Imagine walking through a magnificent cathedral forest with giant trees looming overhead - each one six to twelve feet in diameter. The dominant ones are from 1,500 to 4,000 years old, and the forest wood contains more carbon than any other, save perhaps some of the most superlative coastal California redwood groves. Below the giant trees is a lush evergreen growth of southern beech, laurel, and myrtle trees. Below these are brilliant flashes of scarlet, white, and blue from native Fuchsia, and myriad vines and woody shrubs. The forest resounds with a host of bizarre-sounding birds and mammals, most of them unique to this part of the world. As we near the twenty-first century few scientists or naturalists even know the names of these trees, much less the significance of this unique forest! This is the enigma of South America's oldest trees - the alerce (pronounced ah-LER-say).
So what is the scientific significance of alerce, and why should scientists spend the time and effort required to traverse one of the world's most remote and impenetrable forests to study it? The alerce is one of the most compelling examples of parallel or convergent evolution with the conifer forests of the Northern Hemisphere. Studying it may be the ideal opportunity for testing ideas about how forests have evolved in the face of changing climates and have adapted to these stresses. Perhaps this information could help form the foundation for understanding the implications of global climatic change.
Charles Darwin and the captain of the Beagle were among the first European naturalists to discover the alerce in 1832, and he recorded his impressions while exploring the southern South America coastline on Chiloe Island and San Pedro Island:
From a distance the view somewhat resembles that of Tierra del Fuego [southern tip of South America]; but the woods, when seen nearer are incomparably more beautiful. Many kinds of fine evergreen trees, and plants with a tropical character, here take the place of the gloomy beech of the southern shores.
In the lower part of the mountain, noble trees of winter's bark, and a laurel like the sassafras with fragrant leaves and others the names of which I do not know, were matted together by a trailing bamboo or cane. On the higher parts, brushwood takes the place of larger trees, with here and there a red cedar or an alerce pine. (Charles Darwin, Voyage of the Beagle, 1845)
The alerce still remains relatively unknown today partly because of the remote and inhospitable habitats it occupies. As Darwin noted, "In the winter the climate is detestable and in the summer it is only a little better. I should think there are few parts of the world, within the temperate regions, where so much rain falls. The winds are very boisterous, and the sky almost always clouded." Rain occurs during every month of the year and usually totals 160-270 inches within the alerce region. The alerce only occurs in the northern portion of the Chilean temperate rain forest zone and in adjacent Argentina. In total it covers only four degrees of latitude, a small remnant of its former range throughout much of temperate South America.
The alerce tree, which has variously been classified as a pine, a cedar, or a member of the redwood family, is still somewhat of an enigma to taxonomists today. The common name is Spanish for
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