by Robert van Pelt
Global Forest Society and University of Washington Press
The forests of the Pacific Coast, from California up to British Columbia, and inland to Montana and the Sierra Nevada mountains of California, are home to the largest trees in the world. This book looks at 20 different species in all, from the Giant Sequoia (General Sherman, the largest, has a volume over 55,000 cubic feet, and is more than 250 feet tall), to the Engelmann Spruce -- a relative piker: the largest Engelmann Spruce contains "only" 2,300 cubic feet of wood, and is "only" over 150 feet tall. Still, I bet my jaw would drop.
The reasons this region has so many large trees is because it's also the largest temperate rainforest in the world -- it extends from north of the Golden Gate Bay up through Anchorage, AK.
Robert van Pelt is the founder of the Washington State Big Tree program, and the state coordinator for the National Big Tree program. He found many of these trees, sometimes bushwhacking for days, sometimes finding them by the roadside. The description of each tree (117 in all) is accompanied by a drawing illustrating its height and condition. The drawings capture the trees better than any one photograph could, editing together several viewpoints and capturing the entire height. You can also see how the crowns of the trees have been damaged, sometimes blown over in windstorms. This allows branches near the crown to straighten and become "reiterations," trunks in their own right.
Exactly what makes a champion tree? Measuring a tree isn't as easy as I would have thought. A common measurement is "diameter at breast height" (DBH), taken at 4 1/2 feet off the ground. But what if the slope is so steep, and the tree so large, that 4 1/2 feet above the downslope side is still below ground for the upslope side? What if the tree is so buttressed or misshapen that a difference of a couple inches in height for taking the measurement can make a significant difference in the diameter? How do you compare a short, spreading tree against a tall, straight one? In fact, the old way of awarding trees "points" based on DBH and height worked in favor of tall, straight trees. New technology and new methods of calculation take the whole tree into consideration. To rate his champions, van Pelt uses total cubic feet.
Many of these trees have lived for over a thousand years. Almost none of them would have been the tallest of their species two hundred years ago; those were logged long before measurements were taken. We could probably take a lot of carbon out of the atmosphere by replanting the forest, expanding it as much as possible from its current diminished state.