Sustainable Loudoun by-laws out for comment

Draft Bylaws of Sustainable Loudoun

These are the draft by-laws for the Sustainable Loudoun organization. If you have suggested changes, use the Sustainable Loudoun forum by-laws thread. If you have never registered yet for the forum, go to

Any input we get prior to October 15th will be evaluated for incorporation into the final version that the membership will vote upon at the October 19th meeting. Formatting glitches are due to MS Word => HTML, so ignore those for now.


I.          Organization

The name of the organization is Sustainable Loudoun. 
Its mission is to
promote the development of a local community economy based on environmental stewardship and the sustainable use of resources.  Associate membership is open to all interested parties. 

II.          Officers

The officers consist of a President, Vice President, Secretary, and Treasurer.

Elected officers will serve a term of two years.

The initial election
will be conducted on an expedited basis during October 2010.  For the next election, active members will be given 30 days to nominate candidates for officers (from September 1 to October 1, 2012).  Nominees will be announced October 1 and active members will be asked to vote by October 29.  New officers will assume their duties November 1, 2012.

Duties of Officers

            (1)        The President shall preside at all meetings, appoint committee members, and perform other duties as associated
with the office and as directed by the Board. 

            (2)        The Vice President shall assume the duties of the President in case of the President’s absence.   The Vice President shall also perform other duties as requested by the President.

(3)        The Secretary shall be responsible for the minutes of the meetings, and shall send out copies of the minutes to all members.  

(4)        The Treasurer shall keep record of the organization’s budget and prepare financial reports as needed.

III.         Board
of Directors

The Board of Directors shall serve without pay and shall consist of up to ten members.

The Immediate Past President shall be the first Chairman of the Board and shall be considered an officer for purposes of voting.

Initial Board members shall be appointed by the
Immediate Past President.

Board members shall serve two year terms.

Nominations to fill vacancies can be made by the Board, by the officers, or by active members. 
The nominee will fulfill the term of the vacating Board member.  Election of Board members shall be by a majority of Board members and officers.

The Board will meet two times a year, in January and June, and will advise the officers on the organization’s planned activities.

IV.        Committees

Committees, including temporary and ad hoc committees, may be created as needed by a vote of a majority of the officers.

V.        Meetings

            A.        Regular meetings shall be held on the third Thursday of the month, except for November when the Energy Summit shall be considered the monthly meeting.

            B.         Special meetings may be held at any time when called for by the President or a majority of the officers.

C.         Agendas shall be provided at least four days in advance.


VI.        Voting

A majority of the officers constitutes a quorum.

In the absence of a quorum, no formal action shall be taken except to adjourn the meeting to a subsequent date.

Passage of a motion requires a simple majority (i.e., one more than half of the active members present).   All active members present are entitled to one vote.

VII.       Conflict of Interest

            Any officer or member of the board who has a financial, personal, or official interest in, or conflict (or appearance of a conflict) with any matter pending before Sustainable Loudoun, of such nature that it prevents or may prevent that member from acting on the matter in an impartial manner, will offer to voluntarily excuse him/herself and refrain from voting on said item.

VIII.      Fiscal Policies

The fiscal year of Sustainable Loudoun shall be from January 1 to December 31.

            B.         Funds that are earmarked for special purposes (such as scholarships for the High School Science & Engineering Fair) shall not be used for general purposes.

IX.        Amendments

These by-laws may be amended by a two-thirds majority vote of the active members.

 A copy of the proposed amendment(s) shall be provided to the active members at least one month prior to the tabulation of the vote.


X.         Membership

A.         Any person that has an active Sustainable Loudoun membership shall be entitled to vote.

B.         Membership is kept active by contributing $10 per year to the Sustainable Loudoun general fund, and by keeping the member’s Sustainable Loudoun contact and profile data up-to-date.

Initial contributions are due January 1, 2011.

Any member of the public, whether an active member or not, is welcome to attend Sustainable Loudoun meetings so long as their behavior is civil and constructive.


Loudoun’s Future – What are your ideas?

How do most of us get around? The typical answer would be “car” or “minivan/SUV/pickup”. A few will say otherwise. Should we expect this situation to continue unchanged in the future? And why did Bush say “America is addicted to oil” in his 2006 State of the Union speech (and other speeches)?

We’ve talked in the past about projections of crude oil production peak and decline, so were not surprised recently when a German military think tank internal report draft on future petroleum resources was leaked (and confirmed by Der Speigel), which raised disturbing warning flags.

The report identified serious economic risks Germany faces as a result of peak oil, ranging from a long steady decline in income and standard of living, to a volatile, negative market response (“tipping point”) when it becomes obvious that economic growth will have ended. Some of the report’s main points in the tipping point scenario were;

Intuitively, it may seem rather obvious that a phase of slowly declining oil production also leads to a slowly declining economic output, that Peak Oil would simply turn back the level of prosperity for a while, during which time technological solutions could be found. This intuition is deceptive: economies move within a narrow band of relative stability. Within this space, economic fluctuations and other shocks are possible, but the operating principles remain the same and provide a new equilibrium within the system. Outside of this space, however, this system reacts chaotically.

Banks lose their business base. Cannot pay interest on deposits, because they can not find creditworthy companies.

Loss of confidence in currencies. The belief in the value-preserving function of money is lost. It only comes to hyper inflation and black markets, then to a barter economy at the local level.

Collapse of value chains. Labor processes are based on the possibility of trade in precursors. The processing of the necessary transactions without money is extremely difficult.

Unbound monetary collapse. If currencies lose their value in their country of origin, they are no longer exchangeable for foreign currency. International value chains collapse as well.

Mass unemployment. Modern societies are composed of specialized labor. Many professions have to deal only with the management of this high degree of complexity and nothing more with the direct production of consumer goods. The expected reduction in the complexity of economies would result in a dramatic increase in unemployment.

State bankruptcies. In the situation described, state revenues drop precipitously. The possibilities of acquiring new debt are extremely limited.

Collapse of critical infrastructure. Neither the physical nor the financial resources remain for the maintenance of adequate infrastructures. The problem is compounded by the interdependence between different infrastructure subsystems.

Famines. Ultimately, it will provide a challenge-to produce food in sufficient quantity and distributed.

A shrinking indefinitely economic performance represents a highly unstable state, the inevitable end to a system collapse. The security risks of such a development can not be assessed.

There is also a recent quote from Dr. Robert Hirsch, who was asked when he thought peak oil would occur;

“In years past, there was considerable uncertainty in my mind about when the decline of world oil production might begin. Recently it became clear to me that it’s going to be sooner rather than later. I believe that the onset of the decline of world oil production is likely in the next two to five years. “

Dr. Hirsch, besides being the lead author of the DoE’s Peak Oil Report, has an extensive energy resource background;

  • Manager of Exxon’s synthetic fuels research laboratory
  • Manager of Petroleum Exploratory Research at Exxon
  • Vice President and Manager of Research and Technical Services for Atlantic Richfield Co. (ARCO) (Oil and gas exploration and production).
  • Vice President of the Electric Power Research Institute (EPRI)
  • Senior Energy Analyst, RAND
  • Assistant Administrator of the U.S. Energy Research and Development Administration (ERDA) responsible for renewables, fusion, geothermal and basic research
  • Director of fusion research at the U.S. Atomic Energy Commission and ERDA

So it is clear that life with be dramatically different within the next few years. With unprecedented social and economic changes literally on our doorstep (on top of the current weak economic conditions), what kind of transitions should Loudoun be focusing on for the next 1, 5, and 10+ years? Please offer your comments at the Sustainable Loudoun forum section on Transition.

