Leaf Colors, Gold Seal Awards and Garlic Mustard

Happenings in the Park
The authors of this Blog will be camp hosts at Wyalusing State Park for the month of September. We always look forward to meeting friends and campers. Stop in. Share our campfire. Chat. Enjoy the park. Septembers issues of the FOW blog may be brief. So, this issue focuses on the leaf colors.

Fall Leaf Colors

Every year, mother nature puts on a spectacular show across the Northeast, Southeast and Midwest United States. Autumn colors can be seen in many areas throughout the U.S., and the world for that matter. However, it is certain areas of the United States, including the Northeast corridor, Southeast U.S. along the Appalachian Mountain chain, and much of the Midwest that produces the most striking and vibrant colors. This is attributed to mild autumn days coupled with cool, crisp, but not freezing evenings. During September, October and November, the once green leaves of spring and summer alter their appearance, displaying such colors as brilliant
yellow, glowing orange, fiery red, and rich brown. Each species of tree and shrub has its own unique hues which can vary from year to year. So why do the leaves go through this transformation? This tutorial will help you understand the foliage process.

Science is used to explain many phenomena and foliage is no exception. The two major branches of science which impact the foliage are meteorology, or the weather, and biology.
Temperature
Ideally, the best foliage occurs when autumn days are mild and the evenings are cool and crisp, but not below freezing. However, if daytime temperatures are too warm for a relatively long period of time in the fall, the colors may be less intense. The foliage season may also last one to two weeks longer. Frost tends to inhibit the production of anthocyanin, a pigment producing various shades of red. This is why having temperatures above freezing is advantageous.

The temperature during the Spring can also have an impact on the fall foliage. ;A late Spring may delay the color change by a week or two.

Precipitation
Annual precipitation, which provides moisture for soil and plant life, also plays a role in the foliage. A late spring, which delays the release of moisture through snow melt, may push back the color change by a nearly a week, sometimes longer in extreme cases. Severe drought often causes the leaves of young and distressed trees to turn brown and drop early.

Wind
The third parameter, wind, has a rather obvious impact on the fall foliage. Very windy conditions, like those observed during and after storms, cause the leaves to drop, sometimes before full color has been reached. Therefore, calm winds are most favored during the foliage season.

Ideal Foliage
Weather As you can see, the weather has a strong impact on the foliage season. It can dictate the timing of the foliage, the intensity and type of colors seen, and the duration of time the leaves will remain on the tree.

Ideal foliage is produced by a warm and wet spring, typical summer conditions, and mild, sunny autumn days with cool evenings (which stay above 32° Fahrenheit).

The weather is not the only process affecting the foliage. In fact, the weather is a distant second in importance to the biology of the trees and leaves.

Trees
There are many species of trees and shrubs, each with different characteristics. There are two types of trees, evergreen and deciduous. Evergreen trees (e.g., pine, spruce, fir, etc.), sometimes referred to as conifers, keep their leaves (needles) year round. Deciduous trees however, shed their leaves during the winter or during prolonged droughts.

Leaves
The leaves are responsible for producing food and nutrients for the trees and shrubs. Deciduous trees produced enough nutrients, which are stored by the tree in the trunk and roots, to last throughout the winter. The leaves also allow the trees and shrubs to release excess moisture. The process through which leaves produce food is known as photosynthesis. Photosynthesis breaks down carbon dioxide (CO2) into organic materials such as carbohydrates (e.g., sugars and starches). In order for photosynthesis to take place, energy is required. For plants, this energy is provided by sunlight.

Pigments
To use the sunlight, the plant must have a mechanism for absorbing the light. Plants use chlorophyll and carotenoids, both chemical pigments, to absorb light. Light has color components collectively known as the spectrum. The spectrum consists of red, orange, yellow, green, blue, indigo, and violet. The green light portion of the spectrum is not effectively absorbed by chlorophyll in plants. The green light is either reflected by or passed through the leaf. This is why leaves generally appear green.

