A comparison of multiple phenology data sources for estimating seasonal transitions in deciduous forest carbon exchange

► Phenology metrics from ground- and satellite-based data sources were compared with 11 years of NEE data. ► The phenology metrics from one or more data sources were significantly correlated to each annually recurring transition in NEE. ► No single data source was adequate for describing the full suite of carbon flux phenology transitions. ► Combinations of metrics from different data sources can be used to estimate the timing of phenology events more accurately than any single data source.