Gary Watson, Ph.D.

Position

Senior Research Scientist

Education

Ph.D., University of Illinois, Plant Pathology

Research Interests

The central interest of the urban tree root research program is to understand how to keep trees healthy in urban landscapes by maintaining a healthy balance between the crown and the root system. Trees must cope with challenges in urban soil environments that are not encountered in nature. We need to know how root systems react to these, and how to minimize them. Two approaches are used: attempting to direct more of the tree's resources towards root growth; and improving the soil environment so that it is more favorable.

Accomplishments

Joined the Morton Arboretum research staff in 1986; Adjunct Professor, University of Illinois Department of Natural Resources and Environmental Sciences; Past President of International Society of Arboriculture, the Arboricultural Research and Education Academy, and the Illinois Arborist Association; Chair, Green Industry Working Group on Structural Root Depth 2003-present. He won the award for Arboricultural Research and Richard W. Harris Author's Citation Award from the International Society of Arboriculture. Editorial Board Member, Journal of Environmental Horticulture, and Urban Forestry & Urban Greening, Arboriculture and Urban Forestry.

Selected Journal Articles

• Watson, G. W. 2006. Establishing a Relationship Between Soil Aeration and Fine Root Development of Seven Tree Species Using the Steel Rod Technique.  Arboricultural J. 29:161-172.
• Watson, G. 2006. The Effect of Paclobutrazol Treatment on Starch Content and Mycorrhizal Colonization and Fine Root Density of White Oaks. J. Arboriculture 32:114-117.
• Watson, G.W. and P.D. Kelsey. 2005. The Impact of Soil Compaction on Soil Aeration and Fine Root Density of Quercus palustris.  Urban Forestry and Urban Greening 4:69-74.
• Watson, Gary W. 2004. Effect of Paclobutrazol and Transplanting on Root Growth of Green Column Black Maple and Summit Green Ash. J. Environ. Hort. 22:209-212.
• Watson, Gary W. and E.B. Himelick. 2004. The Effects of Soil pH, Root Density and Tree Growth Regulator Treatments on Pin Oak Chlorosis. J. Arboriculture 30:172-178.
• Watson, Gary W. 2002. Soil Replacement: Long-Term Results.  J. Arboriculture 28:229-230
• Watson, G. 2001. Soil Applied Paclobutrazol Affects Root Growth, Shoot Growth And Water Potential Of American Elm Seedlings.  J. Environ. Hort. 19:199-122
• Watson, G. W. 2000. Tree Root System Enhancement With Paclobutrazol. pp. 131-136 In A. Stokes (ed.), The Supporting Roots of Trees and Woody Plants: Form, Function and Physiology, In the series: 'Developments in Plant and Soil Sciences,' Klewer Academic Publishers, Dordrecht.
• Watson, G.W. 1998. The Effects of Root Loss and Compensatory Pruning. J. Arbori culture 24:47-53.
• Watson, G.W. 1996. Tree Root System Enhancement with Paclobutrazol. J. Arboriculture 22:211-217.
• Watson, G.W., P.K. Kelsey, and K. Woodtli. 1996. Replacing Soil in the Root Zone of Mature Trees for Better Growth.  J. Arboriculture 22:167-173.
• Watson, G. W. 1994. Root Growth Response to Fertilizers.  J. Arboriculture 20:4-8.

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Selected Green Industry Publications

• Watson, G. and A. Hewitt. 2006.  Getting the Roots Right.  American Nurseryman 203(12):35-39.
• Watson, G.W. 2005. Avoiding Excessive Soil over the Roots System of Trees: A Best Management Practice.  Arborist Ne ws 14(2):32-34.
• Watson, G. W. and S. Clark. 2001. Girdling Root Formation, In Landscape Trees.  Arborist News 10(1):50-53.
• Peltier, P and G. Watson, 2000. Transplanting Trees: Preparing the Site and the Tree.  Arbor Age, January
• Peltier, P and G. Watson, 2000. Transplanting Trees: Moving, Storage and Planting.  Arbor Age, February
• Peltier, P and G. Watson, 2000. Transplanting Trees: Establishment and Maintenance.  Arbor Age, March
• Watson, G. W. 2000. Tree Transplanting and Establishment. Arborist News 9(3):33-38.

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Books

• Watson, G. (Ed.). 2007. Trees and Planting: Getting the Roots Right Proceedings Deep Tree Roots
• Watson, G.W. and E.B. Himelick. 2005. Best Management Practices: Tree Planting.  International Society of Arboriculture, Champaign, Illinois.
• Watson, G. W. and E.B. Himelick.  1997. Principles and Practice of Transplanting Trees and Shrubs.  International Society of Arboriculture, Savoy, Illinois. 200pp.
• Watson, G. W. and Dan Neely (Eds.) 1995. Trees & Building Sites: Proceedings of an International Conference Held in the Interest of Developing A Scientific Basis for Managing Trees in Proximity to Buildings.   International Society of Arboriculture, Savoy, Illinois.  191pp.
• Watson, G. W. and D. Neely (Eds.) 1994. The Landscape Below Ground: Proceedings of the International Workshop on Tree Root Development in Urban Soils.  International Society of Arboriculture, Savoy, Illinois.
• Neely, D. and G. Watson (eds). 1998. Landscape Below Ground II. International Society of Arboriculture, Champaign, Illinois. 265pp.

Books are only available by purchasing them from the International Society of Arboriculture. (ISA Catalog of Publications )