Heureka Wiki - User contributions [en]

Spruce bark beetle index

2023-01-18T16:11:02Z

JeanetteEggers:

The spruce bark beetle risk index model is published here: [[https://www.sciencedirect.com/science/article/pii/S2666719322001704 Nordkvist et al. 2023]]

Its implementation in Heureka is based on the forest conditions both before and after management activities in each period, and include the main tree layer as well as overstorey trees in both cases.

Follow the link below to view the detailed model description (only in Swedish):

[[https://www.heurekaslu.se/w/images/1/18/Rapport_Risk_index_granbarkborre_MNordkvist20220314.pdf Spruce bark beetle index model description]]

References: Nordkvist, M., Eggers, J., Fustel, T. L.-A., & Klapwijk, M. J. (2023). Development and implementation of a spruce bark beetle susceptibility index: A framework to compare bark beetle susceptibility on stand level. Trees, Forests and People, 11, 100364.

[[Category:Model]]

Climate Model

2022-12-07T07:07:00Z

JeanetteEggers: /* Input data */

[[Category:Model]]
[DRAFT]. Last updated 2016-03-23.

==Introduction==
In Heureka, the effect of global warming on forest growth can be accounted for based on results from a process-based model called BIOMASS. BIOMASS was developed by McMurtrie et. al (1990)<ref name="BIOMASS_ref">{{:Bibliography:McMurtrie1990_BIOMASS}}</ref> and has been modified and validated for Swedish conditions in a number of studies
<ref>Bergh J., McMurtrie R. E. & Linder S. 1998. Climatic factors controlling the
productivity of Norway spruce: a modelbased analysis. Forest Ecology and
Management 110: 127–139.</ref>
<ref>Freeman M & Linder S. 2001. Boreal forests. In: Long-term effects of climate change
on carbon budgets of forests in Europe (eds. Kramer, K. & Mohren, G.M.J.) pp.
197–203. Alterra-report 194. Alterra, Green World Research, Wageningen, 2001</ref>
<ref>Bergh J., Freeman M., Sigurdsson B. D., Kellomäki S., Laitinen K., Niinistö S., Peltola, H. & Linder S. 2003. Modelling the shortterm effects of climate change on the
productivity of selected tree species in Nordic countries. Forest Ecology and
Management 183:327–340</ref>
<ref>Freeman M, Morén A-S, Strömgren M & Linder S. 2005. Climate Change Impacts on
Forests in Europe: Biological Impact Mechanisms. In: Management of European
Forests under Changing Climatic Conditions (eds. Kellomäki, S. and Leinonen, S.).
ResearchNotes 163, University of Joensuu, Forest Faculty, pp. 45-115.
<nowiki>ISBN 952-458-652-5</nowiki></ref>.
BIOMASS is computationally demanding to run and not suitable to include directly in Heureka’s growth simulator. Therefore BIOMASS has been run for different parts of the country, forest conditions and climate scenarios, and the results have been used to construct an approximation model of BIOMASS.

==How the model works==
A special approach has also been developed to adapt the response of the growth models used in Heureka. The principal idea is to augment or shift the growth function when climate changes. This is done by changing tree ages; the size to age relation of trees is a critical variable in all growth functions used in Heureka. In the system, we differ between actual tree age and biological tree age. The biological age is the one subject to adjustment.

The climate response model affects the following variables directly:
*The biological age or basal area depending on [[ControlTable_Climate_Model#Apply Age Adjustment| user setting]]
*Site index (SIS)
*Vegetation index
*Temperature sum

====Main calculation steps====
#The selected climate scenario has information on relative growth difference (α, see below) between an unchanged climate and a changed climate. This is called the growht response.
#At a given year ''t'', Heureka calculates the growth from year ''t'' to ''t''+5, for an unchanged climate (ΔGempir).
#Calculate Gclim = α · ΔGempir = The expected growth when there is a climate change.
#A new growth calculation is done, with climate-adjusted values for site index and vegetation index (see below)
#Depending on [[ControlTable_Climate_Model#Apply Age Adjustment| whether tree ages]] should be adjusted or not (see control table [[ControlTable_Climate_Model#Apply Age Adjustment|Climate Model]], one of the following is applied:
#;[[ControlTable_Climate_Model#Apply Age Adjustment|Age adjustment]] should be made: By using binary search, all tree ages are adjusted with a certain factor c, until the obtained growth equals Gclim (within a certain tolerance).
#;If no age adjustment should be made: The growth projection length is extended (or shortened if the climate model predicts decreased growth due to drought) until the expected growth is obtained. Non-linear interpolation is used to handle that this will unlikely coincide with an exact five-year interval. All tree attributes in at time ''t''+5 (diameter, height etc) except tree ages are set to the values obtained in the extended (or shortened period).

==Calculation of growth response (changed growth due to climate change)==
====Step 1: Uncorrected growth response (<math>\alpha_{BIOMASS})</math>====
A "climate scenario" file imported to Heureka is not an actually scenario but a table of coeffiicients used to calculate growth modification factors that are then used in the Heureka "climate model".

For a given prediction unit that has soil moisture class j, the growth correction factor is calculated as function of the parameters a, b and c, which depend on scenario, geographic locations, tree species and soil moisture code. 

<math>\alpha_{BIOMASS}(s) = a(s,j) LAI(s)^2 + b(s,j) LAI(s) + c(s,j)</math>

where

''α''''BIOMASS''(i,j) = Growth correction factor for species ''j'' according to model BIOMASS, and
 ''LAI''(''s'') = Leaf area index for species s (m2 leaf area / m2 forest floor area)

Since leaf area is not calculated in Heureka, foliage biomass is used instead, and multiplied with a conversion factor (SLA) to get LAI.

<math>\displaystyle LAI(s) = \frac{fbm(s) SLA(s)}{f(s)}</math>

where
 fbm(s) = Foliage biomass (kg/m2, dry matter / forest floor area), and
 SLA(s) = Conversion factor for biomass foliage to leaf area for species s (m2 projected one-side leaf area / kg dry matter),
 f(s) = Species proportion of species s in the stand, used as indicator for how much of the forest floor area is occupied by species ''s''. The division with the species distribution is done because the divisor (forest floor area) should only include the forest floor occupied by the subject trees.

====Step 2: Corrected response (β)====
<math>\alpha_{BIOMASS}</math> reflects "optimal" stand conditions and should therefore be modified. The response modifier is a linear function of vegetation index.

<math>\displaystyle \beta(s) = c_0 +(VIX-VIX_{min}(s))\frac{1-c_0(s)}{VIX_{max}(s)-VIX_{min}(s)}</math>

where

β(''s'') = Response modifier for species ''s'', and
 ''VIX'' = Vegetation index, and 
 c0(s) = Intercept for species ''s'' (see control table), and
 ''VIX''min = Minimum vegetation index for species s, and
 ''VIX''max = Maximum vegetation index for species s.

