Economic assessment of oak wilt management in U.S. communities, 2009-2019
SUMMARY: Oak wilt is a vascular disease that causes blockage of xylem vessels and rapid wilting of leaves and is the most significant disease of oaks (Quercus spp) in the eastern United States. It is caused by a non-native fungus, Ceratocystis fagacearum, first discovered in Wisconsin in 1948 and currently found in 25 states. Red oaks (section Lobatae) are more susceptible than white oaks (section Quercus) and can die within weeks after infection. A healthy oak tree can be infected with oak wilt by sap beetles (Family: Nitidulidae) carrying the pathogen long distances from other infected trees. The pathogen also spreads by root grafts resulting in characteristic colonies of infected trees.
Oak wilt management activities include monitoring oaks for new infections, removing infected trees, and severing root grafts between pockets of infected trees and neighboring uninfected trees. While there are assessments of the costs of oak wilt damage in selected communities, there is no comprehensive assessment of the potential costs of oak wilt damage and the benefits of management activities in communities throughout oak wilt range. Research has been proposed to estimate the benefits of oak wilt management in a 25-state study area that includes the current range of oak wilt. Results will inform decision makers about the economic efficiency of a national oak wilt management program. Specific objectives are:
1. Estimate the number of oaks and number of oak wilt infection centers on developed land in U.S. Census-defined communities.
2. Estimate oak wilt spread, oak mortality, and removal cost in communities over the next ten years (2009-2019).
3. Estimate the reduction in oak wilt spread, oak mortality, and removal cost from the application of oak wilt management strategies in communities over the next ten years.
EFETAC's ROLE: This project is supported by Eastern Threat Center funding.
PROGRESS: An oak wilt economic assessment was published for Anoka County, MN (a 1,156 km2 mostly urban county in the Minneapolis-Saint Paul metropolitan region), which is the basis for the national assessment described above. Researchers developed a landscape-level model of oak wilt spread that accounts for underground and overland pathogen transmission and predicted the economic damage of tree mortality from oak wilt spread in the absence of management during the period 2007-2016. The metric of economic damage is removal cost, which is one component of the total economic loss from tree mortality. Researchers estimate that Anoka County had 5.92 million oak trees and 885 active oak wilt pockets covering 5.47 km2 in 2007. The likelihood that landowners remove infected oaks varies by land use and ranges from 86% on developed land to 57% on forest land. Over the next decade, depending on the rates of oak wilt pocket establishment and expansion, 76–266 thousand trees will be infected with discounted removal cost of $18–60 million. Although the predictions of removal costs are substantial, they are lower bounds on the total economic loss from tree mortality because researchers do not estimate economic losses from reduced services and increased hazards. Predictions suggest that there are significant economic benefits, in terms of damage reduction, from preventing new pocket establishment or slowing the radial growth of existing pockets.
Haight, R.G., F.R. Homans, T. Horie, S.V. Mehta, D.J. Smith, and R.C. Venette. 2011. Assessing the cost of an invasive forest pathogen: A case study with oak wilt. Environmental Management 47:506-517.
- Robert Haight, USDA Forest Service Northern Research Station, firstname.lastname@example.org or (651) 649-5178
- Robert Venette, USDA Forest Service Northern Research Station, email@example.com or (651) 649-5028
Updated June 2015