Thursday, December 9, 2010

A tree in the living room as an opportunity to teach about carbon

Don and his tree.

I've got a tree in my living room.  It stands a little over seven feet tall, though it was probably closer to eight feet when it stood at the Christmas tree farm out in Clarence.  I was easily able to lift it onto the roof of the car, so I'm guessing it weighs less than 40 pounds.  You might have a tree kind of like it in your living room.  You might use that tree to help you and yours think a bit about carbon.  

Perhaps it could be a little fodder for making those family get-togethers a little more uncomfortable, but please be nice as you nurture understanding along.  Fortunately for me, holiday discussions in my family are decidedly geeky -- the most notable in recent memory had to with which one of my siblings had the greatest volume to surface area ratio.

But I digress.  Let's think about that tree.

A favorite question of mine is, "What's the raw material for a tree?"  It started as a little seed within a pine cone and now some eight or ten years later, it weighs in at about 40 pounds.  Where did those 40 pounds come from?  What did the "stuff" of the tree used to be?

Here's a picture of the tree cookie I cut off after I brought it home.  How old is it?  
The earbuds are included for scale.  It's not really a very big tree.

Lots and lots of people will answer the raw material question with something like, "It comes from the minerals in the soil."  Does that make sense?  What if that were true?  For one thing, it would mean that soil and trees are made of the same stuff.  Is that the case?  Living things are carbon-based.  Is soil carbon-rich?  

Um, no.  Not so much.  

And, if trees got their mass from the soil, wouldn't that mean that really big trees would need to be surrounded by really big pits where they pulled that mass from?  Those holes in the ground would grow over time.  Have you ever seen that?  I haven't but it would make for more interesting walks in the woods.  

Darn near every adult in the country took high school biology and was taught about photosynthesis.  We all learned that plants take in carbon-dioxide and release oxygen.  Then we forgot, or we never really understood it in the first place.  If we stop and think about it, and we remember that life is carbon-based, it ought to give us a little pause -- trees are made out of air!  That is, of course why, as many of you dear readers already know, that planting trees is a way to offset carbon emissions.  

If you already knew that, good for you.  Know that you've got at least a somewhat deeper understanding than the average American.  That's not surprising since you spend at least some of your time reading blog posts about climate change.  

But have you thought about what that 40ish pound tree implies about the scale of tree-planting needed for offsetting emissions?  I wrote a guest post before I was regular here on that in 2009.  I won't repeat that post here, but I'll briefly hit some relevant highlights.  Ten gallons of gasoline weighs about 60 pounds.  If you're burning 10 gallons of gasoline a week, you're releasing about three times that much carbon dioxide as the carbon in the gasoline combines with oxygen in the air to make CO2.  So, a typical driver might release 180 pounds of CO2 a week just by driving.  Photosynthesis does something like a reversal of that process.  Photosynthesis, in other words, can take 180 pounds of CO2 and turn it into something like 60 pounds of tree and 120 pounds of oxygen.  

Now it's time to remember that the 40ish pound tree in your living room is probably eight or ten years old.  So, it doesn't offset a typical driver's week of emissions.  Planting a tree is a good thing to do.  But planting a whole bunch is better.  A bunch of forests is more like what we need.  For each of us.  

Oh, we can't end a holiday post on such a downer.  Then again, maybe we can.  

1 comment:

Edward Robins said...

We don't have to wait for the government to come up with drastic policies to resolve this issue.

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