The modified response for each species ''s'' is: 

<math>\alpha_{c1}(s)=1 + \beta(s)(\alpha_{BIOMASS}(s)-1)</math>

====Step 3: Carbon dioxide response====
Step 1 and 2 can either included the combined effect or water, temperature and carbon dioxide, or add the carbon dioxide component in a third step. In that case, other coefficients are used in step 1. The carbon dioxide response modifier is calculated with the same type of formula as α(s), but with other coefficients.

<math>\displaystyle \gamma(s) = d(s,j) LAI(s)^2 + e(s,j) LAI(s) + f(s,j)</math>

This value is then multiplied with the calculated growth response.

<math>\alpha_{c2}(s)= \gamma(s) \alpha_{c1}(s)</math>

==Temperature sum change==
The change in temperature over time caused by a changing climate is expressed as an average temperature sum change factor (λ) for five years, and is part of the climate scenario input data.

==Site index change==
The site index (sis) change from one five-year period to the next is calculated as

<math>\Delta sis = \lambda (21.9947 \Delta TS - 2.1384 \Delta TS2) </math>

where

<math>\lambda</math> = Temperature change factor for a five-year period
 <math>TS_{t} = \lambda \cdot TS_{t-1}</math> (temperature sum in °C)
 <math>\Delta TS</math> = Change in temperature sum (1000 °C) between two five-year periods<tt>:</tt> <math>0.001\ (TS_{t} - TS_{t-1})</math>) where ''t'' is period index, and
 <math>\Delta TS2</math> = Change between squared temperature sums (in 1000 °C) from period ''t''-1 to period ''t''<tt>:</tt> <math>(0.001 TS_{t})^2 - (0.001 TS_{t-1})^2</math>

==Vegetation index change==
The vegetation index is a mapping of the categorial variable [[Definition:VegetationTypeCode | vegetation type code]], to a nominal variable. The vegetation index is used as one of the explanatory in the Whole-stand growth model (see page 39 in the [http://heurekaslu.org/mw/images/9/93/Heureka_prognossystem_(Elfving_rapportutkast).pdf "Growth modelling in Heureka" document]).

The climate model modifies the vegetation index. The vegetation index increases when the climate model predicts increased growth. The vegetation index is updated in each projection period as a linear function of ΔTS2<tt>:</tt>

<math>\Delta VIX = 1.24 \cdot \Delta TS2 \cdot \frac{periodLength}{5}</math>

==Growth model==
====Case 1: Whole-stand growth model====
In Heureka a stand-level growth model is used (as default) to calculate basal area growth per ha on each plot, in combination with a single-tree growth model that distributes the growth to individual tree objects. Mean age is used as one of the explanatory variables. Different species are not differentiated, and it is not possible to make an adjustment for each species separately. Therefore, the response for all species together is weighted proportionally to the species proportions: 

<math> \displaystyle \alpha_{tot} = \sum_{s=1}^{m} f(s) \alpha_{c2}(s)</math>

where

''m'' = number of species, and
 ''f''(''p'') = volume proportion of species ''s''

====Case 2: Single-tree growth model====
Single-tree or other growth model that used species-wise ages as function parameter. In this case, the growth adjustment is differentiated with respect to species (binary search can be applied to each species group separately when adjusting tree ages), using indexed \alpha_{c2}(s) instead of alpha_{tot}.

==Input data==
With the installation of Heureka, there are three climate model scenarios available:

:'''MPI 4.5''': Based on Max Planck Institute [http://www.mpimet.mpg.de/en/science/models/mpi-esm/ MPI-ESM model] using radiation scenario RCP 4.5, which assumes that radiative forcing stabilises at 4.5 W/m² before the year 2100. See also [https://www.smhi.se/en/climate/future-climate/basic-climate-change-scenario-service/sverige/medeltemperatur/rcp45/2071-2100 RCP4.5 at SMHI's homepage].
:'''MPI 8.5''': Based on Max Planck Institute [http://www.mpimet.mpg.de/en/science/models/mpi-esm/ MPI-ESM model] using radiation scenario RCP 4.5, which assumes that radiative forcing stabilises at 8.5 W/m² before the year 2100.. See also [https://www.smhi.se/en/climate/future-climate/basic-climate-change-scenario-service/sverige/medeltemperatur/rcp85/2071-2100 RCP8.5 at SMHI's homepage]
:'''ECHAMS_A1B''': Based on Max Planck Institute climate model [http://www.mpimet.mpg.de/en/science/models/echam.html ECHAM] using emission scenario SRES A1B.

====About the climate scenarios====
:[http://www.smhi.se/en/climate/climate-scenarios/haag_en.html About SMHI climate scenarios]
:[http://shop.skogsstyrelsen.se/shop/9098/art35/31485335-a7bfe8-Klimat_webb.pdf Climate scenarios used in Heureka in the SKA 15 project]
:[http://heurekaslu.org/help/en/index.html?importera_klimatscenario.htm Import climate scenario in Heureka Helpdoc].

==Model settings that a user can modify==
See [[ControlTable_Climate_Model|Climate Model control table]].

==References==
<references />

Forest Data Results

2022-08-05T06:10:36Z

JeanetteEggers:

This result group contains: [[ResultCategoryDescription::State for each treatment unit. Results include data for each treatment unit, alternative and time period. Please note that species-wise data is placed in a separate group (Data per Species).]]

