Phenology

ChiloquinNews article 3/14/11

Last week I wrote about Growing Degree Days (GDD), and the natural extension of that subject is phenology. Phenology comes from the Greek word phaino, meaning to show or appear and is the study of the timing of natural events, such as leafing out, flowering, ripening of fruit, emergence of insects, and migration of birds. It is also the study of how these events are influenced by variations in climate. GDD measures how much heat is needed for, say, a dandelion to flower in Chiloquin. When we record that flowering day from year to year, then we are recording the phenology of the dandelion. So phenology is really just GDD measured over time.

Phenology is used in many ways. Phenological observations are used to anticipate wildflower viewing or bird migrations, have been used for centuries by farmers to maximize crop production, and are used by many of us to prepare for seasonal allergies. It is used as a modern Integrated Pest Management tool by farmers, to monitor the emergence of insects and their feeding on crop plants. The correlation between flowering of certain ornamental plants and the feeding and egg laying of crop pests is known to be more accurate than calendar date spray schedules. Today, this well established science is also used by scientists to track the effect of global warming and climate change on organisms. Phenological records also allow us to reconstruct historical climate data. For example, records of grape harvests in Europe have been used to reconstruct a record of summer growing season temperatures going back more than 500 years.

 Just as farmers can use Phenological data to anticipate when pests will strike, so can we use it to decide when to prune, or plant our seeds.  Rather than picking a date each year to prune the roses, how much more reliable to wait until we see the willow catkins open. Or, rather than trying to decide if our soil has warmed up enough for lettuce seeds, how much easier to plant those seeds when we see the first daffodil flower. 

 If you would like to contribute phenology data from our area, or just read more about this fascinating science, try this website: USA National Phenology Network

Last week a flock of white-front geese arrived in my backyard, something I really look forward to. I have learned that it really is spring when they arrive, so that’s the good news. Bad news is that I’ve also learned that they leave on the first nice day of the season, so as long as they are here, it might be spring, but it’s definitely ‘Chiloquin spring’.

Flowering in my garden this week: ‘Early Harvest’ tulip, opened March 9th. Last year it opened March 4th.

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