model.joensson.customize: Customize the Jönsson model

In barrks: Calculate Bark Beetle Phenology Using Different Models

Customize the Jönsson model

Description

This page describes the parameters that can be used to customize the Jönsson model. The model was developed by \insertCiteJonsson2011;textualbarrks. Look here to find out how to apply the model.

Arguments

dd_onset_start_date	The date, when the degree days start to sum up ('MM-DD').
dd_onset_base	Base temperature to calculate degree days to trigger the onset.
dd_onset_threshold	Degree days that are required to trigger the onset of infestation. Additionally, the maximum temperature must exceed tfly.
tfly	Minimum temperature that beetles need to fly.
dd_development_base	Base temperature to calculate degree days for development.
dd_total_dev_lower, dd_total_dev_upper	Lower/upper limit of degree days that are required for a generation to fully develop
dev_start, dev_end	Share in total development when the egg development starts and the juvenile beetle's development ends respectively. Usable if the development below/above these thresholds should account for mating, oviposition etc.
dev_mortal_min, dev_mortal_max	The beetles are considered to be in white stages (egg, larva, pupa) if their development exceeds dev_mortal_min and subceeds dev_mortal_max. During these stages, the beetles could die due to a mortality event. NULL means that no lower/upper threshold is defined.
model_end_date	Date when the model ends (no further development will be modeled).
daylength_dia, tdia_min	When the daylength falls below daylength_dia and the average daily temperature falls below tdia_min, diapause will be initiated. The default value for the critical daylength was set to 19.3 hours according to \insertCiteSchroeder2017;textualbarrks who examined the photoperiodic diapause induction in Sweden. If the model is used for other regions, this value should be adjusted.

Details

In barrks, model() is used to customize a model. The following code illustrates which parameters are available for the Jönsson model and specifies their default values.

model("joensson",

      # ==== onset ====

      dd_onset_start_date = '01-01',
      dd_onset_base = 5,
      dd_onset_threshold = 120,

      # ==== onset + development ====

      tfly = 20,

      # ==== development ====

      dd_development_base = 5,
      dd_total_dev_lower = 625,
      dd_total_dev_upper = 750,
      dev_start = 0,
      dev_end = 1,
      dev_mortal_min = 0,
      dev_mortal_max = 1,

      model_end_date = '12-31',

      # ==== diapause ====

      daylength_dia = 19.3,
      tdia_min = 15
)

References

\insertAllCited

See Also

model(), phenology(), model.joensson.apply

Other model customizations: model.bso.customize, model.chapy.customize, model.lange.customize, model.phenips.customize, model.phenips_clim.customize, model.rity.customize

barrks documentation built on Aug. 29, 2025, 5:32 p.m.