We are trying to calculate relative growth rate of perennial grass species. We have a large number of tagged individuals with which we estimate biomass each year. Naturally, every year we experience at least a few mortality events, which are evenly distributed across our treatments (warming, watering and warming x watering).
Could someone(s) please advise on how you would calculate RGR when you have a mortality that does not appear driven by treatment? Do you remove the sample from the population the year it dies? Do you remove completely from the analysis? A hypothetical example: Population RGR from 2009 - 2010 was -0.12. In 2011 an individual died resulting in that individual's RGR from 2010 to 2011 of -20, and a population RGR from 2010 to 2011 of -3. The individual is removed from the population 2010 - 2011 RGR calcuation and now the population RGR goes to 0.1. It is likely that the population RGR from 2009-2010 was negative because the plant was dying. Note: the plant was not damaged, subjected to an insect event and in general appeared the same as other plants in the experiment. Thanks! Tim Wertin USGS - Canyonlands Research Station