Will Stewart

Open letter to Pat Michaels request for information

To talk about global cooling at the end of the hottest decade the planet has experienced in many thousands of years is ridiculous.”  Ken Caldeira, Climate Scientist [1]

You’ve all seen articles saying that global warming stopped in 1998.  With all due respect, that’s being a little bit unfair to the data.”  Pat Michaels, Climate Scientist [2]

Dear Dr. Pat Michaels

I write and edit a column called “Sustainable Planet” [3] for a small local internet news paper in Northern Virginia called the Blue Ridge Leader.  With this open letter, I’m asking if you wouldn’t mind describing your view on anthropogenic global warming (AGW) for my readers.  We are specifically interested in the science and not policy or economics.

The science in support of Svante Arrhenius’ theory of AGW is assessable, unambiguous and coherent.  We can begin with the four IPCC reports but can add to that record a host of text books related to earth sciences and climate physics [see fore example 4 and 5].  There are several really good review papers and one by Stefan Rahmstorf is especially helpful [6].  The video of Richard Alley’s invited lecture at last year’s American Geophysical Union conference summarizes the paleoclimate record and the impact of atmospheric carbon dioxide on Earth’s climate [7].  The peer-reviewed literature is compelling and overwhelmingly in support of the theory as several studies have demonstrated, the latest being Anderegg et al. [8].  Furthermore Arrhenius’ theory is consistent will all science from microbiology [9] to astrobiology [10].

By contrast it is hard to find any science supporting the denialist [11] view.  Not only is this science sparse as evident by reference [8], but it is obscured by the noisy and obfuscating nature of denialist arguments, most of which ignore data, and contradict each other as well as the laws of physics, or simply are outrageous attacks on individuals such as James Hansen, Michael Mann or Al Gore.  The vast sea of arguments on policy or economics is an attempt to put the cart before the horse while the horse has already galloped off in the other direction.  The denialist canard that global warming stopped in 1998 is typical of arguments which ignore data and contradict physical laws. 

Each year Heartland Institute hosts a global warming denier conference.  On March 2, 2008, you were their keynote speaker.  The focus of your talk was the disingenuousness of this particular global warming denialist argument.  You said, addressing the room full of deniers: “You’ve all seen articles saying that global warming stopped in 1998.  With all due respect, that’s being a little bit unfair to the data.”  You then went on to describe why.  Peter Sinclair captured your candid admission in this informative youtube video [2].  While you are more charitable, you are in complete agreement with Ken Caldiera.  That puts you in good company.

You opine “Make an argument that you can get killed on and you kill us all.”  Your meaning, I presume, is that if many denialists make arguments that are easily debunked all global warming denialists, including yourself, will lose their credibility.  You conclude: “Global warming is real and the warming in the second half of the twentieth century, people had something to do with it.”  In the Cato Institute handbook for policy makers [12] you repeat this sentiment: “Global warming is indeed real, and human activity has been a contributor since 1975.

Physics teaches us that a doubling of atmospheric carbon dioxide will result in a radiation imbalance of 4 Watts per meter squared (W/m2) which will directly cause the Earth to warm about 1 degree C.  Your article in the Cato Handbook aligns to this view.  The difference between your view and the consensus view is related to the strength of feedbacks in the Earth’s climate system.  As you point out water vapor is a greenhouse gas and as the Earth temperature climbs as a result in increased atmospheric carbon dioxide, more water evaporates off the oceans.  This additional water vapor reinforces the warming.  You don’t mention but I’m sure you agree that as the temperature climbs, snow and ice at the poles melts.  The exposed darker dirt and water absorb more of the short wave solar energy than the white ice and snow once did, further reinforcing the warming.  In addition, warm ocean water holds less carbon dioxide than cold water, thus as the oceans warm the equilibrium point between the atmosphere and ocean changes.  These are positive feedbacks.   Most identified carbon cycle feedbacks are positive.  The consensus view, the view defended in the IPCC reports, is that including these feedbacks the equilibrium climate sensitivity, the amount the Earth’s surface will warm as a result of a doubling of atmospheric carbon dioxide is between 1.5 and 4.5 degrees C. 

James Hansen’s view as described in [13] is that equilibrium climate sensitivity may be as high as 6 degrees C.  This high value does not contradict the consensus view which, as you know, does not rule out the possibility of higher values. 

In contrast, your view, if I’m interpreting your policy paper correctly, is that climate sensitivity is very low, 1 degree C or less.  This view is outside the bounds of the consensus view.  It means that all of these positive feedbacks must be counterbalanced by some unspecified negative feedbacks.  Pointedly, you do not describe any of these possible negative feedbacks.  In other words, your paper does not address the physics.  Your paper is an attempt to defend a policy based on conservative ideology, and not a defense of your scientific view.  This paper ignores the fact that policy that is not based on credible science or reality can’t help but be bad policy.

What would be helpful instead is a high quality paper defending your opinion that equilibrium climate sensitivity is indeed dominated by unidentified negative feedbacks and therefore that though the Earth’s surface will warm as a result of human emissions of carbon dioxide, the warming will not be very great.  Your policy paper does not do this.  Your logic is based on one peer-reviewed reference, from a May 2008 article in Nature by Noel Keenlyside et al. [14].  Figure 4 from Keenlyside’s paper (see below) shows that they are forecasting temperature (the green curve) to end up in exactly the same place as the IPCC scenarios which you cite (the black curve).  The measured temperature is shown in red and falls in between. 

Keenlyside is forecasting a hot climate than hotter.  It does not support your hypothesis.  I recommend Joe Romm’s blog, including interviews with the authors, in order to better understand Keenlyside’s results [15].  Keenlyside’s forecasts are somewhat controversial and already underestimating warming that is happening, so it is not clear that even if you had interpreted it correctly that this is the best reference to be using.  A paper by Rind and Lean should also be considered [16].

My request by this open letter is if you wouldn’t mind describing for us what your scientific view is on this important issue including references.  I am not looking for a paper of comparable high quality and completeness as the Hansen paper.  I am assuming that perhaps such a paper or papers may already exist in the peer-reviewed literature.  My concern is that science supporting denialist point of view is obscured by the ludicrous nature of most denier argument.  This makes it a difficult and tedious exercise to uncover.  If you could summarize where in the scientific literature possible negative feedbacks are described and verified in the paleoclimate record or by analysis, this would be much appreciated.

At Sustainable Loudoun, we are skeptics and appreciate good references and then validate them.  But we do not discriminate.  We hold everybody’s feet to the fire, especially our own. 

Best regards and thank you kindly

Tony Noerpel

[1] Ken Caldeira

[2] Sinclair


[4] Kump, L. R., Kastings, J. F., and Crane, R. G., The Earth System, 2004.

[5] Lunine, J. I., Earth, Evolution of a Habitable World, 2000. 

[6] Rahmstorf, S., 2008: Anthropogenic Climate Change: Revisiting the Facts. In: Global Warming: Looking Beyond Kyoto., E. Zedillo, Ed., Brookings Institution Press, Washington, pp. 34-53

[7] R. Alley, 2009,

[8] Anderegg, W.,  Prall, J., Harold, J., and Schneider, S., Expert credibility in climate change, Proceedings of the National Academy of Science, 2010.

[9] Gaines, S., Eglinton, G. and J. Rullkotter, Echoes of Life, Oxford, 2009.

[10] Plaxco, K., and Gross, M., Astrobiology, Johns Hopkins University Press, 2006.

[11] The science journal Nature referred to AGW skeptics as denialist in an editorial on so called climate-gate.   “denialists use every means at their disposal to undermine trust in scientists and science.” Nature Editorial Staff, Vol 462 | Issue no. 7273 | 3 December 2009

 [12] Michaels, 2009,

[13] Hansen, J., Sato, M., Kharecha1, P., Beerling. D., Robert Berner, R., Masson-Delmotte, V., Pagani. M., Raymo, M., Royer, D. and Zachos, J., “Target Atmospheric CO2: Where Should Humanity Aim?” The Open Atmospheric Science Journal, 2008, 2, 217-231.

