Although Betty Smith denied every consciously writing a novel with sociopolitical motives, A Tree Grows in Brooklyn cannot be separated from class issues. Nearly every anecdote, character, and chapter represents or addresses the problem of poverty in early twentieth-century America. Being poor means that the characters constantly must think of being poor—how they will buy the next loaf of bread, or what one's house or neighborhood looks like compared to another. Smith shows that poverty does not only imply the absence of food, heat, or comfort. Poverty results in Johnny's worthlessness and death, causes Uncle Flittman to run away, and means that Francie cannot attend high school. Every activity, game, action is planned around a li mited pool of resources. In addition to the Nolan's life, Smith presents an entire poor community, and shows the close connection between poverty and exploitation. Store proprietors take advantage of children's innocence to lure money out of them; piano t eachers beg for tea from their students. Smith's sympathetic treatment of her characters that poverty itself is the evil—not the people. Like the tree man, people just need to think first of their own families and children.
The author often juxtaposes the lower class with people of privilege to further develop this theme. Although having money makes for an easier life, in many cases, the most lovable characters in the book are impoverished, or come from a poor background. The rich doctor reigns as a villain in the book; the charity event is exposed as self-righteous and hurtful. By the end of the book, Neeley and Francie pity Laurie for growing up without any hardship, saying that she will never have as much fun as they did. Like the tree, the author seems to be saying, she "likes poor people."
Although Johnny, Katie, and Mary Rommely vary tremendously in personality, they all agree that education is the way out for the Nolan children. This theme goes along with the immigrant history of the Nolans and Rommelys. Mary Rommely does not even know when she moved to America that education was free; in fact, she still does not even know the word "education," but she rejoices over and over again that her daughters can read and write. Katie has an epiphany part way through the book when she looks at her children who believe that their life is good—who are happy with a Christmas tree and vulgar neighbors and a humble life. She knows that education will save them. This version of "education" is almost always synonymous with "schooling." Although the Nolans do think lessons in life are important, schooling will change their quality of life. Francie is said to have qualities of both her mother and father. Although education will be Francie's way out of poverty, it can also be ostracizing. She and Katie both reflect on different occasions how their relationship will change as Francie becomes more educated and refined; still, the novel privileges the discomfort this separation engenders over ignorance. In the same way, Francie cannot make friends because she talks like characters in Shakespeare, and books eventually replace friends for her.
Gender dictates many different social relations in this novel. Upon Francie's birth, Mary Rommely comments that to be born a woman is to be born into a humble life of pain. This abstract idea of life's pains is juxtaposed with the narrator's consistent reference to the pain of childbirth. At least in the context of this book, women of all faiths and all socioeconomic backgrounds are bound together by the pain of child labor. All in all, the women in the novel are more equipped to handle pain—both emotional and physical—than the men are. Oftentimes, strength is divided on gender lines: Katie is strong, while Johnny is weak; Evy is strong while Uncle Flittman is inadequate; and Katie even sends Neeley to school over Francie, because she is sure that Francie will find a way to go back. One may also think about this theme in terms of geographic spaces. Even in the first chapter, there are certain stores that Neeley enters, but Francie does not, and vice-versa. Women congregate in the kitchen sometimes without men, and the scene of childbirth is considered women's space. Men congregate at the barber or at McGarrity's. Setting and place play such a large role in this novel, that it behooves the reader to consider the way gender interacts with geographic spaces.
Although the novel may seem rather tame to modern readers, there are a surprising number of implicit references to sex and sexuality. The fact that one of the most warmhearted characters—Sissy—has a serious habit of promiscuity suggests that the author is challenging ideas about women and sex in this time period. Joanna's presence in Francie's neighborhood is a startling reminder of how the old world (the stoning women) conceive of women's sexuality. The book rectifies this perspective by showing Francie's reactions to Joanna. Francie sympathizes with her, offers her story for Joanna to read (symbolically offering her knowledge or education), and in general makes clear that the cruelty of the stoners will not be tolerated. Francie's youth implies that in the future women's sexuality will not be confined to narrow and hypocritical conceptions. The continual references to the pains of childbirth also makes visible the idea that women have few sexual health choices; a lack of sexual consciousness, birth control, and technological advances forces them into this experience of pain and suffering.
