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Alex Shigo: The Father of Modern Arboriculture

No matter the field, subject or industry in question, it is always important to understand the role important predecessors played in shaping the world modern world.

For example, horn players should learn about Miles Davis; baseball players should learn about Mickey Mantle and Babe Ruth;and artists should learn about Picasso, Da Vinci and Dali.

But if you are an arborist, tree-care professional or simply someone who loves to learn about trees, you should familiarize yourself with the work of Alex ShigoPh. D. – better known as the father of modern arboriculture.

The Early Years

Alex Shigo was born in Duquesne, Pennsylvania in 1930. He was a talented and dedicated musician from an early age, who played clarinet for the official United States Air Force Band as part of his service during the Korean War. After the war was over, he enrolled in Waynesburg College, where he eventually obtained a Bachelor of Science degree in biology. Soon after, he was admitted to West Virginia University, where he obtained both a Master’s and Doctoral Degree in plant pathology.

Career Path

In 1960, Dr. Shigo was hired to perform tree pathology work for the U.S. Forest Service. Dr. Shigo stayed with the forest service for 25 years, before he retired and began working as an author and lecturer, sharing his knowledge of trees with all who cared to listen or read. A prolific writer, Dr. Shigo authored and co-authored 160 different books, academic papers and popular pieces during this time.

Major Contributions to Arboriculture

A pioneering thinker in the world of tree science, Dr. Shigo turned many time-honored tenants of tree care on their head. Dr. Shigo’s contributions to the world of arboriculture could fill volumes, but a few of his most important lessons and breakthroughs include:

  • In the 1950s, Dr. Shigo began using a newly available technology – the one-person chainsaw – to learn more about trees. During this time, Dr. Shigo dissected more than 15,000 trees to better appreciate their biology. Researchers had already been carrying out tree dissections for many decades, but most of these dissections were carried out on in a crosscut-manner. By contrast, Dr. Shigo began dissecting trees along their vertical axis, which revolutionized our understanding to the spread of decay through a tree.

 

  • Thanks in part to these dissections, Dr. Shigo re-wrote our understanding of tree wounds. Specifically, he argued that trees do not heal – they seal up wounds and grow around them. He coined the term CODIT (Compartmentalization of Decay in Trees) to help explain this process and allow tree-care professionals to benefit from the knowledge.

 

  • Shigo studied the way trees in the forest shed their branches, and compared this with what he learned from his study of decay. In doing so, he realized that the flush-cutting technique preferred by arborists at the time was not the best way to prune trees. Instead, he championed the importance of leaving the branch collar intact, and invented the tree-cut pruning technique, which prevents stripped bark and damaged branch collars.

Dr.Shigo continued to learn about trees and share his considerable knowledge about them for the rest of his life. He died unexpectedly after suffering a fall on October 6, 2006, at the age of 76.

Try to keep Dr. Shigo’s contributions to arboriculture in mind the next time you find yourself looking at a beautiful urban forest. Thanks to his work, those trees will feature full, vibrant canopies and properly trimmed stubs – and they’ll be healthier and more attractive for it.

Sherman Oaks Trees

Laurel Canyon Boulevard trees in Sherman Oaks were trimmed in a project to help reduce the danger of fires in the area. Trees along this road and in a few other Hollywood Hills areas have had limbs that hang down below 14 feet, which is the clearance requirement for fire department trucks to get through to respond to a fire emergency. “This project has been talked about for years. It’s a public safety issue, and it’s getting worse in the Hollywood Hills,” said Fire Department Fire Inspector John Novela.

The state has designated 190,000 parcels as being in a Very High Fire Hazard Severity Zone, and the tree trimming project is within this zone. Previously, 130,000 parcels were within this zone, but more development has meant more parcels are now in this zone. With the increase in residences in this high fire hazard zone, there has also been a decrease in the Urban Forestry budget to trim trees. Trees were previously trimmed on a 13-year cycle. Now they are in a 33-year tree trimming cycle. The fire department is now hiring contractors to trim trees to ensure clearance for their fire trucks and to reduce the chance of fires spreading through the tree tops.

“We learned from the Oakland fire 20 years ago that out-of-control vegetation feeds a fire, especially tree canopies where fire spreads from tree to tree,” Novela said.

An experienced arborist has been helping with the project to ensure mature trees aren’t damaged by the trimming. Trees that are found hazardous due to instability are removed entirely.

Evergreen Arborists Consultants, Inc. has examined thousands of trees. We are Los Angeles certified arborists, tree experts, and tree specialists who provide arboriculture and tree expert advice to Beverly Hills, Brentwood,  West Hollywood, Santa Monica, Malibu, Palos Verdes, Encino, Pasadena, and Sherman Oaks. We specialize in Los Angeles trees, and conducting detailed investigations and providing independent analysis. Please call us today for a consultation.