Woody phenology and weather data related to Trelease Woods, Urbana, IL, USA 1993-2023

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, sub canopy treelets, shrubs, and vines. Data
collection began in the spring of 1993 and continued through the end of
autumn 2023. 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, 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.