 [14] Keenlyside, N., Latif, M., Jungclaus, J., Kornblueh, L., and Roeckner, E., Advancing decadal-scale climate prediction in the North Atlantic sector, Vol 453| 1 May 2008| doi:10.1038/nature06921.

 [15] see and and

 [16] Lean, J., and Rind, D., “How will Earth’s surface temperature change in future decades?”, GEOPHYSICAL RESEARCH LETTERS, VOL. 36, L15708, 5 PP., 2009 doi:10.1029/2009GL038932


 “What distinguishes science from pseudoscience is not whether your theory originated with some particular conviction about how the world works, or whether you feel an emotional attachment to it. What matters is the evidence you find to support it, and whether you are ultimately prepared to accept that it could be wrong.”  Gabrielle Walker, Snowball Earth.

 When, on July 25, 1997, the United States Senate voted 95 to nothing to oppose the Kyoto Protocols under the illusion that doing so would destroy the United States economy, it occurred to me that our reaction to global warming was not going to be nearly as rational as our reaction to the threat posed to the ozone layer by the continued use of chlorofluorocarbons.  Putting aside the science for the moment every positive quarter of economic growth is traditionally attributed to increases in productivity and of course every increase in productivity is due to improvements in efficiency.  Use resources more efficiently and the economy grows.  In 1997 the entire senate was gripped by the irrational fear that further improvements in efficiency would suddenly cause the economy to fall into a tailspin.  The Senate voted 95-0 for Senator Robert Byrd’s 1997 resolution number 98 keeping the United States out of the Kyoto process.  If we all drove Priuses instead of Hummers somehow that would be an economic disaster.  Their logic escapes me, too.  As we all now know, these fine folks did the complete opposite, just in case, and caused the worst economic crises since the Great Depression by voting 90-8 in favor of the Gramm-Leach-Bliley Act in 1999 which in fact did destroy our economy.

 Seeing this coming, I felt compelled to learn the science behind the anthropogenic global warming theory for myself.  I approached this task the way any scientist or engineer would, by reading the peer-reviewed science and climate physics text books. 

 Any discipline of real science is exciting, alive, compelling and leads one to exponentially increasing discovery of even more knowledge and scientific understanding.  Following the scientific trail of AGW led me to the historic papers of Joseph Fourier, Svante Arrhenius and Louis Agassiz and that lead me to the study of the ice ages which inevitably leads one to the greatest ice age catastrophe of all time: Snowball Earth.  Thus, I had already read many of the papers by Paul Hoffman, the hero of Gabrielle Walker’s book as well as those of many other researchers such as Joe Kirchvink and Ray Pierrehumbert.  Knowing the story though did not preclude me from learning a great deal more. 

 Walker is an exceptional writer and her book Snowball Earth is a fascinating account of the development of the snowball Earth theory by the remarkable geologist Hoffman.  In fact the book is full of personal stories not only about Hoffman but many of the geologists who contributed to the development of the theory. 

Brian Harland first proposed that at one time the Earth might have frozen over solid about 600 million years ago because he found evidence of drop stone sediments and glacial scratches in pre-Cambrian rock from all over the world.  But he could not prove it and, if the Earth had in fact frozen over solid, he could not explain how the Earth could have possibly thawed out.  This is because ice is white and reflects all of the short-wave solar radiation back into space.  In other words, once the Earth froze, the sun could no longer warm it up.  Harland published his ideas in 1963.

 Joe Kirschvink first proposed the solution to that problem in a two page paper written in 1992.  Volcanoes emit carbon dioxide at a rate of about 60 million tonnes of carbon a year.  However over geologic time it does not accumulate in the atmosphere because silicate rock weathering, which extracts carbon and buries it as deep ocean sediment, proceeds just as fast.  However, if rocks are covered in ice and snow and if the Earth is so cold that very little water evaporates into the atmosphere, then rock weathering stops and the carbon dioxide accumulates.  Our planet was spared a lifeless fate because of the green house effect of carbon dioxide.  In other words, if Senator Inhofe was right, he would not exist. 

 Paul Hoffman’s place in all this was that he proved the snowball theory.  He was not without adversaries.  The story is full of egos and personalities.  The development and acceptance of the snowball theory is science at its most entertaining and the book reads like a thriller.

There were two episodes of snowball Earth.  The first occurred 2350 million years ago at the boundary between the Archaean and Proterozoic Eons.  Prior to the Earth freezing over solid this first time, atmospheric oxygen is thought to have been just a few hundred parts per million by volume and after the snowball, it had shot up to 1 or 2% of the atmosphere.  Between 750 and 590 million years ago, the Earth froze over again and again oxygen shot up, this time to about the current 20% of the atmosphere by volume.  Thus the most recent episode may have been responsible for the explosion of complex life on Earth, leading ultimately to the evolution of a species which has the mental capacity to actually work it all out and deny it all in one go.  You will enjoy Gabrielle Walker’s book.  It is simply brilliant.

 Tony Noerpel

Solar Energy

 “[Nobel Laureate Wilhelm] Ostwald’s energetic imperative – Waste no energy but value it – is relevant as humankind makes the inevitable transition to a permanent economy based exclusively on solar radiation.” – Vaclav Smil

“My own preference is to fill the Mojave with solar concentrating plants, and save some of this wonderful stuff [oil] for our descendants.” Dave Rutledge

 “I’d put my money on solar energy… I hope we don’t have to wait til oil and coal run out before we tackle that.” – Thomas Edison

 When Edison and Ostwald were alive there were only 2 billion humans on the planet so capturing solar energy offered more than enough low entropy to support human society sustainably with a generous quality-of-life.  In 1972 when the world population was 3.8 billion, the authors of Limits to Growth concluded that global population and industrial activity were still below the levels that could be supported indefinitely by Earth.  Today there are 7 billion people and it is less clear that sustainability is achievable.  In the 2004 edition of Limits to Growth the authors concluded that both population and industrial activity had already grown above sustainable levels [Meadows, 2007].  Sometime in the not too distant future it may become impossible to achieve sustainability, if we do not act responsibly now.

 Fossil fuel resources are running out and we are only arguing about when.  As we will discuss in some future article, nuclear power is severely limited by the availability of uranium resources and reserves and it is a simple fact that we still have no idea how to process or store the waste nor how much whatever the solution (assuming there is one) will cost in terms of energy and money.  That leaves solar, which includes tidal, wind and biomass; and much more limited and dispersed geothermal energy. 

The radiation intensity of the sun through a plane perpendicular to the line connecting the center of the Earth to the center of the Sun measured at the top of the atmosphere is 1366 Watts per meter squared.  This is called the solar constant.  The Earth has a mean radius of 6371 kilometers.  The solar energy flux through the circular area projected by the Earth onto a planar surface is 1366 X 6,371,0002 X p = 174,000 terawatts.  

 According to the British Petroleum 2009 statistical review, humans consumed 11300 million tonnes of oil equivalent energy in the year 2008.  One tonne of oil can produce 12 million Watt-hours according to the same source.  There are 24 times 365 hours in a year.  Thus humans consumed energy at the rate of 15 terawatts in 2008.  BP excludes biomass, solar and wind but these numbers are accurate enough for our purposes. 