This theme relates closely to the American dream motif and the symbol of the tree. The strength of the Rommely women suggests that they can withstand any hardship. When Francie is born sickly, she perseveres like the tree; her mother never doubts her strength. Francie's sickness and persistence only foreshadows many other physical and emotional hardships. When Katie has children, she only becomes stronger, determined to make a better life for her children. Every time Katie could give up a little luxury, she puts the money she would have spent in the tin-can bank. This theme obviously relates more to the Rommely women than it does to the Nolan men.
As a coming of age story, this motif recurs in almost every chapter and helps to develop the themes of the book. As Francie grows up, she learns more and more about the world—more about poverty, class status, gender, and sex. The older Francie gets, the less innocent poverty becomes. As a child, the scarcity in the Nolan house allows Francie to appreciate small material things. As she grows older, the ugly side of hardship becomes more real when her father dies and her ambitions are cut short. Often times, Francie expresses this "fall" in terms of dreaming. She sometimes thinks the sex prowler in the hallway was a dream, or her father's death, or Uncle Willie's leaving. Francie's falls, like any motif of lost innocence gain consequence as the plot escalates. For instance, her run-in with the girl with blackboard erasers is less severe than her vaccination experience. Henny's death is less severe than Johnny's.
The "fall" does not only refer to events that have brought her pain, but also events that have taught her knowledge. Indeed, one may also think of the Tree of Heaven as an allusion to the Tree of Knowledge. In the context of the novel, the tree brings only hope and joy. Likewise, for Francie, learning to read is her first step toward becoming an educated woman. The events of the outside world are another kind of acquiring of knowledge, and they parallel Francie's development into womanhood. Although the imminent war causes much anxiety, technological advancements such as hospital births make it possible for Sissy to give birth. While Francie's broken heart coincides with a man going off to war, this rite of passage allows her to fully appreciate Ben Blake. By structuring the book around a fall from innocence, Smith can address both the life of one girl, and the situation of the world in general.
The dream of a better life in America drives the Nolans to live life the way they do. This motif helps to develop the theme of education in the novel, since education is the way in which daughters and sons will one day live richer lives than their parents. When Mary Rommely gives her advice to Katie at the beginning of the book, she tells Katie how she should raise her children so that they will have more opportunities. Mary's optimism foreshadows Francie's ability to get an education; Mary already sees the dream taking form since Johnny and Katie can read and write. Johnny's love for the Union and staunch support of the Democratic party are examples of this motif's recurrence. Also, the successful characters in the novel ultimately are those who have made this promise a reality; the characters who do not make it—Johnny and Uncle Flittman—feel overrun by life precisely because they have not achieved the dream of a better life. This motif can also be thought about in terms of contrasting old world ways to life in America.
The tree in the title grows in tenement districts, without water or light, even without soil. It symbolizes perseverance and hope amidst hardship. The tree is a recurring symbol throughout the novel; when Francie is born, Katie explicitly likens her life to the tree's. Katie knows she will keep living, no matter how sick she becomes. In Brooklyn, this tree trumps all others. When Neeley and Francie bring home a small spruce to nurture, it dies even as they try to take care of it. But the tree keeps on. The reader should think of the tree not only in terms of Francie, but also the poor community as a whole. It "likes poor people." When Francie leaves Brooklyn at the end of the book, Florrie Wendy symbolically takes her place. The tree grows for Florrie, too, as it must have for Flossie Gaddis before Francie.
Francie sees the Tree of Heaven every single day; it is a touch of beauty in her daily surroundings. When Francie looks down from the fire escape, it looks like the tops of many green umbrellas. It makes sense that Smith would choose an object with which Francie is totally familiar. Here again, the author shows how one may view small, material objects differently. It is not a special tree, in a conventional sense; it grows everywhere where there are poor people. It is not grandiose like the sea or a majestic mountain. It is humble, and its humility makes it all the more powerful.