{| {{table}}
| align="left" style="background:#f0f0f0;width: 30%;"|'''Variable name'''
| align="left" style="background:#f0f0f0;width: 20%;"|'''Unit'''
| align="left" style="background:#f0f0f0;width: 50%;"|'''Description'''
|-
| Mean Age (excl. overstorey)||yr||Mean total age for non-overstorey trees, basal area weighted if established stand, arithmetic of main saplings if young stand
|-
| Mean Age ||yr||Basal area weighted mean age all trees, including overstorey trees.
|-
| Mean Age Main Saplings||m||Mean age of main saplings
|-
| Stand Age||yr||Years since regeneration
|-
| Basal area (incl. overstorey)||m2/ha||Basal area including overstorey trees
|-
| Basal area (excl. overstorey)||m2/ha||Basal area excl. Overstorey
|-
| Basal area (overstorey)||m2/ha||Basal area of overstorey trees (retention-, seed- and shelterwood trees)
|-
| Closure||unitless||Ratio between the volume of the forest, compared to the volume that would be optimal to harness the wood production potential of the site. In young stands, the number of main saplings is used instead of volume.
|-
| {{DgvLink}} ||cm ||Basal area weighted mean diameter of trees, excluding overstorey trees
|-
| {{DgvLink}} Overstorey||cm ||Basal area weighted mean diameter of overstorey trees
|-
| {{HgvLink}}||m||Basal area weighted mean height for non-overstorey trees
|-
| {{HgvLink}} Overstorey||m||Basal area weighted mean height for overstorey trees (retention-, seed- and shelterwood trees)
|-
| Mean Height Main Saplings (arithmetic)||m||Arithmetic mean height for main saplings (calculated as weighted averaged using calculated crop tree probabibilites as weights)
|-
| Mean Height All Saplings (arithmetic)||m||Arithmetic mean height for all saplings
|-
| SI Management||H100 m||Site index for management to be used when calculating minimum final felling age (LSÅ)
|-
| Dominant Species||species||Regeneration species or species with largest basal area or stems
|-
| Dominant Height||m||Dominant height based on the 100 largest trees (with respect to tree diameter) per ha of dominant species
|-
| Dominant Height From {{DgvLink}}||m||Dominant height calculated with a function using Hgv as explantory variable (Björn Elfving)
|-
| Dominant Height From Trees||m||Dominant height calculated from tree list
|-
| Initial Min Final Felling Age||yr||Initial minimum final felling age (in year 0).
|-
| Min Final Felling Age||yr||Minimum final felling age. This can change over time if the next generation is regenerated with another species.
|-
| Volume (incl. overstorey)||{{m3skLink}}||Volume (incl. overstorey)
|-
| Volume overstorey||{{m3skLink}}||Volume of overstorey trees (retention-, seed- and shelterwood trees)
|-
| Volume (excl. overstorey)||{{m3skLink}}||Volume (excl. overstorey)
|-
| Volume ≥ 8cm dbh (incl. overstorey)||{{m3skLink}}||Volume of trees ≥ 8 cm dbh (incl. overstorey)
|-
| Stems||stems/ha||Stem density (all trees)
|-
| <div id="Regeneration Species">Regeneration Species</div>||[[Definition:SpeciesCode|SpeciesCode]]||Species for which the current rotation was regenerated (if even-aged management), or dominant species if regeneration species is unknown
|-
| Waiting State||true/false||True if young stand that has not yet reach 2-3 meters height and is waiting to be activated. Interpolated state.
|-
| SIS (projected)||H100 m ||[[Variable:SiteIndex|Site index]] determined from site index factors, and adjusted for climate change if climate model is actived.
|-
| SIH (estimated)||H100 m ||see [[Variable:SiteIndexH (SIH)]]. Calculated with site index equations for height development of dominant trees. H100, for birch H50.
|-
|
|}

[[Category:Result Variables]]

Carbon sequestration/sv

2022-08-04T13:18:12Z

JeanetteEggers:

{{Languages|Carbon sequestration}}
[[Category:Model]]
{{DISPLAYTITLE:Kolanalyser}}
Heureka kan beräkna hur mycket kol som finns i trädskikt, döda träd och i marken vid varje prognostidpunkt (figur 1). Kol i markvegetationen hanteras inte. Förändringen av kolförrådet under en tidsperiod beror på bortförsel genom avverkning, emission genom nedbrytning, samt upptag genom tillväxt.

'''(1)''' För beräkning av kolförrådet i '''trädkiktets''' ovanjordsdelar används biomassafunktioner för enskilda träd. För äldre skog används antingen <ref name = "Marklund1988">{{:Bibliografi:Marklund1988}}</ref> eller <ref name = "Petersson1999">{{:Bibliografi:Petersson1999}}</ref>, beroende på vilken modell som användaren har valt. För ungskog används <ref name = "ClaessonEtAl2001">{{:Bibliografi:ClaessonEtAl2001}}</ref>. Utifrån beräknad mängd biomassa används omräkningstal från biomassa (torrsubstans) till kolmängd (procent av torrsubstans) enligt följande tabell<ref name = "Skogsstyrelsen2000">{{:Bibliografi:Skogsstyrelsen2000}}</ref>.

{| {{table}}
| align="left" style="background:#f0f0f0;"|'''Träddel'''
| align="left" style="background:#f0f0f0;"|'''Gran'''
| align="left" style="background:#f0f0f0;"|'''Tall'''
| align="left" style="background:#f0f0f0;"|'''Björk'''
|-
| '''Stam'''||48,0||48,8||49,0
|-
| '''Gren'''||50,8||51,2||49,0
|-
| '''Barr/löv'''||48,6||51,2||49,0
|-
|
|}

För övriga lövträdslag används björkfunktioner, med en kvotkalibrering av veddelar. Denna kvotkalibrering baseras på kvoten mellan trädslagets och björkens veddensiteter ([http://sv.wikipedia.org/wiki/Tr%C3%A4slag]). Avverkade träd lämnar systemet. Avverkningsrester och delar från självdöda träd överförs till markmodellen som input till förnamodellen.

'''(2)''' Kolförekomst i [[:Category:Dead Wood|'''död ved''']] beror på ingående mängd, tillförsel från mortalitet och kvarlämnade avverkade träd och träddelar (tex högstubbar), samt nedbrytning. Om mängden död ved inte har inventerats används defaultvärden som baseras på data från Riksskogstaxeringen (finns i kontrolltabellen Dead Wood). Nedbrytning av biomassa beräknas med exponentiell funktion (''e''-''kt'') där trädslagsvisa k-värdena kan ändras av användaren.

'''(3)''' Kol i '''marken''' (för skog på mineraljord) baseras på biomassa i stubbar, rötter och förna, och nedbrytning av dessa.
Förnafall beräknas med utgångspunkt från stående biomassa, kvarlämnad biomassa efter avverkning, samt träddelar från självdöda träd. När det gäller självdöda träd ingår grenar, barr, stubbar och rötter, medan stamdelen, inklusive toppdelen av stammen, förs till död-ved poolen (se ovan). Biomassa i stubbar och rötter beräknas med <ref name ="PeterssonStahl2006">{{:Bibliografi:PeterssonStahl2006}}</ref>. Dessa funktioner inkluderar rötter ned till 2 mm. Rotförna från finrötter (< 2mm) beräknas internt i modellen med redovisas inte som resutlatvariabel i Heureka. Beräkningen görs med omvandlingstal för relation mellan mellanrötter (2-5mm) och finrötter. I dagsläget finns inga biomassafunktioner för stubbar och rötter i ungskog.

[[:Q-model|Q-modellen]] används för att beräkna mängden kol (och kväve) i förna- och humusskikt, och räknar på olika nedbrytningsförlopp för olika förnafraktioner. Detta gäller på mineraljord. På torvmark minskar markkolförrådet över tid om marken är dikad (med hjälp av emissionsfaktorer), medan markkolförrådet antas vara konstant i odikade torvmarker.

