CO2 EMISSIONS FROM LOGGING, CLEARCUTTING AND BURNING

A nearby farm in Hartford, Vermont has 200 acres of open fields, plus 700 acres of woodland. During a recent logging operation, the trunks of the high quality healthy trees were set aside and cut to 8.5, 10.5 and 12.5 ft lengths, for transport to lumber mills, and the less valuable material, such as tops of trees and branches, misshapen trees, standing dead trees, sickly trees, etc., were gathered and piled up for chipping.

 

The less valuable material is fed into very large chippers. It is a noisy sight to behold. A large crane grabs an 18-inch diameter tree, feeds it horizontally into the big hopper, and within about a minute the entire tree has become wood chips that are blown into a 40-ft trailer!

 

The tree roots, a.k.a., belowground biomass, are no longer needed. They die, decay and disappear. The very fine, hair-like roots disappear first. The stumps are the last the go.

 

The aboveground part of a stump decays within about 25 years.

The belowground part of a stump and larger branches decay within about 80 - 100 years.

The decay CO2 is high in the beginning and slowly decreasing at time passes.

 

Clearcutting Holocaust of the 1800s

The NE clearcutting holocaust of the 1800s and early 1900s occurred for two reasons:

 

1) Clearing for farming and pasture (haying for cows and horses and for sheep that produced wool)

2) Production of charcoal for iron working.

 

On hilly land, the clearcutting caused erosion of topsoil and nutrients into nearby streams.

The clearcutting released vast quantities of CO2 due to decay of 1) belowground biomass, 2) dead wood, 3) litter, and 4) soil organic carbon.

New England was mostly reforested by the 1950s; some farmlands became forests again; some forest area was permanently eliminated by human encroachments.

However, the clearcutting had damaged forest soils, which reduced the storage of biomass/acre.

Undisturbed, old forests, on healthy soils, store much more biomass per acre, than young forests on damaged soils.

Acid rain from the 1950s onward has been harmful for forest soil, regrowth and health as well.

Forest Fracturing

A continuous forest is much healthier and has a greater abundance and diversity of flora and fauna than a fractured forest.

Forest fracturing is due to human encroachments, such as roads, paths, transmission lines, wind turbines on ridgelines, partial land clearing for development. See URLs

 

https://harvardforest.fas.harvard.edu/sites/harvardforest.fas.harva...

http://www.windtaskforce.org/profiles/blogs/co2-emissions-from-logg...

http://www.windtaskforce.org/profiles/blogs/the-case-against-intens...

Increased Severity of Logging Harms the Forest and its Flora and Fauna

 

This article and the below image explains cutting and removal of a few trees per acre, say less than 10%, is relatively harmless to the forest and its flora and fauna, because the many remaining trees help the few trees stumps and their roots to continue to be a part of the belowground tree root layer, up to about two foot thick, that serves all of the forest, i.e., the belowground “social fabric” of the forest remains healthy.

 

However, increasingly heavier cutting and removal, increasingly worsens root layer decay. Such cutting and removal lead to: 1) the break-up the root layer, and 2) increased decay, and 3) increased carbon loss, and 4) increased CO2 emissions, i.e., the belowground “social fabric” of the forest becomes increasingly dysfunctional for a long time.

 

Taking wood from the forest, after the damage of cutting, would also deprive it of much-needed nutrients; somewhat like bloodletting to “cure” a patient in the old days. The forest would be: 1) weaker, and 2) more easily succumb to diseases, and 3) have less CO2 absorption ability, and 4) store less carbon. Also, air pollution and acid rain, active since the 50s, continue to debilitate NE forests, another reason for humans to tread lightly on a fragile resource.

 

Manipulating the complex life of a forest and its flora and fauna, so all would become more productive for creating jobs, for providing energy, likely would have unforeseen consequences, as was amply demonstrated during the 1800s and early 1900s, when old growth forests were clearcut, and were eventually replaced with regrown forests of uniform-aged trees, that support a much less diverse flora and fauna.

 

Foresters often recommend periodically cutting a few trees to create openings in the canopy to enable new trees, planted or natural, to get started. The end result would be a forest stand of different ages, with a more diverse flora and fauna. Such a process takes decades.

 

Old, unharvested forests have trees of all ages that are growing, dying, toppling, and decaying in place. Their natural appearance looks “messy”, but they store more carbon, are healthier, and support a greater diversity of flora and fauna; a win-win for Nature. 

https://www.economist.com/science-and-technology/2019/07/25/tree-st...

NOTE: All logging debilitates forests, but clearcutting debilitates forests the most. Clearcutting (100% in the image) results in an about 27% carbon loss of live biomass (belowground biomass and soil organic carbon), much greater than other logging practices, such as: 1) a diameter-limit cut, 2) a selective cut, or 3) un-harvested forests. See URL.

https://www.nature.com/articles/srep03547

NOTE: The Vermont Legislature passed in 1997, H.536 (Act 15) known as Vermont’s “Heavy Cut” law to regulate heavy cutting/clear-cutting of forest lands. The Vermont Department of Forests, Parks and Recreation requires ‘Intent to Cut Notification’ if a landowner plans to heavily cut 40 or more acres in one “treatment”. See page 6 of URL.

https://fpr.vermont.gov/sites/fpr/files/About_the_Department/Rules_...

