Large-scale bioenergy from additional harvest of forest biomass is neither sustainable nor greenhouse gas neutral

I’ve been down and out with the crud this week, so some items I’ve been meaning to post have been stacking up.  Researchers from Europe and the United States have ‘collaborated’ on a new study titled, “Large-scale bioenergy from additional harvest of forest biomass is neither sustainable nor greenhouse gas neutral.”  Below is the abstract and a snipped portion from the study.

Abstract
Owing to the peculiarities of forest net primary production humans would appropriate ca. 60% of the global increment of woody biomass if forest biomass were to produce 20% of current global primary energy supply. We argue that such an increase in biomass harvest would result in younger forests, lower biomass pools, depleted soil nutrient stocks and a loss of other ecosystem functions. The proposed strategy is likely to miss its main objective, i.e. to reduce greenhouse gas (GHG) emissions, because it would result in a reduction of biomass pools that may take decades to centuries to be paid back by fossil fuel substitution, if paid back at all. Eventually, depleted soil fertility will make the production unsustainable and require fertilization, which in turn increases GHG emissions due to N2O emissions. Hence, large-scale production of bioenergy from forest biomass is neither sustainable nor GHG neutral.

Environmental consequences
Homogeneous young stands with a low biomass resulting from bioenergy harvest are less likely to serve as habitat for species that depend on structural complexity. It is possible that succession following disturbance can lead to young stands that have functional complexity analogous to that of old forests; however, this successional pathway would likely occur only under natural succession. A lower structural complexity, and removal of understory species, is expected to result in a loss of forest biodiversity and function. It would reverse the trend towards higher biomass of dead wood (i.e. the Northwest Forest Plan in the United States) to maintain the diversity of xylobiontic species.

Cumulative impacts of bioenergy-related management activities that modify vegetation, soil and hydro- logic conditions are likely to influence erosion rates and flooding and lead to increased annual runoff and fish habitat degradation of streams. Young uniform stands with low compared to high standing biomass have less aesthetic value for recreation and are less efficient in avalanche control and slope stabilization in mountains owing to larger and more frequent cutting. A potential advantage is that younger forests with shorter rotations offer opportunities for assisted migration, although there is great uncertainty in winners and losers (species, provenances, genotypes) in a future climate. Plantations, however, largely contribute to pathogen spread, such as rust disease.

Forests offer several important ecosystem services in addition to biomass and some would be jeopardized by the bioenergy-associated transition from high to low standing biomass. Agriculture provides a visible example for abandoning most ecosystem services except biomass production; communities in intensive agricultural regions often rely on (nearby) forested water sheds for drinking water, recreation and offsetting GHG emissions from intensive agriculture.

9 Comments

  1. So, this study comes to the earthshattering conclusion that clearcutting old growth for biomass is bad?!?! WOW!

    And it’s “NEW”!?!??

    PRESERVE…………. the controversy!!

  2. This is an example of what I call “sleight of science.” see my post on this a few years ago here.

    First, people imagine something that people don’t do, think about possible results and then make inferences related to what people actually do.

    If we used A LOT of biomass, from biomass plantations, then bad things would happen based on our assumptions.

    It’s all on the framing.

    Here in Colorado, it’s “we could burn dead trees in piles or use them to produce energy or wood products, which is best for our land and people?”
    Because a groups of scientists frames a problem a particular way, does not mean that the results are “science” that applies to others’ framings.

    • I agree with this criticism, and I hope you will bring it up every time someone cites a paper saying the fuel reduction as this of that benefit when such a conclusion depends on humans have the ability to predict the location and timing and severity of future fire events. Very common, equally ridiculous, and rarely acknowledged.

      This situation occurs in virtually every paper where the investigators apply a treatment to the forest and they run a fire simulation model to see the effects of fire on the modified fuel structure. Such a study assumes 100% chance of fire right after the treatment, but this is not the real world. We apply treatments then wait. Only a small fraction of treated stands will experience fire in the brief “effective period” after treatment. Therefore, in the evaluation of costs and benefits, before drawing conclusions about the “net benefits” of such treatments, investigators must account for the adverse effects on habitat, soil, and water quality from logging all those places that did not burn. This is almost never done.

      • TreeC123: You are exactly right, and illustrate what Sharon says about framing a question: Can humans predict the location and timing and severity of future fire events? Of course not and, as you say, the very idea is “ridiculous.”

        Here is how I would frame that question: Can humans affect the location and amount of fuel in areas likely to be affected by wildfire at some time in the future? Yep. Of course we can. It would be ridiculous to think we couldn’t.

        The next question should be: Can we maintain those conditions? Yes again. Your unstated assumption seems to be that all treatments only have an effective life of one year (some do) and that no maintenance of desired conditions will be made at future times.

        Most of the “adverse effects” you list cannot be quantified in any meaningful way, making them difficult to “account for” in the type of “cost and benefit” analysis you seem to favor. That’s the main reason it’s “almost never done” — it’s mostly impossible to do.

      • We need Tree to spell out the “adverse impacts”. Where does the thinning of trees averaging 14″ in diameter, leaving fully-stocked, closed-canopy old growth forests produce “adverse effects”? Habitats for goshawks and owls are enhanced. The minimal erosion is mitigated with waterbars, slash, straw and seeding. Impacts to water quality are minimal, as well, with projects operating on slopes mostly less than 30%. Temporary roads are obliterated, and existing roads are brought back to full proper functioning. Many areas are virtually-assured of being burned in the next 50 years, and we cannot allow them to burn at high intensities, knowing that inevitability. These fires WILL happen, and fire impacts can, and will be MUCH higher than careful thinning.

        “Best Management Practices” offer excellent protections from the impacts you want to blame. Yes, there ARE a lot of BMP”s to follow, and yes, they ARE (usually) followed….. (But, we’ll save that story for another day!)

    • There are working biomass plantations, as you call them, already in existence in Europe and the southeastern US. There are biomass “plantations” in VA, NC, SC, GA, and FL that produce pellets for European biomass burners. Additionally, there is quite a bit of development and discussion towards increasing their presence in the US for biomass burners here. Your attempt to say that these don’t already exist is a pipe dream. That being said, there are productive and environmentally sound ways of creating these “plantations” without dramatically affecting the CO2 levels in the atmosphere. Creating a “plantation” like they describe in CO would be a terrible idea due to several factors including a lack of adequate water for most trees to grow there and the rate at which trees grow (due in part to the water issue).

      • I am not so sure that there are “biomass plantations” in the southeastern US; I know there are plantations, but I think that they were established for traditional forest products. do you have any specific examples?

        P.s. saying something is a “pipe dream” is not very respectful . We try to be respectful and evidence-based in our agreements and disagreements on this blog.

        • A friend of mine once worked in the FIA program in the South and told me that private forestland owners were encouraged to grow for both biomass and sawlogs. The market for biomass didn’t materialize, and the land owners were told to thin their plots anyway, with the sawlogs making up the difference. The smear campaign against biomass says that 30 million acres of forest will be immediately clearcut, if biomass gets a subsidy. Anyone want to defend that claim?

          • My point was that people sell trees and replant their land with trees. They are likely to sell them for whatever use offers the best price at the time they need or want to sell the next bunch of trees.

            People have been talking about biomass plantations and crops for at least 30 years. Landowners are unlikely to run out and convert land (making substantial investments) until a market for biomass is proven.

            Then there is the whole question of increasing supply depressing prices over time. And then there’s the literature about the inheriting landowners and their characteristics and wishes for their land. You couldn’t predict large scale land “conversion” to “biomass plantations” unless you understood all those things plus the relative values of land for agriculture, forestry, and residential development.

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