Symbol: The Hoel Chestnut
The Hoel chestnut is a symbol of many things. First, it symbolizes the Hoel family itself—their struggles, their fortitude, their growth and spreading out over space and time. Second, it symbolizes man's impact on nature. The Hoels plant six chestnuts but only one survives. It thrives, survives the blight, and becomes a beacon of hope and delight. However, over time it sickens, just as humans infect the natural world with their greed and desiccation. It is eventually cut down, an augury of greater destruction to come.
Symbol: The Helicopter
The helicopter that comes to order Nick, Adam, and Olivia out of Mimas is truly a hulking, terrifying beast that symbolizes mechanized power, man's puissance and avarice, and the terrible forces brought to bear on the natural world. The helicopter is described as a beast, a monster: "The stench gags Adam. The roar pierces his eardrums, killing all thought" (326). The voice that emanates from it is "metallic" (326). It is so "huge and malevolent" (325), Adam marvels, and its parts seem "beyond the power of any human to assemble, let alone design" (325). The helicopter, as a symbol of corporations and power, "wins" against the feeble protestors, and Mimas is cut down.
Motif: Naming
Names are significant beyond what they may initially connote. First, there is the town of Solace. The concept of solace is one of security and safety and comfort, and this is what many of the characters—Olivia and Nick in particular—find once they arrive there. In Solace they have a purpose and, obviously, solace itself. Second, there are the names the characters take for themselves. Mother N, a minor character, is an authority figure in the way Mother Nature is in a more macro sense. The main characters also choose names that matter for them, such as Mulberry (the type of tree that Mimi's father planted and which she loved as a child), Maple (Adam's childhood tree), and Doug (deriving from Douglas's name but also the types of trees that help galvanize him). Maidenhair and Watchman are names given to Olivia and Nick, each by the other, and exemplify aspects of their personalities—Nick's propensity to watch over Olivia as well as the trees, and Olivia's ancient, prophetic nature.
Allegory: Mastery
Neelay's game Mastery is an allegory for humans' impact on the natural world. Humans spread out, conquer, build, organize, collaborate. They evolve more efficient strategies to get what they want and to achieve domination; this is true in both the game and in actual human history. This is why Neelay eventually wants to move beyond this type of game and do something that allows humans to find a way to live a more sustainable life—to work with the natural world, not against it.
Motif: Suicide
Many of the main characters flirt with the idea of suicide, or people close to them do, or, in Patricia's case, they actually carry it out. Mimi Ma's father takes his own life when he feels the time is right, which, to him, is signified by the sickening of the mulberry tree. Patricia first considers it after her reputation tanks, but decides not to do so. Later, in her old age she realizes that she is ready to demonstrate to the world that the best thing to do for it is to take one's own life to buy a little more time and free just a few more resources. Powers does not condemn these choices, allowing his authorial voice to maintain neutrality. However, he also weaves in suicide in a more meta-way, suggesting that the human race is essentially committing suicide. In an interview with the Los Angeles Review of Books, he stated, "It may be neither hyperbolic nor rhetorical to call the current turn in American politics a collective suicide. Premature deaths, damage to human health, dislocation of populations, destruction of coastal and storm-belt property, disruption of essential components of the food supply: climate change casualties are mounting rapidly, and coping with, let alone trying to reduce them will require one of the greatest concerted public efforts in history . . . the current, proudly suicidal administration is backing out of climate agreements, crippling the solar power industry, subsidizing 'beautiful, clean coal,' opening national monuments to drilling, and revoking or rescinding protections of air, water, and land that took half a century of massive political effort to put in place." When Patricia stands at the lectern and takes her own life, she actually calls it "unsuicide," a phrase which Neelay adopts as well. This term suggests that killing oneself is better than the monumental killing that is currently going on.