EPOW - Ecology Picture of the Week

Each week a different image of our fascinating environment is featured, along with a brief explanation written by a professional ecologist.

12-18 April 2004

Click on images below for larger versions

Humankind Timelines

          left:  Rings of old-growth Douglas-fir (Pseudotsuga menziesii), Olympic 
                  National Forest, Washington
     middle:  Sedimentary rock strata, Humboldt County coast, northern California
        right:  Star trails time exposure, recorded from Oregon

Credit & Copyright: Dr. Bruce G. Marcot

Explanation:   Last week EPOW celebrated its one-year anniversary.  That got us to pondering the dimension of time ... personal, ecological, and cosmic.  

Pictured here, first, are growth rings of an old-growth Douglas-fir tree in the Pacific Northwest, U.S.  Old-growth Douglas-firs can be anywhere from 200 to 1,000 years old, or older.  Consider that an average human life span of approximately 75 years is only 38% to as little as 8% or less of the age of such a tree.  Worse yet, say that the average duration of a forest manager's career is 25 years; this is only 13% to as little as 3% or less of the age of an old-growth Douglas-fir tree! It would take 8 to 40 or more generations of forest managers just to span the age of one old-growth tree! 

Even worse are the life spans of National Forest Plans in the United States (10-15 years), or of U.S. political administrations (4 years).  One old-growth tree can span 50 to 250 or more political generations.  What are the odds that the tree can survive all those changes, all those political firestorms and funding windstorms?

Next, consider the images of sedimentary rock strata and star trails, representing ages of the Earth and the universe.  

If the age of the earth is approximately four billion years old, and Homo sapiens has been on Earth for approximately two million years, then we’ve been on Earth for only 0.0005, or 1/20th of one percent, of the age of the Earth.  Eyes don't blink this quickly!

If the age of the Earth was seen as a 3-hour movie, then humans would occupy only the final 5.4 seconds of the “Earth movie.”

If the age of the universe (about 15 billion years) was seen as a 3-hour movie, then humans would occupy only the final 1.4 seconds of the “universe movie" ... a barely perceptible blip in the cosmic story.

So as our numbers continue to grow, and as we continue to dominate this sparking jewel of a planet, let us ponder how little we have truly known the ecosystems, biosphere, and universe upon which we depend for our continued existence.

Next week's picture:  Thick-tailed Bushbaby


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