Entries by Jim Kellner

Large-area analysis of ecosystems

We developed a series of studies aimed at unraveling how ecosystems respond to changes in the environment. By using time series data from satellite-remote sensing, these studies test hypotheses about biological invasion and changes in vegetation cover across large gradients in latitude and elevation. Using measurements from the NASA Landsat program, we decomposed spectral reflectance […]


Estimates of aboveground carbon stocks are derived from a patchwork of methods that vary in quality and sampling density. Scientists lack consensus about the size of the forest carbon stock and the role of forests in the global carbon cycle. The NASA Global Ecosystem Dynamics Investigation (GEDI) was designed to overcome these challenges by placing […]

Individual-based remote sensing of canopy trees

Constellations of small sensors called cube-sats are working together in space to image the entire land surface of our planet every day at resolutions fine enough to resolve individual plants. These dense image time series provide the combination of high temporal frequency and fine spatial resolution to map individual trees and quantify population dynamics throughout […]

Drone remote sensing

Low-altitude drone flight can produce observations at scales clearly aligned with biological processes, like metabolism, natural selection, and resource allocation within and among individual plants. The quantitative improvement represented by this technology is significant, but the most important advance is conceptual. New measurements from low-altitude drones open the door to characterizing processes that have been […]