Young Trees better than Old: CO2 ??

[M.D. Vaden]

While browsing web pages today, I came across this one at Wikipedia:

http://en.wikipedia.org/wiki/Canopy_research

The page says that young forests can contain ten times the CO2 that grown forests do.

Does the vocabulary sound correct?

If this were the case, would it make sense in urban areas to start cutting down older trees and replacing with younger trees?

With forests, where would the extra CO2 storage be - in the trees themselves, or the whole forest from debris to small plants to the canopy?

This seems like an interesting piece of information.

 

[ShoerFast]

Yes,

That is my understanding.

New growth can make more O2 and old growth makes more CO2 .

 

[windthrown]

Nothing stores more carbon in biomas than a healthy conifer stand, per unit area. Ideally you want the stand growing optimally; plant them closer together and they will grow faster, then after 15 or so years, start thinning so that they continue to grow optimally. Continue to thin every 10 years or so until the point that they slow down in growth. Then cut and replant. Your typical clear cut process, really. But that is evil and vile, and ugly, and all the tree-huggers cannot stand it! As the article says, old mature growth stands and forests do not put on the boimass that a younger stand does. In a tropical or temperate forest.

Also, if you cut mature urban street trees down and replant them, what do you do with the trees you cut? Burning them will release the carbon back into the atmosphere. Letting them rot will do the same thing. :monkey:

 

[pdqdl]

not quite true, but close

...

Also, if you cut mature urban street trees down and replant them, what do you do with the trees you cut? Burning them will release the carbon back into the atmosphere. Letting them rot will do the same thing. :monkey:

The wood that rots is eventually converted by living organisms into some form of biomass, be it fungal spores or the carbon containing amino acids that make up the proteins in our own cells. Not until the carbon is "respired" by some organism is most of the carbon returned to the atmosphere as CO2. Until then, it is mostly stored as the "organic material" reported in our soil samples.

The oil, natural gas, and coal that form our fossil fuels were once the accumulated organic compost from an ancient source. If we let enough forests grow to maturity for the next several hundred millenia, we would have a self-sustaining fossil fuel farm!

 

[ATH]

On the decay: yes, much is converted to "biomass", but the majority is released by all those critters decaying it, like you said through respiration. Unless it is being decayed in an anaerobic environment.

The one thing I'd add to what windthrown said is that the CO2 is best stored if the cycle ends in a long-term use (house, furniture, cabinets, flooring, etc...).

To the original question: "...would it make sense in urban areas to start cutting down older trees and replacing with younger trees?": I think it you look at the energy we put into removing trees, it makes less sense in the urban forest than it does in the traditional forest. The lack of long-term products emphisizes this.

Final thought on trees and carbon cycles: what if they started making biofuels out of trees instead of corn? (FWIW: It has started, and I think it will be happening on a much larger scale on the horizon...)

 

[pdqdl]

Yep.

When they finally figure out how to convert cellulose and lignin into ethanol (or other liquid fuels) we will be knocking down some profitable tree work then! No dump fees! Pay me for each truckload of chips!

It still won't solve the carbon problem, but it will reduce the fossil fuel addition to the environment.

 

[windthrown]

Yep.

When they finally figure out how to convert cellulose and lignin into ethanol (or other liquid fuels) we will be knocking down some profitable tree work then! No dump fees! Pay me for each truckload of chips!

It still won't solve the carbon problem, but it will reduce the fossil fuel addition to the environment.

Uh, that is already possible. You can make methanol from the wood directly, but that is nasty stuff, and has lower efficiency burning than either ethanol or gasoline. You can also treat wood with acid and then ferment it into ethanol. But for all that effort, it would probably be more efficient to burn, or rather, gassify the wood and use it for electrical and heat generation. Burning wood does solve the carbon problem, as much is growing as is being used, and in most cases, more trees are growing than are being cut. The overall forest mass in the US is well above what it was 100 years ago.

Wood fires electrical plants are bing built in Minnesota. We have an OWB here that burns wood directly for heat. We displace $200-300 a month in electricity by doing this. That is all hydro, but that still allows that electricity to be used someplace else, which in turn should displace fossel fuel from being burned. With the rates for timber being so low right now, selling it as fuel has a better return. But total wood energy available is pretty low compared to say, coal. The US has vast reserves of coal, and in my view, we should ramp up and use Hitler's solution to make synthesized gas from coal and burn that instead of gasloline. That would not solve the carbon problem, but it would solve the high cost of oil and gasoline problem.

 

[Ianab]

They may have corrected the article..

It now reads

"While grown forests continue to store carbon dioxide, young forests store up ten times more. "

Now that makes sense, in an old forest trees are dieing, rotting, being eaten by bugs and fungus, catching fire etc. So eventually the CO2 given off is approx the same as that absorbed.

But in a new forest all the young trees are laying down new wood, which contains a lot of carbon. Not many of them are dieing, so the forest aborbs more CO2 than is released.

The trick is then to then take that carbon out of the forest and hide it someplace and grow another young forest. Not allways so practical. Or use it as fuel, then the CO2 produced by your fire. power station, synthetic petrol from wood factory etc, can waft over to the new forest and get absorbed again.

Cheers

Ian