Deforestation, Lumber and Carbon Emissions

[erikbojerik]

Some thoughts on an early Monday morning after I returned from an earth science conference in which much was made of deforestation and carbon emissions (rightfully so). During one session of this conference, lumber use (i.e. logging) got a very bad rap when it came to carbon emissions, because (as is well known) trees remove CO2 from the atmosphere - and add oxygen - as long as they are alive. But I decided to do some research of my own this morning to check their numbers when it came to logging.

To start:
Total global forest cover = 3,869,455,000 hectars or 3.87e+13 square meters as of year 2000 (http://www.mongabay.com/general_tables.htm)
Annual forest growth = 500 grams/square meter on average (http://www.rff.org/documents/RFF-DP-97-37.pdf)
When multiplied by global forest cover, annual forest growth = 1.94e+16 grams/yr.

Annual global deforestation = 7,317,000 hectars or 7.32e+10 square meters annually during 1990-2005 (http://rainforests.mongabay.com/deforestation.html)
Average growing forest density is 800 grams/square meter so:
Annual global deforestation = 5.85e+14 grams/yr.

Average annual global lumber harvest = 53 grams/m2 (http://www.rff.org/documents/RFF-DP-97-37.pdf).
When multiplied by the rate of deforestation we get:
Annual lumber harvest = 3.88e+12 grams/year.
This assumes that lumber is harvested uniformly from all areas that are being deforested - so it is probably an overestimate of the amount of timber that is being converted into lumber, because hauling logs from forest to sawmill requires roads (but agricultural deforestation does not).

OK - (drum roll) - so the annual production of lumber (3.88e+12 grams/year) is 0.66% of the total mass of forest that is being cut down on a yearly basis. And this is probably an overestimate. This means that something like 99% of the world's forests are cleared for agriculture or ranching - meaning, the wood is burned.

Interestingly, the proportion of forest cleared by logging (estimated above) is at least 10-20X less than estimated by one environmental group (http://rainforests.mongabay.com/0803.htm).

Burning of wood releases ~1000 kg of CO2 per cubic meter (dry). So for each guitar you make (1-2 board feet per instrument) you keep 3-6 kilograms of CO2 out of the atmosphere (so please do not burn your guitars when you're done with them!).

Commentary welcome.

[Rickett Customs]

I'll do my best to do my part Erik

Btw, I assume you're back from travel?

[Jazzdogg]

Interesting.

For several years I have operated a sawmill and kilns as part of an Urban Forestry program in conjunction with the California Department of Forestry through which we divert "street trees" that would otherwise go into landfills, be mulched, or used as firewood; we mill these trees into lumber, kiln dry it, and make it available to woodworking students who have an opportunity to work with wood species that aren't typically available commercially (e.g., black acacia, Carolina cherry, torrey pine), it's a great form of carbon sequestration, and no forests are ravaged to obtain the lumber.

One of our goals is to encourage the planting of species in our urban landscapes that are useful to woodworkers - most of it will eventually have to be removed, and I would much rather see streets lined with koa and mahogany than liquidamber or eucaplytus.

[stflbn]

Much of the current trends of environmental concern defies logic and scientific proof.

Doesn't stop people at all from tossing other people's money at the problem though.

[Cy_Miles]

Here in Oregon/Pacific Northwest USA we have a similar situation.

A few years ago, I'd read the statistic that over 85% of the timber harvest was going to paper production. And that was when we were in the middle of huge debates about the use of our forests, and federaly owned forests were being closed for harvest because of overlogging (therby by devestating the state's independent sawmills and surrounding communities).

IMO, if we would make paper from annual crops the remaining old growth timber could be used for high quality lumber for many years to come, and our farmers would benifit.

In the mid 1980's I worked in a sawmill and personally was instructed to dump 24' 4"x12"s to 4"x20"s, into the chipper, because at the time woodchips for paper was bringing a higher price then the lumber. (one of the most regretfull jobs I have ever done)

[Mikey R]

Originally Posted by erikbojerik

Burning of wood releases ~1000 kg of CO2 per cubic meter (dry). So for each guitar you make (1-2 board feet per instrument) you keep 3-6 kilograms of CO2 out of the atmosphere (so please do not burn your guitars when you're done with them!).

Commentary welcome.

Hi Erik, good post - Im going to re-read that again several times.

I have one question about that final sum - each guitar takes 1-2 bdft to make, but a very significant amount of that wood ends up as sawdust and shavings. If you compost these, how much of the carbon locked away in the wood is then released back into the wild?

