Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon Flux Measurements of Montanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

Table 2

Summary of coefficients of determination (R²) found for the best-fit between vegetation indices (VIs) and physiological parameters derived from eddy-covariance measurements in grassland and forest ecosystems. Gross primary production (GPP [μmol (CO₂) m⁻² s⁻¹] = NEE + R); net ecosystem exchange of CO₂ (NEE [μmol (CO₂) m⁻² s⁻¹]); gross light use efficiency (gLUE = GPP/PPFD [g C MJ⁻¹]); radiation use efficiency (LUE = NEE/PPFD [g C MJ⁻¹]). Values of eddy-covariance derived parameters are half-hour averages and values of VIs are averages of more than 400 000 pixels (i.e., average of one image scan acquired in half to one hour intervals), R is reflectance at subscripted wavelength and PRI is calculated as (R₅₃₂ − R₅₇₀)/(R₅₃₂ + R₅₇₀). *Denotes 𝑃<0.1 and ** for 𝑃<0.05, as determined by ANOVA analysis.

Grassland (𝑛=8)					Forest (𝑛=15)
VIs	GPP	NEE	gLUE	LUE	GPP	NEE	gLUE	LUE
PRI	0.20	0.00	0.20	0.42*	0.08	0.07	0.08	0.38
R686/R630	0.49*	0.42*	0.49*	0.00	0.88**	0.85**	0.88**	0.58**
R740/R800	0.02	0.07	0.02	0.05	0.71**	0.69**	0.83**	0.52*