 Humans therefore consume energy at a rate equivalent to 0.008% of the sun’s energy flow.  We would have to intercept 6371 kilometers (km) squared times p times 0.00008 or 10,000 square km of land on Earth beneath the sun with 100% efficient solar collectors and while there is no cloud cover.  We can work out the other bits.  Solar panels are about 15% efficient and if we situate our collectors in the world’s deserts we can ignore any cloud cover.  We then have three remaining issues to consider.  The Earth is a sphere, it rotates and it has a 23.5 degree “seasonal” wobble.  Because the Earth is a sphere we only need 10,000 square km if we build our solar array at the point on the Earth surface directly below the sun.  If we are 10 degrees to the north then we only intercept cosine (10) of the total power or 98%, which is not bad.  But if we are 40 degrees to the North, we only intercept cosine (40) or 77% of the power.  Because the Earth rotates, our selected point 12 hours later will be in the dark of night.  And because the Earth wobbles once a year, the sun is directly overhead in the Sahara desert at noon in the summer but directly over Botswana during the winter. 

 To avoid cloud cover, the best places for our collectors are on the Tropic of Cancer, where the Sahara is located, or the Tropic of Capricorn, in the middle of the Australian Outback.  The cool thing to do right now would be to get a globe and play with it.  You will note that when the Earth rotates and positions the middle of the Pacific Ocean towards the Sun, there are no land masses available for our collectors.  So we would have to be able to store energy.  Concentrated solar thermal power promises to be cheaper than solar photovoltaic panels and easier to manufacture and heat is easier to store than electricity. The United States is a leader in this technology as we once were in photovoltaic technology as late as 1998 before we gave that lead up to Germany and China. 

Getting back to our 10,000 square kilometers, since collectors are 15% efficient, we need 67000 square kilometers and because our surface is not directly under the sun most of the time, we need to increase the area by another 40% or so to 90,000 and if we add a cushion for cloud cover lets round it up to 100,000.   This is a little less than the total area of Arizona. We need several such stations around the Earth to cover night and day.  Concentrated solar thermal power can work round the clock by storing heat generated during the day but it only collects the energy from solar photons during the day.

There are other things we can do though.  I have solar panels in my back yard here in Virginia.  They contribute.   Additional solar collectors can be distributed throughout the economy.  Integrating distributed and concentrated sources of energy is an important part of the Smart Grid evolution.  There are other ways to capture the sun’s energy such as wind, tidal and biomass.   Algae can be used as a solar collector [Westervel, 2010].  And finally, the biggest part of the solution to America’s energy problems, at least, is conservation.  We can simply use less. 

 Still, the big problem with this dream of sustainability is building out the necessary infrastructure.  The entire energy infrastructure we have now was build using fossil fuels when such energy sources had an energy return on energy investment ratio (EROEI) of about 100.  Because we are using all the easy stuff first, the light sweet crude and anthracite, what we have left is tar and lignite with EROEIs closer to 5 or less.  They are also dirtier in every respect.  We need to use the energy from remaining fossil fuels to construct our solar powered future.  Building more nuclear reactors has an opportunity cost since it wastes resources that could have been marshaled to build out solar plant and it has a huge liability cost since we do not know what we have to do with the waste and don’t know how much that will cost.

 Tony Noerpel


[Meadows, 2007] “Evaluating Past Forecasts”, in Sustainability or Collapse, eds. Costanza, Graumlich and Steffen, Dahlam Workshop Reports, 2007.

 [Westervel, 2010]

Fossil Fuels

One of the strangest anthropogenic global warming denialist arguments is that there may not be enough fossil fuels (coal, oil and natural gas) to cause the worst case scenarios described in the IPCC report [1].  It is strange for two reasons.  The first is that unlike other denialist objections, there is actually credible scientific support for this argument.  The second reason is that the policy solutions to problems caused by either global warming or running out of fossil fuels are the same: effecting a rapid transition to alternative sources of energy and conservation. 

 One of the most important figures in the resource depletion discussion is Kjell Aleklett, founder of the Association for the Study of Peak Oil [2].  Aleklett has done as much as anybody to investigate the actual reserves of fossil fuels and inform the public about this possible crises.  Curiously, Senator Inhofe quotes Aleklett [3]:   “the combined volumes of these fuels are insufficient to cause the changes in climate….The world’s greatest future problem is that too many people must share too little energy.”  If Inhofe’s objection to anthropogenic climate change theory were purely academic then citing Aleklett may support that position, but given his objection to the theory is policy-based, i.e., opposition to government support for a transition away from fossil fuels, his reference to resource depletion arguments clearly undermines his position.

I have previously described the impact of even the lowest credible estimates of fossil fuel resources on global warming and shared this information with Supervisor Lori Waters in December, 2008.  The document I gave to Waters is publicly available on the Sustainable Loudoun webs site [4].

 Aleklett’s view is articulated in several of his papers (see for example [5]).  While I have great respect for Aleklett and agree in general with his pessimism regards remaining and depleting resources, I disagree with him that the impact of even the lowest estimates may not initiate a serious climate problem.  Further, while I believe that when we are evaluating our potential energy problems, we need to consider the most pessimistic resource estimates in order to understand the worst case scenario, when we are evaluating potential global warming problems, we need to consider a wide range of resource estimates including the most credible optimistic estimates in order to evaluate the worst case scenarios.  Therefore, I submit that while his criticism of the IPCC may have substantial scientific support, it is not a reasonable objection because there is not one hundred percent certainty in the most pessimistic resource depletion scenario.  The impact on policy is the same in either case.  Aleklett as an academic may be correct to criticize the IPCC for not including an additional low resource scenario.  Inhofe a fossil-fuel industry sponsored politician is foolish to think that argument overturns the need for more enlightened policy.

The lowest estimate for remaining fossil fuels as measured by total carbon content is about 560 Gigatons Carbon (GtC) from Rutledge [6].  The highest credible estimate is about 5000 GtC from Rogner [7].  These represent total estimated recoverable resources and reserves of fossil fuels.  The most disquieting aspect of these estimates is that we don’t have any idea how much fossil fuels was have left to within an order of magnitude.  That is the most compelling argument against Inhofe’s objection to conservation and transitioning to alternative energy sources as quickly as we possibly can. 

 In reference [5], Aleklett presents estimates for remaining fossil fuels which may be used before 2100, assumed by the IPCC, in barrels of oil equivalent.  We can convert these numbers to GtC using the conversion factors described below.  Thus the IPCC report [1] analyzes several scenarios with a range of carbon emissions between 1243 to 1960 GtC during the 21st century.  We observe that these estimates are far below Rogner’s high estimate (5000) but higher than the estimate of Rutledge (560).  The IPCC did not use either the most pessimistic or optimistic estimates for remaining recoverable fossil fuels but instead tacked responsibly up the middle.

 The best case scenario for the climate and the worst case scenario for fossil fuel depletion is Rutledge’s estimate of 560 GtC.  While it is frightening to speculate on the impact to our economy if politicians like Inhofe prevail in preventing us from developing a transition plan to alternative renewable energy sources in time, it is also sobering to speculate on the human impact on climate even in this scenario.  Working in our favor (for the climate and not life in the oceans, unfortunately) is the fact that land and ocean sinks currently absorb about 50% of our emissions, though there is evidence that these sources are becoming saturated [8].  Increasing temperatures and acidity may reduce ocean productivity and this would reduce the amount of our CO2 emissions which can be absorbed by the oceans.  Thus 560 GtC may increase atmospheric carbon by as much as 134 ppmV depending on how quickly it is extracted and consumed (divide 560 GtC by 2.1 to convert to ppmV and then by 2 since 50% is absorbed by the oceans and land sinks).  However, the carbon stock in the Earth’s forests (above ground) is 288 GtC [9].  This can increase atmospheric carbon by another 69 ppmV if it is burned.  Imagine a world inhabited by up to 9 billion humans who have no fossil fuels left to keep themselves warm.  Whatever does not get harvested may be destroyed by insects and fire.  It is not hard to imagine all forests disappearing as this level of devastation has been caused by human societies locally in the past, e.g. Easter Island and Yucatan [10](Diamond, 2005). 

