Kimberly D. Gilliland, Nancy J. Huntly, J.E. Anderson
Many desert perennials are long-lived, but there are few data on ages or population structures of desert plants. We used 2 methods to estimate ages of a population of Yucca brevifolia (Joshua tree)...
http://deepblue.lib.umich.edu/bitstream/2027.42/53002/1/1435.pdf