This dataset includes annual average Julian dates of spring green-up, fall brown-down, and plant productivity from 2000-2010. The data are from remote sensing. The MODIS (Moderate-resolution Imaging Spectroradiometer) satellite provides an image of the park every 10 days, which is used to calculate NDVI (Normalized Difference Vegetation Index) values. This generates an "NDVI curve" from which plant productivity and growing season length are estimated. The growing season begins when the NDVI curve increases consistently in the spring (green-up) and ends when it decreases in the fall (brown-down). Plant productivity is estimated as the area under this curve (the NDVI integral). These data are important because changes in plant productivity and growing season length are predicted to respond to climate change, and changes in these measures may significantly affect habitat and wildlife.