Why is Fall so colorful?

The leaves are turning amazing colors before piling up in your yard.  Reds, oranges, yellows, and browns.  What happened to all the green?

Bright yellow tulip poplars.

Green chlorophyll is what makes trees green.  They can absorb any color but green, so green is all you see.  However, this green-reflecting pigment is expensive to produce.  Its worth it most of the year because the sugar payoff is so high, but with the days getting shorter the trees start to cut their losses and focus on storing up sugar in more protected areas like the trunk and roots.  As the green disappears, other colors start to appear.

Yellows and oranges were always there.  They are other types of chlorophyll that help funnel light into the tree.   The green chlorophyll just got in the way before.

Reds are something different.  I just learned that the reason leaves turned red is because as the tree starts blocking off the veins that lead to the leaves, some of the sugars get trapped in the leaf.  The trapped sugar reacts to the sun and other chemicals in the leaf to turn red!  This is why extra sugary trees like Maples and Sweet Gums tend to be redder than other trees.

Browns are similar to the reds, except instead of sugar being trapped, its just extra trash molecules.  I think that since it is such a mix of random bits and pieces, its like what happens if you mix all your colors of paint together.

Lots of complex thing going on in this red maple leaf.

Next time you see colored leaves, remember how they represent how complex interactions take place in each leaf!

Twig Girdlers

Have you ever noticed that in the fall there are sometimes a lot of small branches on the ground?  Sometimes they almost cover a trail.  Next time you see a small branch, pick it up and see if the end looks like this:

If it looks like it was evening circled and just the middle part broke off, then it wasn't just the wind knocking branches off, it was the Tree Girdler (Oncideres cingulate). 
These little beetles are actually really cool.  They are native and common all over the eastern US.  If you can see some little grooves above the break, the Tree Girdler gnawed some gashes to lay her eggs in before chewing through most of the branch.  Its how they spread their eggs.  Once the branch falls off, the eggs will hatch and the larvae will live inside the branch until its time for them to emerge as adult beetles, the it starts all over again.  They only cut off smaller branches, so the trees are not damaged very much. 
I like to look for the mark of the Tree Girdler to make clearing off the yard or trail slightly more interesting.

Autumn Olive

There is an invasive shrub gaining ground in the US.  Its the Autumn Olive!!!!  Apparently, in England this plant barely every fruits and is used extensively in landscaping.  However, it really likes the climate in America and produces lots of fruit.  This fruit is actually edible and supposed to be tasty for humans.  Alas, they are also delicious to birds who are spreading them everywhere!

Autumn Olive (Elaeagnus umbellate)

This main identification feature is the silvery scales.  You can rub them off with your fingernail, its some type of waxy coating.  Its on the top of the leaves and the berries, but the key is the blinding coating of silvery scales on the underside of the leaf.  Its one of the whitest leaves I have ever seen in nature.  Oh, and watch out for the thorns!

Bonus Slug Caterpillar!

I saw another Saddleback!  This guy was much bigger then the other one.  It has dark colored "antenna" things instead of green like the other one I had taken a picture of.  Somehow I think it looks more dangerous when it is bigger.

Saddleback Caterpillar (Acharia stimulea)

I think the bottom part is the front... 

Jewel Weed

Jewel weed has got to be one of the most beautiful wildflowers in the fall (and summer).  You can find them on the bank of any creek in the east 

Jewel Weed or Touch-me-not (Impatiens capensis)

They not only have an interesting flower, but also an interesting seed pod.  That's where the "Touch-me-not" name comes in.  If you lightly squeeze the seed pod, it explodes!  I recently learned that the seeds taste like walnuts. 

Seed pod before explosion

Seed pod after explosion

Not only is the flower beautiful and the seed pods explosive, but the leaves are awesome too!  I tried and tried to get a good picture of one to show how amazing they are, but none quite did it justice.  Here is the best one.

Jewel Weed Leaf

This is what the plant is named for, the underside of the leaves turn silver underwater!  Its very reflective, which is probably why my pictures don't really do it justice.  You will just have to find a Jewel Weed and try it out yourself!  The leaf is very water resistant, so water will form a film over a pocket of air, making a silver-like reflective surface. 

Jewel Weed is an amazing plant for one more reason, its supposed to help combat poison ivy rash if you rub the leaves on your skin after being exposed to poison ivy.  Just one more reason to love this beautiful/tasty/interesting plant!

European Starling

I saw a bird right outside my window the other day, and I could not figure out what it was.  It looked like a robin-sized bird that was white with brown streaks.  It was being very conspicuous, singing and stretching its wings, but of course my binoculars were nowhere to be found.  I finally grabbed my camera and this is what I saw.

European Starling (Sturnus vulgaris)

My mysterious brown and white bird had turned into an European Starling (Sturnus vulgaris).  This is the bird was loved by Europeans so much, they brought them in boats to America to let them go (100 birds were released in Central Park, New York, NY in 1890).  The starlings really took off in America, you can find them everywhere.  They compete with native species for nesting sites, and create large noisy and messy roosts

Despite their being invasive, you have to admit they do have pretty feathers.  The Europeans did have a point about how they shine in the sun.  We can see their rainbow sheen and brightness, but E. Starlings can see Ultraviolet light.  They see each other in even more color!

Slug Caterpillars!

I had the luckiest day!  Two Slug Caterpillars on one trail at the UT Arboretum!

Slug Caterpillars have to be one of the strangest-looking critters in the forest.  They are called "slug" due to their tiny front 6 legs, and on the rest of their body instead of having prolegs like most caterpillars, they have suction-like disks.  So they move SLOW, like slugs!

This one is called a Saddleback Caterpillar (Acharia stimulea).

Saddleback Caterpillar (Acharia stimulea)

 It looks like someone put a tiny green blanket on the back with a tinier saddle.  Note the hairs on the ends.  DO NOT TOUCH!  This caterpillar has one of the worst stings in the insect world. 

The other one I saw is the Skiff Moth Caterpillar (Prolimacodes badia).

Skiff Moth Caterpillar (Prolimacodes badia)

Yes, I promise this is a caterpillar.  Everyone I show this picture to thinks its a leaf at first.  Its camouflage is so good, it usually forages on the top of leaves.  The spots on the back vary through its range, so predators will not get used to one coloration.

The moths of these two caterpillars are unremarkable.  They are dark brown and are shaped just like a moth.  Its amazing how metamorphosis can change the bizarre to the unremarkable!