By Gail Zawacki: No Mercy (on trees)

It took me a while to read this. When Gail Zawacki writes on the global decline of trees it upsets me, a lot. I can live with the extinction of a frog or an insect, but not trees. I really like trees.

Gail here presents the latest science. It’s not pretty. And you probably won’t read about it anywhere else. But it’s important.

Gail also comments on how our scientific knowledge of the details continues to expand, yet our understanding of the whole, the system, the thing we should actually care about, is in decline.

I think about this a lot. We need more systems experts like Dana Meadows, rest in peace. All of our problems are systemic and complex.

When I first started writing about trees drying around the globe, I was ridiculed and ostracized as being an hysteric.  Scientists and foresters unanimously told me I was imagining the symptoms of an alarming decline.  Merely pointing out the consequences to carbon storage was enough to antagonize virtually everyone from obscure peak oil preppers like John Michael Greer to prominent climatologists like Gavin Schmidt.  Mostly I was ignored by everyone from journalists like George Monbiot to the physicist blogger Joe Romm.

Now, however, the swathes of dead trees are too ubiquitous to deny.  The Ecological Society of Australia claims that “climate change is killing our trees”.  Science Magazine devoted their August issue to forests, which is summed up by one overview article as “Every forest biome on Earth is actively dying right now”.

Since it has become widely acknowledged that trees are threatened and dying prematurely, researchers persist in blaming drought.  One widely distributed study predicting that drought is going to cause massive tree mortality in the Southwest US bases it on the distant year of 2050, which is ludicrous since trees are demonstrably dying right now.  Another equally limited survey reveals that up to 58 million trees in California are estimated to have experienced water loss due to drought.  Unfortunately, that survey only looked back four years, to 2011 – had they bothered to look earlier, they would have found damage prior to the drought.

There is no question that megadroughts and higher temperatures will eventually kill forests.  Climate change is irreversible, and accelerating far too fast for trees to adapt.  However, they are dying ahead of predictions AND in places not in drought.  Indeed, trees dying from pollution are themselves contributing to drought.  Consider that researchers who predicted trees dying from pine beetle attacks would cause increased stream flow, found out the exact opposite has occurred.  And it has been established that ambient ozone reduces stream flow, as well, “…due to an enhanced water loss via the leaf pores.” – and nobody has any idea just how bad the combined effects of elevated ozone and enhanced nitrogen deposition from fertilizers and combustion will be.  But it’s not auspicious.

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