Relation Between Tree Growth and Outbreaks of the Black Hills Beetle

During the past decade losses of ponderosa pine resulting from the work of the Black Hills beetle have been exceptionally heavy. In an attempt to determine the cause of these outbreaks an analysis of the growth rate of trees, as affected by precipitation, was made. Although most of the outbreaks occurred during periods of deficient moisture and relatively poor tree growth, the exceptions strongly indicate that other factors are sometimes fully as important as these.