McClaughry: Wood burning is carbon neutral after a hundred years

By John McClaughry

Three senior environmental scientists have sent a letter to Dartmouth College opposing the planned wood-burning heating plant for campus hot water heating. The signers, all Dartmouth alumni, are George Woodwell, founder of the Woods Hole Research Center, William Schlesinger, emeritus dean of Duke University’s Nicholas School of the Environment, and John Sterman, professor at MIT and director of its Sustainability Initiative.

U.S. Department of Agriculture

Wood pellet stove for home heating

According to the Valley News, the three pointed out that “Burning wood chips could ‘substantially’ increase the college’s carbon emissions and worsen the effects of climate change. Forests are a major pool of carbon dioxide and globally store as much carbon as the Earth’s atmosphere. Carbon is released both when wood is burned and after a tree is cut through soil material and decaying plant material.”

They added: “Whereas forests are renewable, it could take 100 years after cutting before they’re able to again absorb the same levels of carbon. We don’t want to cut forests and burn them up, dumping carbon into the atmosphere because it makes a problem, that is now desperately serious, much worse.”

What’s amusing about this is that the climate change warriors have always excluded wood from their carbon tax schemes because, according to them, wood burning is carbon neutral — new wood growth eventually sucks back the carbon dioxide released from combustion. Now we learn that that takes a hundred years, and according to them, the planet will be ruined in 12 years.

John McClaughry is vice president of the Ethan Allen Institute. Reprinted with permission from the Ethan Allen Institute Blog.

Image courtesy of U.S. Department of Agriculture
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4 thoughts on “McClaughry: Wood burning is carbon neutral after a hundred years

  1. This is something I also have been pointing out for years on the blogs. The rate constants are all out of balance. Imagine that a tree in an old-grow forest has been sequestering carbon at a comparatively low rate over the course of a century or two. Then it is harvested (made into chips) and burned and all of that accrued carbon is released essentially as a spike (maybe a few month’s duration) in the carbon burden. Do that over and over again over the course of a century and you might reach an equilibrium, at a significantly higher carbon burden that you started with.

  2. John,
    You forgot one item
    The C neutrality year

    Logging trees kills the belowground biomass, which starts to decay and releases CO2.

    The decay CO2 release exceeds the CO2 absorbed by new tree growth for about 15 years.
    At that point they are equal

    It takes about another 23 years of new tree growth to offset the 15 negative years
    The C neutrality year is about 15 + 23 = 38 years.

    Any combustion CO2 of year 1 would start its absorption in year 39, and complete its absorption in about 90 to 100 years.

    I checked the above with several forest oriented environmental scientists at Dartmouth College and they all agree the combustion CO2 absorption starts at the end of the C neutrality year.

    See my articles.

    • John,
      1) Here is the URL regarding the net ecosystem productivity, NEP, and the C neutrality period.
      http://www.windtaskforce.org/profiles/blogs/co2-emissions-from-logging-clear-cutting-and-burbing

      2) Additional CO2 Emissions:

      CO2 is emitted from tree stand maintenance, fertilizing, harvesting, cutting, chipping, pelletizing and transport.
      CO2 emissions also occurred, due to setting up and maintaining in good working order the A to Z logging sector infrastructure.

      That CO2, not related to forest regrowth, should be counted, just as any other CO2.
      Very often that CO2 is simply ignored.

      3) BERC is a pro-logging think tank, a part of the Vermont Energy Investment Corporation. It invented a method of calculated CO2 from wood burning plants that has no parallel anywhere else in the academic literature, and is likely not used anywhere else, except by some people in Vermont.

      BERC Stated: “While the recommended carbon emission factor of 29.58 pounds per million Btu is far from the historic “carbon neutral” stance, when compared to the carbon emissions (165.5 pounds per million Btu) from burning heating oil, it represents an 82% reduction in CO2 emissions’. See table 1A, which is based on BERC data and see URL

      The BERC 82% CO2 reduction is based on:

      “Apply a conservative assumption of the minimum percentage of total wood fuel sourced that is from forest management where the harvested stand’s carbon stores will be regenerated within a 20 – 100 year timeframe”

      “Use the resulting carbon emission rate to address the remaining 10% not sourced from forest management where full regrowth is achieved within a 20-100 year time frame”

      Both these statements are a pure invention by BERC that is not supported by any forestry research, such as the above British Columbia example.

      BERC ignored the plant operation CO2 of wood plants is significantly greater than of fuel oil plants.
      BERC ignored the embedded CO2
      BERC ignored the decommissioning CO2
      BERC ignored the “C neutrality period”, which occurs even with managed forests, as in British Columbia.
      BERC ignored the fuel oil boiler plant efficiency is about 85%, versus wood about 75%.
      BERC ignored the absorption of the combustion CO2 does not start until after the “C neutrality period”.

      BERC should have stated:

      The combustion CO2 emissions of both fuels are immediate.
      All CO2 emissions of fuel oil will absorbed, or stay in the atmosphere, just as any other CO2
      The combustion CO2 emission of wood chips is not counted, but it would start its absorption after its 40-year C neutrality period and complete its absorption within about 90 to 100 years.

  3. Wood, brush, old round bales…poison parsnip and other invasives from the highway medians….all stuff that ought to be getting burned to generate electricity.

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