[mikeyswood]

Originally Posted by Mikey R

each guitar takes 1-2 bdft to make,

Are you building them right?

[erikbojerik]

Originally Posted by mikeyswood

Are you building them right?

Make that 1-3 board-feet. Acoustic guitars/basses use much less lumber than solidbodies.

In going from lumber to instrument, a good 50% ends up as offcuts and sawdust. If you compost it, then all of it gets cycled back into the biosphere (same as if the tree fell over and rotted in the forest).

My numbers are global averages, but when you look at specific regions things get a little more variable. In the US, very little of the deforestation ends up being burned - most of it is used in some fashion (lumber, paper, etc) that keeps carbon out of the atmosphere. North American forest management has managed to reduce deforestation to a level that is less than forest growth. In other words, North American forests are experiencing net growth.

Not so in South America and Africa - there the deforestation is dominated by slash & burn.

[ehque]

Hrmmm. Yeah come to think of it, wood furniture, construction, and guitar building is a great way to sequesture carbon dioxide. There's only that much carbon in the whole world, and what's locked up away in wood, carbon fiber, or plastics can't contribute to global warming.

Clearly sustained forestry is the key.

[steelhead2]

there's barely a mill `in operation',in fact after growing up in a timber based economy it's=pretty sad,sad to see all the jobs gone,,i won't `do a rant' it's pointless Oregon(Poregon) has recreated itself albeit with retirees and tech? jobs,healthcare since the boomers have already boomed? and now require advil

sigh,,,all i see when i look(out my windows) is TREES!,gee,can't we whack a few and get this economy back on a happy trip here? i sure miss the BOOM,maybe that's why i thump on a bass?

i've deleated several paragraphs as it is useless to attemp to tell what i know from a lifetime here but i'll do a quick story=dad was a (tree)faller after WW2, uncle owned a sawmill.life was great for them then but the equipment was slow and weak,as time went on and equipment/ technics improved the harvest rate was enormous(by 1980) as was the demand to build in California and reforestation was not as good or as understood but now,,well Oregon has trees,plenty of them but;no demand and hardly a mill open to mill them anyway so,it's done i'm done good night, peace!,pick on south america or south Carolina,Oregon is GROWING

[T-Bird]

Hi.

Seems that quite a few of You are forgetting a very important side of the carbon equation. Not all of You, and that's always a relief.

The fact is that all the carbon, which ever form it exists, above the ground recirculates between the living matter and athmosphere. For carbon emissions it doesn't matter whether the process is slow (decomposition), or fast (burning). About the same amount of carbon is released to the athmosphere and that amount is then used by the living matter, only to be released after a while.

Us humans just don't live long enough to care about cycles that last longer than the half of our cycle. It's our ignorance that creates most of the problems, whether imaginary or real.

Deforestation creates other problems which are far worse than the emissions, but that wasn't the topic. Making stuff out of wood doesn't matter one bit when it comes down to reducing carbon emissions unless the wood is a substitute for "trapped carbon products" ie. coal/oil products.

Finland was once a major manufacturer and exporter of paper, pulp and lumber, but as the manufacturing costs rose, the industry moved elsewhere. Mainly to the developing countries. You might have read about that in the newspapers .

Every bit of carbon from coal and oil products shift the balance of carbon in the biosphere. Using wood doesn't, if the same amount of biomass that's taken away is replaced by reforestation or other means.

Nature has a tendency to correct the inbalancies too, but that isn't always pleasant alternative to the more sensitive creatures (like mammals).

Regards
Sam

[erikbojerik]

Well - when it comes to cutting down trees, it is not quite so simple - if they are converted into lumber then you are removing it from the Earth's surface carbon cycle, but you are also removing something that continually pumps CO2 out of the atmosphere and replaces it with oxygen.

Grass and crops also do this, but they are essentially 2D for a given acre of land (and they are more seasonal than trees). The advantage of trees is that they are a 3D CO2 sink - they pull down more CO2 and release more oxygen per acre than any other kind of plant.

There are many reservoirs in the carbon cycle - the reason most folks concentrate on the atmosphere (rather than land or oceans) is that CO2 is a greenhouse gas and works to keep heat in the atmosphere (i.e. global warming). When you burn wood, yes it is faster than rotting - but also the conversion of wood to atmospheric CO2 is much more efficient by burning than rotting.

[ehque]

Originally Posted by T-Bird

Deforestation creates other problems which are far worse than the emissions, but that wasn't the topic. Making stuff out of wood doesn't matter one bit when it comes down to reducing carbon emissions unless the wood is a substitute for "trapped carbon products" ie. coal/oil products.