{|
|[[Image:CarbonBalance_sv.png|700px|thumb|left|Figur 1]]
|}
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<references />

Carbon sequestration

2022-08-04T13:13:36Z

JeanetteEggers:

{{Languages|Carbon sequestration}}
[[Category:Model]]
{{DISPLAYTITLE:Carbon sequestration}}
Heureka enables quantifying carbon pools in living and dead trees as well as soil, for each projection timestep (Figure 1). Ground layer carbon is not considered in Heureka at present. Changes in carbon stock over time depent on harvesting followed by extraction, emission via decomposition and capturing via photosynthesis/growth.

'''(1)''' Carbon stock in the '''above ground tree layer''' is calculated using single-tree biomass functions. In mature stands both <ref name = "Marklund1988">{{:Bibliografi:Marklund1988}}</ref> and <ref name = "Petersson1999">{{:Bibliografi:Petersson1999}}</ref> are available for usage in Heureka, whereas <ref name = "ClaessonEtAl2001">{{:Bibliografi:ClaessonEtAl2001}}</ref> is used for young stands. Conversion factors from biomass (dry matter) to carbon (percent of dry matter) are then used to estimate the carbon stock<ref name = "Skogsstyrelsen2000">{{:Bibliografi:Skogsstyrelsen2000}}</ref>.

{| {{table}}
| align="left" style="background:#f0f0f0;"|'''Tree part'''
| align="left" style="background:#f0f0f0;"|'''Spruce'''
| align="left" style="background:#f0f0f0;"|'''Pine'''
| align="left" style="background:#f0f0f0;"|'''Birch'''
|-
| '''Stem'''||48.0||48.8||49.0
|-
| '''Branch'''||50.8||51.2||49.0
|-
| '''Needles/leaves'''||48.6||51.2||49.0
|-
|
|}

Other broadleaf species are calculated using birch functions, calibrated for each species wood density relative to birch([http://sv.wikipedia.org/wiki/Tr%C3%A4slag]). Cut trees are removed from the tree layer and their felling residues (unextracted trees and parts) are transferred to the dead wood and/or soil carbon model, along with unextracted trees dead due to natural mortality.

'''(2)''' Carbon stock in [[:Category:Dead Wood|'''dead wood''']] is a function of starting stock, supply of dead stem wood from natural mortality as well as unextracted cut stems and stem parts (e.g. high stumps), and loss due to decomposition. If the initial dead wood stock is unknown the initial stock is simulated based on National Forest Inventory data (settings in control table Dead Wood). Decomposition of biomass is calculated using power functions (''e''-''kt'') where tree species-specific k-values can be adjusted in the control table.

'''(3)''' '''Soil carbon''' dynamics on mineral soils include biomass stock, supply and loss in stumps, roots and litter.
Litter fall is calculated based on standing woody biomass, unextracted biomass after forest management activities and parts - other than stems - of trees dead from natural mortality. Stump and root biomass is calculated using <ref name ="PeterssonStahl2006">{{:Bibliografi:PeterssonStahl2006}}</ref>. These models include roots thicker than 2 mm. Fine roots (< 2mm) are calculated internally using estimated relations between intermediate (2-5 mm) and fine (<2 mm) roots, but not presented as a result variable. No biomass functions for stumps and roots in young forests are currently available for use in Heureka.

The [[:Q-model|Q-model]] is used to calculate the amount of carbon and nitrogen in the litter and soil layers on mineral soils, and to predict decomposition in different litter fractions. On ditched organic soils (peat), soil carbon decreases over time (using emission factors), while the soil carbon stock in unditched peatland remains constant over time.

{|
|[[Image:CarbonBalance_sv.png|700px|thumb|left|Figure 1]]
|}
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<references />

Definition:BottomLayerTypeCode

2022-06-29T07:16:21Z

JeanetteEggers:

{{ForestInputData
|description = Ground layer vegetation type code. Corresponds to Swedish NFI-variable BOTTENSK ([[Media:RIS_Falt.pdf|see RIS]] )
|I_O = Input
|type = integer
|membership = [[Definition:Reference unit|Reference unit]]
|unit_values = {{BottomLayerCodeTable}}
|database = dbo.ReferenceUnit
}}

{{VariableAndDefinitionCategory}}

Definition:BottomLayerTypeCode

2022-06-29T07:15:22Z

JeanetteEggers: Reverted edits by JeanetteEggers (talk) to last revision by Peder

{{ForestInputData
|description = Bottom layer vegetation type code. Corresponds to Swedish NFI-variable BOTTENSK ([[Media:RIS_Falt.pdf|see RIS]] )
|I_O = Input
|type = integer
|membership = [[Definition:Reference unit|Reference unit]]
|unit_values = {{BottomLayerCodeTable}}
|database = dbo.ReferenceUnit
}}

{{VariableAndDefinitionCategory}}

Definition:BottomLayerTypeCode

2022-06-29T07:10:43Z

JeanetteEggers:

{{ForestInputData
|description = Ground layer vegetation type code. Corresponds to Swedish NFI-variable BOTTENSK ([[Media:RIS_Falt.pdf|see RIS]] )
|I_O = Input
|type = integer
|membership = [[Definition:Reference unit|Reference unit]]
|unit_values = {{GroundLayerCodeTable}}
|database = dbo.ReferenceUnit
}}

{{VariableAndDefinitionCategory}}

Definition:BottomLayerTypeCode

2022-06-29T07:10:13Z

JeanetteEggers:

{{ForestInputData
|description = Groundlayer vegetation type code. Corresponds to Swedish NFI-variable BOTTENSK ([[Media:RIS_Falt.pdf|see RIS]] )
|I_O = Input
|type = integer
|membership = [[Definition:Reference unit|Reference unit]]
|unit_values = {{GroundLayerCodeTable}}
|database = dbo.ReferenceUnit
}}

{{VariableAndDefinitionCategory}}

ControlTable Treatment Model

2022-06-14T06:59:00Z

JeanetteEggers: /* Nature Conservation Activities (Tree Retention) */

[[Category:Control Tables|Treatment Model]]
[[Category:Reference Manual]]
Overview of TreatmentModel control table parameters.
 For a more detailed description of the usage, see the [http://heurekaslu.org/help/en/index.html?simulering_av_atgarder.htm help documention] chapters on simulation of treatments, for example:
*Regeneration: [http://heurekaslu.org/help/en/index.html?foryngring.htm Regeneration help documention]
*Cleaning: [http://heurekaslu.org/help/en/index.html?rojning.htm Cleaning (precommercial thinning) help documention]
*Thinning: [http://heurekaslu.org/help/en/index.html?gallring.htm#Utforande Thinning help documention]
*Final felling: [http://heurekaslu.org/help/en/index.html?slutavverkning.htm#Utforande Final Felling help documention]

In the treatment model control table you can configure how individual forest management activities are simulated.

== Regeneration - model ==
Allows you to control how forest regenerations are simulated, regarding planting, natural regeneration using seed trees, and sowing.