 

NOTE: The 40-acre clearcut “treatment” limit is an “accommodation” of the logging industry. Loggers have invested in expensive equipment and clearcutting is the cost-effective way to use that equipment. IMHO, those “treatments” should be a maximum of 2 acres, because clearcutting essentially is a rape of the forest. State and industry dependent foresters are afraid to speak up, lest they lose their jobs, etc. Loggers love clearcutting, because it can yield about 150 ton of wood chips/acre (dead and live biomass); one quick in and out.

 

NOTE: A recent clearcut in New Canaan, NH. See photo. Dartmouth College would need about 55000 to 60000 ton of wood chips per year, as harvested, for its proposed hot water heating plant. The chips would come from an area within 50 miles of Dartmouth College. The Dartmouth College “woodshed” has at least 1.5 million ton of low-grade wood available for burning.

https://mail.google.com/mail/u/0/?shva=1#inbox/KtbxLwGrRmrcqJXsZGnP...

 

NOTE: Whereas light and medium cuts would not be as damaging to the belowground biomass of an area, many more areas would have to be logged to obtain the desired harvest. Total damage on forest floors may, in fact, be greater than clearcutting, which concentrates the damage in one area.

 

NOTE: In New England, the damage to the forest floor and the decay of the belowground biomass would release more CO2 than is absorbed by new tree growth for about 15 years, and then it would take about 20 years of new tree growth to offset the CO2 released during the first 15 years. Any combustion CO2 of year 1 would have to wait for about 35 years to start its absorption period, which lasts about 90 to 100 years. See next sections.

Five Examples of the C Neutrality Period

 

Five examples of clearcutting and carbon release from belowground biomass are described

 

Example 1 is for the effects of harvesting on two Upper Great Lakes forest ecosystems

Example 2 is for the effects of clearcutting on the Canadian boreal forests

Example 3 is for the effects of clearcutting on a planted, fertilized, managed forest in British Columbia.

Example 4 is for the effects of clearcutting of a naturally regrowing forest in the Hubbard Experimental Forest in New Hampshire.

Example 5 is for the effects of clearcutting of forests in Oregon.

 

Example 1; Simulated long‐term effects of harvest and biomass residue removal on soil carbon and nitrogen content and productivity for two Upper Great Lakes forest ecosystems, by Scott D. Peckham and Stith T. Gower

https://doi.org/10.1111/j.1757-1707.2010.01067.x

The image from the article shows net ecosystem productivity, NEP, versus years after harvest.

NEP (Mt/ha/y) = CO2 absorbed by growing biomass - CO2 released by decaying biomass. If decay is high, the NEP may become negative.

The image shows a light harvest as dotted lines. The net ecosystem productivity, NEP, rapidly decreases, but does not become negative. It would take the harvested area some years to get back to the carbon neutral condition to offset the downturn of NEP, and then resume its absorption of CO2 at about the same level as before. And then gradually decrease to the steady state levels of a mature forest.

 

The image shows a heavy harvest as solid lines. The heavier the harvest, the deeper the downturn of NEP, and the longer it takes for the harvested area to get back to the carbon neutral condition, and then resume its absorption of CO2 at about the same level as before.

 

The belowground fauna and flora, which feeds on dead biomass, suddenly finds itself surrounded by an abundance of dead biomass, due to the harvest. Their populations take some time to rapidly increase to “process” it, which produces decay products, such as CO2 released to the atmosphere. About 60% of the biomass of a tree is belowground. See table 3.

 

With a light harvest, the harvested area sequesters less CO2 than before, for a few years.

With a heavy harvest, the NEP of the harvested area becomes negative, i.e., it is a source of CO2.

With a clearcut harvest, the NEP of the harvested area stays negative for about 15 years and then it takes about 20 to 23 years of positive NEP to offset the 15 negative years.

 

Any combustion CO2 of year 1 would have to wait around in the atmosphere until about year 40 to start its absorption period, which takes about 90 to 100 years. After it is fully reabsorbed by new tree growth on our harvested area, it has fulfilled the assertion: “Burning wood is renewable”.

 

 

 Example 2; Accounting for CO2 emissions from clearcut logging in the Canadian boreal forest.  See URLs.

 

https://www.nrdc.org/sites/default/files/accounting-emissions-clear...

https://www.nrdc.org/sites/default/files/pandoras-box-clearcutting-...

Example 3, Clearcutting a Douglas-Fir Plantation in British Columbia: Here is an example of the variation of net ecosystem productivity, NEP, of a planted, fertilized, managed Douglas-fir forest, before and after clearcutting, in British Columbia. This example was chosen because similarly complete NE data was not available.

 

NEP = Carbon absorbed by new biomass growth - Carbon released from soil, forest floor slash, and roots.

