Difference between revisions of "ControlTable Production Model"

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[[Category:Control Tables|Production Model]]
 
[[Category:Control Tables|Production Model]]
 
[[Category:Reference Manual]]
 
[[Category:Reference Manual]]
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<!--See also [{{HeurekaHelpLinkEng}}kontrolltbl_production_model.htm Heureka Helpdoc]. -->
  
In the production model control table you can configure the simulation of the forests' development, i.e. how trees establish, grow, and finally die if not harvested before that.
+
The production model control table contains [[ControlTableDescription::settings that affect forest development, such as tree growth and mortality]].  
  
 
== Growth and yield ==
 
== Growth and yield ==
Allows you to control the net growth and yield from harvests, by applying certain models/-components in the simulations.
+
:Growth model settings
  
'''CalculateStandGrowthForLargeTreesOnly'''
+
====Growth Model Whole-Stand====
:'''True''' implies that stand growth is calculated as the growth of trees with at least 10 cm's diameter only, '''False''' do not (i.e. includes all trees' growth).
+
:'''None''' implies that no basal area development, as the sum for all trees at the plot-level, will be used in growth calculations.
'''CalibrateHeight'''
+
:'''Elfving2009:''' the model by Elfving (2009) will be used in calculation of basal area development at the plot-level (the prediction unit).
:'''True''' implies that tree heights will be calibrated, '''False''' do not. Calibration factors are calculated using sample tree data.
+
 
'''HeightGrowthModel'''
+
====Growth Model Individual-Tree====
 +
:'''Elfving:''' the single tree model by Elfving (2004) will be used in calculation of each trees' diameter development at the plot-level (the prediction unit).
 +
:'''Soderberg:''' implies that the model by Söderberg (1986) will be used in calculation of each trees' diameter development at the plot-level (the prediction unit).
 +
:'''Low Production Nyström:''' implies that the model by Nyström will be used in calculation of each trees' diameter development at the plot-level (the prediction unit). Intended for use on non-productive forest land only.
 +
 
 +
BIOMASS
 +
 
 +
BARK
 +
 
 +
====Growth: Include Thinning Response====
 +
:True if thinning response function should be applied, false otherwise. Only applied to even-aged stands.
 +
 
 +
====Growth and Mortality Adjustment Factors====
 +
:Adjustment factors for basal area and height growth, as well as mortality, in established forest. Default = 1, i.e. no adjustment. From version 2.21, factors are set per period and species' group. If data entry for a period is missing, closest previous period's value will be used. If data entry for a species is missing the user specified default value is used. Should normally not be changed, intended for research purposes.
 +
 
 +
====Volume Function====
 +
:Selected volume function.
 +
 
 +
====Height Development Model====
 
:'''ErikssonElfving''' implies that the model by Eriksson and Elving will be used in calculation of height development.
 
:'''ErikssonElfving''' implies that the model by Eriksson and Elving will be used in calculation of height development.
 
:'''SoderbergWithTreeAge''' implies that the model by Söderberg including single tree ages will be used in calculation of height development.
 
:'''SoderbergWithTreeAge''' implies that the model by Söderberg including single tree ages will be used in calculation of height development.
 
:'''SoderbergWithStandAge''' implies that the model by Söderberg including average stand ages will be used in calculation of height development.
 
:'''SoderbergWithStandAge''' implies that the model by Söderberg including average stand ages will be used in calculation of height development.
'''HeightTresholdPlantToTreePlot
+
:'''Low Production Nyström:''' implies that the model by Nyström will be used in calculation of height development. Intended for use on non-productive forest land only.
:Defines the average tree height at stand-level[?], in meters, when saplings are turned-over and classified as trees.  
+
 
'''InitialHeightModel'''
+
====Height: Initial Height Function====
 
:'''SoderbergWithTreeAge''' implies that the model by Söderberg including single tree ages will be used in calculation of initial tree heights.
 
:'''SoderbergWithTreeAge''' implies that the model by Söderberg including single tree ages will be used in calculation of initial tree heights.
 
:'''SoderbergWithStandAge''' implies that the model by Söderberg including average stand ages will be used in calculation of initial tree heights.
 
