USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Landscape image showing mist rising of water in front of trees that have fall color.

The USDA Forest Service (FS) and the USA National Phenology Network (USA-NPN) collaborate to better understand and respond to climate impacts on forests.

Image credit:
A Rosemartin

USDA Forest Service and USA-NPN Partnership

Definition of Phenology

Why Phenology?

Phenological events are changing in response to changes in climate. These changes impact species abundance, distribution, interactions, carbon and water cycles, agriculture, and the ecosystem services that ultimately benefit human well-being. In addition to being critical to understanding climate impacts, phenology is easy to observe and resonates with many audiences.

A room of people discuss and draw on a white board, they are discussing the web of relationships around Hemlock Wooly Adelgid, a forest pest.


Working with the Climate and Sustainability Office and the Northern Institute of Applied Climate Science, we are suporting efforts to identify and develop climate data sources and tools to support forest plan monitoring. The USA-NPN provides observational data on many species of interest to forest managers, as well as tools for engaging the public in data collection. We are currently collaborating on an analysis of changes in the timing of spring arrival, for each national forest (see map below). In addition, with collaborators at the Northern Research Station and State and Private Forestry, we are covening multi-agency groups to better understand threats to forests and making models and tools more readily available to support management.

Changes in the Timing of Spring at National Forests

Map showing how early recent springs are compared to the historic range of variability for USFS Units

For each USDA National Forest, how do recent dates of leaf out compare to the historic range of variation in leaf out (1901-2012). A designation of "extremely early" means that recent springs fall at the extreme edge of the distribution (below the 5th percentile). Find out more about the Spring Indices.