Enviorment
8:32 am
Thu November 21, 2013

How Rain Brought Fall Colors Back to Austin

Austin's seeing brighter leaves this fall, thanks to recent rainfall.
Austin's seeing brighter leaves this fall, thanks to recent rainfall.
Credit flickr.com/visualpanic

Think of fall’s turning leaves, and Texas may not be the first state to come to mind. But Austinites have seen their fair share of autumnal red and gold this year – thanks in large part to recent rains.

Jerry Brand, a molecular bioscience professor at the University of Texas, says the color changes in the leaves are due to a specific molecule called a carotenoid.  

“These color molecules called carotenoids can come in several different colors depending on the plant, depending on the light intensity they’ve been exposed to, and other environmental factors,” Brand says.

“So that’s why some leaves look more yellow in color, some look brilliant red in color and some look more orange in color,” he continues. “It’s because there’s more categories of these carotenoids, and which ones are dominant depends on the plant species – and that also depends on the environmental conditions they’ve been exposed to.”

One environmental condition defined Texas lately: drought. In a drought, leaves conserve water and fall off early to avoid too much evaporation. That’s why recent years haven’t featured much fall foliage.

But Central Texas’ glut of rainfall in the last two months has improved the health of many of trees in Central Texas – and that’s led to a more colorful fall.

“Plants can respond very quickly to changes in the environmental condition,” Brand says. “If the drought disappears, then the molecules start building their leaves stronger and making them function better in a matter of weeks, or even less.”

The drought is far from over: portions of Travis County are still in moderate drought. You can see statewide drought conditions here. But in Austin, drought stricken trees have had time to rebuild their color molecules making their leaves brighter and more vibrant.  

Brand says fall foliage in Texas peaks about a month later than northeastern and northwestern parts of the country. Trees with the most lively colors are Sumacs, revealing a bright red pigment, and Native Elm Trees, exposing a vivid yellow.

Texas Parks and Wildlife says one great park for fall foliage is just a day trip away: the Lost Maples Natural Area in the Hill Country.