Thoreau’s Notebook of Nature

How can a notebook help people notice changes in nature? Henry David Thoreau, born on July 12, 1817, used journals to record what he saw around Concord, Massachusetts. His notes became a storehouse of details for his writing—and a record of the natural world in his time.

Thoreau was a writer and naturalist, a person who studies nature. As an adult, he walked through woods and fields and along ponds, carrying a notebook. He paid attention to details that were easy to overlook, such as when plants flowered or birds appeared. Recording observations over many seasons allowed him to compare what happened from year to year.

A date beside an observation can be important. If a writer notes when a particular plant first blooms each spring, those records can show whether the timing changes. Thoreau’s journals contain many such observations. Modern researchers have used some of them, along with later records, to study changes in the timing of spring events near Concord. His notes do not answer every question: the amount of detail varies, and a missing record does not necessarily mean an event did not happen.