====Regeneration Model Type====
*Simulation: simulate regeneration from a Weibull distribution.
*Database: simulate regeneration by imputation of plot data from a database (supplied).

== Regeneration - settings ==

====Deterministic Application====
:(only if '''Simulation''' is selected) '''True''' applies deterministic regeneration model components, '''False''' do not (then stochastic).

====Mean Sapling Height When Activated====
(only if '''Simulation''' is selected)
:Defines the arithmetic mean height in meters at stand-level[plot-level?] when trees are initiated, for '''Natural regeneration''', '''Sowing''', '''Spruce plantation''', '''Pine plantation''', and '''Contorta plantation''', respectively. Development before this height is obtained by linear interpolation.

====Regeneration Year====
:Defines the number of years from time of final felling to time of regeneration, applied in simulations of '''Plantation''' and '''Sowing'''.

====Regeneration Settings====
:Defines the number of seedlings per hectare applied in '''Plantation''' (or in '''Sowing''', or in '''Natural regeneration using seed trees''', respectively) following '''Soil scarification''' (or '''Controlled burning''', or '''None''', respectively), regarding the tree species and site index. This seedling consumption table will, obviously, lead to certain regeneration costs.

====Soil Preparation Year====
:Defines the number of years from time of final felling to time of soil preparation, applied in simulations of '''Soil scarification''' and '''Controlled burning'''. Obviously, this number can not exceed settings in '''Regeneration Year'''.

== Cleaning ==
Allows you to control how cleanings, a.k.a. pre-commercial thinnings, are simulated.

====Cleaning Model====
:'''Heureka cleaning''' defines one model of tree removal, actually cutting of saplings, in the cleaning simulations.
:'''Hugin cleaning''' defines another model of tree removal, currently corresponding to the above, in the cleaning simulations.

====Deterministic Application====
:'''True''' applies deterministic cleaning model components, '''False''' do not (then stochastic).

====Mean Height Cleaning====
:'''Min''' defines the minimum arithmetic mean height in meters at stand-level when cleaning is simulated.
:'''Max''' defines the maximum arithmetic mean height in meters at stand-level when cleaning is simulated.

====Min Stems Cleaned====
:Defines the minimum number of stems per hectare to be cut in cleanings. No cleaning will be simulated if stem density is so low that less stems are able to cut, regarding all current tree species.

====Settings for Deciduous Trees====
:'''Alfa''' and '''Beta''' are coefficients in a function calculating the priority factor of deciduous tree species. Deciduous trees, i.e. all broadleaves, will then be retained in cleanings prior to coniferuous trees.

====Settings for Pine====
:'''Alfa''' and '''Beta''' are coefficients in function calculating the priority factor of pine trees. Pines, i.e. ''Pinus ssp.'', will then be retained in cleanings prior to deciduous and other coniferuous trees.

====Settings for Spruce====
:'''Alfa''' and '''Beta''' are coefficients in function calculating the priority factor of spruce trees. Spruces, i.e. ''Picea ssp.'' and ''Abies ssp.'', will then be retained in cleanings prior to deciduous and other coniferuous trees.

== Thinning or Selection Felling ==
Settings in common for thinning and selection felling

====Thinning Configuration====
Opens a dialog where you can select Thinning Algoritm and how different species should be prioritized. See [{{HeurekaHelpLinkEng}}gallring.htm Help doc on thinning settings].

The thinning algorithm that can be selected are:
:'''HuginOld''' Algorithm developed for the Hugin system. It uses three species groups, and groups trees into four diameter classes for each group. See [[Thinning]]
:'''Hugin''' Derived from HuginOld but allows you to specify more species groups, and explicit species distribution targets. The algorithm operates on a species group level in the same way as HuginOld. See [[Thinning]]
:'''LOEriksson''' defines another model of tree selection in the thinning simulations. You enter species groups in the same ways as with Hugin, but the thinning form (above/below) is entered using a relative diameter target value.

The dialog contains parameters for how thinning should be distributed over trees and species, depending on the thinning algorithm chosen.
====Relative Diameter====
(only if '''LOEriksson''' is selected)
:'''First''' defines the relationship between the mean diameters of trees cut and trees retained in first thinning of a stand, expressed in percentage.
:'''Second''' defines the relationship between the mean diameters of trees cut and trees retained in second and following thinnings of a stand, expressed in percentage.

====Thinning Algorithm Parameters====
See [[Thinning Algorithm Parameters]]

====Vary Thinning Grade====
:'''True''': thinning intensity is distributed over PredictionUnits (plots) proportionally to basal area. '''False''': Same thinning intensity on all plots in the treatment unit.

====Min Diameter Cut====
:Defines the minimum diameter, in centimeters, of trees to be cut when thinning or selection felling.

====Min Prop. Thinnable Plots====
:Min proportion of plots (impediment plots ignored) that should be thinned according to thinning guide in order for thinning to be applied. '''''Currently only available when Thinning Guide = StemDensity.'''''

====Min Thinning Grade====
:Defines the minimum thinning grade required in order to apply a thinning, in percentage of basal area, stem density or volume (depending on thinning guide), including any cutting of strip roads. Is thinning grade accoring to guide is lesser, thinning is cancelled.

====Max Thinning Grade====
:Defines the maximum thinning grade, in percentage of basal area, stem density or volume (depending on thinning guide), including any cutting of strip roads. If thinning guide suggest a larger thinning grade, it is set to Max Thinning Grade.

====Thinning System====
:'''These parameters are only used in cost functions and should not be confused with settings for how a thinning should be simulated.'''
:*NotSpecified: defines that non specified thinning types should be simulated.
:*StripRoad: defines that thinnings with strip roads should be simulated.
:*StripRoadMidFieldMachine: defines that thinnings with harvester should be simulated.
:*StripRoadMidFieldChainsaw: defines that thinnings with harvester and manual labour (with chainsaw) should be simulated.

====Harvest Striproads====
:'''True''' simulates the cutting of strip roads if a stand is thinned for the first time, '''False''' do not.

====Effective Striproad Width====
:Defines the effective width of strip roads in meters. Effective means that the harvesting machines can thread (slingra sig fram). A "threading factor" (slingerfaktor) of 75 % gives an effective strip road width of 3 m with an actual strip road width of 4 m.

====Distance Between Striproads====
:Defines the distance in meters between the centre of adjacent stip roads, used in simulation of the first thinning in a stand.

== Thinning ==
Allows you to control how thinnings are simulated.
See [[Thinning]] for a complete description.

====UMin====
(only if '''LOEriksson''' is selected as thinning algorithm in Thinning Configuration Dialog)
:Defines the minimum proportion, regarding basal area, of a single tree of all trees cut at the plot-level, expressed in percentage and value range (0, 20).

