Tree's a Crowd (Japanese: キモリの森！巨大樹を守れ！！Forest of Kimori! Protect the Gigantic Tree!!) is the seventh episode of the Advanced Generation series and the 281st episode of the Pokémon anime. It was first broadcast in Japan on January 9, 2003 and in the United States on November 29, 2003.
Deep in the woods, Ash spies a Treecko. He's wanted to catch a Treecko since he first saw one at Professor Birch's laboratory. He follows the Treecko to an enormous tree that seems to be dying. There, Ash's Treecko has an argument with all of the other Treecko. It seems that Ash's Treecko is very attached to the tree and wants to stay with it, while the rest of the clan wants to move on to a new tree. Ash watches as the lone Treecko struggles to save the tree. He and Pikachu feel badly for the Treecko and try to help. In the end, however, the tree dies and falls. Now that its home is gone, Treecko is ready to make a new home with Ash. He and Pikachu battle, and Ash catches his Treecko!
Ash and his friends are on their way to Rustboro City and are now lost. After a fight between May and Max, Ash sees a bunch of Treecko running through the trees. He says that he had wanted one since he first saw one at Professor Birch's lab. He quickly tosses a Poké Ball, but the Treecko bats it away with its tail, and May sarcastically reminds Ash that you have to battle the Pokémon first. Their talk is cut short when Brock notices that the Treecko are running away. Ash chases after them and the others follow. Ash sees what looks like a huge, odd tree up ahead. Unfortunately, he doesn't pay attention to where he's going and falls face first down a steep hill. When he looks up, he sees that the tree is right in front of him, and it's massive! It's more than twice as tall as any other tree in the forest, very thick, and, as Ash comments, almost magical-looking. It also doesn't have any leaves and looks somewhat dead. Suddenly a sharp twig lands in the ground right in front of Ash's face. He looks up and sees an angry-looking Treecko sitting on a branch with another twig in its hand. Ash challenges it to a battle, and it leaps from branch to branch, then jumps through the air and spits its twig at Pikachu. Pikachu dodges, and Treecko lands next to him and smacks him with its tail. Treecko taunts Pikachu, then when he tries to attack, dodges and hits Pikachu with its tail again. Meanwhile, Team Rocket is watching the whole thing and they're impressed with Treecko's performance. They have a boss fantasy about Treecko giving Giovanni a massage, and decide to catch it, but then they notice that there are now a lot of Treecko surrounding Ash and Pikachu. An old Treecko tries to talk to the one that Ash battled, but is only yelled at and smacked. The other Treecko look pretty mad, but the old Treecko tells them not to attack. Jessie is excited because she loves watching other people's troubles, and asks Meowth for a translation. The old Treecko says that the tree is going to die and all the Treecko need to move to another tree, but the other Treecko answers that it was born on that tree and isn't going to give up on it, no matter what. This really moves James and Meowth, but Jessie doesn't think it's very heroic at all, since life is full of change. She explains all about this, until they notice that all the Treecko are leaving except for one. Once the others are out of sight, that Treecko runs off too. Ash is prepared to follow it, but Pikachu has a better idea, so they stake out in the tree.
Meanwhile, Brock, May, and Max are eating. Max is worried about Ash, but Brock tells him that Ash will be fine, and they agree to go look for him after they're done eating. As the sun sets, Ash and Pikachu are still in the tree. Ash decides to send Taillow to look for his friends, since he's afraid they might be worried about him. As soon as Taillow flies away, Treecko appears carrying a leaf full of water. It carefully waters the tree, then goes off to get more water, as Ash wonders whether it's too late to save the tree. As darkness falls, he and Pikachu start to help the Treecko water the tree. It's angry at first, but it warms up to them when it realizes they just want to help. Suddenly, they hear a commotion and discover that Team Rocket is using a bulldozer to ram all the trees, knocking the sleeping Treecko into their net. When they spot Ash, Pikachu, and Treecko, Team Rocket charges them, sending them flying. After their motto, they take off in their balloon, now covered in neon lights, with all the Treecko in a cage. Ash orders Pikachu to use Thunderbolt, but it turns out that the lights were actually electricity blockers. Ash calls for Taillow, but then remembers that he sent it away to find the others. Team Rocket takes the opportunity to grab Pikachu in a net. But the Treecko that Ash befriended wasn't caught in the net, and now it's angry. It spits its twig at the balloon, but it just bounces off. Team Rocket laughs, and James sends out his Cacnea. Treecko leaps from the top of a tree into the balloon, and starts attacking Team Rocket. Jessie accidentally hits the button that releases the Treecko. Then Treecko leaps onto the balloon itself and taunts Cacnea. Cacnea angrily sends a Pin Missile Treecko's way, but Treecko dodges and the attack punctures the balloon. The Treecko free Pikachu and they all abandon ship as the balloon zooms off into the distance, sending Team Rocket blasting off again.
The Treecko that Ash befriended makes up with the old one, but still doesn't want to give up on the tree. Everything seems to be going well until the giant tree splits in two! The Treecko try to hold it together and Ash gets a rope out of his backpack, but they are stopped when the sun rises, illuminating the tree beautifully. As they look on, Ash and the Treecko have some sort of vision of the tree's life from a seed to the majestic tree it used to be. But the vision fades and they're only looking at a split, dead tree again, and it suddenly splits even more and falls over completely. A seed rolls from the wreckage and stops at Treecko's feet. Ash takes this as a sign of gratitude from the tree for trying so hard to save it. But Treecko doesn't take kindly to this suggestion and hits Ash. He realizes that Treecko is trying to tell him it's ready to battle. Just then, Brock, May, Max, and Taillow show up.
Pikachu uses Thunderbolt, which Treecko dodges multiple times, but finally scores a hit. However, Treecko doesn't seem to have taken much damage, and Max reminds them that Electric attacks aren't very effective on Grass-type Pokémon. Pikachu uses Quick Attack, which Treecko dodges, but that leaves it vulnerable to a Thunderbolt. Thunderbolt does a lot of damage and knocks Treecko out. Max doesn't understand what happened, but Brock explains that usually Electric attacks don't work well because the Pokémon can diffuse the electricity into the ground. Since Treecko was hit in the air, there was nowhere for the electricity to go. Ash throws a Poké Ball and catches Treecko. Ash lets it out of its Poké Ball, and the old Treecko gives it the seed from the dead tree. Treecko plants it, then leaves with Ash and friends as the other Treecko care for the newly sprouted tree.
Although May claimed that Treecko are "creepy" six episodes earlier in Professor Birch's laboratory, she states in this episode that they are "cute".
Brock explains that Grass-type Pokémon resist Electric-type attacks because they diffuse the electricity into trees or the ground. Furthermore, he states that if they are in the air, they are unable to diffuse the electricity and suffer normal damage from Electric-type attacks.
When May and Max are done fighting and the narrator is explaining the situation, Brocks eyes are noticeably different from one another.
The Who's That Pokémon? segment says that Girafarig has a tale that bites, instead of the homophone (and correct) tail.
In the English dub, the PokéNav is referred to by its Japanese name, PokéNavi.
When May, Max, and Brock arrive at Ash's location, Taillow is seen along with them, but the next time they appear onscreen, Taillow is nowhere to be seen, despite Ash never recalling him, and doesn't appear for the remainder of the episode.
After Ash catches Treecko, when he, May, Max, and Brock are leaving, they say, "Goodbye, Treeckos," instead of the singular (and plural) Treecko.
Ash refers to his Treecko as male when, after watching it shove the oldest Treecko to the ground, he states "That's weird; looks like he's not good buddies with the other Treecko."