:'''SoderbergWithStandAge''' implies that the model by Söderberg including average stand ages will be used in calculation of initial tree heights.
'''InitialHeightSource'''
+
 
 +
====Height:Initial Height Source====
 
:'''UseFunction''' implies that the model selected in '''InitialHeightModel''' (above) will be used.
 
:'''UseFunction''' implies that the model selected in '''InitialHeightModel''' (above) will be used.
:'''FromDatabase''' implies that initial tree heights will be obtained from an available database [The Hugin young forest-database?].
+
:'''FromDatabase''' implies that initial tree heights will be obtained from the input database.
'''MortalityFridmanOnly'''
+
 
:'''True''' implies that the model by Fridman and Ståhl will be used in calculation of mortality, '''False''' implies that the model by Söderberg and Bengtsson will be used together with the model by Fridman and Ståhl.
+
====Height Calibration====
'''MortalityModel'''
+
'''True''' means that tree heights will be calibrated, '''False''' do not. Calibration factors are calculated using sample tree data.
:'''Deterministic''' will apply deterministic components in the mortality model.
+
 
:'''Stochastic''' will apply stochastic components in the mortality model.
+
====Mortality Implementation====
:'''None''' will not apply any mortality model.
+
:'''Deterministic''' will apply deterministic components in the mortality model (recommended).
'''MortalityRetainedTreesYear1_5'''
+
:'''Stochastic''' will apply stochastic components in the mortality model  
:'''Aspen''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Populus tremula'' the first five years after final felling.  
+
 
:'''Beech''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Fagus silvatica'' the first five years after final felling.
+
====Mortality Model====
:'''Birch''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Betula ssp.'' the first five years after final felling.
+
:Selected mortality model. Default value for parameter "Calibrate Bengtsson" will depend on what mortality model is selected.
:'''Broadleaf''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of broadleaves other than birch and aspen (sv: triviallöv) the first five years after final felling.
+
 
:'''Contorta''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Pinus contorta'' the first five years after final felling.
+
====Mortality Factor Established Forest====
:'''Deciduous''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of broadleaves other than beech and oak (sv: ädellöv) the first five years after final felling.
+
:Adjustment factor for mortailty in established forest (mean height > about 7 m). Default = 1, i.e. no adjustment.
:'''Oak''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Quercus robur'' the first five years after final felling.
+
 
:'''Pine''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Pinus sylvestris'' the first five years after final felling.
+
====Calibrate Bengtsson====
:'''Spruce''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Picea abies'' the first five years after final felling.
+
:Set to True if mortality rates according to Göte Bengtsson should be applied (for small basal areas), independent of selected Mortality Model. This means the mortality model is only responible for distributing mortality over trees.
:'''Unknown''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of unknown species the first five years after final felling.
+
 
'''MortalityRetainedTreesYear6_10'''
+
====Calibrate Söderberg====
:'''Aspen''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Populus tremula'' year six to ten after final felling.
+
:Set to True if the self thinning limit (for large basal areas) according to Söderberg (1986) should be applied. This means the mortality model is only responible for distributing mortality over trees.
:'''Beech''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Fagus silvatica'' year six to ten after final felling.
+
 
:'''Birch''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Betula ssp.'' year six to ten after final felling.
+
====Mortality for Retained Trees 1-5====
:'''Broadleaf''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of broadleaves other than birch and aspen (sv: triviallöv) year six to ten after final felling.
+
:Mortality rate for retained trees during the first 5-year period, defined per each species group.
:'''Contorta''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Pinus contorta'' year six to ten after final felling.
+
 
:'''Deciduous''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of broadleaves other than beech and oak (sv: ädellöv) year six to ten after final felling.
+
====Mortality for Retained Trees 6-10====
:'''Oak''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Quercus robur'' year six to ten after final felling.
+
:Mortality rate for retained trees during the second 5-year period, defined per each species group.
:'''Pine''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Pinus sylvestris'' year six to ten after final felling.
+
 
:'''Spruce''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of ''Picea abies'' year six to ten after final felling.
+
====Adjust Mortality for Retention Patches====
:'''Unknown''' defines the rate of mortality, in percentage per 5-year-period, of retained trees of unknown species year six to ten after final felling.
+
:Set to '''FixedMortality''' to let mortality in a retention patch depend (i.e. increase) if and when the main stand is clear cut. If FixedMortality is selected, mortality is set in '''Mortality in Retention Patches'''. These parameters are hidden if '''NoAdjustment''' is chosen, meaning that the mortality is not affected by a clear cut of the main stand.
'''OmitThinningEffect'''
+
 
