- September 15, 2008 at 1:38 am #39784
There is a great deal of buzz these day regarding carbon sequestration. I have heard talk of land owners marketing “carbon credits”. Even in this forum (draftanimalpower.com) I have read the term “carbon positive forestry”.
I struggle with the validity of this concept. With the exception of “afforestation” (land use change to a forested condition, typically from a previous land use with less biomass measured in tons / acre) forestry is “carbon neutral” over the long term. And sustainable forestry by definition requires a long term view.
A forest, whether natural or managed in perpetuity, produces exactly as much carbon dioxide as it consumes. By photosynthesis trees sequester atmospheric carbon. Roots, trunk, branches, and leaves are largely built of carbon. Roots, trunk, branches, and leaves all ultimately die and release carbon dioxide by means of decomposition or combustion.
Carbon is not created or destroyed. It merely cycles through the system. The only real problem with fossil fuels is that we are burning them far too fast. In a few short centuries we have burned biomass (yes oil and natural gas are biomass) that took millions of years to accumulate.
I am a strong advocate of sustainable forestry and see it as one of the highest and best uses of our landscape, largely compatible with watershed and wildlife conservation. But I take issue with the portrayal of forestry as a panacea for the industrial footprint of our society. No matter how well I manage my small woodlot here in Vermont it will never offset even a single ton of CO2 produced by combustion of fossil fuels.
I am very interested in hearing your thoughts on this topic.
W. Topsham, VTSeptember 15, 2008 at 11:50 am #47361Gabe AyersKeymaster
Well this is a fuzzy subject, but the forest is far more important than understood by the public in general. This post includes a recent editorial on the issue. Although much of what we do is a temporary altering of the human influence, it is beneficial to keep thinking about all of it. There is no question that using less fossil fuel to harvest timber or grow food is carbon positive, compared to conventional methods. That seems pretty simple. The values provided for the public good by proper forest management are yet to be quantified in a dollars and cents way. This understanding will further justify the cost of superior services, such as animal powered, low production, yet highly sensitive methods of man to age the forest. Look forward to the exchange.
SCIENCE: Old-growth forests found to be potent carbon storers (09/11/2008)
Christa Marshall, ClimateWire reporter
Old forests store more carbon than previously thought and should be considered in calculations of a country’s overall greenhouse gas output, according to a new study.
The finding challenges the long-held assumption that trees older than 150 years are “carbon-neutral” entities that neither spew nor absorb carbon dioxide into the air on average. After examining 519 old-growth forest plots worldwide, researchers found that they usually are “carbon sinks,” or natural storage containers with the potential to release large amounts of greenhouse gas back into the atmosphere if disturbed or burned.
“Many scientists today assume in their carbon models that old forests are carbon neutral. That needs to change,” said Beverly Law, a forest science professor at Oregon State University and one of eight co-authors of the research, published today in the journal Nature.
To reach their conclusions, the scientists measured carbon dioxide fluctuations at hundreds of spots, using chambers that measure gas output from soil. In some areas, they also took advantage of large towers operated by networks such as AmeriFlux that analyze carbon dioxide movements between land and the atmosphere.
The carbon-absorbing power of mature forests has been a hot topic of debate, with some arguing that climate change mitigation strategies should focus more on planting new trees, which can sap the greenhouse gas at high rates before they reach 100 years of age. Law noted, however, that it can take five to 20 years for immature forests to reach the point at which they absorb more carbon dioxide than they release.
A 1960s-era study is rejected
“In fact, young forests, rather than old-growth forests, are very often conspicuous sources of carbon dioxide,” the study’s authors wrote.
This is because decaying debris and soil that release greenhouse gases at a site often outweigh the carbon-vacuuming potential of very young trees, particularly if old trees have been cut down at the site or have been ravaged by fire or other natural phenomena, Law noted.
The study spotlights one of the flaws with the Kyoto Protocol, which assesses forestry threats to the climate based on whether widespread deforestation is imminent, said Laurie Wayburn, president of the Pacific Forest Trust. It also holds relevance, she said, for a potential cap-and-trade system in the United States and for the Western Climate Initiative, a multi-state collaboration which has been debating how to incorporate forests into a global warming strategy.
“We need to be giving credits for maintaining standing forests rather than just trying to protect the last stands,” she said. “That is a very different approach from current policy.”
Many mature forests also are not protected by international treaties, the study says, because of the false conclusion that they stop absorbing carbon after a certain period in their lifespan. That myth was derived from a 1960s-era analysis based on 10 years of data at one location, the study said.
