As Henry David Thoreau walked the woods and fields of Concord, Mass., in the 1850s, he paid special attention to the events that marked the change of seasons. He recorded his observations in his journal, and later organized the information into charts. Biologists and ecologists are now mining these charts to help them understand the effects of climate change on the Concord area.

Among the natural phenomena Thoreau noted throughout the year were the plants that were leafing, blooming, or bearing fruit; the water level at certain locations along the Concord and Assabet rivers; and the birds, mammals and insects that were present or absent.

Elizabeth Witherell, editor-in-chief of The Writings of Henry David Thoreau at UCSB, will discuss Thoreau’s work and his contributions to science in a lecture titled “Henry David Thoreau and Climate Change: The Writer as Scientist.” Part of the UCSB Affiliates Town Forum series, the talk will be at 7:30 p.m. Dec. 2 at First Presbyterian Church Fellowship Hall, 21 E. Constance Ave. in Santa Barbara.

The cost is $8 for UCSB Affiliates or Chancellor’s Council members and $10 for all others. Registration is recommended, and can be arranged by calling the UCSB Office of Community Relations at 805.893.4388.

The Writings of Henry D. Thoreau, which resides at UCSB, is the definitive edition of Thoreau’s work. When completed, the projected 30-volume series will include the contents of all 47 volumes of his handwritten journal, his writings for publication, his correspondence and other uncollected papers.