:'''True''' implies that the usually positive thinning effect upon growth will be omitted, '''False''' do not.
+
'''Note!''' To have effect, parameter '''Retention Patches as Dependent''' must be set to true in the [[ControlTable Nature Conservation#Retention Patches as Dependent | Nature Conservation control table]].
'''SingleTreeGrowthModel'''
+
 
:'''Elfving''' implies that the model by Elfving will be used in calculation of each trees' diameter development at the plot-level (the prediction unit).
+
====Mortality in Retention Patches year 1-5 and 6-10====
:'''Soderberg''' implies that the model by Söderberg will be used in calculation of each trees' diameter development at the plot-level (the prediction unit).
+
:These parameters has the same functionality as Mortality for Retention Trees, but applies to all trees in retentions patches and edge zones if '''Adjust Mortality for Retention Patches''' = Fixed Mortality.
'''VolumeModel'''
+
 
:'''BrandelLesser''' implies that the model by Brandel, with less predictor variables, will be used in calculation of tree volumes.
+
====Site Index Adjustment====
:'''SoderbergFormHeight''' implies that the model by Söderberg, with form height as predictor variable, will be used in calculation of tree volumes.
+
:Adjustment factor for site index. Default value = 1. Intended for research purposes.
:'''BrandelWithIndicatorVariables''' implies that the model by Brandel, with indicator variables as predictors, will be used in calculation of tree volumes.
+
 
'''WholeStandGrowthModel'''
+
====Height Threshold Young/Mature====
:'''None''' implies that no basal area development, as the sum for all trees at the plot-level, will be used in growth calculations.
+
:Defines the arithmetic mean tree height at which a "sapling" stand is considered a "mature" "tree" plot. Calculated for each plot. When at least 90% (?) of the plots are no longer sapling plots, then the stand is classified as a mature stand and not young.
:'''Elfving2005''' implies that the model by Elfving, anno 2005, will be used in calculation of basal area development at the plot-level (the prediction unit).
 
:'''Elfving2009''' implies that the model by Elfving, anno 2009, will be used in calculation of basal area development at the plot-level (the prediction unit).
 
  
 
== Age settings ==
 
== Age settings ==
 
Allows you to control how different types of ages, at tree-level, should be handled in the simulations.
 
Allows you to control how different types of ages, at tree-level, should be handled in the simulations.
  
'''AgeSetting'''
+
====Year to Breast Height Model====
:'''Real''' implies that the real age of the trees should be used in the calculations. The real age is calculated from the time of germination of the seed.
 
:'''Biological''' implies that the biological age of the trees should be used in the calculations. The biological age is calculated from the time when the seedling began to grow.
 
'''AgeToBreastHeightModel'''
 
 
:'''Elfving''' implies that the model by Elfving will be used in calculation of the age of a tree when it reach breast height (1.3 m).
 
:'''Elfving''' implies that the model by Elfving will be used in calculation of the age of a tree when it reach breast height (1.3 m).
 
:'''Tax''' implies that the model from the Swedish NFI will be used in calculation of the age of a tree when it reach breast height (1.3 m).  
 
:'''Tax''' implies that the model from the Swedish NFI will be used in calculation of the age of a tree when it reach breast height (1.3 m).  
'''CalibrateAge'''
+
 
:'''True''' implies that tree ages will be calibrated (using sample tree data[?]), '''False''' do not.
+
====<div id="Calibrate Age To Register Value Established Stands"></div>Calibrate Age To Register Value, Established Stands====
'''InitialAgeSource'''
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:'''True''' implies that tree ages will be calibrated so that the mean age will be as close as possible to the mean age according to the input data. '''False''' do not. Calibration is not applied if the mean age according to Heureka differs by more than 30 % to the input data.
:'''UseFunction''' implies that a build-in function will be used in calculation of trees' initial ages.  
+
 
:'''FromDatabase''' implies that information from database [The Hugin young forest-database?] will be used in derivation [imputation?] of trees' initial ages.
+
====<div id="Calibrate Age To Register Value Young Stands"></div>Calibrate Age To Register Value, Young Stands====
 +
:'''True''' implies that sapling ages will be calibrated. True if computed mean age of main saplings in young stands should equal the mean age according to the input data.
 +
 
 +
====Initial Age Source====
 +
:'''UseFunction''': The built-in function will be used to assign initial ages.  
 +
:'''FromDatabase''' If the database contains tree ages, these will be used as intial tree ages.
  
