Friday, October 7, 2011

Anthocyanin

In wondering about the early color change of the primary maple tree in our yard, I did a little research to find out why some trees turn earlier and why there are all the different colors. We have had a lot of rain the last month or so with the path that this season's hurricanes took across the country. When one came up through the South and the other went up the East coast, the first one couldn't go anywhere. It sat on top of us for nearly a week. As it spun around, the Great Lakes seem to fuel it enough water to keep it going indefinitely until the coast was clear (pun intended) and it could move on out of here. All that water has given the trees here an unusual autumn life. While they typically would be turning brown and getting ready for winter, they have seen a new life. Now that we are experiencing cooler nights and bright sunny days, we are gearing up for quite a show.
Although the annual show of color is a visual treat for humans, it serves a very practical purpose. As trees prepare for the onset of winter, they leech the sugars and nutrients from their leaves, in essence moving valuable sustenance to their protected insides so they can stay alive through the cold and dark of the coming season.


As nutrients are sucked out, the leaves gradually lose their rich green color, fading to the familiar fall colors of yellow and gold.
However, the rich reds on display in autumn are a different story. As summer wanes, some tree species manufacture a substance called anthocyanin, which helps them winterize. Anthocyanin is the same substance that lends red cabbage its purplish hue, and turns leaves crimson and scarlet. In addition to moisture, temperature is also one of the drivers of fall color. Specifically, variation in temperature.


Ideal conditions for bright displays would be sunny, warm days and cold nights. It's that alternating that promotes the production of the anthocyanin pigment. We have certainly seen our share of alternating warm and cold here in Michigan this year as well as extra moisture. We've also seen a lot of wind out of the North. So the fact that our second tree is on the South side and protected from the wind by many other trees could very well be why we have seen no change in it yet. Even the burning bush has had only a few leaves turn red. Now, there's a brilliant display each autumn.


We've also seen an extra growth of lawn weeds this season. They seem to pop up over night and be 3 feet tall by mid-day.


This has been an exceptional year for the area apple orchards and the coming frost should bring us a wealth of my favorite, the granny smith.  You can just smell the autumn in the air. But it will have to wait for a bit as we are forcast to be in the 80's all weekend with cool nights. It's going to be a pretty one!


4 comments:

That corgi :) said...

I can almost taste those apples, Stew! That was interesting to read about the leaves and why they change, etc. Good tha it will still be warm this weekend, as you know the winter will be descending before long, might as well enjoy the nice weather as long as you can!

betty

Jim said...

So that is what happens! Thanks Stew for straightening this out.....you da man!
Speaking of fav apples, we love the Gravenstein......it is kind of like a Grannysmith, tart and juicy. We were just in the valley today and the trees are just laden with apples. Love it!

MorningAJ said...

Having done a bit of travelling over the last couple of weeks I've noticed how much further some trees are into autumn only about 20 miles away from ones that are still nearly all green.
Interesting science.

Stew said...

Gravenstein! Now with a name like that, you'd think it would be my favorite apple too. I'll have to search them out and give them a try.

I guess we're expecting the colors to last longer this year because of all the rain too.