It is difficult to get a man to understand something when his job depends on not understanding it. - Upton Sinclair
I wrote this piece quite a while back ... July 15, 2011, but the big lie about biomass-to-energy plants being "carbon neutral" keeps coming back. So this story, written after a walk in the woods, has to come back too.
picture a BIG stump
This stump got me thinking about truths and lies. Big ones and little ones. And how we as individuals and we as citizens of the west have somehow allowed ourselves to get confused about precisely what constitutes truth, and where our personal responsibility to recognize and see and know the truth ends and our socialized response - the unquestioning acceptance of the oft-repeated lies we are told - begins. And I found myself baffled by the enormity of the problem - the inability of apparently intelligent people to see the difference between truth and fiction. Even when the fiction totally contradicts what they can see with their own eyes. And that got me back to the amazing quote about how hard it is to show a man a truth when his very livelihood depends on him not recognizing it.
There is a lie that vampire foresters tell. About culmination of mean annual increment of growth. And it has been extended now to the idea of carbon sequestration and carbon sinks and is being used to justify carbon neutrality of biomass burning. These trees show that this is a lie. The way to prove the lie is to do the arithmetic: it is very simple.
The story starts in chemistry world, and involves a little bit of bean counting.
Burning stuff is called oxidation for a reason. When you burn stuff, you bind stuff - typically carbon - to oxygen. CO2 ties up two Oxygens for every Carbon that is burned.
Photosynthesis is a nearly magical process that reduces CO2 (from the air) by reacting it with H2O (from the soil) on the surface of a catalyst (inside chloroplasts inside leaves and needles) to produce a sugar and release an Oxygen.
In CO2 the ratio is 1:2 - 1 Carbon to 2 Oxygens
Through photosynthesis, plants bind Carbon and Hydrogen and release Oxygen to produce glucose, which has the formula C6 H12 O6, and has a ratio of 1 Carbon to 1 Oxygen.
Plants further reduce glucose for storage as an energy reserve in the form of other carbohydrates such as starch, or Starch, consisting of two different polymers of glucose, is a readily degradable chemical energy stored by cells, convertible to other types of energy.
Cellulose is another polymer of glucose used by plants as structural component. The Carbon to Oxygen ratio in Cellulose is still approximately 1 Carbon to 1 Oxygen. Actually the formula for cellulose is C6 H10 O5 and the Carbon - Oxygen ratio is now 6:5. Most woods are 40% – 50% Cellulose.
Lignin is a more structural/more durable form of Glucose polymer found in trees, and it is more substantially reduced. Which is to say, a lot more oxygen was released in the process of its creation. Ligin has several forms C9 H10 O2, C10 H12 O3 and C11 H14 O4 with Carbon : Oxygen ratios between more than 4:1 and less than 3:1.
Lignin is 15% – 30% of the wood in a tree. Through the ever-increasing number of Carbon atoms that are tied to each Oxygen molecule, converting these polymers of glucose into Lignin releases Oxygen to the air-breathers and plays a significant role in the carbon cycle, sequestering atmospheric carbon into the living tissues of woody perennial vegetation.
But the REASON that you did that mental arithmetic is so that you really KNOW that inside a tree is a bunch of Carbon locked up in biopolymers based on Glucose and that these biopolymers account for between 60% and 80% of the mass of the tree, depending on species and growing conditions, and that of this mass (the part of it that is made from just these two biopolymers) - slightly more than half is probably actually Carbon.
And that is what you needed to actually figure out, to be able to understand it and carry it forward with real confidence, to use in the next chunk of arithmetic.
