I don't know since I haven't read the novel, but perhaps there could be a young adventurer who is curious about what's behind the trees.
Since we don't have any information about the novel, we can only guess. There could be a protagonist who is on a quest of some sort and the trees are just an obstacle in his or her path. There might be a guide figure, someone who knows the secrets of the area behind the trees. And there could also be antagonists, like people who don't want the secrets behind the trees to be uncovered, or perhaps some natural elements that pose a threat to the characters exploring the area.
There might be a wise old sage in the story. The sage could be the one who guides the protagonist in understanding the significance of seeing behind trees. Or perhaps it's a group of forest animals, and one of them has this special ability, like a fox or a squirrel, and the story follows their adventures using this unique sight.
The main characters in the 'trees graphic novel' could be diverse. There may be a group of environmentalists who are fighting to save a grove of ancient trees. There could be a character who is a botanist and is researching the unique properties of certain trees. And perhaps there are some mythical creatures, like dryads (tree nymphs in Greek mythology), which are an integral part of the story, with their fates intertwined with the well - being of the trees.
Well, it might be about nature and human interaction. Maybe the trees are a symbol of a natural barrier, and the story could revolve around characters trying to overcome that, either physically or metaphorically. It could also be about secrets that are hidden behind the trees, like a long - forgotten place or event.
The main characters in the three trees story are the three trees themselves. They start with their own aspirations. For example, the first tree has the ambition to be a magnificent ship, the second wants to be a throne for a great king, and the third wishes to stay put. As the story progresses, their lives take unexpected turns, but they remain the central focus throughout the narrative.
Since it's about three Christmas trees, the main characters are likely those three trees themselves.
We really can't tell precisely without reading the story. However, if we assume the title is indicative of the main character's name or ability, then it's either a person named Sees Behind Trees or a character whose special power is seeing behind trees. This character might be facing some sort of conflict, like trying to protect their village from an unseen danger that only they can detect by looking behind trees, or perhaps they are on a quest to find something that is always hidden behind trees in their world.
The main characters are the three little trees. These trees are the focus of the story from start to finish. They start out as young, hopeful trees with big dreams. One dreams of holding treasures, another of sailing the seas as a ship, and the third of staying tall on the mountaintop. As the story progresses, they experience various events together, like being cut down and transformed, all while remaining the central elements of the narrative.
The main characters are the three little trees.
There could be a variety of main characters. It might be a group of children who were inspired to plant trees for peace. Maybe they learned about the importance of peace and the environment in school and decided to take action. Or it could be a story of a group of refugees who, in their new land, started the 'Trees of Peace' project as a way to find a sense of home and peace, with each person having their own story of struggle and hope that led them to be part of this project.
Since I don't know the exact '3 trees story', I assume the main characters are three trees.