those in Europe and the United States, have adjusted the
timing of spring activity since preindustrial times. In the
early 1800s, instructors at secondary schools across the
state regularly documented when they observed meteoro-
logical conditions as well as plant and animal activity. They
continued this effort until the Civil War. These data lan-
guished, all but forgotten in dusty annals, until Dr. Conrad
Vispo, cofounder of the Farmscape Ecology Program in
Hawthorne Valley, discovered them in 2014. Vispo imme-
diately began to digitize the old data, appreciating the gold
mine these historical records offered. Yet he recognized that
they had little scientific value without a modern context.
So he searched "phenology in New York" online and dis-
covered the New York Phenology Project, a statewide
phenology monitoring effort that had been initiated in
2012 by Dr. Kerissa Fuccillo Battle. The two scientists were
astounded when they realized the similarity between
the two efforts. They began a collaboration on the spot.
When the two datasets were compared, the findings were
eye-popping. Tulip trees now flower 27 days earlier than
in the 1800s, and common milkweed, a plant that is crit-
ically important to endangered monarch butterflies, now
flowers 13 days earlier. Overall, plants in the study leaf
out 19 days sooner than they did in the early 1800s.
Crimmins also reports that in their 2022 paper called
The Great Acceleration of Plant Phenological Shifts,
Vitasse et al found that in Switzerland, horse chestnut
trees have shifted leaf out by 11 days since the early
1800s, and cherry trees have advanced their flow-
ering time by 30 days over the past 130 years. >>
In New York State, tulip trees now flower
27 days earlier than in the 1800s, and
common milkweed, a plant that is critically
important to endangered monarch
butterflies, now flowers 13 days earlier.
Since they created their Pheno Forecast
map for the wrecking ball that Emerald
Ash Borer (EAB) (Agrilus planipennis) can
be, USA National Phenology Network
(USA-NPN) Director Dr. Theresa Crimmins
and her team have kept City Trees readers
updated on shifts in the timing of key EAB
life cycle events. They steadily expanded
their Pheno Forecasts to include more
insect species of concern to urban for-
esters, like Asian longhorned beetle
(Anoplophora glabripennis), hemlock
woolly adelgid (Adelges tsugae), and
spotted lanternfly (Lycorma delicatula).
Crimmins and team have also created
Pheno Forecast maps for major inva-
sive plant species. For insects or plants,
these maps guide urban forest profes-
sionals to treat for insect pest or invasive
plant species at the optimal time.
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