We gasp in awe at the thought of a redwood, amazed that something that huge could be living. Although we're certainly right to be overwhelmed, don't forget that the bulk of that redwood is dead! No, not a pathological condition, but the normal condition for trees. Within the tree trunk, near to the outer portion, lies a cylinder of tissue called the vascular cambium. This tissue spins off cells externally to form phloem and internally to form xylem.
Phloem moves sugars and other substances around the plant; this is what
Vermonters tap to get maple syrup in the spring as sugar-laden sap moves upwards. The
xylem consists of a series of small pipe-like vessels that carry water and dissolved
minerals from the roots to the rest of the plant. It makes up most of the tree and,
except for the newly formed cells next to the cambium, is as dead as the water pipes in
your house. Gee, it's almost enough to give hope that maybe human deadwood
isn't quite as useless as most of us think!
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.