Further, if CO2 levels remain above 350 ppmV for an extended period of time, permafrost may melt releasing carbon in the form of carbon dioxide and/or methane into the atmosphere as a consequence of increased warming of the climate.  The permafrost is estimated to contain up to 1500 GtC [11, 12].  Other positive carbon cycle feedbacks have been identified but are not discussed here.  The amount of permafrost melt is a function of both the temperature and thus the level of atmospheric carbon, and the length of time the temperature remains elevated.  Higher levels of CO2 means the Earth warms to a higher temperature resulting in a faster melting of the permafrost. 

 The best case climate scenario and the worst case energy scenario assume human emissions of 560 GtC which adds 134 ppmV CO2 to the atmosphere.  This brings the total to 525 ppmV.  The consumption of the planet’s forests adds 69 ppmV bringing the total to 594 ppmV.  This level of CO2 would accelerate the melting of the permafrost and other carbon cycle feedbacks.  Eventually (over centuries) all 1500 might be emitted into the atmosphere bringing the total to 950 ppmV.  An MIT report [13] projects 10 degrees F global warming and 20 degrees F warming in the arctic if the CO2 concentration reaches 866 ppmV. At these temperatures sub-ocean methane hydrate deposits may thaw adding additional carbon in the form of methane or carbon dioxide to the oceans (accelerating ocean acidification) and the atmosphere [14, 15].  The MIT study authors assume we reach 866 ppmV via human emissions but it doesn’t matter where the CO2 comes from.  Current climate models do not account for melting permafrost sources.

 Another important observation (and cautionary note) is that most model projections continue only up to 2100 as if our destruction of the ecosystem, upon which we depend, stops at that time.  It does not.  In another article, Pliocene [16] we observed that between 5 and 2 million years ago, the level of carbon in the atmosphere was the same or a little less than it already is today yet temperatures were between 2 and 4 degrees Centigrade warmer.  It is suggested that this may be because the Earth was cooling off as it was losing atmospheric carbon dioxide and the oceans had already equilibrated to a higher temperature and had to cool down.  Today we are recovering from the Last Glacial Maximum (LGM) some 20,000 years ago and oceans are cooler and have to warm before the surface does.  Most of the energy imbalance in fact is warming the oceans today rather than the atmosphere or the surface.  This will continue for a long time and our problems are only just beginning ninety years from now.

In conclusion, it is possible that even the most pessimistic estimates for fossil fuel resources are enough to cause disastrous global warming especially if positive carbon cycle feedbacks kick in.  Human society will be trying to adapt to increasingly unlivable conditions without the benefit of fossil fuel energy.

 Tony Noerpel

—————————————A note on conversion of units————————————————–

 Strictly speaking barrels of oil equivalent is a relative measure of the energy content of these three fuel types, coal, oil and natural gas, and not exactly proportional in their carbon emissions.  But this is the case even if we consider only coal, since, for example, the quality of anthracite is superior to the quality of lignite in terms of energy available per quantity of carbon emissions.  Following Aleklett we use 42 Giga Joules (GJ) as the energy content of a ton of oil equivalent and 6.12 GJ as the energy content of a barrel of oil equivalent and assume most of the mass of a ton of fossil fuels is carbon.  This is accurate enough for a first order estimate and anyway we are only interested in bounding a problem which has an order of magnitude uncertainty to begin with.  One important caveat is that remaining fossil fuels include a high proportion of dirty fuels such as heavy oils, lignite, kerogen and bitumen which all have higher carbon content per useable British Thermal Unit (BTU) when compared to the light sweet crude oil and anthracite coal we have been using.  Remaining resources require more energy inputs for the same energy output.  For example, the United States coal production as measured in tons has continued to increase but as measured by BTU, or energy content, has actually peaked in 1998 [17].  This is because the quality of remaining coal reserves is diminishing.  Most of the high quality Anthracite has been mined and the remaining resources include sub-bituminous coal and lignite.  

 The conversion of GtC to parts per million by volume (ppmV) of atmospheric carbon is straightforward.   We need to compute the average molecular weight of the molecules in the atmosphere.  The components are 78.08% Nitrogen with a molecular mass of 28, 20.9% Oxygen with a molecular mass of 32 and 0.9% Argon with a molecular mass of 40.  Thus .7808 X 28 + .209 X 32 + 0.009 X 40 = 28.9.  Carbon Dioxide has a molecular weight of 44 but the Carbon content of a CO2 molecule has a mass of 12.  The mass of the Earth’s atmosphere is 5.15 106 Gt.  Thus divide GtC by the factor 5.15 X 12/28.9 = 2.1 to compute ppmV.  The current level of atmospheric CO2 is 392 ppmV [18] which can then be converted to 823 GtC by multiplying by 2.1.


[1] Intergovernmental Panel on Climate Change, 2007,

[2] ASPO web site

[3] Inhofe, Morano, and Dempsey, December 20, 2007, “U. S. Senate Report Over 400 Prominent Scientists Disputed Man-Made Global Warming Claims in 2007 Scientists Debunk ‘Consensus’”.

 [4] sustainable Loudoun web site

 [5] Kook, M., Sivertsson, A., Aleklett, K., “Validity of the fossil fuel production outlooks in the IPCC Emission scenarios, Natural Resources Research, Volume 19, Issue 2, June 2010, 63-81, doi:10.1007/s11053-010-9113-1.

 [6] Rutledge, D., 2007, presentation and excel worksheet can be downloaded here.

Rutledge, D. Hubbert’s peak, the coal question and climate change, APSO-USA World Oil Conference, 17-20 October 2007, Houston, Texas.

 [7] Rogner, H. H., An assessment of world hydrocarbon resources, Annual Review of Energy and the Environment, 22:217-262, 1997.

 [8] Canadell, J. G. et al. 2007 Contributions to accelerating atmospheric CO2 growth from economic activity, carbon intensity, and efficiency of natural sinks.” Proc. Natl. Acad. Sci. USA 104, 18-866-18 870.

 [9] Moutinho, P. and Schwatzman, S. (eds) Tropical deforestation and climate change, Belem, Brazil: Amazon Inst. For Environmental Research.

 [10] Diamond, J., 2005 Collapse, Penguin Books, London.

 [11] Tarnocai, C., Canadell, P.,  Journal of Global Biogeochemical Cycles (GB2023,doi:10.1029/2008GB003327) American Geophysical Union.

 [12] Edward A. G. Schuur, Jason G. Vogel, Kathryn G. Crummer, Hanna Lee, James O. Sickman, T. E. Osterkamp,  “The effect of permafrost thaw on old carbon release and net carbon exchange from tundra,” Nature 459, 556-559 (28 May 2009) doi:10.1038/nature08031 Letter

 [13] MIT: , Report 169,, Probabilistic Forecast for 21st Century Climate Based on Uncertainties in Emissions (without Policy) and Climate Parameters by Sokolov, A.P., P.H. Stone, C.E. Forest, R.G. Prinn, M.C. Sarofim, M. Webster, S. Paltsev, C.A. Schlosser, D. Kicklighter, S. Dutkiewicz, J. Reilly, C. Wang, B. Felzer, J. Melillo, H.D. Jacoby (January 2009) Joint Program Report Series, 44 pages, 2009, also Journal of Climate October 2009, Vol. 22, No. 19 : pp. 5175-5204

 [14] Additional information on these carbon cycle feedbacks:, and, and

 [15] Shakhova, N., Igor Semiletov, I., Salyuk, A., Yusupov, V., Kosmach,D., Gustafsso, O., Extensive Methane Venting to the Atmosphere from Sediments of the East Siberian Arctic Shelf, Science 5 March 2010: Vol. 327. no. 5970, pp. 1246 – 1250 DOI: 10.1126/science.1182221

 [15] brleader Pliocene

 [16] Lehmann, H., et al 2007 Coal resources and future production, Energy Watch Group publication 1/2007



Even if expense were no object, none of these [biosphere] services could be performed at such scales and with such efficacy by any anthropogenic means.  Our dependence on biosphere services is literally a matter of survival, and that’s why the integrity of the biosphere matters.” Vaclav Smil.

