Ozone Killing Trees
I just happened to run across Whispers from the Ghosting Trees, a ScienceBlogs post from back in January. Though we recoil from dark and smelly air pollutants like sulfur dioxide, we rarely consider the invisible emissions of nitrogen oxides that increase low level ozone in the atmosphere:
While we hustle busily through the necessities of our lives, wrapped up in our daily preoccupations – our obligations to our families, our jobs, and our dreams – at the same time all around the world, trees are silently expiring. For those who take the time to look, we can see that the forests are being transformed before our helpless and incredulous gaze into spectral mausoleums, as even the most ancient living wood is consumed by a raging tsunami of pathogens unprecedented in scale and virulence. What has instigated this global explosion of lethal insects, disease and fungus, which is decimating swathes of trees across ravines and mountains, invading city streets and wilderness, rampaging through parks and suburban backyards? What would we hear the trees saying if we understood the language of their injured foliage, if we could discern the message in their tortured splintered branches?
Only the latest in a long tradition of foresters, scientists, and ecologists, I am merely an amateur and a gardener doing what I can to warn society that there is a longstanding trend under way that is ominously accelerating. Until very recently impaired tree health was generally regarded as a regional, episodic problem mostly attributable to acid rain from sulfur dioxide. Now, new satellite technology has revealed that precursors of ozone – reactive nitrogen and methane pollution – travel across continents and oceans, and the toxic reach extends into the most remote and rural places. What was once slow and localized and species-specific has become terrifyingly fast, ubiquitous and indiscriminate.