C release (clearcutting kills the belowground biomass) would be ongoing for about 80 to 100 years; at high rates (MT/ha/y) in early years, and at gradually decreasing rates in later years. See Appendix 5.

https://pics.uvic.ca/sites/default/files/uploads/publications/WP_Fo...

 

Before clearcutting, the NEP was about 4.0 Mt/ha/y

After clearcutting, the NEP became about -6.5 Mt/ha/y, all of it from C released from soil, forest floor slash and roots.

Note the big change of NEP from +4.0 to -6.5; clearcutting is a huge shock to a forested area.

NEP became 0 after about 17 years, about 3.5 Mt/ha/y at age 40, and about 4.0 Mt/ha/y at age 55 to 60.

The forest became productive again (positive NEP), after C absorption of new tree growth became larger than the ongoing C release.

 

It took another 23 years of positive NEP to offset the 17 years of negative NEP. See Appendix 5.

Thus, “C neutrality” was achieved about 40 years after clearcutting.

Any combustion CO2 released in year 1 would start its absorption in year 41, and would complete its absorption over a 90 to 100 year period.

The planted/fertilized/managed forest was allowed to grow for another 15 to 20 years before it was clearcut again at age 55 - 60.

 

NOTE: See Appendix 5 for detailed description and spreadsheet.

Example 4, Clearcutting in Watershed 5 at the Hubbard Brook Experimental Forest, NH in 1983: Previous work on forest carbon stocks took place over short time spans, but Sanderman and his colleagues spent 16 years tracking a single forest in New Hampshire. The research team sampled soils prior to the whole-tree harvest of Watershed 5 at the Hubbard Brook Experimental Forest in 1983, a watershed in New Hampshire, and then sampled again in years 3, 8, and 15 following the harvest.

 

The researchers found that it took 15 years of biomass accumulation to simply offset the carbon losses incurred in the mineral soil, leading to a near-zero net carbon gain over the study period, after including the decay of forest floor slash and roots. “Clearcut harvesting can have sustained negative impacts on soil resources,” Sanderman said. See URLs

 

https://experts.syr.edu/en/publications/losses-of-mineral-soil-carb...

http://whrc.org/study-soil-carbon-fails-to-recover-in-cleared-forests/

 

In other words, the soil loses significant carbon while treeless, and even when the tree canopy returns, the soil’s carbon storage remains well below its original carbon level even after 15 years.

 

“While this is only one location, this study used massive soil sampling campaigns over time to do an excellent job tracking soil carbon pools, so we are very confident in the findings. Most studies of soil carbon changes following forestry use what’s known as a chronosequence – studying several distinct sites of varying ages and assuming they’re representative over time,” Sanderman said.

 

It’s unclear exactly what happens to the carbon in the soil. The two most probable fates are decomposition and release to the atmosphere as CO₂ or runoff into waterways, but the researchers say future studies are needed.

 

The study has implications for forest policy, especially in light of increasing demand for wood burning for heating and electricity production. If forest harvesting is expanded, it will take substantially longer than previously assumed to offset CO2 emissions related to harvesting and subsequent wood burning with carbon uptake during forest regrowth”.

Example 5, Clearcutting Forests in Oregon: Timber harvesting is by far the largest source of greenhouse gas emissions in Oregon. Since 2000, annual emissions associated with removal of stored carbon, sacrificed sequestration, and decay of logging residuals averaged 33 million mt CO2eq.

https://www.angelusblock.com/assets/docs/Oregon-Forest-Carbon-Polic...

 

Yet in Oregon, across the US, and globally, timber harvest emissions are not reported or proposed for regulation, because of a “carbon flux” accounting system developed by the timber industry that, in essence, grants an automatic offset for carbon sequestered by tree plantations managed in accordance with baseline legal requirements. No other sector is able to escape emissions reporting in this way.

 

The lack of regulation has also resulted in a rapid increase in carbon sequestration “dead zones” – recently clearcut lands that emit more carbon than they absorb. Statewide, there has been a net loss of 1.7 million acres of forest cover since 2000 and much of this is due to a rapid rate of clearcutting. See URL, figure 1, for satellite photos of clearcut areas.

 

Research has demonstrated that in western Oregon, where even-aged (clearcut) techniques prevail, sequestration capacity is eliminated for 13 years after harvest. In particular, net ecosystem productivity (NEP) – sequestration by young seedlings and brush minus emissions from decay and combustion of logging residuals – is negative for 13 years after clearcutting, meaning that these lands are not only carbon sequestration dead zones but have net CO2 emissions.

NOTE: The above 5 examples do not include the biomass that would have grown, and CO2 that would have been absorbed, about 1.0 Mt of CO2/a/y, if there had been no logging.

 

Table 1B/Location	Negative NEP period	Positive NEP period	C Neutrality period
Period	y	y	y
British Columbia	17	23	40
Hubbard, New England	At least 15	At least 20	At least 35
Oregon	At least 13	At least 18	At least 31

Burning the Clearcut Harvest for Heating and Generating Electricity in Vermont

 

People often say: Burning wood is renewable and the CO2 should not be counted, because it is absorbed by new tree growth.

