Alex L. Shigo (May 8, 1930 – October 6, 2006) was a biologist, plant pathologist with the

United States Forest Service The United States Forest Service (USFS) is an agency of the U.S. Department of Agriculture that administers the nation's 154 national forests and 20 national grasslands. The Forest Service manages of land. Major divisions of the agency inc ...

whose studies of tree decay resulted in many improvements to standard arboricultural practices. He travelled and lectured widely to promote understanding of tree biology among arborists and foresters. His large body of primary research serves as a broad foundation for further research in tree biology.

Biography

Shigo was born in

Duquesne, Pennsylvania Duquesne ( ) is a city along the Monongahela River in Allegheny County, Pennsylvania, United States, within the Pittsburgh metropolitan area. The population was 5,254 at the 2020 census. History The city of Duquesne was settled in 1789 and incor ...

. He served as a clarinetist with the

United States Air Force The United States Air Force (USAF) is the air service branch of the United States Armed Forces, and is one of the eight uniformed services of the United States. Originally created on 1 August 1907, as a part of the United States Army Signal ...

Band in Washington DC for four years during the

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. After his service, he earned a Bachelor of Biological Science degree at

Waynesburg College Waynesburg University is a private university in Waynesburg, Pennsylvania. It was established in 1850 and offers undergraduate and graduate programs in more than 70 academic concentrations. The university enrolls over 2,500 students, including ...

in Pennsylvania, then a PhD in Plant Pathology at

West Virginia University West Virginia University (WVU) is a public land-grant research university with its main campus in Morgantown, West Virginia. Its other campuses are those of the West Virginia University Institute of Technology in Beckley, Potomac State College ...

in 1960. He joined the U.S. Forest Service as a tree pathologist. He served there as Chief Scientist for 25 years and retired in 1985. Shigo was known for his digressive and philosophical style when writing and speaking, and for his trademarked phrase, “touch trees,” with which he autographed his books.

Research

Early in his career, the first one-man

chainsaw A chainsaw (or chain saw) is a portable gasoline-, electric-, or battery-powered saw that cuts with a set of teeth attached to a rotating chain driven along a guide bar. It is used in activities such as tree felling, limbing, bucking, pruning, ...

s became available. These enabled him to prepare longitudinal sections of trees, which allowed him to study the longitudinal spread of decay organisms within them. A major discovery from this work was that trees have ways of walling off decaying tissues, which he named

Compartmentalization of Decay in Trees Compartmentalization of decay in trees (CODIT) is a concept created by plant pathologist Alex Shigo after studying wood-decay fungus patterns. Theoretical background In keeping with the theory of spontaneous generation, in which living things c ...

(CODIT). This led to reassessment of arboricultural practices such as pruning techniques and cavity treatments, which showed that many then current practices (such as coating cuts with tar) actually promoted decay or were ineffective. The

ANSI The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...

A-300 Pruning Standard reflects his recommendations.

Publications

Shigo produced over 270 publications, including many research papers, books, pamphlets, CDs, and DVDs. In retirement, he and his wife Marilyn published these as Shigo and Trees, Associates. He traveled the world doing presentations, workshops, seminars and demonstrations, sharing his passion for trees. The Shigo and Trees, Associates business was transferred to their daughter in 2005.

Major works

*A New Tree Biology and Dictionary *Modern Arboriculture - Touch Trees *Tree Anatomy

References

* Article
Local man revolutionized tree care: Shigo’s influence on arboriculture felt worldwide
2012

External links

Shigo and Trees, Associates LLCUS Forest Service - Northeastern Area
{{DEFAULTSORT:Shigo, Alex 1930 births 2006 deaths People from Duquesne, Pennsylvania American horticulturists West Virginia University alumni Waynesburg University alumni Biologists from West Virginia