Monday, August 27, 2012

Tree torture

Plant physiologist Nate G. McDowell (photo here) loves trees and leads a project at Los Alamos National laboratory to study them (slideshow here), "But we have to kill the trees to understand how they die. Not a lot of them, just a few." The trees in question include 15' juniper and piñon, and he is documenting exactly what will doom them in the future climate, which is predicted to be an average of 5°F hotter in the area 50-80 years from now. To determine whether and how quickly each species will die, McDowell monitors them in 18 plexiglas chambers. Some contain trees that serve as controls. Others contain trees for which temperature and precipitation are adjusted. Instruments inside and outside the chambers - including a thermal camera - are automated to collect such data as surface heat, tree moisture and transpiration, and soil moisture and respiration. He expects the shrubby oak to live the longest, the junipers to hold on for as long as 3 years, and the piñon to die in a mere 11 months. One of the hypotheses the team is testing is that a long, hot drought damages a tree's foliage and disrupts the photosynthetic mechanism. Rising carbon dioxide and temperature levels, driven largely by the emission of greenhouse gases, simultaneously "cooks" the leaves and prevents the carbon-starved tree from repairing itself. McDowell predicts the results of the experiment to be bleak: "I can't say this with absolute certainty, but I don't expect there to be conifers in Los Alamos or Santa Fe County in 50 years." Craig Allen, an ecologist with the U.S. Geological Survey explains, "So it suggests basically that the main tree populations on our mountains will die. They will not be able to survive there. It doesn't mean there won't be any trees anywhere on these landscapes, but it means the current dominant trees will die." And the forests that die send their carbon into the atmosphere, further accelerating the warming of the Earth.
The Cabinet is made of wood:

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