It could also be about change. Maybe the story uses the mango tree as a constant while the characters around it go through various changes. The tree witnesses their growth, their joys, and sorrows, and through this, the theme of change and the passage of time is explored.
There might be a group of friends as the main characters. They meet under the mango tree regularly, and their friendship, their adventures together, and the conflicts that arise among them form the core of the story.
One possible theme could be community. Since the stories are told under the mango tree, it might be a place where the community gathers and shares stories, highlighting the importance of community bonds.
The main theme could be growth. The fig tree might symbolize growth, either of a character or of a situation in the story.
I think the main theme could be about survival. In many short stories, characters face various challenges and have to find ways to survive, and perhaps 'the fever tree short story' is no different.
The main theme could be isolation. In the story, the characters might be isolated from society or from each other, creating a sense of loneliness.
The main theme could be about the fir tree's longing for something more in life. It might be about its desires and how they lead it through different experiences.
One possible theme is sacrifice. The flowering tree, being a living entity in the story, might have to endure certain hardships or make sacrifices. This could be paralleled with the experiences of the human characters in the story, where they also face situations where they have to give up something for a greater good or for the sake of others.
One possible main theme could be the cycle of life. Just as the apple tree goes through seasons, from budding in spring to bearing fruit in fall and then being bare in winter, it can mirror the life cycle of the characters in the story.
The main theme could be about the power of suppressed anger and how it can grow into something toxic. It shows how holding onto negative emotions can have harmful consequences.
The main theme is often about love and growth. The story might explore how the characters develop in their relationships while being in the setting under the oak tree.