Now, picture a stand of pecker poles
Let's guess that these pecker poles are over 70 and under 100 years old and 100 feet tall. And typically 1 foot to 1.5 feet through. And that between breast height and 60 there is almost no taper and for the top 40 feet it tapers to nothing. If you look at a fresh cut - and I wish I had shot a picture of the fresh cut where one had dropped across the trail and a passage had been cut in it - you can see the thickness of the growth-rings and on this slope they vary from under 1/10" inch to over 3/16" thick depending on the quality if the growing season. It seems to have been pretty dry for the past decade or so and then before that quite wet. And then dry again. The trail was cut through a nearly 4' tree that was hundreds of years old. And here is where the lie emerges. If you calculate the volume of the growth each year and you can calculate area as length times (pi times diameter) and volume as area times thickness and convert volume to mass in your head) you quickly see that it puts on more weight this year than it did last year cuz it is BIGGER and though the slope of the curve flattens somewhat it does NOT go flat. At least not for hundreds of years. Not until the tree falls or is killed.
Now picture a stand of 70 year old pecker poles surrounding giant 200 year old stumps
So, actually calculating how many tons of carbon per year each of these trees is sequestering and how much biomass is being generated per year, in trees, and how much carbon is going to be released by each acre burned, and how many acres it will need to defoliate to have fuel to burn in each plant every year. And how many acres have to be growing to sequester the Carbon in the CO2 released in the burning of each of those trees and by each of those plants.
The number that has been floating around is that a 50 MW plant eats 5000 acres of green trees per year. So a 25 MW plant like ours will probably eat 2500 acres of green trees (or their equivalent in construction debris, which I assume means those thousands of abandoned houses from California's endless supply of foreclosed suburbs)?
But how many trees is that and how many other acres have to be GROWING to get us back to "carbon neutral" ?
Ironically, that calculation has to get started based on peer-reviewed "facts" on data collected by folks whose livelihood depends on averting their eyes from contradictions and failing to notice trends, but here are two "... the highest Douglas-fir growth rates recorded in North America at about 22 cubic metres/ha/yr ... Douglas-fir used to be grown on long rotation regimes of 50 or more years the focus is now on shorter rotations."
Wood is a heterogeneous, hygroscopic, cellular and anisotropic material. It is composed of cells, and the cell walls are composed of micro-fibrils of cellulose (40% – 50%) (C6H10O5)n and hemicellulose (15% – 25%) impregnated with lignin (15% – 30%) C9H10O2, C10H12O3 and C11H14O4. Lignin plays a significant role in the carbon cycle, sequestering atmospheric carbon into the living tissues of woody perennial vegetation.
From this we can calculate both Carbon Sequestration and rate of energy-equivalent accumulation in tissue.
Lignin is one of the most slowly decomposing components of dead vegetation, contributing a major fraction of the material that becomes humus as it decomposes. The resulting soil humus generally increases the photosynthetic productivity of plant communities growing on a site as the site transitions from disturbed mineral soil through the stages of ecological succession, by providing increased cation exchange capacity in the soil and expanding the capacity of moisture retention between flood and drought conditions.
I'm working on a composite image to show a section of a 120 year old tree against the local Palmer Drought Severity Intensity Index graph
Of course there is a very rich body of scientific literature that has already developed over long periods devoted to dendroecology and dendroclimatology, so there is no need to reinvent the wheel here:
So here is a fascinating paper on seasonal variations in water storage within the bole of a 120 year old Douglas Fir tree, a study only spanning 4 years ... but still of interest here.http://treephys.oxfordjour
I'm working on a composite image to show a section of a 120 year old tree against the local Palmer Drought Severity Intensity Index graph http://www.ncdc.noaa.gov/t
the fantasy of thinning and "doghair release" ...
"While thinning may reduce drought stress in some forests, it is not clear that thinning would effectively increase resilience in different forest types or regions, and specific recommendations for target densities or growing stock levels to reduce mortality during periods of warming are lacking.
The complicated interactions following harvesting and the potential differences between short- and long-term responses to treatments make it difficult to understand the utility of thinning in reducing mortality. Results from controlled, replicated studies with multi-decadal datasets are needed to assess the effects of various thinning treatments on mortality." https://profile.usgs.gov/m