How the Heat Has Kept the Leaves Green
It's been a very hot start to the fall here in the Mid-Ohio Valley that much is easy to tell but, it has been record breaking actually and you can see the way it is effecting the enviornment around us.
How hot has it been?
Meteorlogically speaking, Fall is the months of September, October, and November, because of this we will set the period for comparison from September 1st through October 7th (the latest date for temperatures this year in the records).
We will start off with the high temperatures. It has been very hot in both September and October even putting us in the top 10 hottest October high temperatures ever in Parkersburg. This though still has us at 6th hottest year in regards to average daytime highs so we have seen hotter.
Now, we get to the real important stuff and is the main reason that we are still seeing mostly green leaves here in the Mid-Ohio Valley.
Taking a look at the average overall temperatures for this period you can see that we are at the hottest ever on record sitting at 72.3°. Now this is impressive on its own but taking a look at our average low temperatures we were at a record breaking 62.9°! To put that in perspective that number should be in the middle 50's so we were around 7° off of the average!
So why are the leaves green?
Taking a look below you can see how far behind (Around 2-3 weeks behind!!!) we are from last year in regards to color showing up in leaves. The biggest factor for this is the warmer nights which play a very important role in this process.
There are three different things that give leaves their color:
carotenoid (yellow, orange, and brown)
Now, normally you see leaves as green because there are plentiful amounts of chlorophyll but, as the days get shorter the lack of sunlight starts to stunt the production of chlorophyll. Carotenoids are always present year round but are covered up by the chlorophyll, but anthoyanin is produced during the fall, especially during the cooler nights. This year since we have been so warm especially at night it has put off this process and the chlorophyll is still the main pigment we are seeing in leaves. Because of this, we have seen very little change in our leaves compared to years past.