Questions about Biomass Energy and Forest Management Assumptions

I recently attended a talk on biomass energy at the Bend City Club.

The Bend City Club presentation on biomass was another example of a juggernaut premised on unexamined assumptions without question. At every step of the way there are assumptions that are given and accepted. However, if any of these assumptions is incorrect than the entire argument in favor of biomass falls apart.


There are two broad areas where the biomass promotion and forest management intersect.


The first assumption is that we have an excess of biomass (i.e. wood) in our forests that is free for the taking because of forest management.


The forest management paradigm assumes that our forests are out of “whack” and “unhealthy” because of human fire suppression and other activities.


Which leads to the next assumption. Due to this past mismanagement, we now have large wildfires, beetle outbreaks and so forth that can only be “cured” with logging.


And though this logging/thinning loses taxpayer money, the presumed “benefits” make it worthwhile.


The second set of assumptions follows from the first group.


That if you have this so-called “excess” wood one might as well use it for energy production.


And even though biomass is less energy dense (i.e. it takes more of it to create the same work), than other sources of fuel like natural gas, at least biomass “grows” back so is “renewable.”


Biomass releases a significant amount of CO2, especially compared to other fuels even with the best high efficiency burners, thus, the CO2 released will eventually be recaptured by new vegetation growth therefore is “carbon neutral.”


These assumptions are challenged by outside experts.




This is where a critical thinker must follow the money. Most of the advocates of these perspectives have a financial vested interest in promoting these assumptions.


For instance, one of the presenters owns a company that sets up these operations. He’s hardly an objective source of information.


Similarly, most of those advocating logging the forest based on “restoration” or precluding “wildfire” are people whose jobs, funding, and careers are founded on promoting the idea that forests are “unhealthy” and in need of “active” management. Keep in mind that if you are an agency forester, forestry professor, extension service agent, or a timber company forester or mill owner/worker, your job depends on logging the forest which influences the kinds of scientific questions you ask, the interpretation of data, and the conclusions you emphasize.


So, follow the money. Many of the critics of thinning forests are found in other academic disciplines other than forestry like geography, geology, botany, biology, and so forth, though there are certainly some in the forestry schools and working as researchers with the Forest Service. However, most of these folks must use caution and qualifiers that soften their critiques.




Beyond that cautionary remark, there are problems with all the above assumptions. First the forest assumptions.


There is not “excess” wood in forest ecosystems.  Forest management “robs” the forest of both nutrients, physical structure like down wood, and interrupts with natural ecological processes like bark beetles, wildfire and drought that shape forest ecosystems. Dead wood is critical to healthy functioning ecosystems. Many ecologists are concluding, that dead trees and dead wood may be more ecologically important than green trees, in part, because these snag forest habitats are spatially and temporally limited. Numerous plants and animals depend on dead trees and dead wood for their survival.


Second, with the possible exception of some lower ponderosa pine stands, most forest types are not “out of whack” due to fire suppression and so on. They naturally have long fire rotations, often up to hundreds of years between wildfires. However, when they do burn, they often burn at high-severity. Again, this is normal. And many forest species depend on the occasional episodic input of dead trees that results from these fires. Interfering with these fires, and reducing their occurrence or severity will impoverish forest ecosystems. Natural processes like wildfire, bark beetles, mistletoe and other forest processes are ecologically better at modifying forest stands than logging.


Third, large wildfires occur under extreme fire weather/climate conditions of extended drought, high temperatures, low humidity, and high winds. Reduce or eliminate any of those factors, and large high severity fires slow or self-extinguish. Climate/weather, not fuels, drives large wildfires.


Fourth, much new research an inconvenient truth is that logging/thinning does not preclude large wildfires. Any number of reviews show that thinning cannot stop or reduce wildfires burning under “extreme” weather conditions. Since all large wildfires are burning under extreme conditions, the very fires we seek to reduce cannot be affected in any significant way by logging/thinning.


Fifth, even if thinning did work, the probability that any wildfire, must less the fires burning under extreme fire weather, will encounter such thinning in a time when it is potentially effective is exceedingly small.


Sixth, research suggests that logging/thinning activities increases large wildfires and fire severity.


Seventh, logging/thinning negatively impacts forests through the spread of weeds, soil compaction, removal of nutrients, disturbance of wildlife, and most importantly removal of carbon.


Eighth, comparisons between logged/thinned forests and unmanaged forests, ALWAYS have more carbon. Even forests that burn at high-severity have greater amounts of carbon on site than logged/thinned forests. (Of course, you don’t hear this from anyone whose job or organization depends on logging–i.e. like the Forest Service–so follow the money.


Ninth, keeping carbon in the forest, even as dead wood, may be the “highest” and “best” use of public forests. In other words, the value of carbon storage to society is “worth” far more than any wood products or jobs created by logging the forest


Tenth, research has shown that the best way to protect houses and communities is to reduce the flammability in the IMMEDIATE area of the structure. This is a considerably different approach than trying to fire-proof the forest.




With regards to biomass we need to be very cautious about endorsing this energy source. While using wood chips, etc. at sawmills to generate electricity or heat for that operation might make economic and ecological sense, using biomass for non-mill operations has many issues that should be examined, particularly by outside experts. I.e. people who do not have a dog in the fight. So, listening to a company representative about the wonders of biomass energy as occurred in the Bend City Club meeting would not meet that requirement.


First, biomass burning, even with high efficiency operations, release far more CO2 than other conventional fuels like natural gas. Per unit of energy you must burn more wood than say natural gas to get the same amount of “work” i.e. heating of water or whatever.


Second, while the released CO2 is ultimately recaptured and stored by regrowing forests. It takes decades to centuries, especially in slow growing forests east of the Cascades (slow compared to tropical and southeastern US forests) to recover this CO2 by renewed forest growth, and we need to reduce CO2 now, not in a hundred years.


Third, most economic reviews suggest that biomass is only economical with state and federal subsidies including certain tax breaks and exemptions from pollution regulations. If for any reason those tax breaks and subsidies were to end, and/or forest management sources of biomass were to end or be restricted by new science or regulations, then most biomass operations will be in jeopardy. If the past is any hint of the future, there will be tremendous pressure on politicians to find additional funds to keep these failing biomass furnaces operating.


Fourth, a comparison about the desirability of biomass with other carbon fuels is the wrong comparison. Many, many studies show that the best energy source is conservation. In other words, reducing energy use and demand is the cheapest, and most efficient means of coping with CO2 output. Insulating buildings, putting in energy efficient windows, citing buildings to take advantage of solar input, solar hot water, solar electricity, geothermal, and wind all offer other alternative means of energy and/or reducing energy needs. And due to rapid technological advances, these alternative methods of saving energy or getting energy are becoming more efficient and less expensive.


Fifth, if we are going to subsidize biomass energy with tax dollars and tax breaks, the best way to proceed is to use that money to promote non-carbon measures.



  1. rork Avatar

    I particularly liked praising dead wood, and the part about houses and fire-proofing forests. Thanks.
    I can note the shrooms benefit too. I have started a project near me that might work where you live – pour over areal photographs of your area taken around 1940. Where you see trees, visit. Near me it’s mostly very grim – agriculture was attempted everywhere, even ridiculous locations, with giant erosion gullies. Even just grazing steeper slopes means the soil vanished, cause droughts happen, and then end. Most of my rec area consists of those settler’s land. It didn’t look fragile to them when they removed their enemies, the giant trees (and wetlands).

George Wuerthner is an ecologist and writer who has published 38 books on various topics related to environmental and natural history. He has visited over 400 designated wilderness areas and over 200 national park units.

Subscribe to get new posts right in your Inbox