Lab Girl

by Hope Jahren

Leaves make sugar. Plants are the only things in the universe that can make sugar out of nonliving inorganic matter. All the sugar that you have ever eaten was first made within a leaf. Without a constant supply of glucose to your brain, you will die.

Trees are a unique type of plant because their stems can be more than one hundred yards long and are made of this amazing substance that we call wood. Wood is strong, light, flexible, nontoxic, and weather-resistant; thousands of years of human civilization have yet to produce a better multipurpose building material. Inch for inch, a wooden beam is as strong as one made from cast iron but is ten times more flexible and only one-tenth as heavy. Even in this age of high-tech man-made objects, our preferred construction material for housing remains lumber hewn from trees. In the United States alone, the total length of the wooden planks used during the last twenty years was more than enough to build a footbridge from the planet Earth to the planet Mars.

every plant growing on land is striving toward two prizes: light, which comes from above, and water, which comes from below. Any contest between two plants can be decided in one move, when the winner simultaneously reaches higher and digs deeper than the loser.

tree grows by producing one new sheath after another. When a sheath is outgrown, its woody skeleton is left behind, progressively forming the rings that we can see in cross section after a tree is felled.

tree’s wood is also its memoir:

An unusually thick ring could signify a good year, with lots of growth, or it could just be the product of adolescence,

ring that is thick on one side of the tree but thin on the other tells the story of a fallen branch. When a branch is lost, it upsets the balance of the tree, triggering cells within the trunk to reinforce the side that must now support the newly uneven burden of the crown.

For trees, losing limbs is the rule,

Within a year after the loss, the cambium will cast a healthy new sheath fully over the broken base of what used to be the branch, and then layer upon it year after year until no scar is visible at the surface.

a coveted internship at the Miami zoo,

Karen’s job was to apply anti-inflammatory cream to monkey genitalia, which were in need of daily soothing due to their constant and indiscriminate use.

most monkeys proved considerably more responsive to her reluctant manipulations.

her many animal behavior classes had provided her with the intuition necessary to condition these monkeys to the concept of a glory hole; the downside was that seeing them lined up and “standing at attention” through a chain-link fence first thing in the morning was enough to make her rethink a career