Frontiers of Science: Trees That Talk!


Trees That Talk!

What do you think it was like to be alive at the time of the founding of the Church in this last dispensation? How about at the time of the writing of the United States’ Constitution? Or what about 1492, the year Columbus “sailed the ocean blue?” Some pine trees you can see today near Flagstaff, Arizona, were alive and flourishing when all of these important events happened.

Now, five hundred years is a long time to live. But five thousand years is approaching antiquity. Did you know that there are some trees alive today that have actually lived that long? It’s true. The gnarled and twisted bristlecone pine tree that inhabits the rocky slopes of western North America has been proven to have lived for almost five millennia.

Think of it! Some of these trees were already 3,000 years old at the time of Christ’s mortal ministry upon the earth. They lived during the times of many of the Old Testament prophets, easily predating all of the Book of Mormon history of the Americas. “What tales they could tell,” we say, “if only they could speak.” And they can!

Dendrochronology—the science of extracting information from the yearly growth rings of trees—is a fascinating science that has grown enormously over the past 20 years. It was begun in the early 1900s by Andrew Ellicott Douglass, an astronomer at the Lowell Observatory in Flagstaff, Arizona, who thought that he could use the growth rings of trees to learn something about what the weather was like prior to the time that weather records were kept. His pioneering work led eventually to the founding of the Laboratory of Tree-Ring Research at Tucson, Arizona, in 1937, which is today the world center for dendrochronology.

It is amazing to contemplate all that tree rings have to tell us. In addition to providing an accurate calendar and dating technique that is widely used for archaeological purposes extending back over 8,000 years, they can be used to reconstruct the history of many dramatic events such as landslides, floods, earthquakes, glacial advances, volcanic eruptions, forest fires, and even the occurrence of unusual solar activity on the sun. But it is in the area of climate that their tale is most impressive.

The basic idea behind using tree ring data to figure out what the climate was like in years past is that a good growing year produces a wide annual growth ring, while a bad year produces a narrow one. This is especially true for trees that do not receive enough rain and that are consequently always under stress. The proper study of rings from several trees in such an area can be used to determine past patterns of rainfall, temperature, and basic types of weather patterns. In fact, from a computerized study of nearly 1,000 living trees at 65 locations in western North America, scientists at the Tree-Ring Laboratory have prepared maps of these computations for each season of the year across the United States since 1600.

Another interesting offshoot of this work is the ability to predict future climatic trends. By studying repeating weather patterns that emerge from the tree ring data, it is possible to project into the future, based upon trends that have occurred regularly in the past.

Thus we see that the humble bristlecone pine tree occupies a very important position in the world of science; for some weatherworn stumps that still stand may well have been alive when Adam himself walked the Earth, while other living trees may have locked within them prophecies of these not-so-silent sentinels of history.

[illustrations] Illustrated by Mike Rogan

[photo] 1 Andrew Ellicott Douglass, the “father” of tree-ring research, taking a core from a pine tree near Show Low, Arizona, in the spring of 1929. (Photo courtesy of the Laboratory of Tree-Ring Research.)

[photo] 2 A typical bristlecone pine tree that has withstood thousands of years of harsh weather and difficult growing conditions still puts forth a flush of new growth in the spring. (Photo courtesy of the Laboratory of Tree-Ring Research, University of Arizona.)

[photo] 3 A cross section from the stem of a tree that grew under generally poor conditions is examined for particular patterns of wide and narrow rings so it can be cross-dated with other trees on nearby sites. (U.S. Department of Commerce photo by Bob Broder.)

[photos] 1 Two actual ring patterns from different trees showing how they are matched to each other. (Photos courtesy of the Laboratory of Tree-Ring Research.)

[illustration] 2 An example of how ring patterns from different sources are matched to each other to extend backward to very early times in archaeological history.