Is Biomass Energy Sourcing as Ecologically Sound as We Want it to Be?

Written by Sophia Anner, ESLLC 2016-2017

(The image shows beetle-killed trees, red, and live trees, green, in the Rocky Mountain National Park.)

The topic of energy is in the forefront of every sustainably-minded person’s thoughts. I attended the Sustainability Council meeting last Tuesday, March 28th, and energy was one of the main topics of the morning. Notably, the Vice Chancellor of Facilities, James Rosner, detailed the potential future for renewable energy on campus. He talked about how solar isn’t as feasible due to the gross number of panels needed to make a significant increase in energy derived from renewables. He explained that technically wind power is feasible, but the wind farm would be in Texas, and he expressed concern for how students would understand the sustainable measures being taken if the project was so far away from campus. Finally, Rosner touched on biomass. He explained that there is a facility in Colorado that creates electricity with biomass, notably with trees that have been killed by beetles in the forest.

This struck me as curious. Usually, the view point is that leaving nature alone is often the best bet, as natural processes can generally work out the problems. I thought I should consider more details. First off, the premise of biomass is that burning the biomass (often wood, for example) releases the energy stored during the process of photosynthesis. The electricity generation follow the classic method of burning to make heat to boil water to make steam to go through a turbine, like Don discussed in class. Biomass energy generates about the same amount of electricity as fossil fuels, but the emissions are less potent. One of the reasons it hasn’t taken off is because deforestation is generally frowned upon, and it would take as much land as one third of the United States to farm plants (such as genetically modified fast growing trees or grass) that could be used to power all the U.S. This is where it fits in nicely to use already dead trees killed by the beetle epidemic in Colorado. The first plant to do this in Colorado is in Gypsum, and began providing electricity in 2013, with a goal of covering electrical needs for 10,000 homes.

What made me skeptical of this is from my Global Environmental Change class with Don. In it, we learned about natural wildfires. Low-intensity wildfires occur semi-regularly in many areas, including Colorado, as a way for the biomass on the forest floor to be decomposed, which helps keep the forest soil fertile. Many trees are adapted to survive these frequent, lowintensity fires, as they are part of the natural ecosystem. For example, some species exhibit self-pruning, which means they don’t have branches below a certain height. This allows small fires to sweep through without killing the tree itself. Some trees even need fire to survive – for example, lodgepole pines have serotinous cones, which means the cones will not open without the heat from fire. When humans began to establish towns near forests, a problem arose – humans do not like fire. We see the low-intensity burns as dangerous (as if it wasn’t the fault of us decided to live near them) and so, we like to stop these fires. The problem with this is that when the typical fire rolls through, it now has much more built up biomass to burn through, creating a high intensity burn that can often kill the trees in the forest. In terms of the beetle, since they have always been a part of the forest ecosystem, I suspected that removing these trees might have some link to higher intensity burns.

I found an article from the NASA website (albeit written in 2010) detailing the investigation into exactly this concern – does removing the trees prevent fires or make them worse? The article explains that common sense would tell you that having dead, brittle trees would provide better kindling for fires, and therefore having the trees taken out for biomass energy production is a win-win. In fact, by comparing beetle-killed tree locations with satellite fire maps, the researchers explain that live trees contain more volatile flammable oils. As trees die, these oils break down and so the dead trees are less flammable. They also pointed out that these dead tree zones might even slow down fire, as there is no kindling in the area to continue feeding a fire sweeping through, and so the fire can be minimized.

Clearly, there is still a lot left to be known about tree and beetle ecology, and how keeping the dead trees in might affect the ecosystem and aesthetic value of the forests, but it is safe to say that if the University seriously considers biomass, all aspects of the process must be analyzed in depth.


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