Tonawanda News

October 8, 2012

Summer drought conditions could weaken fall colors

By Danielle Haynes
The Tonawanda News

— Temperatures are dropping, fresh apple cider is being pressed, pumpkin patches are being prepped, but one tell-tale sign of fall weather might be a bit lacking this year.

Due to record-breaking high temperatures and lack of precipitation over the summer, there’s a possibility much of the Northeast will have meager offerings this fall when it comes to colorful foliage.

Figures for North Tonawanda indicate the city’s trees will have average coloration, but an abbreviated season.

Karl Niklas, Cornell University professor of plant biology — whose research focuses on the relationship between plants and their physical environment — predicts a weak and spotty year for leaf watchers.

“The prognosis for this year’s coloration is not good,” throughout the Northeast, he said.

“I wish I was wrong, but I’m predicting that this year’s autumn coloration will not be as grand as in years past,” he added. “Why? Because of sustained high temperatures and the drought that plagued the Northeast. In combination, high temperatures and a lack of soil water have stressed trees to a point where many trees are already shedding their leaves and those that have leaves are bearing browned leaves.”

Niklas described this year’s fall coloration is being a “patchwork of good and bad” throughout the Northeast depending on whether areas experienced a severe drought with simultaneously high temperatures in the 90s to low 100s.

“The high temperatures are not bad by itself, the is drought not bad by itself, but put those two together and it really damages the leaves,” he said.

This perfect storm of drought-like conditions causes a particular chemical change in leaves that prevents the brilliant reds, yellows and oranges from being exposed come time for cooler weather, Nicklas said.

“When you see the forest in its autumn coloration, the pigments that cause those colors are by and large in the leaf during the entire summer, but they’re hidden by the more intense chloraphyl concentrations,” he explained.

“What happens in the fall is the trees metabolically draw nutrients from the leaves into the stems so those molecules can be used again in the following season. In the process, the chloraplasts begin to die, and once the green pigment is naturally broken down it exposes the other colors.

“If you damage leaves, the chloraphyl will begin to be bleached, the leaf tissue will reach high temperatures and those (red, yellow and orange) pigments will begin to break down so when the chloraphyl breaks down, you won’t have that intense color,” he said.

Jack Kanack, a North Tonawanda National Weather Service observer said readings from his backyard weather station indicate that while temperatures didn’t reach quite as high as the 100s, this summer was certainly an anomaly in his 30 years of weather watching.

“This is a very unusual year. I don’t recall anything like this,” he said of the hot, dry weather.

Readings from his Meadow Drive home in North Tonawanda indicated temperatures and precipitation levels for the month of July, in particular, broke at least three of his 30-year records.

July 2012 had the highest average high temperature for any month in Kanack’s 30 years of record keeping at 87 degrees. The normal average high for July is 80.4 degrees and the previous record was 86.23 in 2011. July 2012 also had the highest average average temperature for any month at 75.08 degrees, breaking the previous record of 74.9 in 2011.

July 2012 also received the least amount of precipitation for any month in 30 years at 0.99 inches. The normal average precipitation for July is 4.01 inches, and the previous record was 1.09 inches in 1989.

While not record-breaking, June and August’s totals were similarly outside the normal range, Kanack said.

The average high temperature for June 2012 was 79.47 degrees, up 3.74 degrees from the normal of 75.7 degrees. The average high temperature for August 2012 was 83.71 degrees, up 6.21 degrees from the normal of 77.5 degrees.

North Tonawanda received 2.40 inches of rainfall in June 2012, compared to the normal June total of 4.01 inches. August 2012 saw 1.35 inches of rainfall, compared to the normal August total of 2.96 inches.

Compounding the high temperatures and low rainfall was an abnormally dry winter, Kanack said.

“What got us into trouble is normally in the winter we have snow and snow is potential water that’s locked up. We really had no snow in the winter so the soil got to dry out and then March, which is usually wet, was 80 degrees and the soil dried out even more,” he said.

“The soil was dry to begin with and then we had the hot summer. Water takes five times longer to warm up or cool down than land so if you have a wet soil, it takes longer for that soil to warm where if you have a dry soil it really heats up. Part of our heat that we had during the summer was due to a lack of soil moisture in the soil.”

Kanack said so much moisture was evaporated from the soil, but Mother Nature didn’t put much back in.

“That’s why your trees are losing leaves,” he said. “The leaves like rain and they don’t like to be stressed. They were stressed this year with the heat and I think that’s going to hurt them now.”

After reviewing North Tonawanda’s temperature and precipitation figures for the summer, Niklas predicted North Tonawanda will experience average fall coloring, but a shorter season.

“Everything will be accelerated, and more ‘brown’ leaves than colorful ones,” he said.

So if and when you see that colorful tree in your neighborhood, be sure to take a quick photo, because it might not last long.

Contact features editor Danielle Haynes at 693-1000, ext. 4116.