Modelling of mountain pine beetle transport and dispersion using atmospheric models

The mountain pine beetle population in the British Columbia central interior has reached epidemic proportions. Mountain pine beetles move actively through flight over a few kilometers within a stand, and passively through advection by the wind, within and above a forest canopy. Passive dispersal is likely responsible for between-stand and landscape-scale spread of the population. A strategy for the testing and use of atmospheric numerical models to predict the passive movement of mountain pine beetles is described. Preliminary synoptic climatology results indicate that typical weather patterns associated with weather conducive to mountain pine beetle flight are similar to average summertime conditions, except the surface high pressure ridge influencing the weather over BC is stronger than normal. An atmospheric simulation of a situation conducive to mountain pine beetle emergence and flight showed that the above canopy winds and temperatures had considerable spatial and temporal variability, indicating that treating the atmosphere simplistically as a "constant" in mountain pine beetle population models may not lead to satisfactory results.