The Amazon rainforest. Photo by Rhett A. Butler.
Analysis of satellite imagery has cleared up a controversy over whether the Amazon rainforest ‘greens up’ during the dry season.
The study, published in the journal Nature and led by NASA scientist Doug Morton, finds that earlier research concluding that photosynthesis increases in the Amazon during the dry season is based on faulty interpretation of satellite imagery.
Nature News explains: “The forest does not become greener during dry periods at all. It just looks that way when the sensor and the Sun are both in the south of the sky. It is not photosynthesis that drives the apparent greening of the forest at such times, but a lack of shadow.”
The result confirms subsequent studies concluding that drought has no effect on Amazon greenness. It also suggests that water availability is a more important factor in the rate of photosynthesis.
CITATION: Douglas C. Morton et al. Amazon forests maintain consistent canopy structure and greenness during the dry season. Nature (2014) doi:10.1038/nature13006 Published online 05 February 2014