All that is true, but when would the CO2 be absorbed by new tree growth?

 

Burning wood adds carbon dioxide to the atmosphere.

That carbon dioxide is removed from the atmosphere, only if the forests regrow and keep that carbon sequestered in biomass and soils.

Regrowth takes time.

Regrowth is not certain. Fire, insect damage, additional harvesting of the same area, or forest conversion to other uses (e.g., agriculture, development, recreation, such as skiing) will limit or prevent biomass regrowth and thus reduce carbon absorption. See MIT article in this URL

https://mitsloan.mit.edu/shared/ods/documents/?DocumentID=4581

 

Burning the Clearcut Harvest in Year 1: If our clearcut harvest had been burned in year 1, the combustion CO2 would start its absorption in year 1 + 35 = 36, after its 35-y “C neutrality” period. See note.

 

C release due to biomass decay would still be ongoing for about 55 years after year 35. 

Our combustion CO2 would just hang around in the atmosphere until the time of its absorption. 

All the other sinks already are busy absorbing other CO2. 

No spare sink is available for our CO2. 

Our combustion CO2 cannot push other CO2 aside by claiming a holier than thou pedigree.

Our combustion CO2 needs to be absorbed by our new tree growth, so our wood burning can be claimed to be “renewable”.

 

Year 2: The combustion CO2 of year 2 would have its own clearcut area, with new tree growth, and NEP, etc., and would start its absorption in year 2 + 35 = 37, its “C neutrality year”. 

 

Year 40: The useful service life of a woodchip plant usually is (very optimistically) about 40 years. The CO2 of year 40 would start its absorption in year 40 + 35 = 75, its “C neutrality year”. 

 

Time Period to Absorb Our Combustion CO2 in Vermont: 

Carbon is about 50% of wood, by weight. 

Standing forest is about 50% water, by weight

Vermont aboveground carbon was 72.53 Mt/ha, in 2015, per USFS.

Wood chips for burning would be {73.53/(0.5 x 0.5)} x 0.85 = 250 Mt/ha (or 101.17 Mt/a), if 85% of all aboveground biomass were removed. 

The rest (slash, underbrush, dead wood, etc.) would be left to decay on the forest floor.

Combustion CO2 is about 1.0 Mt/Mt of as-harvested (wet) wood chips.

Combustion CO2 would be about 250 Mt/ha

Vermont absorption period of combustion CO2 would be about (250 Mt/ha) / (2.421 Mt of CO2/ha/y) = 103 years. See table 1 

Remember, the absorption of our combustion CO2 would start after the “C neutrality period”.

 

NOTE: If Vermont had planted/fertilized/managed forests the 2.421 would be greater, say 3.0, and the absorption period would be shorter, but the below category “Additional CO2 emissions” would be higher. 

There would appear to be a free lunch, if "Additional CO2 Emissions" were ignored, as is often the case. 

See next paragraph.

 

Additional CO2 Emissions: 

CO2 emissions occurred due to tree stand maintenance, fertilizing, harvesting, cutting, chipping, pelletizing and transport, about 10%, if burning wood chips, about 15%, if burning wood pellets

CO2 emissions also occurred due to setting up and maintaining in good working order the A to Z logging sector infrastructure. 

CO2 emissions also occur due to operating the heating or power plant and, if applicable, its hot water/steam distribution system

 

That CO2, not related to forest regrowth and combustion, should be counted, just as any other CO2. 

Very often that CO2 is simply ignored.

Vermont Forest Carbon

Vermont’s net CO2 emissions were 10.0 - 4.39 = 5.61 million Mt in 2015, or 8.992 Mt/person, near the lowest in the US.

https://fpr.vermont.gov/sites/fpr/files/Forest_and_Forestry/The_For...

https://www.fs.fed.us/nrs/pubs/ru/ru_fs119.pdf

 

Table1/Vermont, 2015	Units
Vermont forest land	acres		4,488,000
CO2 absorption	million Mt	Calculated by VT-FPR	4.38
CO2 absorption rate	Mt/a/y	4.38/4.488	0.976
CO2 absorption rate	Mt/ha/y	0.976 x 2.471	2.421
C absorption rate	Mt/a/y	0.976 x 12/44	0.266
C absorption rate*	Mt/ha/y	0.266 x 2.471	0.658

* Vermont mixed forest. The rate would be about 1.90 Mt C/ha/y in the US southeast. See table 6.

 

Table 2/Vermont Forest carbon	1990	2015		1990	2015	1990 - 2015
Forest area, 1000 hectare	1841	1826
Forest area, 1000 acre; see URL	4550	4511
	C store	C store	C store Incr.	C/a	C/a	C incr./a
	MMt	MMt	%	Mt	Mt	%	%/y
Live aboveground biomass	110.1	131.8	19.71	24.20	29.22	20.74	0.757
Live belowground biomass	22.1	26.4	19.46	4.86	5.85	20.49
Dead wood	11.7	14.8	26.50	2.57	3.28	27.59	0.979
Litter	29.2	29.5	1.03	6.42	6.54	1.90
Live soil organic carbon	275.7	277.9	0.80	60.59	61.60	1.67

Table 3 shows about 60% of carbon is belowground and about 25% of carbon is aboveground. See URL. 

