Impacts of management on Mountain Pine Beetle spread and damage: A process-rich model

The Mountain Pine Beetle (MPB, Dendroctonus ponderosae) is a major forest pest at epidemic densities, capable of killing entire stands of mature pine. There are a variety of tactics used by forest managers to control MPB epidemics, but the ecology of the insect and the large scale of MPB infestations make it difficult to evaluate the effectiveness of any management strategy. Using a partial differential equation framework, we develop a mathematical model describing the interactions between beetles, beetle pheromone, and susceptible trees across multiple years. We use our mathematical model to examine the effectiveness of various existing management approaches used to limit the spread of the MPB. In particular, our study focuses on management activities that were used in Banff National Park, in Alberta, Canada. Comparing the indirect controls of prescribed burning and clearcutting, we found the success of these methods is critically dependent on the level of MPB attraction to, and productivity in, partially burned trees. Our analysis also indicates that pheromone baiting in combination with tree removal is successful at reducing MPB impact at high beetle densities, but may lead to greater forest impact and greater MPB population growth at low beetle densities. Finally, we found that removal of beetle-attacked trees in the absence of baiting is the most successful strategy if managers are able to locate areas with significant MPB activity.