Remote imagery of Cedar Pines Park, San Bernardino National Forest, CA

This forest stand is the most affected by air pollution deposition in the U.S.A., and is only second (to forests surrounding Mexico City) to the worst deposition in North America. The sequence of remote imagery above was constructed from red, near-infrared, and thermal wavelengths at 5 km above the forest canopy. The yellow dot denotes the same location in each image. The forest stand is a mix of ponderosa pine, California black oak, white fir, incense cedar, and sugar pine. A dirt road and bare soil or dead herbaceous vegetation is indicated in fuchsia. On 7-20-01, the third year of a chronic drought, the first sign of bark beetle attack occurred on the site near the yellow dot (copper-colored trees). On 5-27-03, after three years of chronic drought and an acute drought (2002), additional points of bark beetle infection were observed, including some possible drought-induced mortality (more scattered, individual dead ponderosa pine near the bottom of the image). On 9-18-03, after the drought years plus the wet year (2003), tree mortality continued to accelerate, primarily ponderosa pine, white fir, and some sugar pine. On 7-10-04, tree mortality was further increased (purple and fuchia-colored areas) after the Old Fire swept through the area on 10-12-03. At the stand level, the tree mortality for the first three dates, respectively, was: 0%, 5%, and 42%. Observed mortality (estimated from proportion of pixels) declined to 32% in the 7-10-04 image due to needle loss on standing dead trees.

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Copyright: Public Domain