Table 3/Vermont Forest Carbon	1990	2015
	C/a	C/a
	%	%
Aboveground	24.5	27.4
Belowground	4.9	5.5
Dead wood	2.6	3.1
Litter	6.5	6.1
Soil organic carbon	61.4	57.8
Total	100.0	100.0

“Sustainable” Logging is a Fallacy

 

Vermont forest biomass/acre grew about 20.74% from 1990 - 2015, a compound growth rate of 0.757%/y. See table 2. The US Forest Service recommends harvesting at 50% of growth, i.e., only 0.488 US ton, wet/acre is allowed for removal. A cord of wood weighs about 2 to 2.5 US ton, i.e., only one or two trees/acre would be allowed for removal. See table 3A.

 

If that practice were followed no logger could stay in business. Loggers prefer to take at 30% - 50% of the aboveground biomass, live and dead; a medium cut. If they have a customer for wood chips, they will chip it all. Or, the more valuable trees are sent to lumber mills, with the less valuable trees chipped on site.

 

Table 3A/Growth to Harvest Ratio		2015	2015
Forestland	Acre	4511000	4511000
Aboveground biomass		Live	Dead
Carbon	MMt	131.800	14.8
Dry wood	MMt	270.637	30.390
Wet wood	MMt	541.273	60.780
.
Wet wood	Mt/a, 2015	119.990	13.474
Compound growth rate	%/y	0.757	0.979
Wet wood	Mt/a, 2016	120.898	13.606
Gross aboveground biomass growth	Mt/a	0.908	0.132
Gross aboveground biomass growth	US ton/a	1.001	0.145
Net aboveground biomass growth	US ton/a	0.856
.
Harvest area, on 20 - 40 y rotation	Acre	2500000
VT Harvest, 2015	US ton	2428665
Harvest/acre	US ton	0.971
Net growth/Harvest ratio, 0.856/0.971		0.881
.
2204.62	lb
2.5	US ton
0.4870
0.5000

Burning Wood to Generate Electricity is Very Inefficient

 

Generating electricity with various fuels releases CO2. A standard wood chip power plant in New England emits about four times the CO2 of an equivalent natural gas plant. The wood chip power plant wastes at least 3 out of 4 trees. The lb CO2/million Btu values are the EPA values for combustion only. See table.

 

Table 4/Fuel/Plant type	lb/million Btu	Plant eff., %	lb CO2/MWh	CO2 Ratio
Wood chip; McNeal/Ryegate; standard plant*	213	25	2907	4.0
Wood chip; Denmark, very modern plant	213	30	2423	3.3
Bituminous coal; super-critical plant	206	41	1712	2.4
No. 2 fuel oil; standard plant	161	35	1572	2.2
Natural gas, gas turbine; CCGT plant*	117	55	726	1.0

*Combined-cycle, gas turbine

Additional CO2 Emissions: 

CO2 emissions occurred due to tree stand maintenance, fertilizing, harvesting, cutting, chipping, pelletizing and transport, about 10%, if burning wood chips, about 15%, if burning wood pellets

CO2 emissions also occurred due to setting up and maintaining in good working order the A to Z logging sector infrastructure. 

CO2 emissions also occur due to operating the heating or power plant and, if applicable, its hot water/steam distribution system

 

That CO2, not related to forest regrowth and combustion, should be counted, just as any other CO2. 

Very often that CO2 is simply ignored.

Sequestering Combustion CO2 From Wood Chip Burning Plants Takes Decades

 

Here is some information for those who have been led to believe, or persuaded themselves to believe, wood burning is environmentally friendly.

 

Forests have aboveground and belowground new growth, which absorbs CO2 from the air and carbon, C, from the soil. Removing live trees (low-grade and high-grade) reduces CO2 absorption.

In Vermont, about 50% of tree removal is used for higher-grade purposes (the C stays sequestered, until some of it is burned or landfilled); and about 45% is used mostly for burning (the C becomes CO2 and is released to the atmosphere), and about 5% is used for pulp/paper mills (the C stays sequestered, unless some of it is burned or landfilled).

 

Wood burning power plants (McNeil and Ryegate in Vermont) emit about 4 times the combustion CO2/kWh of high-efficiency gas turbine power plants. See table 4.

 

NOTE: The combustion CO2 of wood burning would be reabsorbed by new tree growth, if:

 

1) Logged forests would have the same acreage (they likely would not)

2) Forests would not further fragmented by roads or developed (they likely would be)

3) Forest CO2 sequestering capability, Mt/a/y, remains the same (it could be less). See note

 

NOTE: Regarding the time period for sequestering the combustion CO2:

 

- 40 years is a US average, as promulgated by EPA. See Note.

