Monitoring plant and animal changes

by Helen M. Scott
Wednesday, June 6, 2007 1:46 PM MDT

Climate change is monitored by a very interesting subject called phenology.

Phenology, which is derived from the Greek word “phaino,” meaning “to show or appear,” is an ancient study of periodic plant and animal life cycle events that are influenced by environmental changes, especially seasonal variations in temperature and precipitation driven by weather and climate.

For example, the migration of birds is event associated with climate and season. Likewise, the appearance of flowers in the spring is a response to the local weather and climate.

The early appearance of blossoms indicates a mild winter and warmer climate, whereas a late blossom date indicates longer, harsher winters and a cooler climate. The Japanese, for instance, have kept tables and graphs for centuries on every aspect of the cherry trees in Japan.

Timings of phenological events are ideal indicators of the impact of local and global changes in weather and climate on earth, and are a crucial tool in tracking the earth’s warming.

Other subjects of phenological study include the flight of butterflies, the date of leaf coloring in deciduous trees and the dates when birds lay their eggs. These phenomena are very sensitive to small variations in climate, especially to temperature, and make for very interesting and enlightening studies.

Phenology is not the same as folk forecasting, such as whether Punxsutawney Phil will see his shadow and burden us with six more weeks of winter, or whether woolly bear caterpillars can predict the severity of the upcoming winter by the ratio of brown to black coloration.

Gardening phenologists keep track of the dates of the first and last frosts, when the ground freezes and thaws, the best time to pick asparagus, the planting and blooming of landscape plants and the emergence of insect pests.

Crabgrass, the bane of most gardeners, germinates when the soil temp at four inches stabilizes at 55 degrees F. This is important to know if you are going to apply herbicide to prevent crabgrass seed from germinating.

Gardeners have all kinds of “phenomena” going on in their own backyards each and every day in all seasons. Their activities often are influenced by phenological indicators, such as:

“When the daffodils begin to bloom, it is time to plant peas

When the blossoms of the apple tree begin to fall, plant your corn seeds

When dandelions are blooming, plant beets and carrots

Plant potatoes when the shadbrush flowers

When elm leaves are the size of a penny, plant kidney beans”

Print this story   |   Email this story