Growth rates and age of native palms in the Baja California desert

For the benefit of management and basic biology, we studied growth rates and age–size relations in two palms native to the desert of the central portion of the Baja California peninsula, using a new method for estimation of long-term growth with repeat photography. For both Washingtonia robusta and Brahea armata we found no well-defined relation of growth to height, but crown diameter tended to change with height. W. robusta was more sensitive to microhabitat but generally grew faster than B. armata. Reproductive maturation occurred at c. 8 m height in W. robusta and c. 4 m in B. armata; the tallest palms in our sample were 32.0 m and c. 18.9 m, respectively. Age estimates based on growth in recent decades suggests that potential longevity in both species exceeds 500 years.