- 80 to 100 years in northern climates with short growing seasons, such as northern Vermont and Maine. 

- 40 to 50 years in moderate climates with longer growing seasons, such as New Jersey and North Carolina

- 25 years between harvests of planted/fertilized/managed forests of fast-growing pines in Georgia. 

https://www.pfpi.net/wp-content/uploads/2011/04/PFPI-biomass-carbon...

 

NOTE: On an A to Z basis, there would be about 10% of additional CO2 that has nothing to do with combustion, in case of wood chips, or about 15%, in case of wood pellets. This includes non-wood-burning CO2, such as from:

 

- Fuel used for managing wood lots, fertilizing, logging, chipping/pelletizing and transport,

- Energy to run the heating or power plant,

- Energy for decommissioning and reuse/landfill of the plant,

- Embodied energy in the A to Z infrastructures of the logging industry.

Piling up the Combustion CO2 Year After Year

 

Re-growing trees would sequester the combustion CO2 of Year 1 of plant operation over about 90 to 100 years, in New England, after the C neutrality period.

 

The CO2 of year 2 would be added to the CO2 of year 1, and be sequestered in a similar manner, except shifted forward by a year.

 

In year 40, there would be 40 layers of CO2 and 40 forest areas in various stages of regrowth, as a result of cutting trees for burning.

 

Year 40 is assumed to be the last year of plant operation. It is likely that plant would be replaced to repeat the cycle.

 

During year 40 through 80, there would be 40 to 80 layers of CO2 and 40 to 80 forest areas in various stages of regrowth, as a result of cutting trees for burning. It should be clear this would do next to nothing to alleviate global warming.

APPENDIX 1

Florida forest of planted fast growing southern pine (managed, fertilized; 20 to 25 years between harvests)

 

Stored carbon increases from 0 in year 1, to about 135 Mt/ha in year 25, similar to an S-curve.

 

Rate of storing carbon increases from 0 in year 1, rapidly increases to about 12.5 Mt/ha/y in year 7, and then gradually decreases to less than 1.5 Mt/ha/y in year 25. See URL and image.

 

Average rate of storing carbon is about (135 Mt/ha)/25y = 5.4 Mt/ha/y. See note.

http://sfrc.ufl.edu/extension/ee/climate/wp-content/uploads/Activit...

 

NOTE: The average can be up to 9 Mt/ha/y in tropical planted pine forests.

NOTE: C release due to clearcutting and the C neutrality period were ignored by the author of the image.

 

APPENDIX 2

Average Carbon Storage Rates in US Southeast

 

Planted fast-growing southern pine forests store carbon at 3.80 Mt/ha/y, on average (Binford et al., 2006). The rate is higher than in most other forested landscapes because southern pine trees grow quickly in the long, warm growing season.

 

Mixed forests in the Southeast store carbon at 1.90 Mt/ha/y, on average (Turner et al., 1995). The rate is lower due to the slower growing trees found in mixed forests and less-intensive management

 

Urban forests in the Southeast store carbon at 0.80 Mt/ha/y, on average (Norwak & Crane, 2002). The rate is lower than
for other forest types because of lower tree density.

 

Croplands in the Southeast store carbon at 0.10 Mt/ha/y, on average (Morgan et al., 2010).

Grasslands in the Southeast store carbon at 0.07 Mt/ha/y, on average (Morgan et al., 2010).

NOTE: Average rate of storing carbon in Vermont was 0.658 Mt/ha/y in 2015. See table 1.  

 

Tropical Forests of Planted Fast-growing Pine and Eucalyptus: Average rate of storing carbon can be up to about 9 Mt/ha/y (Myers and Goreau).

http://www.unm.edu/~jbrink/365/Documents/Calculating_tree_carbon.pdf

US Average for all Forests: 0.23 Mt C/a/y* x (44 units CO₂/12 units C) = 0.85 Mt of CO2/acre/y 

Please note that this is an estimate for “average” U.S. forests in 2016; i.e., for U.S. forests as a whole in 2016.

Significant geographical variations underlie the national estimates, and the values calculated here might not be representative of individual regions, states, or changes in the species composition of additional acres of forest.

 

To estimate carbon sequestered (in Mt CO₂) by additional forestry acres in one year, simply multiply the number of acres by 0.85 mt CO₂ acre/year.

 

In the US, annual average C sequestration, from 2006-2016 was:

 

Average 0.59 Mt C/ha/y (or 0.24 Mt C/a/y)

Minimum 0.57 Mt C/ha/y (or 0.23 Mt C/a/y) in 2015

Maximum 0.61 Mt C/ha/y (or 0.25 Mt C/a/y) in 2011.

https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculato...

