Can a Hands-on Model Help Forest Stakeholders Fight Tree Disease?


When a new, more aggressive strain of the pathogen that causes sudden oak death turned up in Oregon, scientists and stakeholders banded together to try to protect susceptible trees and the region’s valuable timber industry.

oak death is a serious threat. Since 1994, the disease has killed millions of
trees in California and Oregon. If the disease spreads from an isolated
outbreak in Curry County, Oregon, to neighboring Coos County, the impact could
be severe: a 15% reduction in timber harvest, loss of 1,200 jobs and about $58
million in lost wages, according to an Oregon
Department of Forestry report

Researchers with North Carolina
State University’s Center
for Geospatial Analytics
reached out to help in Oregon, offering
Tangible Landscape, an interactive model that allows people of all skill levels
to control complex simulation models with their hands and collaboratively
explore scenarios of management decisions.

While predictive models can provide
useful forecasts about where the pathogen may go, they can be tough to work with,
requiring coding or technical software experience, says Devon Gaydos, lead
author of an article in Philosophical
Transactions of the Royal Society B: Biological Sciences
and an NC State
doctoral student. 

“The Tangible Landscape system
makes it a lot easier because people can interact with the model by touch instead
of through the code or the computer,” Gaydos says. “People can add objects to a
3D model of the landscape to represent different types of management, and then with
the click of a button we see how that action may affect the disease’s spread
within a few moments.”

The model also allows participants
to factor in budgets for disease management to try out different approaches to
stop its spread, both on a large and small scale, Gaydos says. 

“You can think of our disease spread model like a weather forecast: Knowing what the weather may look like this afternoon can help you decide if you want to bring an umbrella to work,” she explains. “Similarly, knowing how the pathogen may spread over the next year can help people gather resources, figure out which areas to target for surveillance or management, and request funding.”

Researchers took a participatory modeling approach because the disease could affect many stakeholders in Oregon – private landowners, timber producers, U.S. Forest Service managers, tribal groups that consider tanoak trees sacred, and thousands of local residents, including those employed in the timber industry. They began by working with a dozen local and regional experts, in the spirit of learning from each other.

idea of co-creating models with stakeholders is that by involving the people
who are most affected, you’re going to get better data as a scientist because
they have a lot of information about local dynamics and on-the-ground
management that you may not know,” Gaydos says.

all about working together as partners to frame questions and problems, improve
models and decide how to use those results for sustainable solutions,” adds
co-author Ross Meentemeyer, NC State Forestry and Environmental Resources
professor and director of the Center for Geospatial Analytics. 

this case, the team found out that some of the data used in the model needed to
be more accurate at a fine scale – a problem participants could help with. In
addition, the model needed to show the impact of decisions at more frequent
intervals to capture the complexity of field operations.

team also learned that collective action is paramount. Meentemeyer notes that
“just a few uncooperative landowners ‘opting out’ of management could allow the
pathogen to escape quarantine and the put the region at huge economic risk.”

After making adjustments,
researchers plan to use an updated version of Tangible Landscape with a larger
group of stakeholders in Oregon, as well as pursuing new research.

Aerial view of landscape with trees killed by sudden oak death
Aerial view of trees killed by sudden oak death. Photo by Danny Norlander, Oregon Department of Forestry

“More and more stakeholders are
becoming interested in using the model, and the Oregon Department of Forestry
wants to use it in an economic analysis of the situation and to test different
management scenarios for the future,” Gaydos says.

“We are excited to collaborate with
more teams and apply our modeling approach to forecast and control emerging
infectious diseases of other plant, animal and human populations,” Meentemeyer

The article, “Forecasting and control of emerging infectious forest disease through participatory modelling,” appears in Philosophical Transactions of the Royal Society B: Biological Sciences. Co-authors include Anna Petrasova of NC State’s Center for Geospatial Analytics, Richard C. Cobb of California Polytechnic State University and Meentemeyer.

work was supported by The U. S. Department of Agriculture Forest Service’s
Pacific Southwest Research Station Forest Health Protection Special Technology
Development Program (grant R5-2016-05) and the National Science Foundation as
part of the joint NSF-National Institutes of Health Ecology and Evolution of
Infectious Diseases Program (grant 2015-67013-23818).   

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Note: An
abstract of the paper follows.

“Forecasting and
control of emerging infectious forest disease through participatory modelling”

Authors: Devon
A. Gaydos, Anna Petrasova, Richard C. Cobb and Ross K. Meentemeyer

Accepted: Philosophical Transactions of the Royal
Society B: Biological Sciences

DOI: 10.1098/rstb.2018.0283

Abstract: Epidemiological models are powerful tools for
evaluating scenarios and visualizing patterns of disease spread, especially
when comparing intervention strategies. However, the technical skill required
to synthesize and operate computational models frequently renders them beyond
the command of the stakeholders who are most impacted by the results.
Participatory modelling (PM) strives to restructure the power relationship
between modellers and the stakeholders who rely on model insights by involving
these stakeholders directly in model development and application; yet, a
systematic literature review indicates little adoption of these techniques in
epidemiology, especially plant epidemiology. We investigate the potential for
PM to integrate stakeholder and researcher knowledge, using Phytophthora ramorum and the resulting
disease sudden oak death as a case study. Recent introduction of a novel strain
(European 1 or EU1) in southwestern Oregon has prompted significant concern and
presents an opportunity for coordinated management to minimize regional
pathogen impacts. Using a PM framework, we worked with local stakeholders to
develop an interactive forecasting tool for evaluating landscape-scale control
strategies. We find that model co-development has great potential to empower
stakeholders in the design, development and application of epidemiological
models for disease control.

article is part of the theme issue “detection, forecasting and control of
infectious disease epidemics: modelling outbreaks in humans, animals and
plants. Part 2.