Why Trees are Cool

Closeup of spruce branches

I got involved with Ecology Ottawa because I saw the organization as a great way to take local action to fight climate change. After about six years of volunteering I can say I was correct in that thinking.

Imagine sitting by the lake, as I was, one hot, hot summer day surrounded by spruce, balsam and pine trees. It was so hot. I could smell the resins being being baked out of the trees. It was like that great forest smell you get, except stronger.

I thought, here's another impact of climate change; extra stress on forests. It costs those trees something to produce those chemicals. If higher temperatures make more of the natural chemicals evaporate then the trees have to work harder to survive.

But today I heard on the podcast of the journal Nature that several recent studies are showing that the gasses emitted by trees contribute to cloud formation. In effect forests make their own clouds. Cool!

Jasper Kirkby, one of the scientists interviewed on the podcast said "it's interesting to speculate...they haven't evolved these vapors to make it pleasant for us to go on hikes through forests, there must be a deeper reason for it. I think it takes very little imagination to say that they are protecting themselves."

There are two implications here. One is that forests seem to be able to help generate their own clouds and since clouds are where rain comes from; trees can generate their own rain to some extent, and have evolved to do so. On those extra hot days like the one I experienced, the trees are working extra hard to produce those vapors. The reason they're doing it is because in that heat they'd benefit from a little shady cloud or even more from a little rain so they're trying to bring it on.

That's pretty cool.

The other, as the podcast points out, is that modeling clouds in climate models is notoriously difficult and these findings are likely to mean that climate change predictions for future global temperatures may be a smidgen less hot.

That's literally cool.

And that makes me appreciate the link between Ecology Ottawa's climate change work and its Tree Ottawa work.

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