A college student who struggles with her academic and personal life in her early twenties. After she survives an accidental electrocution, she experiences a sudden shift in perspective and begins to hear voices that compel her to drive to California. She possesses a natural confidence and an intense, newly discovered dedication to environmentalism.

A young artist descended from Norwegian immigrants who settled an Iowa farm. He inherits his family's generations-long connection to a singular, blight-resistant chestnut tree on their property. Lacking direction after a devastating family tragedy, he channels his grief into the creation of massive nature-inspired art installations.

The highly intelligent daughter of a Chinese immigrant, raised in Illinois. She works as a successful engineer and frequently travels the world for her well-paid corporate job. She treasures childhood memories of visiting national parks with her father, which eventually pulls her into the world of environmental protests.

An orphaned veteran who struggles to find his place in society after serving as a loadmaster during the Vietnam War. Following a near-fatal fall where a jungle tree breaks his descent, he returns to the United States and spends years planting thousands of fir seedlings to make amends for the destruction he witnessed.

A socially awkward child who grows up fascinated by the intricate mechanics of nature, particularly ants. Bullied by his siblings and peers, he eventually turns his analytical mind toward psychology. He studies cognitive biases and the human behaviors that cause environmental blindness.

A dedicated botanist and forestry expert born with a hearing defect. Taught by her father to appreciate the subtle communications of nature, she dedicates her life to studying trees and eventually authors a groundbreaking book which suggests that trees are social creatures that communicate and share resources.

The son of Indian immigrants who discovers a profound talent for computer programming at a young age. Following a severe childhood accident that leaves him paralyzed, he channels his immense intellect into the creation of incredibly successful, sprawling video games inspired by the complex ecosystems of the natural world.

A highly successful intellectual property lawyer living in St. Paul. Though initially indifferent to the natural world, he maintains a complicated, on-again-off-again relationship with his wife, and eventually develops a profound appreciation for a planted garden in their backyard.

A stenographer who spends years avoiding permanent commitment before finally marrying Ray Brinkman. She struggles with infertility and marital dissatisfaction, filling her time with numerous hobbies and reading before finding solace in the overgrown nature outside her window.

Born Sih Hsuin Ma, he flees the communist revolution in China to study electrical engineering in the United States. He maintains a quiet, private connection to his heritage through his love of national parks, ancient Buddhist scrolls, and a carefully tended mulberry tree in his suburban backyard.

The American wife of Winston Ma and mother to three daughters. She provides a stable foundation for her family in Wheaton, Illinois, though she eventually begins to show early signs of cognitive decline.

One of Mimi Ma's sisters, who grows up taking family trips to national parks. She eventually attends Yale to study economics.

Mimi Ma's sister, who displays an early sensitivity to nature and wildlife. She grows up to nurse wounded animals in Colorado.

A Norwegian immigrant who marries Vi Powys and establishes a farm in Iowa. He plants six chestnuts on the day he proposes, unwittingly starting a family legacy centered around the singular tree that survives the elements.

Jørgen Hoel's wife, who joins him in moving west to Iowa to start a farm and a large family.

The eldest son of Jørgen and Vi Hoel. He modernizes the family farm with new technology and begins a multi-generational tradition of photographing the massive chestnut tree once a month.

John Hoel's son, who inherits the farm and diligently maintains the photographic record of the chestnut tree until he is drafted into World War I.

The grandson of John Hoel, who keeps his promise to continue photographing the chestnut tree for decades. The tradition leads him to accumulate hundreds of pictures that give his life a quiet sense of purpose.

Adam Appich's older sister. She mysteriously disappears while on spring break with her friends, an event that deeply fractures the family and pushes Adam further into isolation.

One of Adam Appich's sisters. After Leigh's disappearance, she organizes a secret memorial service in the forest for the remaining siblings to process their grief.

Adam Appich's older brother, who frequently bullies Adam during their childhood. He once forces Adam to eat grass while Adam conducts experiments on ants.

The youngest of the Appich siblings, born into a household already defined by the older children's rivalries and their respective assigned trees.

A practical and supportive scientist who manages the research station in the Pacific Northwest. He bonds with Patty over their shared dedication to forestry, eventually marrying her and helping to maintain her ambitious seed bank project.

Olivia Vandergriff's abusive ex-husband. Their brief, tumultuous marriage was built on a foundation of lies to spite Olivia's parents before ending in a lengthy divorce.

The informal leader of the environmental protest camp in the California redwoods. She directs the efforts to protect the trees and assigns tasks to the incoming volunteers.

A journalist who loves the *Mastery* game series and interviews Neelay. Neelay feels a quiet attraction to him but lacks the confidence to act on it.

Adam Appich's wife and the mother of his young son. She struggles to understand his secret history with environmental extremism.

Adam Appich's graduate advisor. She is the one who initially suggests he focus his research on the plant rights protests, inadvertently setting his life on a new path.