Remote sensing technologies provide an increasingly efficient way to monitor large tracts of forest canopy conditions in near-real-time and seasonally. Observational systems, such as ForWarn's MODIS-based product line, provide a continuous weekly stream of observational data that can be readily processed in ways that are useful for summary reports on changing forest conditions. Remote sensing approaches to regional monitoring are particularly powerful when they use consistent measures, sophisticated baselines for defining "normal", and cross jurisdictional boundaries.
ForWarn has potentially identified an anomaly in vegetation greenness in the Santa Fe National Forest near Santa Fe, New Mexico, including portions of Sangre de Cristo Mountains in 2016. It is speculated that the decline may be due to an insect outbreak.
Remote sensing is adept at identifying and qualifying many forest disturbances, but there remains a substantial need to further quantify actual impacts in many cases. Traditionally, vegetation change-detection approaches, such as that used by ForWarn, identify and measure disturbance severity as the magnitude of change of some measure of reflected light between two dates or periods. ForWarn tracks the percent change in NDVI relative the prior year or years, with this index falling or rising as foliage cover shifts.
ForWarn has identified an anomaly in the lowlands of Hiawatha National Forest in Mackinac County, Michigan in July 2016. An insect, spruce budworm, was active at the time of the event and is the most likely cause of defoliation leading to decline in vegetation greenness.
ForWarn has identified a disturbance on July 2, 2016 in central Oregon. Decline is likely due to Pandora Moth defoliation of pines in the area.
ForWarn has detected anomalies in the Connetquot River State Park Preserve and the surrounding area in Long Island, NY from June 8 to July 12, 2016. Gypsy Moths and Southern Pine Beetles have historical association with this data and the likely cause of this event.
ForWarn detected a decline in vegetation greenness in Jefferson National Forest, Virginia. Gypsy Moth outbreak in the area is the confirmed cause.
ForWarn has detected a defoliation event in Carbon county, Pennsylvania in May to June 2016. Insect infestation is the likely cause of the event.
ForWarn detected a defoliation event in eastern Conneticut, western Rhode Island, and eastern Massachusetts in June-July 2016. Gypsy moth catepillar defoliation is the likely cause of the event.
ForWarn has identified several potential threats to the Sequoia National Forest, California in May, 2016. Potential drought-induced delay in spring greennup created elevation banding within the forest. There is historical decline in vegetation greenness due to the western pine beetle causing tree mortality as well as tree vulnerability to disease during this time of year.