NOAA-supported National Phenology Network data shows plants leafing out 10-20 days earlier than normal

Posted by Jeff on Feb 21, 2017 @ 7:04 am in Conservation | 0 comments | Last modified: February 20, 2017

The USA-National Phenology Network is tracking the start of the spring season across the country using models called the Spring Leaf and Bloom Indices.

HOW DOES THIS YEAR STACK UP AGAINST THE RECENT PAST?

We can evaluate whether spring is arriving early, late, or right on time this year at a location by comparing the day of year the Spring Leaf Index requirements were reached in 2017 to the day of year the Index is typically reached. We determine what is typical for a location by averaging the day the Index was reached over the 1981-2010 period. The number of days between when the Index was reached this year and when it is typically reached at a location is called the “anomaly.”

In 2017, we see very large anomalies in the southeastern United States on the Spring Leaf Index map, where the Index was met up to three weeks earlier than what is typical for these locations.

The timing of leaf-out, migration, flowering and other seasonal phenomena in many species is closely tied to local weather conditions and broad climatic patterns. The Spring Index maps and Accumulated Growing Degree Day Maps offered by USA-NPN shed light on plant and animal phenology, based on local weather and climate conditions.

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