This research team aims to validate the sensitivity of high-resolution hyperspectral satellite imagery (HRHSI) by comparing satellite-derived estimates of canopy nitrogen with true field measurements.

Remote sensing as a powerful tool 

Remote sensing  can offer insights across forest landscapes. Hyperspectral remote sensing captures detailed plant biochemical traits, such as foliar N, through tens to hundreds of spectral bands. These data are typically collected using handheld or airborne sensors, but large-scale applications are often limited by high costs and logistical challenges, especially in forested areas. High-resolution hyperspectral satellite imagery (HRHSI) presents a promising alternative. Wyvern, a commercial space company, operates four satellites capable of capturing hyperspectral data at a 5.3-meter spatial resolution. Their sensors cover the visible to near-infrared spectrum with spectral resolutions ranging from 18 to 35 nm–offering the highest spatial and spectral resolution available. These advancements may enable more precise and frequent measurements of foliar N, which is essential given its variability across species, leaf morphology, and phenological stages. Improved wide-scale foliar N data can enhance forest ecosystem assessments, refine land surface models, and support forest preservation as a nature-based climate solution.

Research objective

This proposal addresses gaps in spaceborne foliar trait research by using Wyvern HRHSI to estimate mass-based canopy foliar nitrogen (%N) in forest communities at Jasper Ridge. Researchers hypothesize that spaceborne HRHSI can yield moderately accurate estimates of canopy %N that positively correlate with field measurements, as hyperspectral data in the visible to near-infrared range are known to capture spectral features associated with foliar N content. Ultimately, these results will be used to develop a model that leverages HRHSI data to predict canopy chemistry across the preserve, producing workflows and mapped products to be made available to other with JRBP researchers, inform management decisions, and promote public science communication.

Ireland uses a potato gun to shoot a bean bag and cordage across canopy branches, then ties the cord to a chain that she can pull back and forth to "saw" the branch and retrieve canopy foliage. 

Watch Ireland in action!

Ireland also used this field sampling technique to collect leaves of blue oaks (Quercus douglasii) for NASA scientist, Nancy Kiang, who is measuring leaf optical properties for parameterization of a canopy radiative transfer model which is implemented in a demographic global vegetation model.

Ireland is supported in the field by long-time docent, Bill Gomez, as well as undergrad research assistants Zoe Colloredo-Mansfeld and Lillian Sanders.

This project is supported by an A.W. Mellon Grant for Student Research.