Notes for "The Marriage Tree"

1. In many early cultures, trees, like mountains, were thought to be the axial center of the universe, soaring as they do above human
entanglements. It wasn't the tree I saw first but the clearing beneath it: dappled with sunlight, it seemed altarlike, as if we were meant to kneel there. The tree is a live oak soaring straight like a mast but thick as ten masts lashed together. Far up, branches hold moss from their arms as if weighing stories for truths, balancing every disparity in their elegant, judicial spread. Cheek against bark, I look past leaves into the becalmed eye of a Florida morning: "Querous." Oak. That's the tree's Latin name. It sounds like a question.

2. A tree represents the zenith of botanical evolution, it is an aerial garden, far from its oceanic beginnings. The tree is a thought, an abstraction stopping the flow of the wind and light, trapping water, housing insects, birds and animals, and breathing in and out. How treelike the human, how human the tree. It is like a thumb held up or a leg striding, the kind of obstacle that causes human and botanical consciousness to occur.

Even the words used to describe the human brain are botanical: limbus referring to the limbic system, where all emotion occurs is a word whose ancient meaning was "limb of a tree." Cortex, that deep part of the brain where language and abstract thought happen, means "bark."

I am told of the delicate nature of the tree's parts: of cambium, the inner layer of cells between phloem and xylem, and how remarkably sensitive it is to any strain on the tree. And the way bark acts as a waterproof covering to the thin layer of living tissue within. A tree's breathing is slow and slight. The respiratory pores in the bark, called lenticels, must have ample space. As the tree ages, the central heartwood thickens and the girth of the trunk widens to accommodate decay.

3. …the physiology of memory…Thoughts arise as electrical impulses; bits of thought and sensation are neural plasma shuttling from cell to cell, spreading like a net. There's a rhythmical pattern of firing activity, and wild chemical reactions occur: calcium is released and in turn activates an enzyme called calpain, which scrubs connective tissue between neurons "the rootlike dendrites" cutting into the cytoskeleton and, in this way, exposing receptors. Through these, information is absorbed; memory is etched in, and the dendritic brainscape, a place that looks like the cracks in ice on my lake, changes its shape forever.

From "Island, The Universe, Home," by Gretel Ehrlich