Weather Science

Rochester’s mild drought didn’t affect the fall foliage! How temperature and rainfall affect leaf colors.

Before you venture out apple picking this fall, be sure to have your camera on standby as the vibrant upstate New York foliage is predicted to be as spectacular as ever this year. Many Rochesterians were able to experience the beginning of the foliage season this weekend, especially apple pickers who flocked to festivals all over the area such as the 32nd annual Hilton Apple Fest held at Hilton Apple Fest Farm Market.
It has been a disappointing season for apple pickers this autumn due to the significant decrease in production. Although many apple farms have been at a loss of words with the notable decline in apples this year, people all over the region will be able to enjoy the brilliant colors of autumn as peak hits this next week.

Some speculated that the dry conditions we have seen in Upstate New York will have a negative impact on the foliage this fall, however as you may have already noticed, that is far from the truth.

Map of the height of this summer’s drought, via the University of Nebraska’s Drought Watch

Over the past four months or so, upstate New York has been entrenched in a moderate drought, which has led to an increase in food prices and distraught flowers. Along with these impacts, many New Yorkers expressed their concern over the lack of vibrant colors they would see due to the drought. However, Donald Leopold, chairman of environmental and forest biology at SUNY College of Environmental Science and Forestry, explains that drought is not always bad for foliage: “Mild droughts are generally good for fall leaf color. It can enhance production of certain pigments in leaves that produce color”.

An example of the “scorching” that occurs in leaves when the environment is too hot and dry. Via

It’s common sense that trees need the necessary water and sunlight to survive: this beautiful concept is known as photosynthesis. But too much rain or sunlight throughout the spring and summer could have a negative impact on the health of the tree and more importantly, the leaves.
According to meteorologist David Epstein, an abundance of precipitation can encourage disease on the leaves, creating dull or bland colors. While not enough precipitation causes the leaves to dry up and fall early, not allowing for colorful leaves. Luckily, our moderate drought was not severe enough to have a negative affect on the foliage.

As for temperatures, colder temperatures, especially at night, breaks down chlorophyll in the leaves, exposing the red and orange pigments we are so accustomed to during autumn. On the other hand, warmer temperatures don’t allow for this breakdown in chlorophyll, creating delay in pigments and accordingly delay in foliage change.

Regions such as the Midwest have not been as lucky as we have this fall. A persistent severe drought has not only killed the economy of the Midwest but foliage is almost nonexistent this autumn, thanks to the drought. Rochesterians should cherish this falls’ colors, as you never know what next fall brings.