important forest species is the exploitation of natural tree resistance, which we have documented in coast live oak.
The aim of our research at The Ohio State University is to understand the mechanisms of oak resistance to P. ramorum infection and to develop methods for predict- ing resistance within natural populations. The identifica- tion of field resistant oak will allow us to protect valuable trees from pre-emptive eradication efforts and urban development, and provide valuable genetic material for breeding of resistant tree stock.
By partnering with David Bienemann, the Bowling Green municipal arborist, we have been able to establish an oak plot with over 400 trees in Bowling Green, Ohio. The site contains 13 completely randomized blocks of 32 oak trees each, and includes species of red oak (Quercus rubra) and members of the white oak group (Q. alba, Q. macrocarpa, and Q. bicolor). Due to federal restrictions regarding P. ramorum—a USDA/APHIS-quar- antined pathogen—we will not be infecting trees in the field. Instead, we will use our oaks in Bowling Green to generate biomass for future studies. The City of Bowling Green is providing the site, labor, and equipment to help maintain the oak plots for this study.
Bowling Green City Forester David Bienemann says,
"The goal is to be proactive and ahead of sudden oak death. Oak trees are very important to the City of Bowling Green and our heritage. City Park and Oak Grove Cemetery have over 200 oak trees with an average diameter of 30 inches (76 cm). It would be a loss of $1,052,283 in benefits (i-Tree Streets v. 4.0) if the City lost the oak trees."
Viscous exudate (left) and a main stem canker (right), symptoms of Phytophthora ramorum infection on coast live oak (Quercus agrifolia). www.urban-forestry.com 31
