A new study suggests we can track evergreen trees’ photosynthesis patterns by detecting their fluorescent glow — from space.
Deciduous trees are photosynthesizing when their leaves are green. When that process is done for the year, the foliage dries up, turns brown, and falls off. It doesn't get any simpler than that.
But with evergreen trees, it’s not that simple. Since they stay green all year-round, it’s not that easy to tell when these trees begin turning sunlight and CO2 into energy.
Researchers need this information for climate modeling, which relies on how much CO2 evergreen forests pull from the atmosphere.
According to Sierra Club, a new study suggests we can track evergreen trees’ photosynthesis patterns by detecting their fluorescent glow — from space.
“Decades ago, researchers realized that chlorophyll gives off a tiny, difficult-to-detect fluorescent glow. When sunlight hits chlorophyll—the green pigment that produces energy in most plants—it bumps it into an excited energy state. When the chlorophyll returns to its normal state, it emits 2 to 4 percent of that energy as a photon, or light particle, in the red and far-red light wavelengths.”
This glow is called solar-induced fluorescence (SIF) and, although not visible to the naked eye, can be detected by spectrometers carried by NASA satellite probes.
Not only can researchers use this technique to measure the amount of carbon evergreen forests pull in, but also to monitor forest health, as photosynthesis drops with drought, insect infestation, and early stages of tree diseases.