Last year in the fourth year of drought, bark beetle populations soared. Reduced levels of sap flow in stressed trees resulted in beetles overcoming tree defenses and girdling great numbers of ponderosa and sugar pines, primarily in low elevation forests of the region. When the snow and rain amounts this past winter and spring reached average levels, there was hope that more vigorous trees could repel new beetle attacks. Instead, exceptionally high numbers of bark beetles have already killed millions of conifers, and there is an unprecedented level of tree mortality.
CSERC staff has served as one of the most informed forest monitoring organizations, traveling across the local region to assess beetle impacts and to identify some of the hardest hit areas. The Highway 108 corridor has gotten a high level of media publicity due to large patches of dead pines so vividly obvious to those driving up the highway. But the Groveland District of the Stanislaus Forest has an even higher amount of dead trees, with a new wave of conifers dying over recent months. For summer visitors to Yosemite Park, the western belt of the Park south of the Rim Fire currently shows high numbers of beetle-killed trees, including many old growth trees that were centuries old.
To learn more about the ecological and economic consequences of the current conifer die-off, and to see more photos of recent tree mortality, click here.