Does day and night sampling reduce spurious correlation between canopy photosynthesis and ecosystem respiration?

We then expanded this analysis to the FLUXNET database that spans a spectrum of climate and plant functional types. We found, on average, that the correlation between gross photosynthesis and ecosystem respiration, using day-night sampling, was close to minus one (−0.828 ± 0.130). For perspective, a large fraction of this correlation was real, as the degree of spurious correlation (Eq. (22)) was −0.526. We conclude that the potential for spurious correlation between canopy photosynthesis and ecosystem respiration across the FLUXNET database was moderate. Looking across the database, we found that the least negative spurious correlations coefficients (>−0.3) were associated with seasonal deciduous forests. The most negative spurious correlations coefficients (<−0.7) were associated with evergreen forests found in boreal climates.