Forest Owners to EPA: Massachusetts made wrong choice

The National Alliance of Forest Owners (NAFO) recommended to the U.S. Environmental Protection Agency (EPA) that they defer the regulation of greenhouse gas (GHG) emissions from biomass for three years. the EPA is considering regulating biomass energy the same as fossil fuels. David P. Tenny, President and CEO of NAFO, underscored NAFO’s desire for the EPA to conduct comprehensive reviews of the science and policy, “This week, Massachusetts issued proposed regulations that effectively shut the door on renewable biomass energy in that state. This appears to be what officials wanted when they initiated a study on biomass energy that limited the area and timeframe considered in a way that significantly skewed the outcome. The flawed study resulted in a flawed policy. EPA can learn from the unfortunate outcome in Massachusetts to put in place an even-handed review.”

Tenny noted that EPA’s review is more a question of policy than science, “The science is really a settled question – the cycle of biogenic carbon is biology 101. Carbon released from biomass energy is replaced in real time through continued forest growth without increasing overall carbon in the atmosphere. The question EPA must answer is how policy can best apply this science to meet our renewable energy needs and reduce unrecyclable fossil fuel carbon emissions. Unlike Massachusetts, we are hopeful that EPA will conduct a review of policy options free of arbitrary assumptions or parameters that skew well settled science.”

NAFO’s comments to the EPA provide answers with supporting science to the policy questions EPA must answer:

* Forest carbon is most accurately measured on a national scale over a continuous timeframe rather than applying arbitrary time and space limitations on carbon measurement

* Because forests remove more carbon from the atmosphere than they release through natural and human activities, biomass energy emissions don’t increase carbon in the atmosphere and should be excluded from GHG regulations for stationary sources

* EPA should not impose a regulatory “baseline” or “business-as-usual” requirement on forest carbon that would compel forest owners to continually increase the carbon stored in individual forest tracts.

Tenny reminded the EPA that NAFO, “stands ready to work with the Agency to establish a policy recognizing the full carbon and landscape benefits of forest biomass as an energy source.”

NAFO’s comments were submitted as part of the public comments for the proposed rule entitled, “Deferral for CO2 emissions from Bioenergy and Other Biogenic Sources under the Prevention of Significant Deterioration and Title V Programs.” NAFO full comments on this rule and the Call for Information are available on their website.

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Trees ain’t thermometers

I used to work on Mountain Home State Forest in the southern Sierra. MHSF has about 3000 specimen-sized sequoia within its boundaries. Dendrochronolgists often visited to see the stumps from logging in the mid to late 1800s. These were often over 2000 years old when they had been cut.

The Dendrochronolgists were interested in the tree-ring patterns. Trees grow fast or slow in response to many factors and these seasonal factors (light, water, nutrients) created ring signatures or patterns. Certain years might have been favorable for growth with plentiful water, light and nutrients (each favorable year would be marked a large, wide ring) and certain years might have had poor conditions for growth–drought, late spring conditions, early winter–marked by thin (in some cases–microscopic) rings. In general, the wider the ring the more favorable the growing season, the narrower the ring the poor the growing conditions. These ring patterns can be distinctive and can be used to date archeological sites (where wood is present).

Oxford’s Tree-ring Laboratory put it this way:

The way dendrochronology works is relatively simple. As a tree grows, it puts on a new growth or tree-ring every year, just under the bark. Trees grow, and put on tree-rings, at different rates according to the weather in any given year: a wider ring in a favourable year and a narrower ring in an unfavourable year. Thus, over a long period of time (say 60 years or more) there will be a corresponding sequence of tree-rings giving a pattern of wider and narrower rings which reflect droughts, cold summers, etc. In effect, the span of years during which a tree has lived will be represented by a unique fingerprint, which can be detected in other geographically-similar tree-ring chronologies.

Using tree rings as a proxy for temperature however is fraught with caveats and pitfalls.

Mike D.‘s of the Western Institute for Study of the Environment comment (on William M. Briggs’ blog) about using tree ring data as proxies for temperature is an excellent explanation of the problems of using tree ring growth for temperature. He starts with how tree rings are laid down:

Diameter growth on any tree is theoretically a sigmoid growth function. No tree puts on constant radial growth year after year. Trees grow by adding a layer of new wood at the cambium, under the bark. Each year a larger surface area is added. If growth is constant, the rings get narrower. But growth is never constant. There is significant deviation from ideal (model) sigmoid diameter growth in individual trees regardless of the weather. Even when sigmoid growth models are used, the natural variation adds statistical error.