 

Table 6/Average Carbon Absorption Rates	Planted	Fertilized	Managed	Rotation, y	Mt/ha/y
Pine and eucalyptus in Tropics	yes	yes	yes	25	9.000
Pine in Florida	yes	yes	yes	25	5.400
Pine in Southeast	yes	yes	yes	25	3.800
Mixed in Southeast	no	no	minimal	n/a	1.900
Urban in Southeast	yes	yes/no	minimal	n/a	0.800
Cropland in Southeast	yes	yes	yes	1	0.100
Grassland in Southeast	no	minimal	minimal	1	0.070
Douglas-fir in British Columbia	yes	yes	yes	55 - 60	4.000
Mixed in Vermont	no	no	minimal	n/a	0.658
US average for all forests	no	no	minimal	n/a	0.580

APPENDIX 3

Scientists say Dartmouth College’s Wood Chip Heating Plant is a Bad Idea

https://www.vnews.com/Scientists-Call-for-Dartmouth-to-Stop-Biomass...

 

The Valley News article is about prominent scientists sending a signed letter to Dartmouth opposing the planned wood-burning heating plant for campus hot water heating. The signees are:

 

George Woodwell, a 1950 Dartmouth graduate and founder of the nonprofit Woods Hole (Mass.) Research Center

William Schlesinger, a 1972 graduate and emeritus dean of Duke University’s Nicholas School of the Environment

John Sterman, a 1977 alumnus, professor at the Massachusetts Institute of Technology and director of its Sustainability Initiative

 

Excerpt from VN article:

 

Burning wood chips could “substantially” increase the college’s carbon emissions and worsen the effects of climate change, the scientists said in a letter to the Dartmouth community dated July 5.

 

Forests are a major pool of carbon dioxide and globally store as much carbon as the Earth’s atmosphere.

Carbon is released both 1) when wood is burned and 2) after a tree is cut through soil material and decaying plant material.

Whereas forests are renewable, it could take 100 years after cutting before they’re able to again absorb the same levels of carbon, said Woodwell, who drew early attention to the dangers of climate change and was a founding trustee of the Natural Resources Defense Council and a founder of the Environmental Defense Fund.

 

“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,” he said.

Woodwell and his co-authors say Dartmouth should endeavor to make its buildings more energy-efficient, retrofitting them to better retain heat.

Dartmouth Response to the Letter: Rosi Kerr, Dartmouth’s director of sustainability, and Josh Keniston, its vice president for institutional projects, wrote in a response on Wednesday to the letter from the alumni scientists.

 

Excerpt from Dartmouth Response to Signees:

 

IMHO, the response did not address the claims made by the scientists. One item stands out:

 

The college estimates that burning wood chips to distribute hot water to buildings is 89% efficient.

 

Reality check: I do not know where Kerr and Keniston obtained the 89% (they do not provide sources), but that percentage is very optimistic. See page 8 of URL

 

Boiler manufacturers could state the 89% in their sales literature.

It likely is based on 1) full load operation, 2) steady output operation, 3) steady input and output conditions, and 4) test quality wood chips.

The 89% efficiency would be = net energy leaving the boiler as hot water {(temp out - temp in) x mass flow} divided by energy of the test wood chips fed to the boiler.

The 89% (if true) is a much higher percentage than the overall efficiency of the entire system, which likely would be about 70%, on an annual average basis. See URL http://www.basisbioenergy.eu/fileadmin/BASIS/D3.5_Report_on_convers...

 

The real-world efficiency of the entire system, on an annual average basis = (heat delivered to the building Btu meters) divided by (1. the energy into the heating plant (electricity for operating various plant auxiliary equipment and systems, including air pollution cleaning systems; and 2. thermal energy from the wood chips (not of uniform quality); and 3. any supplementary energy from oil firing) is about 70%, including hot water distribution system losses. See URL and Appendix 6

https://www.biomasscenter.org/pdfs/Wood-Chip-Heating-Guide.pdf

NOTE: The present, 50-y-old steam distribution system is highly inefficient and should not be used as a rational basis for comparison with new hot water and $savings calculations and CO2 reductions, as Dartmouth did. The comparison basis should be modern vs. modern, not modern vs. decrepit.

Highly Sealed, Highly Insulated Buildings and Heat Pumps is a Much Better Approach

 

A central plant, burning whatever, with hot water distribution system is ancient, 100-y-old technology.

Dartmouth would not lead, but be laughed at.

 

It would be much better for Dartmouth College to become really modern, i.e., use ground source heat pumps in highly sealed, highly insulated buildings to provide heating and cooling. They could have multiple holes up to 1000 ft deep, or have piping systems under parking lots, etc.

The students would actually learn from such a setup

The students would also learn, the forests, left undisturbed, would maximize C storage. 

 

NOTE: Here are some URLs of ongoing ground source heat pump projects at universities. No wood chips required.

 

https://www.buildings.com/news/industry-news/articleid/21486/title/...

http://eprijournal.com/electric-university/

https://apps.carleton.edu/geothermal/assets/Comparing_geothermal_sy...

https://www.nwf.org/-/media/PDFs/Campus-Ecology/Reports/Geothermal-...

https://www.eenews.net/stories/1060025882

APPENDIX 5

This appendix is part of the above section “Example 1, Clearcutting a Douglas-Fir Plantation in British Columbia”. 

 

Table 7 shows NEP = C release due to decay - C uptake due to new tree growth. 