====UMax====
(only if '''LOEriksson''' is selected as thinning algorithm in Thinning Configuration Dialog)
:Defines the maximum proportion, regarding basal area, of a single tree of all trees cut at the plot-level, expressed in percentage and value range (80, 100).

====Thinning Guide====
:A thinning guide is used to determine whether thinning should or could be done, and the thinning intensity.
:'''Hugin''', '''Skogsstyrelsen''', '''Ingvar''', '''Logarithmic''' and '''Polynomial''' are defined for basal area.
:'''StemDensity''' is defined for number of trees. 

<div id="Thinning Guide Hugin Settings"></div>
<div id="Thinning Guide SKS Settings"></div>
<div id="Thinning Guide Polynomial Settings"></div>
<div id="Thinning Guide Logarithmic Settings"></div>
<div id="Thinning Guide Ingvar Settings"></div>
====Thinning Guide Settings====
:;All guides but StemDensity and Ingvar:Opens dialog with coefficients for thinning guide (such as site index and dominant height, respectively) used in calculations of the tree species' basal area, before and after thinning.

:'''Thinning Guide Stem Dens. Beta:''' Setting for thinning guide "StemDensity", parameter β = Domainant height at which first thinning should be done.

<div id="Thinning Guide Stem Dens. Delta"></div>
:'''Thinning Guide Stem Dens. Delta''':Setting for thinning guide "StemDensity". This parameter controls slope of function.

<div id="Ingvar Version for Pine, Larch and Contorta"></div>
<div id="Ingvar Version for Spruce"></div>
:'''Ingvar version''': Ingvar thinning guide (by Skogforsk) has different levels.

====Max Relative Age====
:Time for last thinning in terms of maximum relative age. If relative age is larger, then no more thinning will be simulated. Relative age is an approximation for how close a stand is to culmination of mean annual growth (MAI). It is computed as mean age divided by 1.1*LSÅ, where LSÅ = minimum eligible age for final felling according to Swedish Forestry Act.

====Min Height Thinning====
:Min dominant height required for thinning.

====Max Height Any Thinning====
:Max dominant height (m) when last thinning can be applied. '''''Currently only available when Thinning Guide = StemDensity.'''''

====Max Height First Thinning====
:Max dominant height (m) when first thinning can be applied. If dominannt height is larger and stand has never been thinned, then it is considered too late to do first thinning, due to risk of felling damages on remaining trees.

====Thinning Guide Reduction Factors====
:Thinning guide reduction factors for upper and lower curve. Applies to basal area thinning guides. Example: 0.95 for upper curve means that upper curve is lowered by 5 percent.

====Previously Thinned Threshold====
:Threshold for when stands of a given SIS is considered previously thinned if thinning history is not available. If stems/ha is lower than given value, stand is assumed to have been thinned.

=====Pine Threshold=====
:Maximum stem density (stems/ha) in pine stands to consider them as previously thinned if thinning history is missing.

=====Spruce Threshold=====
:Maximum stem density (stems/ha) in spruce stands to consider them as previously thinned if thinning history is missing.

=====Other Threshold=====
:Maximum stem density (stems/ha) in deciduous stands to consider them as previously thinned if thinning history is missing.


====Understorey Max Diameter====
:Upper diameter limit for understorey trees in thinnings (cm). Trees with dbh lesser than this value will be considered understorey trees (in mature stands, not in plantations). Note: Setting this to 0 means that no trees will be considered understorey trees.
:Default: 8 cm

====Understorey Cleaning Stems Threshold====
:Minimum understorey stem density required for understory cleaning to be performed (stems/ha). If the number of understorey stems is less than this parameter, no understorey cleaning will be performed, but the harvester cost may increase due to the hindrance of understorey. For example, with 4000 undestorey trees, the harvester productivity will decrease with 3 percent.
:Default: 800 st/ha

====Min Understorey Stems Retained====
:Minimum number of understorey trees left when understorey cleaning is done.
:Default: 200 st/ha

====Understorey Proportion Removal====
:Proportion of understorey stems to remove when and if understorey cleaning is performed (%). The program may adjust so that parameter 'Min Understorey Stems Retained' is not violated.
:Default: 90%

== Selection felling ==
(only if '''Hugin''' is selected as thinning model)
Allows you to control how selection fellings (usually applied in "continuous forestry") are simulated.

====SelectionControlParameter====
Equivalent to [[#Thinning Algorithm Parameters | Thinning Algorithm Parameters]] but other settings for selection fellings.

==Young Stand Thinning==
Criteria to determine whether a stand should be considered a young stand. Biofuel thinning is only allowed in stands classified as young. Also, to determine whether a stand is a young stand thinned for the first time (swe: förstagallring), this information is used.

====Max Relative Age====
Max relative age for a stand to be considered young. Relative age is a ratio of stand age and "mature" age, see [{{HeurekaHelpLinkEng}}relativ_alder.htm]].

====Max Age ====
Max age for a stand to be considered a young stand

====Min Height====
Minimum height for a stand to be considered young, but old enough for thinning

====Max Height====
Maximum height for a stand to be considered young

====Thinning Type====
:;Ordinary:
:;Biofuel:

====Understorey Density Trigger Biofuel Thinning====
(From version 2.11) Understorey stem density when thinning is automatically switched to biofuel thinning (stems/ha). In this case no understorey cleaning will be done. Leave blank or set to a negative number to inactivate.

== Final Felling ==
Allows you to control how final fellings (sometimes referred to as "clear cuttings") are simulated.
 '''See also''': [http://heurekaslu.org/help/en/index.html?slutavverkning.htm#Utforande Help chapter on final felling ]

====Min Diameter in Final Felling====
:Defines the minimum diameter, in centimeters, to be cut in the simulations.

====Seed Tree Retention====
(only if '''SeedTree''' or '''Shelterwood''' is selected)
Same as [[#ThinningControlParameter | ThinningControlParameter]]

====Shelterwood Retention====
(only if '''Seed Tree''' or '''Shelterwood''' is selected)
Note: Do not confuse with Tree Retention in control table [[ControlTable_NatureConservation | Nature Conservation]]
*RetainedBasalAreaLowSI: The basal area, in m2/ha, of seed trees and shelterwood to be retained in stands with site index less than 20 m. *RetainedBasalAreaHighSI: The basal area, in m2/ha, of seed trees and shelterwood to be retained in stands with site index greater than 20 m.
*RemovalTime: The number of years from final felling to when retained trees are cut.
*RetainDominantSpecies: If '''True''', retain trees of the dominant tree species, '''False''' do not.
*MinimumRetainedBasalArea: The minimum basal area, in m2/ha at the stand-level, of seed trees and shelterwood to be retained.
*RetainedSpecies: (only if '''RetainDominantSpecies''' is '''False''') The tree species to be retained as seed trees and shelterwood.



