Planet (The Doctor, the Widow and the Wardrobe)

A snowy planet was considered by the Eleventh Doctor to be the most peaceful planet he knew. It contained forests of Androzani trees.

The Doctor planned to take Cyril, Lily and Madge Arwell to this planet. He used a portal disguised as a gift box to connect the years 1941 and 5345. In the latter, harvest rangers from Androzani Major had come to harvest the forest for fuel. The trees knew of both events and had planned for them. They grew into a spacecraft and used Madge to transport their lifeforce, allowing them to escape the harvesting. (TV: The Doctor, the Widow and the Wardrobe)

Behind the scenes
The Doctor Who Character Encyclopedia (Updated Edition) named the planet as "Tree Farm 457."