From what i see, the general idea is Biomass (plants, animals) + Atmospheric CO2 + Sequestered Carbon = Total Available Carbon

Of course building stuff (sequestered) out of wood doesn't affect the concentration of carbon dioxide in the atmosphere at all. We agree on this aspect. What i see on the other hand is reforestation. By cutting down trees (and not allowing them to rot or burn) and then growing more trees where they were cut down, more CO2 is pulled out of the atmosphere into solid products. If the trees were simply cut down and burned/decomposed, the carbon would get back into the atmo. Same thing if the area was not reforested (no change to atmo concentrations of CO2)

In fact, imagine if we stockpiled humongous amounts of (non-rotting) wood - in our buildings, furniture, and appliances. If the forests that were cut down to provide that wood were replanted with tree seedlings, the carbon required by those trees to grow then would be pulled down from the atmo.

[T-Bird]

Hi.

In a short time-span that's true, but as organic materials or goods made out of them don't generally last that long for several reasons, the long time effects in either direction are minimal. Unless some plants evolve to process CO2 into something else, or the SciFi-like propositions for trapping carbon compounds and removing them from the ecosystem become reality, we are forever stuck with the carbon compounds we release from the coal and oil products. I can't see how that would change any day soon.

As for the rotting (slow combustion) producing less carbon byproducts than burning (fast combustion), I'd like to see some equations about that. I'm a BEng Mech., so moderately complex chemistry isn't a problem. Never been able spot clever derailing equations though .

Regards
Sam

[erikbojerik]

Seedlings (obviously) pull down way less CO2 than a full grown tree - but a young growing tree pulls down more CO2 than a mature full-grown tree once it gets above a certain size.

Burning obviously releases most of the wood mass as CO2, but some carbon monoxide (CO) is produced when burning is <100% efficient (which is always) and leaves some charcoal behind. The CO pretty quickly reacts with atmospheric oxygen to make CO2.

Rot occurs mainly when microorganisms eat the tree - most of that carbon is used to make new baby microorganisms, some becomes less-complex hydrocarbons crapped out by micros (metabolized cellulose, kerogen, etc), some is released as methane (CH4) by farting termites (not kidding) but that quickly reacts with oxygen to make CO2 and water.

Don't forget - a living tree is already sequestered carbon that is also an active CO2 pump. So when its cut down and burned, it's a double-hit to atmospheric CO2.

[Rattman]

Originally Posted by stflbn

Much of the current trends of environmental concern defies logic and scientific proof.

Doesn't stop people at all from tossing other people's money at the problem though.

. . . Amen to that!! Junk science and 'herd hysteria' and now the sky is falling Chicken Little!!! Global warming just continues to persaude the weak-minded masses to do....to do....to do what? Just do something quick!!! . .

[erikbojerik]

Well - there certainly is no doubt that the planet is heating up a bit. No serious scientist doubts this. Ice the world over is melting like never before - ice cover is drop-dead easy to measure by satellite, and you cannot melt ice without adding heat. No brainer.

Now - the cause of the heating is another story. There are many many ways to heat a planet's atmosphere. And I (for one) believe it is folly to think that mankind can steer climate in any particular direction - there is just too much natural momentum, and the feedbacks are too poorly known.

In parallel with the heating, the amount of CO2 in the Earth's atmosphere has been increasing steadily since ~1900. This is also easy to measure - and it is easy to conclude that, because CO2 is a greenhouse gas, this rise is what is causing the heating. But I have heard equally persuasive arguments that the increase in CO2 is an outcome of the Earth heating up (rather than a cause).

[Mikey R]

Originally Posted by erikbojerik

But I have heard equally persuasive arguments that the increase in CO2 is an outcome of the Earth heating up (rather than a cause).

If this were the case, doesnt this make a positive feedback loop?

[erikbojerik]

Originally Posted by Mikey R

If this were the case, doesnt this make a positive feedback loop?

You betcha - that's one of the big worries for the climate guys.

Maybe we'll end up like Venus - 95% CO2 atmosphere, 400° daytime surface temperature, and all the oceans turned into steam and evaporated to space.

In the category of "inconvenient truth" - it is not very well known that the most important greenhouse gas in the Earth's atmosphere is actually water vapor. CO2 traps ~20X more heat per molecule than H2O, but the amount of H2O in the air is about 200x higher. The "inconvenient" part is that climate guys KNOW there's no way to control the humidity of the entire planet.

[mikeyswood]

Anybody remember this?