Tucson, AZ

The bark of these trees contain chorophyl - notice the green hue - that allows them to photosynthesize year round.
We drove up the Catalina Highway from Tucson to the top of Mt. Lemmon (elevation 9100'). This is the view into Tucson from about 3000'.

You can't see them very well, but the hillsides are covered with saguro cacti. After you reach about 3500' the cacti disappear and trees begin; little scrubby trees at first, but by the time you reach the top of the range they are full-size evergreens.