Publication Summary

The authors compared a historical dataset of plant phenology recorded in New York state from 1826-1872 to contemporary observations collected through Nature’s Notebook from 2009-2017. On average, plants flower 10.5 days earlier and leaf out 19 days earlier now than 200 years ago. The authors found impacts of urbanization, greater advancement of flowering timing in earlier season species and greater advancement in trees and shrubs than forbs, and greater advancement in insect-pollinated species. The standardized observations you record in Nature’s Notebook are invaluable for understanding the direction and magnitude of changes in the timing of life cycle events of plants and animals.

The authors of a new study combined plant phenology observations contributed to Nature’s Notebook with two other phenology datasets and data products collected by satellite-borne sensors to estimate the timing of brown down of leaves (senescence) for 93 plant species across the United States and Europe. They then looked at the effects of human population density and temperature on the timing of leaf senescence and growing season length. The authors found that in cold regions, urbanization was associated with later leaf senescence and a longer growing season while in warm regions, urbanization was associated with earlier leaf senescence and a shorter growing season. As urbanization increases and temperatures warm further with climate change, we may see more areas that experience shorter growing season length.