3.3.2 - Vegetation stress

Following changes in vegetation, and therefore in foliar chemistry and membrane structure, the vegetation spectral signatures may be substantially modified. Stress is indicated by a progressive decrease in near-Infrared reflectance accompanied by an increase in middle-Infrared reflectance. In the visible domain, changes are limited to variation in colour, as shown in the previous subchapter.

Figure 3.10 – Reflectance spectrum of healthy and stress sugar beets (Kyllo, 2003).

Exercise: Below we find three conditions for vegetation; Healthy, stresses and severely stressed vergetation. Can you place them on the correct place?

figure extracted from http://rst.gsfc.nasa.gov/, accessed in 2010.