The number of large-diameter trees in Yosemite National Park have declined 24-percent between the 1930s and 1990s.

The findings are based on a study done by the U.S. Geological Survey and the University of Washington. Scientists compared tree densities from 1932-1936 to those from 1988-1999 where large-diameter trees are those with a diameter greater than three feet.

Along with large-diameter tree loss, they also found a shift to fire-intolerant trees. Amazingly, this shift was experienced in areas that hadn’t seen a wildfire in nearly a century. Trees changed from fire-tolerant ponderosa pines to fire-intolerant white fir and incense cedar. In burned areas, however, the pines remained dominant.

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The first national geothermal assessment done in 30 years by a governmental agency, the report indicates that the U.S. has “identified conventional” sources of geothermal systems that, if fully developed, are capable of generating 9,057 megawatts-electric (MWe). An additional 30,033 MWe of potential power generation is available from “conventional undiscovered” geothermal sources, and 517,800 MWe from unconventional Enhanced Geothermal Systems (EGS) or high temperature, low-permeability resources.

By developing the already known conventional sources, the reports says, geothermal electric power production could expand 260%, adding 6,500MWe to the total of slightly more than 2,500 MWe currently generated.

We’ve heard a lot about drilling for oil offshore and in Alaska as a means to increase our domestic sources of energy, but the clamor for “drill now” has overshadowed the significant contribution geothermal can contribute to our domestic “energy portfolio”.

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