The Lightning Tree is a tall tree located at Maithwaite Forest, so named because it was struck by lightning.
The tree was in danger of falling so Jack and The Pack were sent to fix it. Max and Monty were racing recklessly and crashed into the tree. Alfie, Kelly, and Oliver managed to keep the tree up long enough for Jack to get the props Thomas had brought to support it.
It only appeared in A Tale for Thomas.