Challenging the biggest champ - General Sherman sequoia - National Register of Big Trees

American Forests, Jan-Feb, 1990 by Nancy Ross Hugo

CHALLENGING THE BIGGEST CHAMP

Since the beginning of the American Forestry Association's Big Tree Program in 1940, the General Sherman sequoia has reigned as biggest of the nation's big trees. It has beat out challengers from among other sequoias - plus contenders from all over the world, notably the great baldcypress in Oaxaca, Mexico, now believed to be several trees fused together - to earn the title of the most massive living thing on earth.

To appreciate just how big the General Sherman is, consider this. If a man of average height were standing next to the General Sherman, the weight of the portion of the tree below his waist would total several tons more than a Boeing 737. At 275 feet tall and 83 feet 2 inches in circumference, the behemoth General Sherman is estimated to weigh 6,167 tons. A tree big enough to challenge it would take about 3,500 years to grow.

Where, then, has retired naval officer Forest Clingan found a tree that may dethrone the General Sherman? Read on.

First of all, know that neither the champion nor the challenger is a redwood. Many people confuse redwoods and sequoias and think redwoods are the largest trees in the world. The redwoods are the world's tallest trees. (The tallest redwood soars 362 feet.) But remember that the American Forestry Association considers girth, height, and crown spread when it establishes champion trees, and the giant sequoias, although generally shorter than redwoods, are more massive.

The confusion is compounded by the fact that both coast redwoods and giant sequoias grow in California, both have reddish wood, and both once shared the botanical name Sequoia. But the redwoods, Sequoia sempervirens, grow on the northern California coast, and the giant sequoias, or Bigtrees, grow at higher elevations farther inland, on the western slopes of the Sierra Nevada. The giant sequoia's botanical name - once Sequoia giganteum - has been changed to Sequoiadendron giganteum because botanists now recognize too many differences between the two trees to include them in the same genus.

Local pride led to the first official measurements of the giant sequoias in 1931, when a team of engineers was called in by the Fresno Junior Chamber of Commerce to settle a controversy over which of two counties was home to the largest tree. The engineers' calculations gave the nod to the General Sherman sequoia in Tulane County.

Another challenge 15 years ago led to a remeasuring of the General Sherman and a challenger, the Bull Buck tree in Sierra National Park. Again the General Sherman won. And in 1987, retired school teacher Wendell Flint published his book To Find the Largest Tree, in which he listed comparative measurements for 34 of the largest sequoias and concluded that the General Sherman was indeed the most massive tree on the planet.

So who is Forest Clingan to challenge such a well-documented claim? In addition to being a retired naval officer, he's the son of a ranger who served in the Sequoia National Forest, but Clingan's best qualification for challenging champion trees is that he reads newspapers. It was an article about the dimensions of some of the nation's biggest trees in U.S. News and World Report that alerted him to the possibility that if sequoias were compared based on American Forestry Association standards, the General Sherman wouldn't rank first. In a letter to AFA, Clingan cited figures in U.S. News and World Report and in Flint's book to argue that the biggest tree in the country was not the General Sherman but the General Grant sequoia in King's Canyon National Park.

Could it be true? The answer may depend upon how you compare tree sizes.

AFA compares big trees by using a point total combining each tree's height, circumference in inches at 4 1/2 feet off the ground, and average crown spread in feet. Using the figures last submitted to AFA on the General Sherman, that tree has 1,300 points, and until now, no other tree ever officially nominated has had more points. Clingan cites figures in Flint's book, however, to argue that even without considering crown spread, which is not listed in the book, the General Grant with its 267-foot height and 1,091-inch circumference has 48 more points than the General Sherman. In fact, he argues that four other sequoias would have point totals larger than the General Sherman's if one assumed each tree's crown spread were one-third of its height!

When Flint and others concluded that the General Sherman is the largest tree in the world, they did so based on the tree's volume - the mass of its enormous trunk. "Though other trees are taller and a few specimens are larger at the base, what makes this tree the largest is its great trunk diameter from breast height to the last big limb," says Wendell Flint. According to Flint, the General Sherman is 52,508 cubic feet in volume, some 4,500 cubic feet bulkier than its nearest competitor.

Flint believes volume should be the standard for comparing sequoias. "My feeling is that the AFA standards should not apply to giant sequoias. Unlike other trees, a sequoia's size really involves the mass of the tree. For sequoias, AFA standards put too much weight on circumference at 4 1/2 feet, which on sequoias isn't even above root swell. Consequently, it can't be a true measure at all. On most trees it's not a problem, but on coast redwoods, swamp cypresses, and sequoias, you don't get a true measurement until you get much farther up the tree. Total trunk volume is the only reasonable standard for ranking sequoias."