Most old-growth trees sit on 30 percent of the world’s forest land mass, with half of that in the Northern Hemisphere.September 15, 2008 at 2:55 pm #47363Carl RussellModerator
I also think important distinction should be made about the impact of the soil ecosystem on carbon cycling. Even though Co2 is lost from a site through decomposition and respiration, the more woody debris left to the soil, the more complex the soil ecosystem becomes, so that even though carbon is not stationary, it is captured at the site while it cycles within the relationships between organisms.
The other component to that, is if all low quality woody biomass is harvested, by conventional methods, there is a burning of fuel for harvest and transport to manufacturing that creates products like paper, or energy, all of which quickly disseminates stored carbon directly into the atmosphere.
By using animal powered harvesting, non-commercial thinning, crop tree release, and growing high quality trees in highly stocked stands that are managed regularly with light strategic harvests to produce high value products that are put to use in items that are used for long term purposes, like structures, furniture, etc, then we can in fact work within the parameters of the ecological process that is actually an accumulator of carbon, thus carbon positive.
Yes, we cannot create carbon, but we can change our use of the natural process to reverse the destruction that we have begun.
No one is talking about replacing the industrial foot print, I think we are talking about changing habits to prepare for a sustainable future.
CarlSeptember 15, 2008 at 4:21 pm #47365Crabapple FarmParticipant
Soil organic matter is a medium term carbon sink, that becomes long term if the soil is not disturbed causing the release of that carbon back into the atmosphere.
As a farmer, not a forester, I’m reminded of the theory of managed pulsed grazing, which has been shown to significantly increase soil organic matter. By harvesting top growth, causing root die back and decomposition without soil disturbance, soil microorganisms can effectively sequester significant amounts of the carbon in the roots into humus. By managing a pasture for maximum active growth, the maximum amount of atmostpheric co2 is absorbed and put into the soil.
Similarly, it seems that actively managing a forest stand for maximum active growth of the trees without disturbing the soil would have a similar impact. The report Jason posted indicated that young forest stands give off co2, because of the disturbed soil implicit in an even-aged young stand. In an uneven aged stand, managed to minimize soil disturbance, the ability to absorb carbon ought to be significant. Up until the management changes, that soil gets disturbed, and all that soil organic matter goes up into the atmosphere.
But no, not significant enough to offset the widespread burning of fossil fuels. There is no real way to do that.
-TevisSeptember 15, 2008 at 5:44 pm #47367
First and foremost I have to say that I am a huge fan of this forum. I strongly support the tremendous efforts of Carl, Jason, Simon, and many others. Promoting sustainable forestry and the use of animal power are pursuits that benefit society as a whole. I appreciate the thoughtful responses to my original post.
Jason, I looked up the article that you referenced (http://www.earthportal.org/news/?p=1023), or at least a summary thereof. Unfortunately I haven’t located the study itself. My interpretation is that one of the primary conclusions was that it is a bit premature to include forestry in carbon trading systems because forest carbon models simply aren’t accurate enough … yet.
I fully agree that maintaining, and increasing where possible, the organic content of the soil is extremely beneficial. The fundamental tenet of organic farming, in my myopic view at least, is “feed the soil not the plants”. The healthy diverse food web that Carl eludes to is vitally important to the health of the forest.
That said, I see the forest as a tremendous reservoir of carbon. If we manage it poorly (land use conversion, soil disturbance, etc) we can drain that reservoir in a hurry. “Do no harm” is the highest management goal we can aspire to from a carbon sequestration perspective. Economic return is beyond the scope of my post.
There appears to be quite a bit of debate within the scientific community regarding net carbon sequestration by forest. Then again the link between lung cancer and tobacco was controversial throughout my entire childhood. Climate change is a more recent example. A round earth is a much older example. Many of these “controversies” stemmed from adamant denial on the parts of governments, industries, and religions with insanely scarey amounts of momentum behind them.
My world view is largely shaped by a handfull of simple engineering principles that my father taught me. Conservation of mass. Conservation of energy. And you can’t push with a rope. Those principles lead me to suspect that an old growth forest cannot sequester any net carbon. If vast quantities of carbon were somehow being pumped into the soil then old growth forest would be on some of the deepest and richest soils in the world. The reality is that these soils tend to be rather shallow. The rain forest is a great example. There’s a reason why swidden (slash and burn) agriculturists had to move so often. A few short years of cropping rapidly deplete the forest soils.
