Terry M., Trout K., Williams B., Herrera T., Fowler N., Limitations to natural production of Lophophora williamsii (Cactaceae) III. Effects of repeated harvesting at two-year intervals for six years in a South Texas (U.S.A.) population, Journal of the Botanical Research Institute of Texas, 2014, 8(2):541-550
The third report covers six years of the field experiment. It compares survival in separate two-year intervals, estimated plant size and changes in crown number. It also presents a statistical power analysis that limits conclusions about the degree of recovery after a single injury. Repeated injuries were associated with a smaller above-ground part and poorer survival.