Tree Care
By Brandon M. Gallagher Watson
Phenology: A Timely Topic
lde timey gardeners are full of all sorts of useful advice.
Plant tomatoes when lily-of-the-valley blooms. Plant peppers when the iris bloom. Plant corn when oak leaves are
the size of a squirrel's ear. People have been observing and
recording these coinciding events going back thousands of
years. The Chinese have the earliest written records of these arrival
dates, dating to around 974 B.C., and the timing of peak cherry
blossom bloom have been recorded every year for the past twelve
centuries in Japan. Who knew your grandpa was passing along ancient knowledge when he vociferated you with "corn should be
knee-high by the Fourth of July"?
Today, powered by the Internet and smartphones, these provincial
observations have evolved into a global network of data with tens
of thousands of professional and amateur contributors. What were
once just farmer's colloquiums are now under the umbrella of phe-
O
nology. Literally meaning "the science of appearance," phenology
studies the timing of life cycles in all living things. The date of bud
break, sighting of the first spring flowers, insect emergence, bird migrations, and first leaf turning red in the fall are all observations
recorded by phenologists.
What are we learning from this information at the global scale
and, more importantly to us, how do we use it to improve how we
do tree care?
The measurement of phenology
Your grandpa may know to plant peppers when iris bloom, but
when exactly is that? Plants don't have calendars to know when
spring has sprung, and, regardless what the calendar says, the first
day of spring happens significantly earlier in Atlanta than it does in
Minneapolis. Although one aspect of phenology is observing the
Cherry flowering has been recorded in Japan for centuries. — All photos provided by Rainbow Treecare Scientific Advancements
12 Landscape and Irrigation November/December 2013
www.landscapeirrigation.com
