Bark Beetle Risk In Mature Ponderosa Pine Forests In Western Montana

The boles of 71 mature ponderosa pine trees killed by Dendroctonus brevicomis LeConte (Coleoptera: Scolytidae) were analyzed to determine the distribution of the attacks by endemic populations of this bark beetle and those of several phloem -feeding associates. The longitudinal -circumferential distribution of the attacks fitted dia- grammatically into four distinguishable bole infestation patterns. The characteristics of the patterns and similarities with comparable ‍?attacks of D. brevicomis in northeastern California are discussed.

A mathematical fire model for predicting rate of spread and intensity that is applicable to a wide range of wildland fuels and environment is presented. Methods of incorporating mixtures of fuel sizes are introduced by weighting input parameters by surface area. The input parameters do not require a prior knowledge of the burning characteristics of the fuel.