A question for all you science whizzes :D

[ramanth]

Been really admiring the Fall colors, and I was wondering. Do certain types of trees only change a certain color?

What denotes that one tree will turn red and another yellow?

If an oak tree turns red one year, will it always go red or can it turn different colors every season?



Inquiring minds want to know.

[Barbara]

I had no idea but the question made me curious too. I found a German website that resolved some of it:
Very shortly: In the process of autumn or however you might call it, the chlorophylle will decay. In summertime, it covers some colour pigments (called xanthophyllines which means "yellow leaf stuff") that are contained in the leaf. As there isn't chlorophylle anymore, the xanthophyllines can be seen in autumn.

On that basis I suppose that the kind of xanthophyllines is typical for the single plant, i.e. that maple has slightly different pigments than maple.

I am happy for any botanic wiz who provides more information.

Ramanth: thanks for the question. I never thought of all that and now I want to know too

[Kater]

I'll e-mail my Mommy about this -- she is professor of Botany in Hawai'i. She may not know as she may have forgotten a lot about "mainland" plants since she's been studying tropical plants for the past decade -- her whole career as a professor. But I know she will have access to the answer at least. I'll get back to you on this Kimmy.

[Freckles]

Why Leaves Change Color

[ramanth]

Thanks everyone!

Freckles ~ nice link! My searches came up empty.

Certain colors are characteristic of particular species.
Oaks turn red, brown, or russet; hickories, golden bronze; aspen and yellow-poplar, golden yellow; dogwood, purplish red; beech, light tan; and sourwood and black tupelo, crimson. Maples differ species by species-red maple turns brilliant scarlet; sugar maple, orange-red; and black maple, glowing yellow. Striped maple becomes almost colorless. Leaves of some species such as the elms simply shrivel up and fall, exhibiting little color other than drab brown.

[Kater]

Hehehe, well I already e-mailed my Mom so I guess we'll just see if she has anything to add.
Nowdays you can be an internet whiz and look like you're a science whiz! Very quick work, Freckles!

[wolfsoul]

All I know is that the chloropyhll in the leaves is reflects every single colour but green by the sunlight, which makes the leaves appear green. When the sun leaves, so does the chlorophyll. As for different types of trees, I wouldn't know lol.

[Barbara]

Thanks Freckles!

The description is both short and thorough -purrfect

[Kater]

Here is my Mommy's cute explanation (it says pretty much the same things as the website Freckles linked to):

Hi Kate. I'm sure that there are some websites that could give you more detailed information, but just to give you some of what I know.

First: there are two groups of pigments involved: one are the yellows (xanthophylls) and the orange to red-orange(carotenoids - yes the same that gives carrots their color.) These two groups of pigments occur naturally in leaves of plants and are sometimes called accessory pigments in the photosynthetic process, because they capture some of the sunlight energy wavelengths that chlorophyll cannot, and "pass" that light energy on to the photosynthetic process.

When the leaf dies with the onset of cold weather, the chlorophyll pigment breaks down and disappears. However, the yellows and orange pigments last longer and give many leaves that color. Eventually they break down and the leaves turn brown.

The second group gives the red to red-blue colors in the leaves that are due to the pigments called anthocyanins. They also give flowers red to purple colors, as well as red cabbage and beets. When growing conditions and weather are just right (has to do with temperature and rainfall), these colors will develop more intensely and as I understand are related to sugars the leaves make and somehow (I don't know why) convert into these bright red-blue pigments.

As you may have noticed, some very colorful leaves have all these colors highly developed, others seen to specialize in one or two colors only.

As to certain species of trees having certain color patterns, that is certainly the case. I used to know which certain species of oaks and maples had which types of colors, but can't remember all that now. If an oak tree turns red this year, I think it is pretty much genetically determined that it will every year. However, the climatic conditions I mentioned above have a big impact on the intensity. So some years, fall coloration will be very intense for all trees, and other years, not so much of a display.

Also, in recent years, hybridists have developed cultivars of maples, and maybe for other trees, which have especially enhanced fall coloration!

What a smart and eloquent lady! I'm so proud to be her daughter!

[ramanth]

Great reply from your mum, Kater!

What are you studying in Wisconsin?

[Kater]

I'm a pre-veterinary student but UW-Madison doesn't have any kind of "pre-veterinary" major. I hope to double major in Zoology and Chinese. We'll see if I can fit all those credits into 4 years....

[ramanth]

Whew!! Best of luck to you!

[gini]

What a fascinating thread. Kimmy, thank you for starting it, and Kater, thanks for asking your Mom.

This is something that I had never thought about, but am delighted to learn.

And Kater, good luck in school!

Freckles, also, thank you for the link.

[lynnestankard]

Great question Kimmy - I'd never even thought about that!

Great find Freckles - very easy to understand too.

Kater - Many thanks to your Mum too.

No wonder Autumn is my favourite time of year - all this beautiful colour.

Lynne