Sensing at Orchard Scale
Orchard-level NDVI image from a 2008 time series in a study orchard is shown in Fig. 1.
The strong variation in canopy size and closure, as an indicator of vigor is demonstrated in Fig. 2. The image was classified in a color ramp of Green Normalize Difference Vegetation Index (GNDVI) "greenness index" values, and used for developing sampling location within the variation of apparent vigor.
Further exploration is limited by the spectra bands and width, however the high resolution is useful in comparing canopy density to Bruce Lampinen's light bar measurement under the canopy. Using these NDVI measurements, the greenness of study orchards can be tracked over time (Fig. 3).
Fig. 2. GNDVI color intensity model
Fig. 3.NDVI values track the greenness of 2 orchards in 2008
Comparing & Calibrating Data
Airborne and satellite remote sensing of canopy and leaf condition will be linked to recorded yield, nutrient and water status in the experimental orchards. The hyperspectral LiDAR imagery, calibrated with ground data, shows promise of estimating leaf chlorophyll, leaf area, tree crown shape and size that will be used in modeling.
Initial analysis of the the NASA MASTER (airborne MODIS and ASTER) satellite simulator demonstrated the relationship of temperature to plant water variation using the Crop Water Stress Index. Landsat imagery for the past 20 years is available and we have begun downloading and processing the data for the time series analysis in raster layers.
Tree samples in on-going studies by Brown, Shackel and students will be associated with satellite data analysis for modeling study orchards.