Nor do we permanently sequester carbon by crafting houses or fine furniture. That would may be preserved for a few generations (human generations that is). But ultimately the bulk of it will return to the atmosphere. Ashes to ashes as it were. Seen any thousand year old wooden houses lately?
Carl made an excellent point that animal power reduces the carbon footprint of harvesting operations. Amen to that. I concurr 100%. And Jason if I interpret “carbon positive” forestry as a huge improvement over the alternative we are in 100% agreement. However if “carbon positive” is strictly interpreted to mean sequestering more carbon than is released (year in and year out), then you’ll have to convince me over a few cold malt beverages (I forgot about the carbonation … rats).
Again, you all are doing great work here and I strongly support your efforts. I hope I haven’t ruffled anyones feathers too badly.
W. Topsham, VTSeptember 16, 2008 at 1:56 am #47366Crabapple FarmParticipant
@mstacy 2677 wrote:
… an old growth forest cannot sequester any net carbon. If vast quantities of carbon were somehow being pumped into the soil then old growth forest would be on some of the deepest and richest soils in the world. The reality is that these soils tend to be rather shallow. The rain forest is a great example. There’s a reason why swidden (slash and burn) agriculturists had to move so often. A few short years of cropping rapidly deplete the forest soils.
Ah, but take those old growth forests that are still left standing today for us to look at in context: they are still standing today. All of the forests on nice soil were cut down centuries ago, and a few times since. The base soil in the rainforests in light and prone to leaching, and the climate increases the leaching tendancy. Most old growth stands in north america are in mountainous, rocky or otherwise unfavorable terrain. Terrain that cropping would, as you say, deplete rapidly.
There is also a difference between old growth forest (in which growth has slowed due to the average age of the stand) and a managed, harvested, mature stand (with a higher percentage of young, actively growing trees).September 16, 2008 at 2:39 am #47362Gabe AyersKeymaster
Well Matt, I don’t have any feathers, but it does kind of rub one the wrong way.
It seems a bit dismissive, condescending, marginalizing and reductionism, although kindly patronizing, thank you, bless your heart.
Back at the original post I say “temporary altering of the human influence”, that is the gist of carbon positive forestry definition in a common sense way. Do what we can immediately to make the forest and soil as healthy as we can.
We know that our horses and culture don’t create matter.
But restorative forestry, using animal power – is the best thing to do anyway anyone really wants to look at it or measure it, strictly interpreted or not.
There are many small patches of old growth forest in the coves of Appalachian that are some of the deepest and richest soils in the temperate world.
We know that this work alone won’t erase the modern use of fossil fuels. Those fuels are finite so they won’t last forever.
When they run out maybe this culture will provide a way of survival for our future generations, evidenced by our agreement in it being the best thing to do today…
That’s my story and I’m sticking to it, carbon positive is just one spin on the current buzz word carbon.
Thanks for your support Matt.
What is your draft animal power story?September 16, 2008 at 4:17 pm #47368
Restorative foresty is indeed one of the best things we can possibly do on the land. I agree with you.
And I do apologize for offending you. You inquired about my draft animal experience. Extremely limited. I raised a water buffalo for about a year during my stay in Thailand. The locals thought I was absolutely nuts for trying to teach him voice commands. They were probably right … but we did get him to plow a bit in the paddies.
I am getting a couple of young steers in January as soon as they are fully weened (milking devons). I am eager to learn whatever they can teach me. With a bit of perseverence I’m hopeful that we can drag a bit of firewood to the house.
-Matt StacySeptember 16, 2008 at 5:01 pm #47364Carl RussellModerator
No ruffles feathered here.
Just know that carbon is only part of the equation. Unfortunately, it is a measurable part, and therefore in our modern scientifically unbalanced world, it gets a lot of attention.
In terms of the ecological balance that is disrupted, currently being measured, and evaluated using the carbon cycle, there are many aspects beyond our current understanding.
We live in a world where only those things that are measurable have value, failing to recognize that uncertainty, or the unknown, cannot be delegated a percentage as it relates to certainty, or the known.
The secret as I see it, is not in trying to justify our practice in measurable units, but using our innate abilities as participant organisms in a natural system to observe the processes that are fundamentally entrenched in the ecosystems that we depend on, and allow them to continue to function, regardless of whether we ever fully understand, or can measure, them by managing our impact on them.
This is the kind of conversation that must be linked to animal powered forestry. I am very pleased that we have this site to host it, and to share it with others.
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