S.P. McClenahan Company, now in its fourth generation of McClenahan family management, was founded in 1911 by Seymour P. McClenahan. The original office consisted of desk space in the Mercantile Exchange Building in San Francisco. During this period, the company provided agricultural services in various locations throughout the state. In 1915, in response to growing demand on the San Francisco Peninsula, Seymour McClenahan moved the base of operations to Palo Alto. From 1915 to 1968, the company operated from the McClenahan residence on the 1900 block of Waverley Street, Palo Alto.

S.P. McClenahan historical photo

During the early years, most of the company's clients were living on large estates. In the mid-1930's, the company was contracted by architect Julia Morgan to perform extensive tree surgery operations at the Hearst Castle in San Simeon. In the late 1930's, S.P. McClenahan Company accomplished a forestation project at the Hearst Estate on McCloud River in Shasta County which involved the transplanting of some five hundred Pine trees. During the decade of the 1930's, the company employed on average, six men.

During World War II, the company continued operation on a limited scale with two employees. Seymour McClenahan was an invalid during this period. The company was managed by Herbert G. Hammers, an associate of the firm since 1923, who became an active member of the Board of Directors until his death in 1988.

Seymour McClenahan died in 1945. In 1946, Henry I. McClenahan, Seymour's youngest son, returned from World War II and later that year, he assumed management of the company. In the era of prosperity following the war, the company began to recruit new employees and to acquire new equipment. As the population of the Peninsula increased, so did demand for arboricultural services among individual homeowners. Eventually, the company's range of operations became centralized on the Peninsula, from San Francisco to Morgan Hill. From the post war years to the present, management has sought to adapt and infuse new technology into the company's operations. The company has enjoyed a steady rate of annual growth and was incorporated in 1959.

During the 1960's, as a result of considerable expansion, the company outgrew its Palo Alto location. In 1968, a new company headquarters’ was designed and built in Portola Valley, a beautiful rural area West of Stanford University.

Henry I. McClenahan retired in 1977 and James M., Henry's son was elected President and Chief Executive Officer of the company. James has been associated with the company since his youth. Henry's daughter, Susan McClenahan Pitt served as Chief Financial officer from 1971 until her death in November 2001.

James has been working with McClenahan Companies since 1964 and has been President since 1977. James is a registered consulting arborist, elected (#249) into the American Society of Consulting Arborists in1984. James McClenahan is a licensed Pest Control Operator, licensed contractor in the State of California, is a member of the California Arborist Association, International Society of Arboriculture, Society of Commercial Arboriculture, and the Tree Care Industry Association. Under his direction, S.P. McClenahan Company continues its reputation of excellence in the field of arboriculture and has flourished in the industry.

John Henry, the fourth generation of the McClenahan family to join the business, started in 1993. John Henry graduated from Cal Poly, San Luis Obispo, with a Bachelor of Science in Ornamental Horticulture. He is an ISA Board-Certified Master Arborist, Licensed Pest Control Adviser, and serves as the Vice President of S.P. McClenahan Company. John has served on the board of directors of Canopy Trees for Palo Alto and California Association of Pest Control Advisers and continues to establish himself in the pest control and tree care industry in California.

John and Jim McClenahan

Joshua, the younger brother of John Henry, joined the firm in 2006. He transitioned to the family business from a Commercial Insurance Loss Control Consultant position. Josh received his Bachelor of Science in Aeronautical Science in 2001 and his Master of Science in Safety Science in 2002 from Embry Riddle Aeronautical University in Prescott, AZ. He obtained TCIAs Certified Treecare Safety Professional designation in November 2006 and BCSPs Certified Safety Professional designation in June 2009. Joshua is the Director of Risk Management for the firm.

S.P. McClenahan Company is one of the largest and one of the oldest family owned arboricultural firms servicing the private sector in Northern California. The company has averaged 55 employees over the last decade, including seven supervisory personnel. The company’s operations include consultation, diagnosis, appraisal, pruning, removal, planting, transplanting, bracing, cabling, cavity repair, treatment of root crown disease, spraying, fertilization and aeration.

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Your guys did an excellent job—and we are very pleased with the service provided and clean-up. Thanks Mike, Portola Valley

TCIA Accredited Certified Treecare Safety Professional Quality - Integrity - Confidence ISA Board-Certified Master Arborist International Society of Arboriculture