 
== Regeneration ==
 
== Regeneration ==
Allows you to control how...
+
Allows you to control how the forest regeneration, the establishment of new trees, should be handled in the simulations.
 +
 
 +
====Deterministic Simulation====
 +
:If True, a deterministic approach will be applied when simulating establishment of new stands (stem density and height distribution), and when simulating mortality and damages in young stands. This mean that the results will reflect an "average" regeneration, and for example mortality probabilities will be handled as frequencies, by adjusting the tree weight factors for the tree objects. If False, a stochastic approach will be applied. The default is determinstic.
 +
 
 +
====Ingrowth Model====
 +
:'''Deterministic''' applies deterministic ingrowth model components, where ingrowth is defined as the establishment of other seedlings than those planted.
 +
:'''Stochastic''' applies stochastic ingrowth model components, where ingrowth is defined as the establishment of other seedlings than those planted.
 +
:'''None''' applies no ingrowth/establishment of other seedlings than those planted.
 +
 
 +
====Min Mean Age Invoke Ingrowth====
 +
:Minimum mean age before invoking ingrowth function. When a young stand enters the established phase, part of the tree population may be truncated. Originally, the idea in Heureka was that trees smaller thatn 4 cm, should not be transferred to the established phase but instead represented by the new trees generated by the ingrowth functions. This has been modified, so that with diameter &ge; 2 cm are transferred. Running the ingrowth function immediately after the established phase is started, would overstimate the number of samll trees. It has been found resonable that at a stand age of 50 years, no trees that come from the young phase are less than 4 cm, allowing us to activate the ingrowth function at that age.
 +
 
 +
:This means that the value of this parameter should depend on the minium diameter you set. If set to 4 cm, set this parameter to 0.
 +
 
 +
====Ingrowth Species====
 +
:Allows you to deactivate the ingroth function for selected species.
 +
 
 +
====Max Age Ingrown Trees====
 +
:Age limit for ingrown trees (brh). The minimum of this and the age calculated with the tree age function will be used (in the first period the ingrown trees occurs).
 +
 
 +
====Sapling Diameter Model====
 +
Model for assigning sapling diameter (based on height-diameter relation)
 +
:'''Elfving''' implies that the model by Elfving will be used in calculation of the saplings' diameter.
 +
:'''NystromSoderberg''' implies that the model by Nyström and Söderberg will be used in calculation of the saplings' diameter.
 +
 
 +
====Skip Ingrowth Step One====
 +
:'''True''' means that the first step in the ingrowth model (Wikberg P-E), is skipped in the first 5-yr period and replaced with the actual number of small trees. This requires that your input data has information on the number of small trees in an established stand (for example NFI data). '''False''' if this step should be included (default).
 +
 
 +
<div id="Sapling Damage Factors"></div>
 +
====Sapling Damage Factor====
 +
:Weight factor for the mortality rate and occurrence of damages on young trees. The larger the weight, the larger the mortality and number of damaged trees. With 0 weight, no mortality and damages occur. Default value = 1.
 +
 
 +
 
 +
<!--
 +
== Growth ==
 +
Allows you to control if spatiality should be taken into account in the growth simulations. The results of a spatial growth model will depend on the trees' positions.
 +
 
 +
'''Spatial'''
 +
:'''True''' implies that spatial growth models are to be used, '''False''' do not.
 +
 
 +
== Ingrowth calculations (only if spatial growth modelling is '''True''') ==
 +
Allows you to control the establishment of new trees, as naturally regenerated seedlings.
 +
 
 +
'''IngrowthAffectingRadius'''
 +
:Defines the radius, in meters, of a circular area around a tree that will have impact on the ingrowth of new trees.
 +
'''IngrowthRasterCellsize'''
 +
:Defines the size, in meters, of the side of a square cell in which the ingrowth simulation is to be made.
 +
 
 +
== Virtual plot (only if spatial growth modelling is '''True''') ==
 +
Allows you to control the initial state of the forest regarding tree positions, when these positions are to be simulated.
  