[T]he accumulation of atmospheric oxygen paved the way for significant leaps in biological evolution in the Paleoproterozoic with the rise of macroscopic oxygen-breathing organisms and in the Neoproterozoic-Cambrian with the emergence of animals.” Dominic Papineau

When economists try to put a value on the biosphere, they are kidding themselves and us.  As Vaclav Smil points out without a healthy biosphere, humans cannot survive [1].  Our dependence is existential.  Nor is this dependence limited to the current biosphere.  We owe our existence to the biosphere extending back through deep time.

 The Earth is 4.55 billion years old and its history is divided into four eons.  The earliest the Hadean Eon ended 3800 million years ago.  The Hadean Earth was dominated by the kinetic energy of constant collisions as it swept up debris scattered along its orbit in the young solar system.  A magma ocean bubbled on its surface, a frightening uninhabitable place.  The Archean Eon lasted from 3800 million years ago until 2500 million years ago.  The Archean Earth climate was temperate despite the faint young sun we’ve discussed in a previous article [2].  James Kasting proposed that it was moderated by carbon dioxide and the methane produced by methanogenic Archaea [3].  These methane-producing microorganisms kept the Earth from freezing solid, while the sun’s fusion reactor gradually intensified through the Archean, giving the rest of life a chance.

 The Proterozoic Eon began where the Archean left off and ran until the Cambrian Explosion 544 million years ago, the start of the present Eon, the Phanerozic.  But we are interested today in two remarkably similar events which bookend the Proterozoic.  These events have in common the breakup of a supercontinent, several snowball Earth episodes, where the Earth’s oceans may have frozen to the equator, interspersed between hothouse climates, a rise in atmospheric oxygen and a leap in biological evolution as described by Papineau [4].

 As the Archean Eon gave way to the Paleoproterozoic nickel isotope sedimentary deposits suggest that the productivity of the methanogens were winding down [5].  Methanogens use nickel in their metabolism to produce the atmospheric methane which along with the principle greenhouse gas carbon dioxide was keeping the Earth warm.  At the same time the supercontinent Kenorland was breaking up.  Rifting of supercontinents is accompanied by increased weathering of the newly exposed surfaces.  When the most recent supercontinent Pangaea broke up 200 million years ago the rift valley forming between South America and Africa became the Atlantic Ocean which is still spreading.  The rifting of the supercontinent Rodinia during the Neoproterozoic, about 700 million years ago gave rise to the Iapetus Ocean.

 Increased weathering released phosphorus into the seas.  Phosphorus is the most limiting element in the biosphere presently, as discussed by Dave Vaccari in a recent Sustainable Planet article [6, see also 4 and 11].  Even today plants concentrate phosphorus and can contain up to seven times the concentrations in the surrounding soils.  At the same time methanogens were becoming less productive at the end of the Archean, ancestors to present day cyanobacteria bloomed as a consequence of increased phosphorus which these microbes need for oxygen photosynthesis.  From Susan Gaines remarkable textbook on molecular fossils Echoes of Life [7] and from Plaxco and Gross’ Astrobiology [8] text book we learn that these bacteria may have been around for several hundred million years waiting for this opportunity. 

Oxygen photosynthesis increased the level of atmospheric oxygen after the breakup of Kenorland from essentially zero to about 2% of the atmosphere.  Oxygen is poisonous to methanogens so this turn of events created the opportunity for an entirely new biological regime.  But it also drew down the atmospheric carbon dioxide.  As a consequence of the loss of methane and carbon dioxide the Earth froze over.  Since the ice and snow which now blanketed the planet reflects most incoming short wave solar radiation rather than absorbing it, there is no known way which the Earth could have recovered except for volcanic activity and the release of carbon dioxide.  Enough carbon dioxide accumulated in the atmosphere over millions of years to melt back the ice and snow by trapping long wave heat radiation from the Earth surface.  Once the ice melted away completely, the huge quantity of carbon dioxide necessary to melt it in the first place now created a superheated greenhouse effect.  The subsequent increased weathering of silicate rocks [9] and additional bacterial blooms kick started the process all over again, drawing down the carbon dioxide leading to yet another snowball earth episode.  Each cycle may have pumped more oxygen into the atmosphere.

Essentially two chemical reactions take place which draw down carbon dioxide in a hot house climate.  The first is inorganic and involves the weathering of silicate rocks.  This is the Earth’s thermostat [9] and is given by the following simplified equation.

CO2 + CaSiO3 -> CaCO3 + SiO2

 In a hot house climate more water evaporates off the oceans and forms carbonic acid with the carbon dioxide in the atmosphere.  This weak acid rains out onto rocks weathering them.  Note that in this equation carbon dioxide is drawn down when the calcium carbonate and silica are “buried in marine sediments and eventually into the geological record [9].”  This process extracts excess carbon dioxide from the atmosphere but does not create free oxygen.

 However, oxygenic photosynthesis performed by the bacterial blooms, encouraged by the newly releases phosphorus performs the following reaction.

 CO2 + H2O -> CH2O + O2

 When organic compounds, here represented by CH2O, are buried as sediment without being oxidized and consumed by other organisms there is a net draw down of carbon dioxide and atmospheric oxygen is created.  Note that while rock weathering can act as the Earth’s thermostat by controlling the amount of carbon dioxide in the atmosphere, it cannot create atmospheric oxygen.  We need life for that.  The free oxygen created an opportunity for heterotrophic bacteria and eukaryotes to exploit and they did.  It also relegated methanogens, the heroes of the Archean, to anoxic hideouts such as deep ocean sediment, swamps and cow stomachs. 

 The Neoproterozic rifting resulting in the breakup of the supercontinent Rodinia about 750 million years ago had the same effect.  This rifting forming the Iapetus Ocean is recorded in the geological record of Loudoun County [10].  The sun was much warmer now, about 94% of today’s sun and the Earth was kept warm by its blanket of carbon dioxide.  With the breakup of Rodinia, the events of the Paleoproterozic were repeated.  Increased weathering of the continents increased burial of both inorganic and organic carbon with a subsequent rise in atmospheric oxygen, this time from about 2% to 20% of the atmosphere.   Again the Earth’s climate oscillated between a snowball and a hothouse several times between 750 and 580 million years ago [4].  While Eukaryotes were certainly already around, it was this rise in oxygen, due to photosynthesis, which allowed the evolution and radiation of metazoans; complex life. 

So we are alive today, not just because of the other inhabitants of our biosphere, the Earth’s environment but we also owe a debt of gratitude to the biospheres in Earth’s past.

 Tony Noerpel

 [1] Vaclav Smil, Global Catastrophes and Trends, the next fifty years, 2008


[3] Kastings, J., “When Methane made Climate”, Scientific American, 2004.

[4] Papineau, D., “Global Biogeochemical Changes at Both Ends of the Proterozoic: Insights from Phosphorites,” Astrobiology, Vol 10, Number2, 2010.

[5] Konhauser, O., et al.  “Ocean nickel depletion and a methaogen famine before the Great Oxidation Event,” Nature vol 458, April 9, 2009.


[7] Gaines, S., Eglinton, G. and J. Rullkotter, Echoes of Life, Oxford, 2009.

[8] Plaxco, K., and Gross, M., Astrobiology, Johns Hopkins University Press, 2006.

 [9] Berner, R., The Phanerozic Carbon Cycle, Oxford University Press, 2004.

 [10] Southworth, S. et al.  Geologic map of Loudoun County, Virginia, U.S. Department of the Interior, to accompany map OF-99-150 U. S. Geological Survey.

