what if the trees are not replacing grassland?

The key here is albedo -- reflectivity of light. Trees are darker than the grass they replace.

What if the trees are replacing the asphalt of a deserted city lot, are adding shade to city sidewalks, are part of a restoration effort of a landscape scarred by wildfire?  Would these tree plantings still be considered to produce a net warming effect?

I'm still not sure I'm buying the significance of the albedo issue.  Granted, I'm not a forestry scientist, so should have no rights to question the conclusions of the paper... yet, it just doesn't make sense to me.  By that logic, Maine, which has tons and tons of dark, leafy trees, should be warmer than Kansas, which is flat prairie land.  No?

FWIW, I did not take David's post as anger that Gristmill posters disagreed with him.  I read it as annoyance at the tone of the posts... instead of a glass-half-full viewpoint, like "Hey, it's great that the NFL are recognizing global warming and want to do something about mitigating their impact.  However, with the inherent problems of tree planting & carbon offsets, I wish they had considered...... (XYZ great idea that would contribute to mitigating the SuperBowl's greenhouse gas effects)" the tone of many of the comments, on that and other threads, was, IMO, a bit nitpicky and superior.  I do not presume to speak for David, because, clearly, he is perfectly capable of doing that for himself; perhaps I am merely projecting my own feelings regarding those posts into his comments.  For me, the bottom line is that we all love great debate and the sharing of ideas - otherwise we would not be here.  It is fabulous that we have this forum in which to exchange ideas, witticisms, compliments and insults with each other - the other side of the fabulous Internet coin is the utter lack of expression it gives to our words, leaving many statements wide open to the reader's interpretation.

Kaela

I was so smug all these decades about how my fast growing Douglas Fir forest made me carbon neutral.  The trees became huge, the forest cool and dark.  Now those trees are dying from global warming.  Dead trees lie everywhere and the canopy is now just bright sky.  The carbon release from these dead and decaying trees is enormous.

My greatest fear is that passion will flame out and we all become flat, quiet, accepting death as it is.

My passion is on fire.

We can not expect the Christians to defeat the Roman legions.  And they may be falsely blamed for touching Rome.  They can stay home in their adobe huts.

Our greatest hope is that the emperors see God before we all burn up with hell on Earth.

I felt pall and impatience after SOTU and was quiet depressed (and smart enough to keep my mouth shut the following morning).  At best, DR was complaining about (and contributing to) irrelevant babble.

are the killers.  We no longer get hard freeze weather (excepting this year, my prayers were answered).  We get plenty of forest rain water, that is not the problem here in Western Washington.

My heart bleeds, Tom.

I think most of us understand that the tree-planting off-set industry is complicated.  Hopefully.  Hopefully, most of us understand by now that where trees are planted matters, regarding reflectivity vs. absorption of solar radiation.

Also, as a Latin teacher, I think it would be nice if people curious about "albedo" should start reaching out curiously to the Latin teachers in their neighborhoods.  E.g., there is a reason why I fly the flag of my Little White Dog as "Canis Candida," and not as "Canis Alba."

There was nothing particularly "true" about David Roberts' rave, except inasmuch as he felt "truly" insulted that his point of his view was not accepted universally as gospel "truth."

I really have no interest in that magical house whatsoever.  I do indeed dislike the graceless way in which DR reacted to certain criticisms of it, regardless of their value.

And syntax-wise, it is not clear whom good old Tom Philpott is accusing of "pretty reactionary and specious terms."

DR himself?  OK, he is the boss, he gets to write whatever the hell he wants to write, the rest of us do not, so let him defend himself: not that he has not already done so adequately, and more than adequately, ad nauseam.

Somebody other than DR?  Gevalt!  Whom?!  Shame on you, Tom Philpott.  NOBODY who has criticized DR on this matter is opposed to good general environmentalist values, and you know so.

The point is DR's style, not the content of everyone's discussion.  Nicht wahr?

One of my best beloved prophets, Sunflower, writes:
<<
My greatest fear is that passion will flame out and we all become flat, quiet, accepting death as it is.

My passion is on fire.

>>

A dread of mine is that DR is doing his best to flame out passion, to get us to become flat, and to accept death.  While looking very very cute and radical.

Everyone's passion should be on fire.

God knows, we do not, damn it, need to wait for David Roberts to give us the green light to proceed.

Chickens are our cousins! So are other sensitive animals! Enough is enough! No more factory farms!

I predict that any successful rebuttal will show such a small net sequestration per tree that you can gain much greater reductions by investing money in expensive PV electricity generation. In fact, I will bet a Super Bowl t-shirt on that, if anyone is interested in a wager.

No bet.  And I liked the corn ethanol analogy.

