NDVI assessment versus two impact factors analysis (separate analysis based on chlorophyll content and leaf cellular structure): which method is more effective to detect declining health of an individual tree?

Figures & data

Note: In NIR reflectance, rise implies improvement and fall indicates deterioration. But if it surges and declines drastically, it implies internal abnormality/instability. If it rises and falls or falls and rises, it means fluctuation. In the Red band, higher reflectance implies less chlorophyll content to absorb Red light and lower reflectance implies more chlorophyll content to absorb Red light.