'''IngrowthModel'''
+
'''SmallestDistanceBetweenTrees'''
:'''Deterministic'''
+
:Defines the minimum distance, in meters, between two adjacent trees.
:'''Stochastic'''
+
'''VirtualPlotSize'''
:'''None'''
+
:Defines the radius, in meters, of a circular plot virtualized in the simulations.
'''PlantDamageFactor'''
+
-->
:Defines...
 
'''PlantDiameterModel'''
 
:'''Elfving'''
 
:'''NystromSoderberg'''
 
'''PlantHeightGrowthModel'''
 
:'''ElfvingHugin'''
 
:'''NystromSingleTree'''
 
'''SkipIngrowthStepOne'''
 
:'''True''', '''False''' do not.
 

Latest revision as of 15:24, 5 October 2023


The production model control table contains settings that affect forest development, such as tree growth and mortality.

Growth and yield

Growth model settings

Growth Model Whole-Stand

None implies that no basal area development, as the sum for all trees at the plot-level, will be used in growth calculations.
Elfving2009: the model by Elfving (2009) will be used in calculation of basal area development at the plot-level (the prediction unit).

Growth Model Individual-Tree

Elfving: the single tree model by Elfving (2004) will be used in calculation of each trees' diameter development at the plot-level (the prediction unit).
Soderberg: implies that the model by Söderberg (1986) will be used in calculation of each trees' diameter development at the plot-level (the prediction unit).
Low Production Nyström: implies that the model by Nyström will be used in calculation of each trees' diameter development at the plot-level (the prediction unit). Intended for use on non-productive forest land only.

BIOMASS

BARK

Growth: Include Thinning Response

True if thinning response function should be applied, false otherwise. Only applied to even-aged stands.

Growth and Mortality Adjustment Factors

Adjustment factors for basal area and height growth, as well as mortality, in established forest. Default = 1, i.e. no adjustment. From version 2.21, factors are set per period and species' group. If data entry for a period is missing, closest previous period's value will be used. If data entry for a species is missing the user specified default value is used. Should normally not be changed, intended for research purposes.

Volume Function

Selected volume function.

Height Development Model

ErikssonElfving implies that the model by Eriksson and Elving will be used in calculation of height development.
SoderbergWithTreeAge implies that the model by Söderberg including single tree ages will be used in calculation of height development.
SoderbergWithStandAge implies that the model by Söderberg including average stand ages will be used in calculation of height development.
Low Production Nyström: implies that the model by Nyström will be used in calculation of height development. Intended for use on non-productive forest land only.

Height: Initial Height Function

SoderbergWithTreeAge implies that the model by Söderberg including single tree ages will be used in calculation of initial tree heights.
SoderbergWithStandAge implies that the model by Söderberg including average stand ages will be used in calculation of initial tree heights.

Height:Initial Height Source

UseFunction implies that the model selected in InitialHeightModel (above) will be used.
FromDatabase implies that initial tree heights will be obtained from the input database.

Height Calibration

True means that tree heights will be calibrated, False do not. Calibration factors are calculated using sample tree data.

Mortality Implementation

Deterministic will apply deterministic components in the mortality model (recommended).
Stochastic will apply stochastic components in the mortality model

Mortality Model

Selected mortality model. Default value for parameter "Calibrate Bengtsson" will depend on what mortality model is selected.

Mortality Factor Established Forest

Adjustment factor for mortailty in established forest (mean height > about 7 m). Default = 1, i.e. no adjustment.

Calibrate Bengtsson

Set to True if mortality rates according to Göte Bengtsson should be applied (for small basal areas), independent of selected Mortality Model. This means the mortality model is only responible for distributing mortality over trees.

Calibrate Söderberg

Set to True if the self thinning limit (for large basal areas) according to Söderberg (1986) should be applied. This means the mortality model is only responible for distributing mortality over trees.

Mortality for Retained Trees 1-5

Mortality rate for retained trees during the first 5-year period, defined per each species group.

Mortality for Retained Trees 6-10

Mortality rate for retained trees during the second 5-year period, defined per each species group.

