Fall colors

Fall colors
Trees in Simpson Plaza, UW Campus - Oct 11, 2013 (photo: Ramesh Sivanpillai)

Thursday, December 4, 2014

Use of remote sensing tool to study the senescene of Gambel oak leaves

-- E Kelienpaste, VR Joshi, A. Renneisen, S. Swoboda-Colberg, D. Smith

The interaction of electromagnetic radiation with leaf pigments in plants has become an essential diagnostic variable for examining phenology. This study is an attempt to understand the phenological event of senescence of the Gambel oak during the fall season through the application of remote sensing tools. A portable spectrometer was used to record reflectance values of the leaves. NDVI values were calculated by dividing the difference of infrared and red reflection values by the sum of infrared and red reflection values. NDVI values were regressed over time to develop the best line of fit representing the relationship between these two variables. The second order polynomial regression showed the best fit model. Initially lower NDVI values increased slightly with improved weather conditions for first few days and then dropped sharply with decreasing air temperatures. The results of this study show that declining air temperatures are an important factor in senescence. It shows NDVI values of Gambel oak leaves decrease as the fall season progresses.

No comments:

Post a Comment