“Official” fall foilage show forecasts aren’t coming right out and saying it, but it’s self-evident that leaf colors will be muted this year in western North Carolina.
Unusually warm weather lasted too long into autumn to produce anything close to a good year for leaf colors.
This past weekend was the traditional peak weekend for fall colors in the North Carolina mountains, said Dr. Howard Neufeld, a biologist and Appalachian State University’s “Fall Color Guy.”
This year, Neufeld said, it looks like peak color (such as it is) could run about 10 days late if cooler temperature that finally arrived this past weekend don’t help.
Like turning a page to start a new chapter, something closer to autumn-like weather moved in after Tropical Storm Michael moved out Friday.
Neufeld said it’s conceivable that trees could catch up to their normal schedule, but the long-range forecast calling for more warm weather doesn’t indicate so.
And saying that colors may be muted might turn out to be an understatement, since there’s a good chance that many yellow poplars, red maples and other tree species will simply drop their leaves before they ever show much color.
That appears to already be happening, which was the case last year when we also had unseasonably warm autumn weather. Orange and yellow colors dominated then.
Neufeld said early this month that nighttime temperatures in the North Carolina mountains averaged 9 degrees above normal for September this year. He said that made it the region’s warmest September on record.
The weather this fall is unprecedented as far back as records go, so it follows that responses of trees to the unusual weather will also be unprecedented.
Neufeld reported that the dominant color was still green when he traveled the Blue Ridge Parkway from the Great Smoky Mountains National Park back to Boone the last weekend in September. Elevations above 5,000 feet would normally have significant color by then.
Two key factors impact fall foliage color: day-length and temperature. As the days get shorter in August and September, trees sense this and begin losing chlorophyll, the green pigment that plants use to capture light for photosynthesis, and the synthesis of anthocyanins, which give leaves their red color.
For those not already down-hearted by this year’s autumn color outlook, the ASU Biology Department listed the ways global warming could increasingly impact the seasonal show.
In addition to higher temperatures and altered timing and/or amounts of precipitation, global warming is expected to result in changes in humidity; changes in cloud cover and light striking the trees; increases in growing season length and displacement of timing of leaf out and leaf fall; higher levels of nitrogen inputs to ecosystems from agricultural practices; acidic deposition causing nutrients to leach out of soil; migration of trees farther north to escape the heat; extirpation of trees that can’t migrate for one reason or another; and changes in competition due to more insect pests or invasive exotic plant species.