By Maria Popova (themarginalian.org)

This essay and poem are part of the Universe in Verse book.

Trees grant us some of the richest metaphors for our own lives — a polished lens on the quality of attention we pay the world. “The tree which moves some to tears of joy is in the eyes of others only a green thing which stands in the way,” wrote William Blake. Walt Whitman considered them our greatest teachers in living with authenticity. For Hermann Hesse, the key to existential joy was in learning how to listen to the trees.

But far beyond the realm of human-wrested metaphor, trees are sovereign marvels of nature, dazzling in the native poetics of their biological and ecological reality. Their photosynthesis is nature’s way of making life from light. Chlorophyll — which shares a chemical kinship with the hemoglobin in our blood — allows a tree to capture photons, extracting a portion of their energy to make the sugars that make it a tree — the raw material for leaves and bark and roots and branches — then releasing the photons at lower wavelengths back into the atmosphere. A tree is a light-catcher that grows life from air — an enormous eye tuned to the light of the universe.

Art by Ofra Amit for The Universe in Verse.

Trees hungrily absorb red light — the longer wavelengths of the visible spectrum — but the neighboring infrared passes straight through them. Under the canopy, where fierce competition for these wavelengths rages, red light is depleted and infrared dominates. Even though trees cannot absorb infrared, they, unlike humans, can “see” it with chemical photoreceptors called phytochromes. The ratio between the two types of light tells trees how much to grow and in which direction, with phytochromes acting as on-off switches for growth. An abundance of red light under uncrowded skies turns the switch on, signaling to the tree to spread its branches wide into any gaps in the canopy; in the crowded shade where infrared dominates, the switch turns off, reducing the growth of side branches and prompting the tree to grow straight up, reaching for the open sky above.

Ever/After by Maria Popova. (Available as a print, benefitting The Nature Conservancy.)

As summer recedes into autumn, cooling the air and dimming the light, the alchemy of transmuting light into growth becomes too metabolically costly for deciduous trees. Chlorophyll begins to break down, revealing the other pigments that had been there all along — the yellow of xanthophyll, the orange of carotenoids, the reds and purples of anthocyanins, turning the canopy into an aria of color.

Meanwhile, the layer of cells by which the stem holds on to the branch is fraying. Leaves begin to let go — a process known as abscission.

But as they denude the branches, they reveal the subtle nubs of the new buds that had been forming all summer, readying next spring’s growth.

Skeletal and pulmonary, winter trees rise into the leaden sky, their skin a braille poem of resilience.

Winter Moon at Toyamagahara, 1931 — one of Japanese artist Hasui Kawase’s stunning vintage woodblocks of trees. (Available as a print.)

OPTIMISM
by Jane Hirshfield

More and more I have come to admire resilience.
Not the simple resistance of a pillow, whose foam
returns over and over to the same shape, but the sinuous
tenacity of a tree: finding the light newly blocked on one side,
it turns in another. A blind intelligence, true.
But out of such persistence arose turtles, rivers,
mitochondria, figs — all this resinous, unretractable earth.