Canis, I must tell you--this is the first time it's been remotely relevant--that when I hear "candida", I think "yeast infection."  Sorry about that! :)

I am a total failure at Latin, though.  Greek, too.  I thought it would make me feel smarter to read Plato in Greek, but all it did was make me stay up till 4AM studying every single night my freshman year...

I am very stupid, and ill-informed.  By all means, I want to learn all I can about all animals, including Homo sapiens, in every aspect, regardless about aspects that Little White Dog is reluctant to tell me about what she has discovered ...

Chickens are our cousins! So are other sensitive animals! Enough is enough! No more factory farms!

   While I am not going to argue that mono culture forestry is a good idea, there are other benefits to tree planting than fighting global warming.  In some cases, it may help fight the steady march of deserts, and certainly it helps create a more pleasant urban environment.

   I do agree that the idea that tree planting as a carbon offset doesn't always work, but there are other reasons to plant them.  Aren't there?

   (hopeful smile)

patrick

provide shade on a hot summer day, cooler and cleaner air when planted in cities and parking lots. They prevent soil erosion. They provide beauty, grace, and inspiration, homes for animals and birds, and food for them, too. Trees are food for our spirits and the oldest of them offer wisdom to those who would listen.

>there are other benefits to tree planting than fighting global warming.  In some cases, it may help fight the steady march of deserts, and certainly it helps create a more pleasant urban environment.

>I do agree that the idea that tree planting as a carbon offset doesn't always work, but there are other reasons to plant them.  Aren't there?

Sure. Just don't plant them for those other reasons, and then sell carbon offsets from them. Let me see if I can be much more succinct than usual:

Tree good. Phony carbon offset for planting tree bad.

>What if the trees are replacing the asphalt of a deserted city lot,

To do that you either have to tear up the asphalt or add pots - a fair amount of energy expenditure. If the latter case you will have to add irrigations (since trees in pots can't tap groundwater) and significant pest management (since you can't use biodiversity as a defense).

>are adding shade to city sidewalks, are part of a restoration effort of a landscape scarred by wildfire?  Would these tree plantings still be considered to produce a net warming effect?

Depends. However the key is you are not going to generate many carbon credits. Carbon credits from trees requiring planting lots of the things. And that probably means displacing existing plants. Look trees are great things. There are lots of reasons for planting them. But generating phony carbon offsets from them, and using those offsets as an excuse to continue burning fossil fuel is not one of those reasons.

I'm still not sure I'm buying the significance of the albedo issue.  Granted, I'm not a forestry scientist, so should have no rights to question the conclusions of the paper... yet, it just doesn't make sense to me.  By that logic, Maine, which has tons and tons of dark, leafy trees, should be warmer than Kansas, which is flat prairie land.  No?

I'm not a climate scientist or a forester either, but here's my take on it:  The difference in albedo translates into a relatively small forcing (positive or negative).  Not sure what the magnitude is, but I'd guess it's of order 0.1 watts/m^2.  So small enough that other local effects (like latitude and mega-currents in ocean and air) easily overwhelm it, but large enough that very large areas can change the energy balance of the planet.

Certainly I believe this result when comparing snowy plains to forest.  Snow has a very low albedo (~0.1?).  Forest is much higher (0.4-0.6 if I recall, though I may be off), which means a 4x - 6x increase in the amount of heat absorbed from solar radiation.

>I'm not a climate scientist or a forester either, but here's my take on it:  The difference in albedo translates into a relatively small forcing (positive or negative).  Not sure what the magnitude is, but I'd guess it's of order 0.1 watts/m^2.  So small enough that other local effects (like latitude and mega-currents in ocean and air) easily overwhelm it, but large enough that very large areas can change the energy balance of the planet.

>Certainly I believe this result when comparing snowy plains to forest.  Snow has a very low albedo (~0.1?).  Forest is much higher (0.4-0.6 if I recall, though I may be off), which means a 4x - 6x increase in the amount of heat absorbed from solar radiation.

Thanks GreenEngineer.

That last paragraph was quoted, and I meant to reply to it, but missed it in posting so thank you for doing so, and incidentally doing a better job than I would.

Cloud cover will prevent reflected visible light escaping back into space.  And light absorbed is converted to infrared which is emitted ~ 80% from wood and re-emitted from clouds and CO2 back to Earth.  The rate of infrared emission exchange is dependent on the temperature difference between the trees and the sky to the fourth power.  So, if the forest is cool and the grass is hot then the emission from grass is significantly greater.  Ambient temperature differences may be covered in the report, I hope.

My grandfather once said, "Don't let the truth interfere with a good story".  Reducing fossil carbon by planting trees is like holding your breath for longer life.  Planting trees will not work, but it was a good story.

If trees are burned to displace the burning of fossils, then carbon credits are well earned.  Trees are a carbon neutral source of energy.