====Remove Existing Overstorey====
Regulates how shelterwood, seed trees or retention trees (trees left for the next rotation) will be handled. With the latest template for stand register, you will also be able to specify suggestions for treatments and control how they are used in each stand. Existing trees retained for nature conservation can also be treated separately in the new version.

====Use SI Management====
Set '''Use SI Management''' to True if you have typed values in the Site Index Management column in the stand register (version 3), and you want to use them to govern the minimum age of final felling. If you use the Forest Management Planning Package (FMPP) and have a stand register linked to it with values for the Site Index Management column, the latter will be given precedence. If SI Management is set to False, or SI Management is missing, SIS is used (Site quality index according to site factors).

== Fertilization ==
Allows you to control how fertilizations are simulated.

====FertilizerAmount====
:Defines the amount of fertilizer in kilogram per hectare used in the simulations.

====FertilizerSubstance====
:'''AN''' defines that ammonium nitrate is the active substance in fertilizations.
:'''UREA''' defines that urea, i.e. ammoniac[?], is the active substance in fertilizations.

====MaxAnnualGrowth====
:Defines the maximum annual growth, in m3sk/ha, if fertilization of the stand is to be simulated.

====MeanHeightLimitFertilization====
:Defines the minimum average height (basal area weighted) in meters if fertilization of the stand is to be simulated.

====MinConiferProportion====
:Defines the minimum proportion of conifers, in percentage of basal area, if fertilization of the stand is to be simulated.

====SiteIndex====
:'''Min''' defines the minimum site index value in meters if fertilization of the stand is to be simulated.
:'''Max''' defines the maximum site index value in meters if fertilization of the stand is to be simulated.

== Intensive Fertilization ==
Allows you to control how intensive fertilization is simulated.

''Note that intensive fertilization can only be simulated if the soil moisture is mesic or mesic-moist, in the southern part (latitude <58° N) and the central part (58-61° N) of Sweden also moist soils are possible to intensively fertilize. Moreover, the site index (H100, m) must in the northern part of Sweden (>61° N) be below G26, in the central part below G30, and in the southern part below G34, to allow for intensive fertilization.''

====HeightIntensiveFertilization====
:'''Min''' defines the minimum average height in meters if fertilization is to be initiated in the young stand.
:'''Max''' defines the maximum average height in meters if fertilization is to be initiated in the young stand.

====MinSpruceProportionIntensiveFertilization====
:Defines the minimum proportion of spruce, in percentage of basal area (or of stems per hectare), if fertilization is to be initiated in the young stand.

====MinStemsIntensiveFertilization====
:Defines the minimum number of stems per hectare if fertilization is to be initiated in the young stand.

== Biofuel ==
Allows you to control how forest fuel extractions are simulated.

====Restrictions====
:*MinSpruce: defines the minimum proportion of spruce, in percentage of basal area, if extraction is to be simulated.
:*MaxDiamStump: defines the maximum diameter, in centimeters, of the stump if extraction is to be simulated.
:*MinDiamStump: defines the minimum diameter, in centimeters, of the stump if extraction is to be simulated.

====Stump Extraction====
:Selection of species for which stumps and roots can be extracted. For each species to extract, set value to True.

====Utilization====
:*Top: defines the proportion, in percentage, of the top (incl. stem, branches, and needles) that is utilized in extraction.
:*BranchesNotTop: defines the proportion, in percentage, of the branches below the top that is utilized in extraction.
:*BranchesTop: defines the proportion, in percentage, of the branches of the top that is utilized in extraction.
:*DeadBranchesNotTop: defines the proportion, in percentage, of the dead branches below the top that is utilized in extraction.
:*DeadBranchesTop: defines the proportion, in percentage, of the dead branches of the top that is utilized in extraction.
:*NeedlesTop: defines the proportion, in percentage, of the needles of the top that is utilized in extraction.
:*NeedlesNotTop: defines the proportion, in percentage, of the needles below the top that is utilized in extraction.
:*Stump: defines the proportion, in percentage, of the stump that is utilized in extraction.

== <div id="TreeRetention"></div>Nature Conservation Activities (Tree Retention) ==
(moved here from Nature Conservation control table in version 2.9)
 Allows you to control if trees should be retained, as a part of the simulation of the biological considerations to be taken.

=== Tree Retention Settings ===
(only if [[#Retain Trees|Retain Trees]] = '''True''')
Allows you to control how trees are to be retained.

<div id = "Retain Trees"></div>
====Retain Trees?====
:'''True:''' Selected trees (according to settings below) should be left after final felling or after selecion felling, and left until the next final felling or selection felling at which a new decision taken what trees to retain.
:'''False:''' No nature conservation trees should be retained.

====Retained Trees/ha====
:Mumber of trees to retain (per hectare).

====Retention Priority====
:Priority settings for which trees to retain as nature conservation trees, regarding species, age and size.

====Retention Time====
:Defines for how long trees are retained (in years). After this time the retained trees will be transferred to downed, coarse woody debris (the "dead wood").

<div id = "High Stump Settings"></div>
===Retention of High Stumps===
<div id = "Leave High Stumps"></div>
====Leave High Stumps?====
:If set to True, high stumps will be "created" at final felling. Unlike retention trees, high stumps immediately become part of the dead wood pool of standing dead trees, with a volume reductions for the part of the tree that was harvested.

<div id = "High Stumpsha"></div>
====High Stumps/ha====
:Mumber of high stumps to create (per hectare).

<div id = "Height Of High Stumps"></div>

====Height of High Stumps====
:This is set in the Pricelist Manager (which control the bucking of trees when harvesting).

====High Stump Priority====
:Priority settings for which trees to leave high stumps for, regarding species, age and size.

=== Leave stems in forest after treatment ===
Allows you to control the proportion of stems to be left in the forest as deadwood, after a thinning or selection felling.

Structural Diversity Results

2022-03-18T06:43:48Z

JeanetteEggers:

[[Category:Result Variables]]
This result group contains results that describe the [[ResultCategoryDescription::Structural diversity of the trees in a treatment unit]].

