The Father of Modern Arboriculture
Dr. Alex Shigo (1930-2006) is considered the father of modern arboriculture, which is the care of trees for either landscaping or commercial purposes. Shigo is also attributed as the father of the modern tree dissection. With training in biology, botany and genetics Shigo spent most of his professional career with the United States Forest Service becoming that agency’s Chief Scientist.
Early in his career, the first one-man chainsaws were invented (during the 1950s), which allowed Shigo to look at trees in a way no one else ever had: by making longitudinal cuts (along the stem) rather than transverse cuts (across the stem). This technique led to many important discoveries, many of which were incorporated into CODIT (Compartmentalization of Decay in Trees), a groundbreaking biological idea that led to many changes and additions to commercial tree care practices.
A prodigious researcher and teacher, Dr. Shigo authored over 270 publications, including many research papers, books, and pamphlets. The topics range from tree biology, arboriculture practices, proper pruning techniques, decay in trees and tree myths.
Dr. Shigo’s discoveries went against many arboricultural conventions that existed prior to his research. Many techniques that were staples of arboriculture for hundreds or even thousands of years were shown to be unnecessary or harmful. It took many years, but Shigo’s conclusions have been confirmed by other researchers, and valuable discoveries are rooted in his initial work. Current ANSI standards for tree pruning reflect his recommendations.
“A tree is much more than a chunk of dead wood,” wrote Shigo. “Trees are alive; they live all year ’round, not just for a short time in the summer. They work during the winter, too. Many people spend time on what goes wrong with a tree; I wanted to study what goes right.”
By cutting trees longitudinally instead of only across the trunk, Shigo discovered that many commonly-held concepts about heart rot and decomposition and other theories were wrong. “I could either go with the book [theories] or go with what I saw in the tree. Either the books were wrong or the trees were wrong. I chose to go with the trees,” Shigo said.
“I started to see trees in a different way because a tree is a living thing… When you hit a living thing, it reacts. When YOU hit a tree, it does something. When a tree is threatened, it doesn’t just stand there. It establishes boundaries. People should know that trees are generating organisms, instead of re-generating organisms like human beings,” Shigo stated. “Trees generate their own food from carbon
dioxide, sunlight and water, while human beings must intake food from elsewhere. Therefore, tree food is a misnomer. While such supplements, like fertilizer, provide important elements, they do not provide an energy source.”
In his books and lectures, Dr. Shigo disagreed with other popular theories about trees. Among those theories that Shigo disputed is the idea that trees are mostly dead wood. “While humans put new cells in old places countless times during a lifetime, trees continue to put new cells in new places. Similarly, a tree doesn’t heal, because it doesn’t replace injured cells with new ones.”
With these and other theories that go against conventions, Dr. Alex Shigo taught us not only to see, but to respond to our world in new ways.