TITLE: Using Land Surface Phenology as the Basis for a National Early Warning System for Forest Disturbances


SESSION TITLE: B51P. Beyond Earlier Spring: Diverse Phenological Responses to Climate Across Species and Ecosystems II

AUTHORS: William Walter Hargrove1, Joseph Spruce3, Steven P. Norman1, Forrest M. Hoffman2

1Eastern Forest Environmental Threat Assessment Center, USDA Forest Service, Asheville, NC, United States.
2Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States.
3Computer Science Corporation, NASA Stennis Space Center, Stennis Space Center, MS, United States.

ABSTRACT BODY: The National Early Warning System (EWS) provides an 8-day coast-to-coast snapshot of potentially disturbed forests across the U.S.. A prototype system has produced national maps of potential forest disturbances every eight days since January 2010, identifying locations that may require further investigation. Through phenology, the system shows both early and delayed vegetation development and detects all types of unexpected forest disturbances, including insects, disease, wildfires, frost and ice damage, tornadoes, hurricanes, blowdowns, harvest, urbanization, landslides, drought, flood, and climate change. The USDA Forest Service Eastern Forest Environmental Threat Assessment Center is collaborating with NASA Stennis Space Center and the Western Wildland Environmental Threat Assessment Center to develop the tool.

The EWS uses differences in phenological responses between an expectation based on historical data and a current view to strategically identify potential forest disturbances and direct attention to locations where forest behavior seems unusual. Disturbance maps are available via the Forest Change Assessment Viewer (FCAV) (http://ews.forestthreats.org/gis), which allows resource managers and other users to see the most current national disturbance maps as soon as they are available.

Phenology-based detections show not only vegetation disturbances in the classical sense, but all departures from normal seasonal vegetation behavior. In 2010, the EWS detected a repeated late-frost event at high elevations in North Carolina, USA, that resulted in delayed seasonal development, contrasting with an early spring development at lower elevations, all within close geographic proximity. Throughout 2011, there was a high degree of correspondence between the National Climatic Data Center’s North American Drought Monitor maps and EWS maps of phenological drought disturbance in forests. Urban forests showed earlier and more severe phenological drought disturbance than surrounding non-urban forests. An EWS news page (http://www.geobabbble.org/~hnw/EWSNews) highlights disturbances the system has detected during the 2011 season.

Unsupervised statistical multivariate clustering of smoothed phenology data every 8 days over an 11-year period produces a detailed map of national vegetation types, including major disturbances. Examining the constancy of these phenological classifications at a particular location from year to year produces a national map showing the persistence of vegetation, regardless of vegetation type.

Using spectral unmixing methods, national maps of evergreen decline can be produced which are a composite of insect, disease, and anthropogenic factors causing chronic decline in these forests, including hemlock wooly adelgid, mountain pine beetle, wildfire, tree harvest, and urbanization. Because phenology shows vegetation responses, all disturbance and recovery events detected by the EWS are viewed through the lens of the vegetation.


[0480] BIOGEOSCIENCES / Remote sensing,
[0468] BIOGEOSCIENCES / Natural hazards,
[1632] GLOBAL CHANGE / Land cover change,
[4341] NATURAL HAZARDS / Early warning systems.

SPONSOR NAME: William W Hargrove

Previously Presented Material: 30% presented at IUFRO 2010, Seoul, South Korea

CONTACT: William W Hargrove <hnw at geobabble dot org>