits fit in. As nothing do they propose that he make a new line about hobbits. Treebeard asks them who calls them that and when they answer that only they do themselves he warns them to not go telling these names to everybody.
This strange meeting, among other things, makes Treebeard wonder what Gandalf – and Saruman – are up to and Pippin and Merry say they might be able to tell some. Treebeard says they should go somewhere else to talk because it is getting darker and he picks the hobbits up and go towards one of his homes in the deeps of the forest where they’ll be able to both talk –and eat.
While they’re walking Pippin asks the Ent why Celeborn warned them against entering Fangorn and Treebeard says he might have said the same if they had gone in the other direction. Then he starts telling them how the conditions have changed in both Fangorn and Lothlórien and also about the withering of the woods and the effect this has on some trees that are now growing Entish. He says there are black places in the forest, darker even than the Old Forest near the Shire. He says the Ents are also starting to grow treeish, that their power is less than earlier when the forests spread throughout most of all of Middle Earth and he sings to them.

At last they come to Wellinghall, one of Treebeard’s homes and the place where they will spend the night. Treebeard prepares some bowls of water –a large one for himself and two smaller for Merry and Pippin. The water has a rich and earthly taste and quenches both their thirst and hunger. When Treebeard has emptied his bowl he lies himself on a bed and Merry and Pippin, sitting on the ground, start telling their tale avoiding all mentioning of the Ring and though they let Treebeard ask as many questions as he’d like he does not ask them what the reason was for them to embark on their travel.
Treebeard wonders about these news and the hobbits ask them who Saruman is and he tells them how he met him when he came to Isengard and how at first the wizard treated the Ent politely and respectfully, asking permission to walk in Fangorn and listening to all Treebeard said but that slowly his mind turned mechanics and industry. Therefore, with this knowledge in the back of his head, Treebeard works out that grand affairs are not only happening far away in Gondor and Mordor, but also that Saruman has bred a new race of Orcs and are ruining his land. Even though this hastiness cools of quickly he lies pondering in his bed thinking of what to do and how many Ents he’ll be able to summon on a short notice.
Through these calculations Merry and Pippin find out how few Ents there are left and they ask why that is. Treebeard tells them that there’s no longer any Entings and that they’ve lost the Entwives long time ago. On request from Pippin, Treebeard tells gives the account of how they lost the Entwives and the Ents hunt for them in later days. He also mentions that some say that when both Ents and Entwives have lost everything they’ll finally be able to find a place where both might be happy. He then goes on to chant an Elvish song of this and then he rises to get some sleep and the hobbits cuddle up in Treebeard’s bed.
The next morning after the hobbits have taken a bath, Treebeard picks them up again and they walk to Derndingle, the place where Treebeard have summoned other Ents to Entmoot.

Some changes
– In the movie Merry compares the feeling he gets in the forest to that in the Old Forest. In the book this does not happen, instead Pippin compares it with the feeling you get in the Old Room where Old Gerontius Took lived in the Great Smiles at Tuckburough.
– In the movie the hobbits meet Treebeard when he saves them from a pursuing Orc while in the book they meet him on a hilltop.
– In the movie when Treebeard says he is an Ent Merry recognises the word and knows what an Ent is whereas in the book he is as clueless as Pippin.
– In the movie Treebeard suspects the hobbits of being Orcs for quite a while after having heard their voices, in fact he is not easy until he has had the white Wizard’s confirmation that they’re not. In the book the hobbits’ voices convince Treebeard that they’re not Orcs and therefore they aren’t set before the White wizard either.
– In the movie the hobbits are alone when drinking the Entwater while in the book they’re with Treebeard. Also in the movie the growth-effects of the Entwater is discovered from the beginning and therefore the drinking part is not so much done because of thirst but from an ambition to grow bigger.
– In the movie Pippin and Merry are “caught” by a tree. This does not happen in the book at this time instead this takes place while the four hobbits are still in the Old Forest.
– In the movie Treebeard says he is on nobody’s side because nobody’s on his side and that nobody cares for the woods anymore. In the book he says he isn’t altogether on only one side because nobody cares for the woods as he does but that sometimes he joins forces with one or other. This is only a small change but the wording changes the content of what he says somewhat.
– In the movie the hobbits fall asleep when Treebeard talks and sings whereas in the books they’re interested in hearing what he says and ask him many things themselves.
– In the movie Treebeard hears of what is going on in the outside world from Gandalf, in the book he is told of it by Merry and Pippin.

Mistakes
-Treebeard claims the song he sings about the Entwives is one of his own compositions, but the text heard in the movie resembles the song that he in the book says is made was made by the Elves. Moreover does Treebeard say, in the book, that the Ents are content with calling the Entwives names from time to time instead of making songs of them.

Bookie Details
– Treebeard saving Merry and Pippin from an old tree is a deliberate reference to the events in The Old Forest, which was cut out off ‘The Fellowship of the Ring’. There, Tom Bombadill rescues the Hobbits from Old Man Willow.