Carotenoids represent a collection of two groups of pigments, carotenes, and xanthophylls. Carotenes are similar to vitamin A and are responsible for the coloration of carrots (the name carrot is derived from this pigment), pumpkins, and yellow and orange leaves. Xanthophylls are yellow pigment responsible for the coloration found in dandelions, sunflowers, corn, egg yolks, and yellow leaves.

In addition to carotenes and xanthophylls, three other chemical pigments play a role in foliage coloration. Anthocyanins produce blue, red, and violet colors. If the plant cell fluid is acidic, the coloration will be red. Conversely, if the fluid is basic, then the color will be blue. Tannins produce brown colors often seen in tea, chestnut bark, and in oak leaves in the fall. The final pigment is a group known as flavones. They are also yellow and are found in sumac, horse chestnut, tea and onions.

Autumn Change
Now that you have a basic understanding of trees, leaves, and the chemical pigments found in the leaves, we can now look at how leaves alter their colors in the fall. So often, people talk about the "changing of the leaves". It may be more accurate to say that the leaves are actually losing their color. Leaves contain the pigments mentioned in the earlier section but are overshadowed during the spring and summer by an abundance of chlorophyll, which is green.

As autumn approaches, the amount of available sunlight decreases. This signals the tree that winter is approaching and that it is time to begin the process of shedding its leaves. As a result, the production of chlorophyll ceases and breaks down. Because of this, the green color of the leaf disappears allowing the other pigments to show off their hues.


A maple leaf loses its chlorophyll and other pigments become visible.

Other changes are also taking place during the autumn season. At the point where the leaf stem joins with the branch, a layer of cells develops which blocks the transfer of water to and from the leaves. The veins that carry fluid into and out of the leaf gradually close, trapping sugars and promoting the production of anthocyanins in the leaf. Once the cell buildup is complete, the leaf is ready to fall.

A Look Through Recent Peak Color History for Wisconsin



Fall Color Report Link

Blurbs from Publications
Time for Surveys

Each summer, the Friends invite the campers, bikers, hunters, hikers and anglers to vote on their favorite features at the state parks and trails they visit. Votes are cast at Friends of Wisconsin State Parks, counted up and Gold Seal awards are presented each year at the Friends annual meeting in mid-October.

In 2007, Wyalusing State Park won a Gold Seal Award for one of the Best Electric Campsites in Wisconsin. ( More...)

Let's hear it for Wyalusing State Park. Go to the latest Friends of Wisconsin State Parks web site and vote for Gold Seal Award (Link). The survey taker doesn't have to complete all of the blanks of the survey. Might I suggest The best sunset view - Wylausing state park- ? Just a suggestion.

The FWSP (Friends of Wisconsin State Parks ) also has a nomination site for State Park or Trail Hero. (Link).

Friends Activities
Lots to discuss at next meeting: September 8, 2008, 6:30 P.M.
Plans for Spirit Night...
Are you coming to the meeting? RSVP?

Recipes
Garlic mustard. What do do with it? Feeling like a challenge? How about this?
Garlic Mustard (Alliaria petiolata) Pesto*

1/2 Cup Olive Oil

1 Cup Pine Nuts or Walnuts
1/2 Cup finely grated Parmesan Cheese
Enough Garlic Mustard leaves to choke a horse (or to clear a forest floor)

Finely mince the walnuts and garlic mustard. An electric coffee grinder
works like a charm.
Add Oil and Cheese, serve with pasta or rice or other whole grain. For
vegan pesto use Nutritional Yeast instead of Cheese.

Harvesting Garlic Mustard: take out the entire plant including the roots
early in the season before it has a chance to flower. Young first leaves
are best for pesto (and for salads or as a steamed green). Use only the
leaves for this recipe. Remove the roots from the area you are clearing as
they will re-establish themselves if left in a pile on the ground. If you
pull up garlic mustard after it has flowered beware as it will develop the
seedhead even after it is pulled from the ground.

*The author or web person in no way endorses the above recipe. It merely brings possibilities.