Fall arrives at different times and in different ways across the Observatory. Thanks to the phenocams across the NEON field sites, here's a glimpse at how autumn is unrolling across the continent and how 2023 looks compared to 2022.
Fall Phenology: North to South and East to West
In the context of plant phenology, "fall" (or autumn) is defined by specific biological events and changes observed in plants as they respond to the decreasing daylight and cooling temperatures typical of this time of year in the northern hemisphere. In habitats with deciduous trees, the most noticeable and dramatic sign of fall is the changing color pallet, as green leaves turn vibrant shades of red, orange, yellow, and eventually brown. Other phenological signs of autumn include leaf drop (for deciduous plants), fruit ripening or seed dispersal for some species, changes in growth patterns, and the onset of dormancy for many trees and plants. The timing of these events is closely tied to latitude, geography, and climate. In North America, fall generally starts first in the northern latitudes due to the cooler temperatures and greater variation in daylight length. The timing of color change and other phenological events is also tied to elevation, regional weather patterns, and other variables.
Ozarks Complex (D08)
Pacific Northwest (D16)
Pacific Southwest (D17)
Fall from Year to Year
The variation in fall phenology from year to year is significantly influenced by weather patterns. These variations can alter the timing and intensity of typical autumnal events like leaf color change, fruit ripening, and the onset of dormancy in plants. In 2023, scorching heat and drought in some areas, and too much rain in others, meant many regions expected a less colorful leaf display. In the Northeast, it also seemed that peak color came a little bit later in the season.
Great Lakes (D05)
Want More Fall Phenology?
Check out our phenocam images to see what's happening at every NEON field site. The latest image for each site is shown on this page. Past images are housed by the PhenoCam Network and available in the NEON Data Portal.