Report: Forest fires in Sierra Nevada driven by past land use

This topic has been discussed in numerous posts. This report is worth a look: Forest fires in Sierra Nevada driven by past land use. It will not come as a surprise to people who have traced the Indian use of fire in the Sierras and more recent actions/policies.

“We were expecting to find climatic drivers,” said lead co-author Valerie Trouet, a UA associate professor of dendrochronology. “We didn’t find them.”

Instead, the team found the fire regimes corresponded to different types of human occupation and use of the land: the pre-settlement period to the Spanish colonial period; the colonial period to the California Gold Rush; the Gold Rush to the Smokey Bear/ fire suppression period; and the Smokey Bear/fire suppression era to present.


That said, drought is certainly a factor in the current and expanding die-off of pines in the Sierras, but that may not be a climatic change.

8 thoughts on “Report: Forest fires in Sierra Nevada driven by past land use”

  1. Seems intuitive to me. If you look at shorter periods of time, the effect of climate (which used to change more slowly) is going to be obscured by more direct drivers. Here is what they had to say about the current time period: “However, the shifts from one fire regime to another did not correspond to changes in temperature or moisture or other climate patterns UNTIL TEMPERATURES STARTED RISING IN THE 1980S. If they are suggesting that fuel treatments in this warming climate could be just as effective as in the past, I’m skeptical.


      Average temperatures in California have been rising since 1895, the earliest date tracked by the National Climate Data Center (part of NOAA, And probably have been rising since 1850 or earlier, wherever one puts the end of the Little Ice Age. The trend since 1985 is 0.2 degrees F per decade. See this chart:

      FWIW, the trend is influenced to a significant degree by unusually warm years in 2014 and 2015. From 1980 to 2013, the trend line is nearly flat.

  2. The other big issue that is getting missed is the change in suppression efforts. There needs to be a hard look at the additional acres and costs associated with these tactics.

  3. Some time back on this blog, there was some discussion about Thomas Bonnicksen, PhD, and his work about America’s ancient forests, particularly the Sierras. There were some who rejected Bonnicksen’s work. However, it is interesting that this U. of Arizona/Penn St. paper seems to follow Bonnicksen’s work. Both seem to say that people, including those pre-settlement, intentionally managed the landscape around them to better suit their needs – something people have done since the dawn of human civilization. As we are finding, without the presence of humans on the landscape (e.g., wilderness and, increasingly, federal forests), forests and fuels change; it follows that fire will probably change accordingly.

  4. Of course, we should consider Chad Hanson’s quote about the Sierra Nevada die-off. He says that 100,000,000 dead trees (plus all those green dead trees not counted) are “not too many”. This seems to fit right in with his idea that we need more high intensity wildfires. It fits in perfectly with the desire to have a pre-Man landscape in a Man-dominated world.


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