Phenological Green Chromatic Coordinate Dataset for a Mongolian Oak Forest Mt. Jeombong, South Korea

Temperate deciduous forests are sensitive indicators of climate variability, and near-surface phenocam observations provide high-frequency records of their canopy dynamics. We present a 7-year green chromatic coordinate (GCC) dataset from a Mongolian oak (<i>Quercus mongolica</i>) stand at the Mt. Jeombong Ecological Tower, Korea, collected within the National Long-Term Ecological Research program. A digital camera mounted above the canopy acquired RGB images every 30 minutes; images taken between 10:00 and 14:00 from 12 April 2018 to 31 December 2024 were used. A fixed region of interest over the oak canopy was defined, mean RGB values were extracted, and daily GCC was computed as G/(R+G+B). Time series were quality-controlled with the night, spline, and max filters implemented in the R package phenopix. Missing days were left as gaps without interpolation. The dataset, archived in EcoBank, supports studies of forest phenology, validation of satellite vegetation indices, and evaluation of ecosystem and climate models.