NORTH CAROLINA – Our forests are changing rapidly, and with this comes the need to both understand and track how and where this change is happening. Monitoring forest disturbances is critical for effective decision making, yet our ability to do so was largely insufficient until recently. Researchers can now track a significant amount of these changes with new technologies like HiForm.

Forest managers’ fundamental need for monitoring led to the development of two remote sensing tools that USDA Forest Service scientist Steve Norman has been involved with HiForm and ForWarn II technologies, both of which use satellite imagery to capture forest disturbances like hurricanes, wildfire and insect defoliations soon after they occur.

“While ForWarn relies on twice-daily satellite imagery that gives us reliable cloud-free views, the imagery is really coarse spatially,” explains Norman. “Each grid cell is 240 meters across, or about 14 acres, and that means that a lot of crucial details are lost.”

To fill those gaps, HiForm relies on detailed imagery at a resolution of 10 meters. “Until recently it was difficult to efficiently analyze this extra volume of data, but advances in cloud computing changed that in a profound way,” adds Norman.

HiForm integrates a user-friendly script with Google Earth Engine to map changes in the Normalized Difference Vegetation Index, a simple indicator that is commonly used in remote sensing for tracking vegetation vigor.
Ongoing projects using HiForm include monitoring and assessing damage resulting from severe weather, wildland fire, and insects and diseases.
A key component of HiForm is how it represents change with its carefully crafted color palette that makes maps more readable and useful. “We’ve tried to guide interpretation while retaining flexibility,” says Norman. “Interpretation can be arduous, and we’ve worked to make that easier.”

As extreme weather events such as wildfires and hurricanes continue to increase in strength as a result of climate change, the need for remote sensing tools such as HiForm and ForWarn will become even more critical. “The remote sensing community has made incredible progress in recent years and we’re prepared to help meet some of the challenges that lie ahead,” explains Norman.