best of cc.com Carbon Neutral Denali Climb May 2008

[salbrecher]

Feck, the main point you were trying to prove by the Science article is, according to the article, unanswered; “are forested landscapes different in their sink capacity depending on whether they have old-growth forest or young fast rotating stands?

These questions cannot be answered with certainty yet."

 

I think a key question is what we are defining "old growth" as. Many articles I look at are defining mature as 60 years old which is by no means the old growth I was referring to, and hopefully is still the first part of that trees life. When I said that young planted trees would sequester more carbon in the first part of their lives than old growth I was meaning a mature forest that was in or would soon be in stages of decay and therefore releasing carbon. Given a 100 year period a young planted forest will sequester more carbon than a mature forest that in the same 100 years will be decaying.

 

I also never said that the planted forests were replacing a forest that was the result of logging. Your articles take into account the release of carbon stored in soils that are emitted as a result or soils being disturbed by logging.

 

I have however been forced to take a closer look at my statement and have been reading a number of neat articles on the subject. More reading necessary for me at this time.

 

[salbrecher]

Ecological Modeling Volume 164, Issue 1, 1 June 2003, Pages 33-47

 

"A forest stand can be a carbon sink for up to 200 years old with a peak at 30–40 years old. Old-growth stands are carbon neutral to the atmosphere in the long term."

[AlpineK]

Planting New Forests Can't Match Saving Old Ones in Cutting Greenhouse Gases, Study Finds

 

A new study has cast doubts on an important element of a proposed treaty to fight global warming: the planting of new forests in an effort to sop up carbon dioxide, a heat-trapping gas.

 

The research concludes that old, wild forests are far better than plantations of young trees at ridding the air of carbon dioxide, which is released when coal, oil and other fossil fuels are burned.

 

 

...But it turns out that the soils in undisturbed tropical rain forests, Siberian woods and some German national parks contain enormous amounts of carbon derived from fallen leaves, twigs and buried roots that can bind to soil particles and remain for 1,000 years or more. When such forests are cut, the trees' roots decay and soil is disrupted, releasing the carbon dioxide.

 

Centuries would have to pass until newly planted trees built up such a reservoir underground.

 

New forests are fine as long as they are planted on land that was previously vacant, Dr. Schulze said, adding, "but there has to be a focus on preserving the old growth."

 

 

 

 

Source

 

The analysis, published in the journal Science today, was done by Dr. Ernst-Detlef Schulze, the director of the Max Planck Institute for Biogeochemistry in Jena, Germany, and two other scientists at the institute.

 

 

[salbrecher]

The study mentions old trees but not how old. What I said in my last post and will say again is that I was finding many of the studies were calling 60 year old trees "old", which is not what I was referring to. My brash post also made no mention of carbon sequestering in soils, just the trees, for the reason that a planted forest would not necessarily have to be planted to replace logging or make up for the carbon given off as a result.

[AlpineK]

A tropical rain forest is older than 60 years, so is a Siberian forest. The study notes material that was stored under trees for 1000 years. 1000 > 60.