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Woody phenology and weather data related to Trelease Woods, Urbana, IL, USA 1993-2022

Cite this dataset

Augspurger, Carol; Zaya, David (2022). Woody phenology and weather data related to Trelease Woods, Urbana, IL, USA 1993-2022 [Dataset]. Dryad.


In this study, weekly phenological observations throughout spring and autumn were made annually over 30 years for 22 woody plant taxa of multiple growth forms in Trelease Woods, a mature old-growth deciduous forest remnant near Urbana, Illinois, USA. The growth forms included canopy trees, saplings, subcanopy treelets, shrubs, and vines. Data collection began in the spring of 1993 and continued through the end of autumn 2022. The phenological data set is paired with weather data collected from a nearby weather station in Champaign, Illinois. These two data sets were used to determine if dates of phenological events and durations of phenophases were changing over time, possibly in connection with changing weather related to global climate change. To supplement these phenological data, two older phenological data sets are made available here. First, Charles Smith, Woods Custodian at the University of Illinois, made comparable observations from 1949 to 1964 of seven of the same phenological events on six of the same woody species. Data were collected from Trelease Woods and Brownfield Woods. The latter is an old-growth forest separated by 2 km from Trelease Woods, and the two sites were connected in a larger forest before the mid-19th century. Second, Thomas Mikesell, a farmer from Ohio, USA, made comparable observations from 1883 to 1912 of six of the same phenological events on 11 of the same woody species. Mikesell’s data were collected in a deciduous forest near Wauseon, Ohio, USA. Because of the distance between the Mikesell study site and the site of the current study in Urbana, Illinois, in order to compare the two data sets, adjustments were made to the event dates in the Mikesell data set based on bioclimatic laws. Comparison of the current data to those collected by Charles Smith and Thomas Mikesell provides evidence as to whether the trends in phenological event dates observed from 1993 to 2021 held consistent when investigated at longer time scales.


The phenological observations from 1993-2022 at Trelease Woods were collected using binoculars; see metadata for the details on each data file.

Usage notes

The data files are in .csv format and can be opened with any spreadsheet program.