We have several long-term studies examining the responses of fine root dynamics to aboveground herbivory, N fertilization, and interannual variation in climate. The program allows for the identification and tracking of individual roots over time by storing the length and diameter tracings of each root from each time period to a data-base file. Annual values for fine root production and mortality are simply the sum of gross growth and mortality across all actual sampling intervals throughout the year. The identification of models follows the notation of Lebreton et al. The model with the lowest AIC is the most parsimonious model.
MARK estimates survival rates and recapture probabilities for all time intervals.
We have confidence in this known-fate approach, because it is highly unlikely that many roots would appear, die and completely decompose between sampling periods. Fine root decomposition estimates are then simply taken as 1 - dead root survival. A similar model selection approach to that used for fine root longevity is used to determine factors affecting fine root decomposition. Ruess, R.W., R.L. Hendrick, and J.P. Bryant. Regulation of fine root dynamics by mammalian browsers in early successional Alaskan taiga forests.