Adjust Mortality for Retention Patches

Set to FixedMortality to let mortality in a retention patch depend (i.e. increase) if and when the main stand is clear cut. If FixedMortality is selected, mortality is set in Mortality in Retention Patches. These parameters are hidden if NoAdjustment is chosen, meaning that the mortality is not affected by a clear cut of the main stand.

Note! To have effect, parameter Retention Patches as Dependent must be set to true in the Nature Conservation control table.

Mortality in Retention Patches year 1-5 and 6-10

These parameters has the same functionality as Mortality for Retention Trees, but applies to all trees in retentions patches and edge zones if Adjust Mortality for Retention Patches = Fixed Mortality.

Site Index Adjustment

Adjustment factor for site index. Default value = 1. Intended for research purposes.

Height Threshold Young/Mature

Defines the arithmetic mean tree height at which a "sapling" stand is considered a "mature" "tree" plot. Calculated for each plot. When at least 90% (?) of the plots are no longer sapling plots, then the stand is classified as a mature stand and not young.

Age settings

Allows you to control how different types of ages, at tree-level, should be handled in the simulations.

Year to Breast Height Model

Elfving implies that the model by Elfving will be used in calculation of the age of a tree when it reach breast height (1.3 m).
Tax implies that the model from the Swedish NFI will be used in calculation of the age of a tree when it reach breast height (1.3 m).

Calibrate Age To Register Value, Established Stands

True implies that tree ages will be calibrated so that the mean age will be as close as possible to the mean age according to the input data. False do not. Calibration is not applied if the mean age according to Heureka differs by more than 30 % to the input data.

Calibrate Age To Register Value, Young Stands

True implies that sapling ages will be calibrated. True if computed mean age of main saplings in young stands should equal the mean age according to the input data.

Initial Age Source

UseFunction: The built-in function will be used to assign initial ages.
FromDatabase If the database contains tree ages, these will be used as intial tree ages.

Regeneration

Allows you to control how the forest regeneration, the establishment of new trees, should be handled in the simulations.

Deterministic Simulation

If True, a deterministic approach will be applied when simulating establishment of new stands (stem density and height distribution), and when simulating mortality and damages in young stands. This mean that the results will reflect an "average" regeneration, and for example mortality probabilities will be handled as frequencies, by adjusting the tree weight factors for the tree objects. If False, a stochastic approach will be applied. The default is determinstic.

Ingrowth Model

Deterministic applies deterministic ingrowth model components, where ingrowth is defined as the establishment of other seedlings than those planted.
Stochastic applies stochastic ingrowth model components, where ingrowth is defined as the establishment of other seedlings than those planted.
None applies no ingrowth/establishment of other seedlings than those planted.

Min Mean Age Invoke Ingrowth

Minimum mean age before invoking ingrowth function. When a young stand enters the established phase, part of the tree population may be truncated. Originally, the idea in Heureka was that trees smaller thatn 4 cm, should not be transferred to the established phase but instead represented by the new trees generated by the ingrowth functions. This has been modified, so that with diameter ≥ 2 cm are transferred. Running the ingrowth function immediately after the established phase is started, would overstimate the number of samll trees. It has been found resonable that at a stand age of 50 years, no trees that come from the young phase are less than 4 cm, allowing us to activate the ingrowth function at that age.
This means that the value of this parameter should depend on the minium diameter you set. If set to 4 cm, set this parameter to 0.

Ingrowth Species

Allows you to deactivate the ingroth function for selected species.

Max Age Ingrown Trees

Age limit for ingrown trees (brh). The minimum of this and the age calculated with the tree age function will be used (in the first period the ingrown trees occurs).

Sapling Diameter Model

Model for assigning sapling diameter (based on height-diameter relation)

Elfving implies that the model by Elfving will be used in calculation of the saplings' diameter.
NystromSoderberg implies that the model by Nyström and Söderberg will be used in calculation of the saplings' diameter.

Skip Ingrowth Step One

True means that the first step in the ingrowth model (Wikberg P-E), is skipped in the first 5-yr period and replaced with the actual number of small trees. This requires that your input data has information on the number of small trees in an established stand (for example NFI data). False if this step should be included (default).

Sapling Damage Factor

Weight factor for the mortality rate and occurrence of damages on young trees. The larger the weight, the larger the mortality and number of damaged trees. With 0 weight, no mortality and damages occur. Default value = 1.