 [11] Filippelli, G., “The global phosphorus cycle: past, present and future,” Elements, Vol. 4, pp 97-104, April, 2008.

Edible Landscaping: Apples – Part 1

Apples would be the first fruit mentioned when the subject of fruit trees is raised, so we would be amiss not to start with them.

There are excellent orchards in Loudoun that are sources of a wide variety of apples, so we continue to PYO at these orchards frequently, even buying excess that we make into applesauce. As you will see, the list of pests and diseases that can potentially attack an apple tree or its fruit is quite extensive, requiring long hours of studying and possibly numerous sprayings throughout the growing season, so leaving apple growing to the local orchards might be the approach to take. Don’t worry, there are many other fruits and nuts to pick from, so don’t be dissuaded right off the bat.

Let’s take a look at our criteria (and add a couple) to see how apples may (or may not) be a factor in our landscape;

Disease resistance: In the Mid Atlantic, there are many diseases which can affect apple trees and their fruit, which can be reviewed at the Mid-Atlantic Orchard Monitoring Guide and at the WVU Index of Fruit Diseases. While these lists are long, some of the more troublesome ones in this area tend to be Apple Scab, Cedar Apple Rust, Fireblight, and Powdery Mildew. The good news is, there are varieties that are resistant in varying degrees to these diseases. To simplify matters, let’s take a look at those cultivars that are [1];

VR = Very Resistant

R = Resistant

MR = Moderately Resistant

Variety Resistance ratings Tree growth habit Comments
Apple scab Cedar apple rust Fire blight Powdery mildew
Dayton VR MR R MR Semi-vigorous, spreading Sometimes prone to bitter pit
Enterprise VR R R MR Moderate to high vigor Best flavor after Very resistant month in storage
Freedom VR R R R Vigorous, spreading Good pollinator for Liberty
Jonafree VR MR MR MR Moderately vigorous, may have some bare wood Similar to Jonathan in appearance, not prone to Jonathan spot
Liberty VR VR R R Vigorous, spreading One of the best disease-resistant cultivars, a McIntosh-like fruit. Susceptible to European Red Mite and San Jose Scale
Nova Easygro VR VR R R Moderately vigorous, spreading Developed in Nova Scotia
Novamac VR VR R MR Vigorous, upright and spreading Susceptible to preharvest drop, developed in Nova Scotia
Priscilla VR VR R MR Moderately vigorous, thin branched Fruit cracking when overmature
Pristine VR R MR R Moderately vigorous, spreading, wide crotch angles Less susceptible to bruising than Lodi
Redfree VR VR MR MR Vigorous, spreading,wide crotch angles Some bare wood on limbs
Trent VR R MR R Moderately vigorous, slightly upright Susceptible to bitter-pit, from Ontario
William’s Pride VR VR R R Vigorous, spreading, large tree size Not recommended on a MM. 111 rootstock due to bitter-pit, prone to water core

Pollination: Apples require pollination from another cultivar that flowers during the same time (crabapples can also be used as a pollinator). Semi-dwarf trees should be within 50 feet of their pollinator; dwarf trees within 20 feet.

Cultivar Pollination time Typical

harvest time



Fruit characteristic
Pristine early late July 1.5 months Medium-large; yellow

with blush; slightly tart

Williams’ Pride early/mid late July 1.5 months Medium-large size; red fruit;

softens quickly; spicy,

well-balanced flavor

Redfree early/mid early Aug 1 month Medium size; bright

red; well-balanced flavor

Jonafree early/mid early Sept 2 months Similar to Jonathan
Liberty early/mid early Sept 5 months Small-medium size;

red over green color;

McIntosh-type of fruit;

tart with coarse texture

Enterprise mid/late mid Oct 6 months Large; bright red;

spicy and juicy

Trent mid/late late Oct 6 months Medium-Large; Red blushed

over light green, sub-acid

,less than McIntosh

Fruiting Schedule: See above chart for times.

Harvest: To ensure maximum storage life, apples should be harvested when mature but not yet fully ripe or overripe. If harvested before they have matured, apples will have poor eating quality, will be more susceptible to storage disorders such as scald, cork spot, and bitter pit, and may not ripen properly. [2]

Storage: See above chart for storage duration. An apple continues to live and respire after it is picked. Although respiration cannot be halted completely, the objective of postharvest cooling is to slow the process and thus increase storage life. Even if apples are to be stored for only a short period, it is still very important that the field heat be removed from them as soon as possible. Apples respire and degrade twice as fast at 40 F as at 32 F. At 60 F they will respire and degrade more than six times faster. The optimum storage temperature for apples depends on the variety, but all are within the range from 30 to 40 F. [2] Ventilation keeps ethylene and carbon dioxide from building up to damaging levels. While refrigerators are generally used by commercial orchards/wholesalers, backyard orchardists can also take advantage of root cellars and barrels in garages for late season apples, as long as humidity levels can be maintained.[3][4]

Size: The size is predominantly determined by the rootstock. Virtually all commercially available apples (with some exceptions) use a rootstock to impart size and disease resistance qualities to a grafted variety. Some common rootstocks are shown below along with their sizing tendencies. Note: Standard size apple trees are very difficult to manage, due to the need to prune, harvest, and inspect. Semi-dwarf trees are much more manageable, and dwarf trees are by far the easiest.

There are many other rootstocks available, and it helps to know which rootstock a nursery is offering with a tree (though often times that information is not at the fingertips of the person answering the phone. I normally discover the rootstock on the tag when the tree arrives.)

Growing Techniques: These range from the ordinary freestanding to espalier, trellis, and spindle (advanced trellis) techniques. Most beginner backyard growers default to the usual freestanding central leader, which is fine for simple purposes. Espalier produces a decorative look that also provides support for dwarf varieties. Trellising gives easy access to a number of dwarf apple trees that can be space efficient. Spindle systems are by far the most productive in terms of space, productivity, and time to full bearing [5][6].

Technique Density per acre Spacing
Freestanding 132-290 12’x 20′
Trellis 605 6’x 12′
Slender Axis 908 4’x 12′
Tall Spindle 1320 3’x 11′
Super Spindle 2178 2’x 10′
Tall Spindle

Tall Spindle

Super Spindle

Super Spindle

Part 2 will cover pests and miscellaneous.

— Will Stewart


1. University of Missouri Extenstion Office, Apple Cultivars,

2. NC State Extension Service, Postharvest Cooling and Handling of Apples,

3. Maryland Extension Office, Root Cellars,

4. Purdue Extension Office, Storing Fruits and Vegetables at Home,

5. Terence L. Robinson, Cornell Department of Horticultural Science, Modern Apple Training Systems,

6. Michael L. Parker and C. Richard Unrath, Department of Horticultural Science, North Carolina State University, High Density Apple Orchard Management,

Landscaping with fruit and nut trees…and more…

5 years ago, I decided I was going to shift from a native plantings landscaping theme to one that turned my yard into a sylvan garden.  I had read about “Edible Landscaping” and “Permaculture”, and decided that approaching tough economic times could be mitigated by growing more of my own food in a manner that did not require a large degree of manual labor. After all, we are supposed to have several helpings of fruit each day, and nuts have been shown to be very healthy sources of protein and essential fatty acids (and even lowering cholesterol). My family likes to PYO at local orchards or buy at farmer’s markets, and felt that augmenting those purchases with our own fruits and nuts meant that we would rely even less on the local supermarket.

Where to start?

So how does someone go about determining what they can or can’t grow well in this area, or in a specific yard? First, one needs to know what hardiness zone they are in, to eliminate plants that will freeze in their area. We used to be on the edge of hardiness zones 6 and 7, but global warming trends now have us well into zone 7 (as calculated by the Arbor Day Foundation).  Thus, we can remove from our potential list all plants that require at least zone 8 (or 9, etc). Conversely, some plants require colder climes than zone 7.

