Pokémon FireRed and LeafGreen/Viridian Forest

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New Pokémon Available
Red Green
Caterpie

Weedle
Pikachu

The nature preserve is smack-dab in the middle of Route #2, the route that runs between Viridian City and Pewter City. Pokémon are plentiful within its borders, and many trainers come here to capture new specimens for their collections or to challenge other trainers. It's easy to lose yourself in Viridian Forest if you don't know where you're going.

Viridian Forest
Viridian Forest
1Bug CatcherImage:Pokébuck.png72
WeedleLV6
CaterpieLV6
2Bug CatcherImage:Pokébuck.png84
WeddleLV7
WeedleLV7
KakunaLV7
3Bug CatcherImage:Pokébuck.png96
CaterpieLV7
CaterpieLV8
4Bug CatcherImage:Pokébuck.png84
MetapodLV7
CaterpieLV7
MetapodLV7
5Bug CatcherImage:Pokébuck.png108
WeedleLV9
A Poké Ball
B Potion
C Antidote
D Potion
Viridian Forest encounters
Caterpie 40% 40%
Metapod 5% 10%
Weedle 40% 40%
Kakuna 10% 5%
Pikachu 5% 5%

[edit] Through the woods

Duels with Trainers
You'll find rival trainers everywhere you go, and they'll usually challenge you as soon as they see you. Trainers can have anywhere from one to six Pokémon, and you can't Run from a duel with a trainer, so always be prepared for an extended battle. Keep in mind that the tame Pokémon trainers use are often more powerful than the wild Pokémon found in the surrounding area.

Viridian Forest serves as your first "maze" stage. Its hard to get lost in there, but first timers may wish to explore it slowly to get a feel for the layout. As you cross Viridian Forest, you'll be attacked by both wild Pokémon and various trainers. While encounters with wild Pokémon are random, trainers will only come at you when you cross their line of vision, so you have a degree of control over when they challenge you. Unfortunately, they are usually placed in positions that you have no choice but to pass in front of, but a few can be avoided by walking around them.

If you are having trouble defeating trainers in a given area, it probably means that your Pokémon aren't strong enough and need to be leveled up higher. The highest level Pokémon that a trainer in Viridian Forest has is Level 9, so as long as most of your Pokémon are level 8 or above, you should be in good shape.

The pets and the wildlife that you encounter in the forest may seem tough, but much of it won't be. Wild and challenger-trained Kakunas and Metapods can't attack, they can only harden (which can make for some long battle that wear down your Pokémon's PP, so be careful). Never try to capture a wild Metapod or Kakuna. Instead, capture Weedles and Caterpies and level them up so they evolve into Kakunas and Metapods that retain their offensive abilities. They evolve fast: Both will be at their third stage of evolution by Level 10!

Pikachus are extremely rare and will take extensive periods of walking around through grass to find them. Be sure not to leave the forest without snagging one. Defeating Misty will be difficult without their help!

#10 Caterpie #13 Weedle
Caterpies aren't worth getting too excited about. Deciding which of the two bugs to collect comes down to whether you want an awesome Pokémon sooner, or later. If you'll willing to invest a lot of time with Caterpie, he will ultimately end up as a Bug and Flying-type Butterfree that will eventually learn powerful psychic attacks.
Weedle doesn't start out much differently than Caterpies. He's pretty weak when you get him, and evolving him into Kakuna doesn't make him much better. But his evolution continues at a lightning pace, and at level 10 you'll have an awesome (at least for the early part of the game) Beedrill.
#25 Pikachu
Pikachu compensates for his weak defense with a good dose of power and its lightning speed. Electric is also one of the best all-around types in the game and while it makes Pikachu weak against Ground enemies and Grassers, Electric attacks absolutely shred the game's plentiful Flyers and Water-based creatures... You can see this at work as Pikachu's Thundershock fries the Pidgeys hanging around in Route #2. Pikachu can evolve into a Raichu, but only with the aid of a Thunder Stone.