THE THREE POWER-PACKED PIGMENTS THAT CREATE AUTUMN’S COLOR

This fall in the Midwest, and perhaps particularly in the Driftless Area, the leaf color has been over the top.

The view to the north from our porch.

The view to the north from our porch.

Breathtaking, heart-stopping gorgeous.

In the sun the leaves radiate color like stained glass, and on rainy days they take on an iridescent intensity.

Coming up our drive.

Coming up our drive.

Every day is a feast for the eyes.

Some years, the color is muted.  It’s kind of — what?  Was that fall?

But other  years, like this year, the colors are astonishing, riveting, resplendent!

Young red oaks that were knee high 11 years ago and now are 12-18 feet tall.

Young red oaks that were knee high 11 years ago and now are 12-18 feet tall.

In our 11 years at Underhill, I don’t think I’ve ever seen an autumn quite so lovely.  Our first autumn here was wonderful.  I remember it particularly.  But our relationship with our land had the giddiness of a honeymoon that year, and I probably would have found any autumn beyond beautiful.

What our view to the north looked like 10 years ago.

What our view to the north looked like 10 years ago.

Since then there has been a range from quite nice to wonderful autumns, but this year has knocked it out of the park.  It’s not just my opinion.  Everyone is talking about it.  You can check  fall color around the country and in years past at the Foliage Network .  They agree that this is a prime autumn.

Our mail box.

Our mail box.

What creates these differences from year to year?

According to the USDA Forest Service the vividness of the display is created by 3 things:

  1. Leaf pigments
  2. Length of night
  3. Weather

PIGMENTS:

The 3 power-packed pigments in autumn’s palette:

  1. Chlorophyll – As we all know, this is what makes leaves green.  Plants make chlorophyll to capture the energy of the sun and convert it into chemical energy which generates the sugars that plants need.  Animals live by eating the energy-rich plants or by eating animals who have eaten the plants. The green of summer feeds us all.
  2. Carotenoids – They make the yellow, orange, and brown colors we see in corn, carrots and maple leaves. We humans value carotenoids because of their health benefits.  They play a part in protecting us from baddies like cancer and eye disease.
  3. Anthocyanins – These give color to cranberries, red apples, blueberries. Anthocyanin pigments have been linked in folk medicine and recent research to a range of health benefits.  According to the National Institutes of Health, the interactions of these phytochemicals are very subtle, and we don’t understand it very well yet, but a lot of effort is being poured into figuring them out.

Both chlorophyll and carotenoids are doing their thing in leaves all summer, but the chlorophyll is the only one we see.  Then in the autumn when plant leave cells are full of sugars, the bright light triggers production of most of the anthocyanins.

As the nights lengthen, chlorophyll production slows down and then stops, and as the chlorophyll disappears, the curtain goes up on all those yellows and oranges, reds and purples we know and love.

The weather we are having while that happens affects the extent and brilliance of fall color.

A walk at Wyalusing State Park where the Wisconsin and Mississippi rivers converge.

A walk at Wyalusing State Park where the Wisconsin and Mississippi rivers converge.

WHAT MAKES AN AMAZING FALL COLOR YEAR LIKE THIS ONE?

Getting a series of warm, sunny days and cool, crisp but not freezing nights is apparently the win/win combo.  Not only are these conditions pleasant to experience, but they set the stage for the best fall color.

DSC_0181Because the carotenoids are already in the leaves, the yellows don’t change a lot from year to year, but the warm days enhance sugar production in the leaves, while cool nights and the seasonal closing of veins trap the sugar in the leaves.  These are the conditions (see above) that spur production of the brilliant anthocyanin pigments that manifest as reds, purples and crimsons.

And, as we can all see, it’s the interplay and contrast between the constant yellows and the accenting reds that makes such a memorable show like the one we’re experiencing.

Soil moisture, which varies greatly from year to year, plays a role too.  A late spring, severe summer drought, can push back fall color by weeks.  A heat wave with warm nights in fall can mute the color show.

The best combo seems to be a warm wet spring, classic good summer and a series of sunny days and cool nights in early fall.  Win/win.

Tamarack needles turn such an intense yellow, they seem to be lit from within.

Tamarack needles turn such an intense yellow, they seem to be lit from within.

This doesn’t happen every year.

Three cheers for this visually magnificent autumn!

Are you seeing spectacular color this year?  

What has moved you the most?

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s