From this point, we need to understand a few specifics about our site;

  • Disease-resistance: Many popular fruit varieties (that often show up in local chain store inventories) require extensive spraying to control a wide array of diseases, many of which have been imported from other countries and attack local species that have no inherent immunity.  Considerable effort has gone into creating hybrids of species with numerous immunities to produce species that are resistant to a wide variety of disease.  Once you decide on the types of fruit you would like to grow, learn about the diseases that are endemic in your area. Then select varieties that are resistant to those diseases. (More on this in future articles)
  • Pollination: Some species are self-pollinators and do not require a second specimen or variety to produce fruit.  Many species, however, require a second specimen or even another variety to produce fruit.  In this case, you must consider the other varieties that are needed, the timing of the spring bloom (which must overlap sufficiently), and an extra specimen so that the loss of one tree does not eliminate the ability to pollinate.  Also note how close pollinators should be (e.g., “no further than 25 feet”).
  • Fruiting schedule: Be cognizant of the timeframes in which your fruits will ripen; the best approach is to try to cover as much of the calendar year with harvest as possible.  For example, I’ve chosen 4 varieties of apples that will provide fruit from July through November, with the later apples able to be stored through the winter (“winter-keepers”).  Other choices include strawberries (May) and June berries for early fruit and Lingonberries for late fruit (December).  This way, one can enjoy fresh fruits almost year around.
  • Pests: Find out from your local horticulture agent which pests are likely to attack the types of fruits or nuts you’ve chosen.  Often, disease-resistant varieties also have some resistance to common pests.  Many natural pesticide products exist to keep insects from damaging your trees or fruit crop, and there are natural predators that can be encouraged (with their favorite habits) to take up residence in your yard.
  • Size: Standard sizes of common fruits such as apples, pears, and others are often too large for homeowners to maintain and harvest.  Dwarf and Semi-dwarf varieties are very popular now with home gardeners, and they also bear fruit much sooner.  The size (and other attributes such as disease resistance) depends greatly upon the rootstock used. Nut trees can be large without much issue.
  • Harvest/Storage: When will each plant bear their crop? How long can it be stored? What are the preferred storage conditions (temperature, humidity)? Can they be dehydrated/canned/etc?

Initial List

After performing the above analyses, I came up with the following list;

Fruit Trees:

  • Apple
  • Asian Pear
  • Plum
  • Pawpaw
  • Jujube (Chinese Date)
  • Persimmon (American)
  • Persimmon (Asian)
  • Watermelonball Tree (Chinese Mulberry)


  • Blueberry
  • Raspberry
  • Grapes
  • Ligonberry
  • Juneberry
  • Elderberry
  • Gooseberry
  • Goumi
  • Aroniaberry
  • Black Huckleberry
  • Figs
  • Kiwi


  • English Walnut
  • Heartnut (Japanese Walnut)
  • Northern Pecan
  • Filbert
  • Chestnut

Does this look like a lot of plants? It is, though one’s yard can be artfully planned out to yield a large amount of fruits and nuts with a thoughtful design approach. For example, one family in Chicago has a planting of 97 apple trees (and other fruits) in a 1/4 acre yard!

97 Apple trees in the yard

Our own yard is approximate 1/3 acre, though we have many acres in sheep pasture. Coincidentally, the sheep also need some relief from the summer sun, so plantings just inside the electric fence (protected by circular fence cages) serve dual purposes.

In coming articles, we’ll talk about laying out plans, the types of fruits and nuts that are doing well here, and how to put it all together to begin executing your plan early this fall.

Come discuss your thoughts at the Sustainable Loudoun forum entry forum for Fruit Trees.

–Will Stewart

Biofuel Potential for Loudoun County

The recent Green Energy Partners’ power plant application provides an excellent stimulus for us all to begin thinking about Loudoun’s energy future. A few weeks ago, several members of the business (including GEP), agricultural, and environmental community pooled their efforts to write a briefing on the subject of bio-fuels.  We have submitted it to the Board of Supervisors as a “Friend of the Board” submission.

Bio-fuels have received a lot of attention in recent years, but the discussions are usually about corn-based ethanol, mid-western farmers, or massive industrial concerns like Archer-Daniels-Midland. The briefing our team submitted to the Board addresses the economic, agricultural, technical and environmental considerations of using bio-fuels as a potential component of our energy supply right here in Loudoun.

Some readers may object to the concept of using plants as a source of energy assuming it is not technically possible, or is not economically competitive with regular fossil fuels.  But that may no longer be the case.

Plants are hydrocarbons, just like fossil fuels.   Our coal resources were once plants which for the most part lived about 300 million years ago during the Carboniferous Period.  Our petroleum resources were marine diatoms and coccolithophores and other phytoplankton.  There are several maturing technologies for converting plants into diesel fuel, gas, lubricants, and even plastic. Some plants, such as algae, are nearly 70% oil by weight. Another plant that can be made into bio-fuels is switchgrass. Switchgrass looks a lot like hay, and is planted, grown, harvested, and stored just like hay – using the very same equipment, and the same types of land, and the same rainfall pattern – and a lot less fertilizer.

There is one difference between using fossil fuels and bio-fuels: bio-fuels recycle CO2 back to the atmosphere where the plants harvested it in the first place, instead of creating new atmospheric CO2 which happens when fossil fuels are burned. If Loudoun County used bio-fuels to generate all of our electricity, our CO2 creation would drop by about 29%.

From an economic and agricultural perspective, the new power plant will spend nearly $140 million per year on fuel. If that fuel was bio-fuel instead of fossil fuel, much of that $140 million per year would go to Loudoun’s farmers. It’s worth noting that Loudoun still has 140,000 acres of highly productive farmland, of which about 40,000 acres are devoted to hay production.

In addition to fueling the power plant biofuels could be used to run our cars, our school busses, our commuter busses, and our tractors and heat our homes.

The briefing we submitted to the Board of Supervisors can be downloaded from the Sustainable Loudoun website at . Hopefully, you will find it entertaining reading and well-researched.   Our paper discusses the pluses and minuses including most importantly the energy recovered as a function of the energy that would need to be invested, i.e., the energy cost of the fuel.  We have identified the most conservative estimates as our baseline.

In a 2005 study conducted by Pimental and Patzek [Pimentel], switchgrass production was analyzed for EROEI, with these results:

The average energy input per hectare for switchgrass production is only about 3.8 billion calories per year. With an excellent yield of 10 tons per hectare per year, this suggests for each one thousand calories invested as fossil energy the return is 11,000 calories — an excellent return.

So the energy recovered over the energy invested is about 11:1 for switchgrass production looks promising. The next question, of course, is how much energy it takes to convert that switchgrass to fuel and to distribute that fuel to the end-user. The task of making the conversion and distribution functions cost-competitive with fossil fuels is the subject of considerable research and development at the moment [DEP].

Of course we must also consider competing uses of our farm land such as growing food.

The bio-fuels briefing we prepared provides a readable, short, and very informative survey of the potential for a new bio-fuel economy here in Loudoun. You may be surprised by what you read, and get inspired to discuss it with other members of the Loudoun business, agricultural, and environmental communities. To join our list-serve e-mail discussion system, just send an e-mail to Please include the word “help” in the subject line, and we’ll send you instructions to join the list. To download the briefing from our website, just point your browser to

Tom Pfotzer, Will Stewart and Tony Noerpel

[Pimentel] Ethanol Production Using Corn, Switchgrass, and Wood; Biodiesel Production Using Soybean and Sunflower. Pimental and Patzek, January 2005.

[DEP]U.S. Department of Energy briefing on BioFuel technology methods and trends.

« Older entries