Okay, I'll admit it.  I have an obsession with trees.  Wherever I go, I seek out the "local" tree -- that indigenous expression of what it takes to survive and thrive and have long life in that particular little piece of the planet.  I have countless pictures of giant sequoias, and yellow oak trees, and weeping willows, and red maples, and...well, you get the idea. I've just returned from a quick trip to Albuquerque, NM, and I had a chance to take some great pictures of cotton wood trees as I walked along the Paseo del Bosque, part of Albuquerque's great Open Space system.  Truth be told, I was surprised…