Fall foliage puts on spectacular show, thanks to recent rain

A red maple leaf on the campus of Sacramento State in Sacramento on Wednesday, Nov. 18, 2015.
A red maple leaf on the campus of Sacramento State in Sacramento on Wednesday, Nov. 18, 2015.

That welcome rain that fell in October and early November left a side benefit for the City of Trees – brilliant fall foliage.

This week, some trees look particularly gorgeous, with maple, scarlet oak, Chinese pistache and liquidambar at their peak of color.

“I do believe it’s caused by the rain,” said Matt Van Donsel of the Sacramento Tree Foundation, where the current eye-catching display has been a favorite topic. “That early rain is making it much more colorful than expected.”

The recent rain refreshed the trees, Van Donsel said. “We’re actually seeing some things that you usually see in the spring. Some trees are starting to even bloom.”

The rain also cleaned summer dust and grime off foliage, making leaves look brighter. More importantly, a lack of strong wind has allowed leaves to linger a little longer on their branches.

The foliage on trees turns color as days get shorter, signaling the onset of winter and dormancy. Chlorophyll – which helps plants produce their food and gives leaves their green color – dissipates. That allows the leaves’ yellow and orange pigments, usually masked by green chlorophyll, to show through. In addition, glucose trapped in the leaves may turn red or purple.

The brightest hues are triggered by warm daytime temperatures and chilly – but not freezing – nights. So far, this November has been sunny and mild, with daytime temperatures hovering in the mid- to high 60s while lows have flirted with the high 30s.

A sudden shift from very warm days to cold nights intensifies the color, said Ellen Zagory, horticulture director for the UC Davis Arboretum. “We had days in the 90s (in October), then a sudden drop in temperatures. When temperatures change more gradually, the color is not nearly as intense.”

But enjoy all that gold, orange and red while you can. This fall show may be short.

“We’ve got a surge of color, but it won’t extend over several weeks,” Van Donsel said. “As it gets colder at night, (those leaves) will fall fast. But right now, it looks great outside.”

Many observers expected California’s prolonged drought to also cancel our fall color show. Foliage on drought-stressed trees tends to turn crunchy brown and drop early. That made this fall’s brilliant color show a pleasant surprise.

“We just hope we keep getting that rain,” Van Donsel said. “We’re keeping our fingers crossed. The trees need it.”

Debbie Arrington: 916-321-1075, @debarrington