Two sigmoid curves. The taller is the period annual increment for cubic feet; the lower smoother S curve is for mean annual increment of cubic feet.

So as the diameter expands, the amount of material put on would need to be more if the ring’s width was to stay the same as the previous season. Think of a clay disk that you add the same amount of clay to in successive rings. The volume of clay would be the same but the thickness of each new ring would decrease. The ring growth is S-shaped (sigmoid) because initially the tree has little foliage for photosynthesis and often puts its initial years into root development for survival. Then once roots are deep enough the tree puts its growth into height and width.

He then points out that tree-to-tree competition for light, water, and nutrients also affects the ring growth:

Dense stands exhibit narrow rings on individual trees, sparser stands may have wider ring growth, yet both stands may have equivalent gross growth. That’s why only open-grown trees are supposed to be selected for ring studies. But nobody knows what the tree density surrounding an individual tree was 100, 200, 500 years ago. Competitors could have arisen and died without leaving evidence of their presence so long ago. More error.

Besides competition, disease and injury can affect growth.

Trees can sustain injuries that affect growth, such as top and branch damage, that are difficult to detect 200 years later, especially a few feet off the ground where the rings are sampled. There are very few pristine, undamaged trees. I know, having searched for such across broad acreages. Open grown trees at high elevations are always damaged. A heavy winter snow can snap off branches and the tree will exhibit reduced diameter growth for a few years, even if growing season conditions are ideal.

This makes using tree ring data as stand-ins for temperature problematic.

Ring width has all but been abandoned as a temperature proxy. Instead, the latest technique is sampling rings for O18 ratios, under the assumption that O18 varies with temperature. Regardless of the ring width, the O18 ratio is supposed to have recorded growing season temperature. But that theory is fuzzy and mushy, and O18 ratios in living trees correlate very poorly with known growing season temperatures. In other words, it calibrates with much error at best.

Trees are not thermometers, but even thermometers have some serious measurement error problems.

Tree ring studies are a fad akin to phrenology and other discredited pseudosciences that has not dissipated as it should have decades ago.

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Deforestation changes climate not the other way around

3-year Project for One Million Trees to be Planted in Africa’s Mt Elgon Region Begun

Women walking down from Mt. Elgon national park with firewood. Cutting down of trees has led to massive deforestation of Mt. Elgon range in eastern Uganda. Photo: © Charles Akena/IRIN

A three-year project to increase forest cover and help local communities in eastern Uganda reverse the effects of deforestation has begun.

While the project is billed as one to help reverse the effects of climate change (A UK Department for International Development official said: “We very much hope this project will enable the people of Mbale region to provide the rest of the country with a vivid example of how to creatively mitigate against the effects of climate change in a way that also contributes to economic growth.), the actual reason may be more prosaic: deforestation.

Joseph Wesuya, an official of the African Development Initiative – a community organization in Manafwa district – said high population density in the Mt Elgon region had put a lot of pressure on the area’s eco-system. “Our environment is depleting at a fast rate; people are cutting down trees up the mountain, encroaching into wetlands,” he said. “The snow caps high on Mt Elgon are melting and you hardly see frost.”

This pattern mirrors what is happening on Mt Kilimanjaro due to deforestation.

The link between forests and rainfall and runoff have long been known. Forester and soil scientist, Walter Lowdermilk pointed to the link nearly a century ago. In 1923, he and engineer O.J. Todd made a two-thousand-mile survey up into the province of Shaanxi to find why the Yellow River caused trouble. Experts of the day pointed to catastrophic climate change. He found “the country was cut with enormous gullies…I measured one up to six hundred feet deep.” Yet in the midst of this devastation he found island of green. He found “[Buddhist] temple forests which priests had preserved for places of meditation, and managed for growing timber for repairs…there was no erosion of soil within them, that the ground was covered with forest litter and the trees were reproducing themselves naturally, in response to the climate and rainfall of the day.” Here was a clue that clearing of vegetation affected climate. He set out experiments. He conclusion were that “erosion alone was sufficient to account for the decline of a civilization and that we didn’t need to rely on a theory of change of climate.”

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