Where the climate meets the road: Frozen road declarations


A few years back, I was digging around for an example of the impacts of climate change that might be real and tangible to those in the forestry sector. At the time, I came across data from the Wisconsin Department of Transportation (WI DOT) on frozen road declarations1. As explained on their website, it is legal to carry more weight on log trucks when roads are frozen. If loggers can carry more weight, then they can make fewer trips, thereby reducing fuel, labor, and other costs. The figure above reflects a simple charting of data2 posted by the WI DOT (pdf). Where road closure dates varied regionally in a given year, a simple average of the days per year was calculated–nothing fancy. A simple regression analysis indicates that a slight downward trend (i.e., fewer frozen days per year over time). Visual inspection indicates increasing variability over time. For example, between 2002 and 2003, the swing was nearly 40 days. Both of these are consistent with climate change predictions. However, I would not say they are evidence of climate change without much more data collection and analysis3. The point, though, is simple. Regardless of how one views or understands climate change as a scientific or politicaltopic, there are continuing real business implications for timber production if the current trend continues. The two most salient that I came up with are:

  1. Fewer days with heavier loads implies additional costs.
  2. Greater variability from year-to-year suggests greater uncertainty.

1 These only apply to state roads. Local road restrictions are determined locally. 2 Only data from 1984 to 2010 were available on-line. 3 For example, do frozen road declarations correspond to changes in historic lake freezing and thawing? NOTE: Comments disabled due to spamming.

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