Fig. 4. Coefficients of determination (r²) for the linear relationship between (a) leaf reflectance and total leaf nitrogen concentration, (b) reflectance at 755 nm divided by reflectance at wavelength indicated by the horizontal axis, and (c) reflectance at 700 nm divided by each wavelength. All plot means of spectral reflectance and chlorophyll collected during the two-month study (n = 60) were included in the correlation analyses.