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Fun Facts about Trees

Image of trees changing colors in the fall

The Splendor of Autumn

Every autumn we revel in the beauty of the fall colors. The mixture of red, purple, orange and yellow is the result of chemical processes that take place in the tree as the seasons change from summer to winter.

During the spring and summer the leaves have served as factories where most of the foods necessary for the tree's growth are manufactured. This food-making process takes place in the leaf in numerous cells containing chlorophyll, which gives the leaf its green color. This extraordinary chemical absorbs from sunlight the energy that is used in transforming carbon dioxide and water to carbohydrates, such as sugars and starch.

Along with the green pigment are yellow to orange pigments, carotenes and xanthophyll pigments which, for example, give the orange color to a carrot. Most of the year these colors are masked by great amounts of green coloring.

Chlorophyll Breaks Down

But in the fall, because of changes in the length of daylight and changes in temperature, the leaves stop their food-making process. The chlorophyll breaks down, the green color disappears, and the yellow to orange colors become visible and give the leaves part of their fall splendor.

At the same time other chemical changes may occur, which form additional colors through the development of red anthocyanin pigments. Some mixtures give rise to the reddish and purplish fall colors of trees such as dogwoods and sumacs, while others give the sugar maple its brilliant orange.

The autumn foliage of some trees show only yellow colors. Others, like many oaks, display mostly browns. All these colors are due to the mixing of varying amounts of the chlorophyll residue and other pigments in the leaf during the fall season.

Other Changes Take Place

As the fall colors appear, other changes are taking place. At the point where the stem of the leaf is attached to the tree, a special layer of cells develops and gradually severs the tissues that support the leaf. At the same time, the tree seals the cut, so that when the leaf is finally blown off by the wind or falls from its own weight, it leaves behind a leaf scar. Most of the broad-leaved trees in the North shed their leaves in the fall. However, the dead brown leaves of the oaks and a few other species may stay on the tree until growth starts again in the spring. In the South, where the winters are mild, some of the broad-leaved trees are evergreen; that is, the leaves stay on the trees during winter and keep their green color.

Only Some Trees Lose Leaves

Most of the conifers - pines, spruces, firs, hemlocks, cedars, etc. - are evergreen in both the North and South. The needle- or scale-like leaves remain green or greenish the year round, and individual leaves may stay on for two to four or more years.

Weather Affects Color Intensity

Temperature, light, and water supply have an influence on the degree and the duration of fall color. Low temperatures above freezing will favor anthocyanin formation producing bright reds in maples. However, early frost will weaken the brilliant red color. Rainy and/or overcast days tend to increase the intensity of fall colors. The best time to enjoy the autumn color would be on a clear, dry, and cool (not freezing) day.

Enjoy the color, it only occurs for a brief period each fall.

Text prepared by Carl E. Palm, Jr.

 
Fun Facts
General
  • Trees keep our air supply fresh by absorbing carbon dioxide and producing   oxygen.
  • In one year, an acre of trees can absorb as much carbon as is produced by a car   driven up to 8700 miles.
  • Trees provide shade and shelter, reducing yearly heating and cooling costs by   2.1 billion dollars.
  • Trees lower air temperature by evaporating water in their leaves.
  • The average tree in metropolitan area survives only about 8 years!
  • A tree does not reach its most productive stage of carbon storage for about 10   years.
  • Trees cut down noise pollution by acting as sound barriers.
  • Tree roots stabilize the soil and prevent erosion.
  • Trees improve water quality by slowing and filtering rain water as well as   protecting aquifers and watersheds.
  • Trees provide protection from downward fall of rain, sleet, and hail as well as   reduce storm run-off and the possibility of flooding,
  • Trees provide food and shelter for wildlife.
  • Trees located along streets act as a glare and reflection control.
  • The death of one 70-year old tree would return over three tons of carbon to the   atmosphere.
Tree Biology
  • Trees are the longest living organisms on earth.
  • Trees and other plants make their food through a process called photosynthesis.
  • The inside of a tree is made of cork, phloem, cambium, and xylem.
  • The xylem of a tree carries water from the roots to the leaves.
Trees and the Environment
  • Trees renew our air supply by absorbing carbon dioxide and producing oxygen.
  • The amount of oxygen produced by an acre of trees per year equals the amount   consumed by 18 people annually. One tree produces nearly 260 pounds of oxygen   each year.
  • One acre of trees removes up to 2.6 tons of carbon dioxide each year.
  • Shade trees can make buildings up to 20 degrees cooler in the summer.
  • Trees lower air temperature by evaporating water in their leaves.
  • Tree roots stabilize soil and prevent erosion.
  • Trees improve water quality by slowing and filtering rain water, as well as   protecting aquifers and watersheds.
  • The cottonwood tree seed is the seed that stays in flight the longest. The tiny   seed is surrounded by ultra-light, white fluff hairs that can carry it on the   air for several days.
Record-setting Trees
  • One of the tallest soft wood trees is the General Sherman, a giant redwood   sequoia of California. General Sherman is about 275 ft or 84 m high with a   girth of 25 ft or 8 m.
  • The 236 ft or 72 m high Ada Tree of Australia has a 50 ft or 15.4 m girth and a   root system that takes up more than an acre.
  • The world's tallest tree is a coast redwood in California, measuring more than   360 ft or 110 m.
  • The world's oldest trees are 4,600 year old Bristlecone pines in the USA.
Trees and Science
  • Dendrochronology is the science of calculating a tree's age by its rings.
  • Tree rings provide precise information about environmental events, including   volcanic eruptions.
  • A mature birch tree can produce up to 1 million seeds per year.
  • Moon trees were grown from seeds taken to the moon by Stuart Roosa, Command   Module pilot of the Apollo 14 mission of January 31, 1971. The effort included   400-500 seeds, which orbited the moon on the first few days of February 1971.   NASA and the USFS wanted to see if being in space and in the moon's orbit would   cause the seeds to grow differently than other seeds.