Categories for Autumn

Dormancy Onset In Trees

October 16, 2019 By , ,

The nights are quickly becoming longer in the northern hemisphere and the average temperatures are dropping, triggering dormancy in trees. Dormancy is a winter weather survival mechanism in which tree shoot growth is significantly reduced to protect soft tissues from freezing temperatures. In the fall, the decreasing daylight triggers the production of abscisic acid, a hormone that impedes growth. Abscisic... Read More

Seasonal Evergreen Foliage Changes

September 27, 2018 By ,

Autumn in the Pacific Northwest is heralded by the bright leaf color change in prominent deciduous tree species. Many Portland area residents are surprised to learn that many evergreen trees also exhibit seasonal change in their foliage at this time of year. Deciduous and evergreen trees have foliage that converts sunlight into energy. Deciduous trees lose all of their leaves... Read More

Fall Foliage

September 24, 2018 By ,

“Autumn is a second spring when every leaf is a flower” – Albert Camus When the air turns cold and sunlight wanes in the Portland area around the end of September and early October, our hillsides and neighborhoods turn a fiery gold, red and orange as the deciduous trees prepare for the dormant season. As the green chlorophyll fades, the... Read More