Calculates plant drought stress indices, at different temporal scales, from simulation results.
Arguments
- x
- index
A string with the index to be calculated, either
"DI","NDD","ADS","MDS"or"WSI"(see details).- freq
Frequency of stress statistics (see
cut.Date). Normally, either"years"or"months"for yearly-based or monthly-based indices.- bySpecies
Allows aggregating output by species.
- draw
A boolean flag to indicate that a plot should be returned.
Value
A data frame with periods (e.g., years or months) in rows and plant cohorts (or species) in columns.
Values are the calculated stress index. If draw=TRUE a ggplot is returned instead.
Details
The currently available drought stress indices are:
"ADS": Average of daily drought stress values for the period considered."MDS": Maximum daily drought stress during the period considered."DI": Drought intensity, as defined in De Cáceres et al. (2015)."NDD": Number of drought days, as defined in De Cáceres et al. (2015)."WSI": Water stress integral, as defined in Myers (1988).
References
De Cáceres M, Martínez-Vilalta J, Coll L, Llorens P, Casals P, Poyatos R, Pausas JG, Brotons L. (2015) Coupling a water balance model with forest inventory data to predict drought stress: the role of forest structural changes vs. climate changes. Agricultural and Forest Meteorology 213: 77-90 (doi:10.1016/j.agrformet.2015.06.012).
Myers BJ (1988) Water stress integral - a link between short-term stress and long-term growth. Tree Physiology 4: 315–323 (doi: 10.1093/treephys/4.4.315)