NEP = 0 in year 17. See below image or URL

https://pics.uvic.ca/sites/default/files/uploads/publications/WP_Fo...

 

The image shows the NEP = -6.5 Mt/ha/y right after clearcutting.

The area of the triangle on the left of the crossover point is about 47.83 Mt/ha. 

In year 40, the area of the triangle on the right of the crossover point is about 47.76 Mt/ha. See table 7 and image.

During year 0 to 17 the clearcut forest area was a C source

During year 18 to 40 the C absorption of new tree growth offset the C release of the source years

It took about 26.40 + 79.28 = 105.68 Mt/ha of C absorption by new tree growth over 40 years to achieve "C neutrality".

 

Year 40 is called "the C neutrality year".

Only after year 40 could the clearcut area absorb any combustion CO2!!

That means combustion CO2 of year 1 (hanging around in the atmosphere) would not have “renewable” status until year 41.

The frequently mentioned statement by environmental scientists "combustion CO2 absorption takes about 100 years", should be revised to "100 years starting after the C neutrality period".

The sooner that gets understood and widely known, the sooner people would consider and better quantify the damages due to logging.

Most industry paid pro-logging studies blissfully ignore the C neutrality period, largely because the authors never heard of it, or would rather leave sleeping dogs lie.

They would rather say, "burning wood is renewable", to not upset carefully crafted PR images in the public mind.

However, burning wood is not a timely CO2 reduction solution, plus any electricity from burning wood is inefficient (3 out of 4 trees are wasted), and costs about 10 c/kWh, two times the NE annual average wholesale price of 5 c/kWh, which has been unchanged since 2008, courtesy of low-cost (5 c/kWh), low-CO2 natural gas and low-cost (4.5 - 5.0 c/kWh), near zero-CO2 nuclear.

SPREADSHEET

Table 7/Clear Cutting	NEP	C release	C uptake	Decay rate	Uptake rate	NEP sum	C release  sum	C uptake sum
British Columbia	Mt C /ha/y	Mt C /ha/y	Mt C /ha/y	Mt C /ha/y	Mt C /ha/y	Mt/ha	Mt/ha	Mt/ha
year
0	-6.50	6.50	0.00			Harvest
1	-5.12	6.13	1.01	-0.059	0.010
2	-4.75	5.78	1.02	-0.059	0.011
3	-4.41	5.45	1.04	-0.059	0.013
4	-4.07	5.13	1.06	-0.059	0.015
5	-3.75	4.84	1.09	-0.059	0.018
6	-3.42	4.56	1.14	-0.059	0.022
7	-3.11	4.30	1.19	-0.059	0.025
8	-2.80	4.05	1.25	-0.059	0.028
9	-2.45	3.82	1.37	-0.059	0.035
10	-2.11	3.60	1.49	-0.059	0.040
11	-1.76	3.40	1.64	-0.059	0.045
12	-1.36	3.20	1.84	-0.059	0.051
13	-1.03	3.02	1.99	-0.059	0.053
14	-0.59	2.85	2.25	-0.059	0.058	Max
15	-0.40	2.68	2.28	-0.059	0.055
16	-0.19	2.53	2.33	-0.059	0.053
17	0.00	2.38	2.38	-0.059	0.051	-47.83	74.23	26.40
18	0.17	2.25	2.42	-0.059	0.049
19	0.42	2.12	2.54	-0.059	0.049
20	0.67	2.00	2.66	-0.059	0.049
21	0.91	1.88	2.80	-0.059	0.049
22	1.16	1.78	2.94	-0.059	0.049
23	1.41	1.67	3.09	-0.059	0.049
24	1.66	1.58	3.24	-0.059	0.049
25	1.92	1.49	3.40	-0.059	0.049
26	1.90	1.40	3.31	-0.059	0.046
27	2.14	1.32	3.46	-0.059	0.046
28	2.38	1.25	3.63	-0.059	0.046
29	2.62	1.17	3.80	-0.059	0.046
30	2.42	1.11	3.52	-0.059	0.042
31	2.63	1.04	3.68	-0.059	0.042
32	2.85	0.98	3.83	-0.059	0.042
33	3.07	0.93	4.00	-0.059	0.042
34	3.30	0.87	4.17	-0.059	0.042
35	2.35	0.82	3.17	-0.059	0.033
36	2.50	0.78	3.28	-0.059	0.033
37	2.66	0.73	3.39	-0.059	0.033
38	2.81	0.69	3.50	-0.059	0.033
39	2.97	0.65	3.62	-0.059	0.033
40	2.84	0.61	3.46	-0.059	0.031	47.76	31.52	79.28	3.5
50	3.15	0.34	3.49	-0.059	0.025
60	3.55	0.19	3.74	-0.059	0.022	Harvest			4.0
70	4.24	0.10	4.35	-0.059	0.021
80	3.84	0.06	3.90	-0.059	0.017
90	3.82	0.03	3.86	-0.059	0.015
100	4.04	0.02	4.05	-0.059	0.014				4.0