Tinker Bell: Secret of the Wings

At the beginning of winter, everyone prepares for the final season of the year. Out of curiosity, Tinker Bell wants to go to the Winter Woods. The tinker fairies make snowflake baskets which are delivered by snowy owls. Later that day, she helps Fawn take the animals to the Woods to hibernate. While Fawn is busy, Tink crosses the border, and her wings start to glow. Seeing this, Tink is convinced that she is meant to explore the Woods. But Fawn warns her that her wings are freezing and rushes her to the fairy hospital. After being examined, she remains curious about her wings. Tink then flies off to the Book Nook, where she finds a book on Wingology, but finds the page on "Sparkling Wings" chewed up by bookworms. A reading fairy tells her that the Keeper, the author who lives in the Winter Woods, might be able to help her.
Preparing herself and using the final shipment as her only chance, she sneaks into the workshop and climbs inside one of the baskets. She gets picked up by a novice owl and makes her way across the border. The owl then accidentally drops the basket, and she crashes into the snow. Realizing her book has been flung from her bag, she tries to get it back. However, Milori, the Lord of the Woods, finds the book and asks Sled to return it to the Keeper. Tink then follows him to the Winter Library. Upon arriving, she spots the Keeper, Dewey. But before she can talk to him, another winter fairy rushes into the room and proclaims that her wings sparkled the day before. Tink meets the fairy, whose name is Periwinkle. Suddenly, the girls' wings start to glow. Astonished, Dewey brings the two to a platform and positions their wings before the whole chamber becomes filled with images explaining their origins: that Tinkerbell and Periwinkle were born of the same baby laughter. The two then realize that this would make them sisters. Suddenly, Lord Milori arrives, concerned about the book, warning him to send any warm fairy back. Dewey tells the two they can spend a day together before Tink has to return home.
Periwinkle shows Tink her world, meeting Peri's friends and spending the day together. That night at Peri's home, as Tink builds a fire, she realizes that if she can make it warm there, she can, in turn, make it cooler at her home. Suddenly, the floor melts beneath them. Seeing this, Dewey tells them that Tink has to go home. She then comes up with a plan. When they reach the border, she tells Peri to meet her at the border tomorrow. When Tink arrives home, she asks Clank and Bobble for help, and they bring her other friends to help. The next day, Tink arrives at the border with Bobble and Clank, pulling along a snow-maker. Now able to keep her cold enough, Peri crosses the border to the warm side of Pixie Hollow. She meets Tink's friends and continues her tour. After a while, Tink then notices Peri's wings wilting; the machine is running out of ice. They then return to the border. Lord Milori appears and instructs Peri on how to fix her wings. Queen Clarion also arrives and sadly explains that they can never see each other again.
As the girls leave, the machine gets knocked by Milori into the stream and creates a massive snowstorm. Later that day, Queen Clarion tries to explain to Tink why the rule is important, as does Lord Milori with Periwinkle. They are told the story of two fairies, one warm and the other a winter fairy, who met and fell in love. As their romance grew stronger, they disregarded the dangers across the border. Sadly, one of them broke a wing, for which there is no cure. From that day, Queen Clarion realized that some fairies should remain apart. Meanwhile, the trapped snow-maker begins to freeze the Autumn Woods. They, along with Tink's friends and the Ministers, arrive at the stream and find Clank and Bobble attempting to free it. They succeed, but a freeze is coming. Queen Clarion tells everyone to save the tree for the freeze will kill it, eternally stopping the flow of pixie dust. They try everything they can to save the tree. Tink then notices that a Periwinkle that Peri had covered in frost is still alive, despite its cold surroundings. She flies to the Winter Woods but, on her way, falls into the snow. She then asks Peri and her friends about the frost around the flower, and Gliss explains that frost acts like a blanket, keeping the warm air inside. This gives Peri the idea that they could frost the tree before the freeze comes, and they then head to the tree. Meanwhile, at the tree, their plan is failing to the Queen's disappointment, but then Tink and the others arrive. They explain the power of their frost, but Spike realizes that the tree is too big for three of them to finish in time. The rest of the frost fairies then arrive to help. Accomplished of frosting the whole Hollow, Milori states that they've done all they can. He then warns the warm fairies that the freeze is upon them and they must take cover, including the Queen whom he gives his cape to, revealing his broken wing and that he and Queen Clarion were the fairies in the story. He then orders all the winter fairies to stand guard all over the tree.
Some time later, the freeze begins to melt and pixie dust begins to flow again. All the fairies celebrate. However, Tink reveals that she broke a wing when she flew to the Woods and warns Periwinkle to go back before her wings wilt. As the twins hold hands and say goodbye, they touch their wings and blindingly white light bursts from their wings, which slowly heals Tink's broken wing. In an epilogue, it is shown that warm fairies now cross over into the Winter Woods and that the two "seasons" now interact and become good friends, even lovers.

Question: Who gets the idea to frost the tree before the frost comes?
Answer: Peri