{| {{table}} width = 700px
| align="left" style="background:#f0f0f0;width: 35%;"|'''Variable name'''
| align="left" style="background:#f0f0f0;width: 10%;"|'''Unit'''
| align="left" style="background:#f0f0f0;width: 55%;"|'''Description'''
|-style="vertical-align:top;"
| Even-aged Class||code||Even-aged type. <ol start="0"><li>Unknown: No information <li>EvenAged: If at least 95% of the volume is within a 5-year range. <li>MostlyEvenAged: If at least 80% of the volume is within a 20-year age range <li>UnevenAged: Otherwise.</ol>
|-style="vertical-align:top;"
| Tree Size Diversity (Gini Coefficient)||0-1||The [http://en.wikipedia.org/wiki/Gini_coefficient Gini coefficient] is an equality index between 0 (=maximum equality, i.e. all trees have the the same size) and 1 (=maximum inequality). The index has been proposed to be used for forestry planning by Lexerød & Eid (2006)<ref name="LexerodEid2006_GiniCoeff">. {{:Bibliografi:LexerodEid2006_GiniCoeff}}</ref>.
|-style="vertical-align:top;"
| Tree Size Diversity Class (Hugin def.)||code||Tree size diversity class according the Hugin system definition. Trees are grouped into four diameter classes, with class width = (dbhmax-dbbmin)/4. If the number of trees in classi > classi+1, the diameter class distribution is set as InverseJShaped, otherwise as Homogeneous.
|-
|}

==Calculation of Gini coefficient in Heureka==
The Gini coefficient is calculated with the formula for a discrete probability distribution (see https://en.wikipedia.org/wiki/Gini_coefficient).

First trees are sorted in ascending order so that ''gi'' < ''g''''i''+ 1, where ''gi'' = basal area of type tree ''i''. Basal area is used to take into account that the stand volume is highly affected by the largest trees (see Lexeröd and Eid 2006).

<math>\displaystyle G = 1 - \frac {\sum\limits_{i=1}^n (f(g_i))(S_{i-1} + S_i) }{S_n} </math>
 where
<math> S_i = \sum_{j=1}^i f(g_j)g_j</math>, and
 ''S''0 = 0, and
 ''f''(''g_i'') = Frequency distribution, where ''gi'', ''i'' = 1..''n'', are the tree basal areas, indexed in increasing order (''gi''< ''g''''i''+1)

==References==
<references />

Growth Results

2021-11-19T05:23:22Z

JeanetteEggers:

This result group contains: [[ResultCategoryDescription::Volume growth results]].

==Gross vs. net growth==
Gross growth includes mortality while net growth only includes survived trees.
==MAI and CAI==
Reported for all species and per species.
{| {{table}}
| align="left" style="background:#f0f0f0;width: 30%;"|'''Variable name'''
| align="left" style="background:#f0f0f0;width: 20%;"|'''Unit'''
| align="left" style="background:#f0f0f0;width: 50%;"|'''Description'''
|-
| CAI ... || [[Dictionary:m3sk|m3sk]]/ha,yr|| Current annual increment (from the beginning or midpoint of the previous period)
|-
| MAI ... || [[Dictionary:m3sk|m3sk]]/ha,yr|| Mean annual increment since year 0 or from the time for final felling of the previous rotation. '''Reset after final felling'''.
|-
|
|}

==How growth is calcualated==
[[File:Growth.png|450px]]

====CAI net====
The current annual '''net''' volume growth is the same as the volume change from one time (before harvest) to the next (before harvest). Mortilty is not included. CAI net is calculated as: 

<math>G_{t+a} = \displaystyle \frac{V_{t+a}- V_a + H_t}{a} </math>

where 
''Gt+a'' = Annual volume net increment from time ''t'' to time ''t + a'', and 
''Ht'' = Volume harvested at time t, and 
''a'' = number of years

====CAI gross====
The current annual '''gross''' volume growth includes mortality and is calculated as CAI net but with mortality added: 

<math>G_{t+a} = \displaystyle \frac{V_{t+a}- V_a + H_t + M_t}{a} </math>

where 
''Gt+a'' = Annual volume net increment from time t to time t + a, and 
''Ht'' = Volume harvested at time t, and 
''Mt'' = Mortality volume from time ''t'' to ''t+a'', and 
''a'' = number of years

This is the same as the volume change from one time (after harvest) to the next (before harvest), plus mortality.

====MAI====
MAI is calculated similarly to CAI but the first time is set to year 0 or, if a final felling has been simulated, the year for the last final felling. The harvest and mortality variables in the equations are replaced with sums over the harvesting and mortality that occurs between the time points. The result is the same as taking the average of CAI.

[[Category:Result Variables]]

Net present value

2021-08-04T10:10:57Z

JeanetteEggers:

<noinclude>
{{Languages}}</noinclude>
===Net present value===
In PlanWise and StandWise, Heureka calcuates the net present value (NPV) for each treatment unit and management schedule generated. It is the sum of discounted revenues minus costs, for an approximately infinite time horizon, and with the real discount rate set by the user. For even-aged management, Heureka approximates an infinite time horizon by assuming that the third forest rotation management regime will be repeated in perpetuity. For uneven-aged management, the last cutting is assumed to be repeated in perpetuity with a cutting time interval equal to the time elapsed between the last two cuttings projected.

Note that RegWise does not calculate net present value in a satisfactory manner, since it only include values until the last period and ignores the value of the ending inventory. RegWise is thus not suitable for economic analysis and valuation purposes. However, users can choose to prolong the time period for which net present value is calculated using the 'additional periods' setting in the simulation window.

For each even-aged program generated in PlanWise (and the NPV-tool in StandWise), Heureka generates up to three unique rotations. The reason for not just repeating the second management regime is to allow for the possible change of growth conditions over time. The climate model, if activated in a simulation, affects site fertility so that a certain rotation will have a different growth potential than the previous one, and consequently the management regime should be adapted to that. The growth of plantations will also be affected by the planting year, since breeding effects is assumed to increase over time. For example, trees planted in twenty years will give higher yields that trees planted today.

====Even-aged management====
The net present value for even-aged management is calculated as 

<math>NPV_{evenaged} = \displaystyle \sum_{t=0}^{S} \delta_t R_t + \delta_{S}\cdot SEV</math> 
where 
''S'' = Final felling year for the rotation preceeding the last rotation simulated, and 
<math>R_t = </math>Net revenue in year ''t'', with ''t'' = 0 marking year 0 of the planning horizon, and 
''r'' = Real discount rate, and 
<math>\delta_t = \displaystyle (1+r)^{-t}=</math>discount factor for year t, and 
''SEV'' = Soil expectation value as given below

====Soil expectation value====
The soil expectation value (SEV) is by definition the net present value for an infinite time horizon when starting from bare land. In Heureka, the soil expecation value refers to the net present value of the last rotation simulated (assumed repeated in perpetuity). If you want to calculate the SEV with Heureka starting from today (year 0), you should use bare land as initial state.

The SEV is calculated as: 

<math>SEV = \displaystyle \alpha_{SEV}\sum_{t=0}^{T} \delta_t R_t </math>
where 
where ''T'' = Rotation length for the last forest generation, 

''αSEV'' = "discount repeat factor" derived from a [https://en.wikipedia.org/wiki/Geometric_series geometric series]. A geometric series is the sum of an infinite number of terms that have a constant ratio (qSEV) between successive terms. If ||''qSEV''|| < 0, then

<math>\alpha_{SEV} = \displaystyle \frac{1}{1-q_{SEV}}</math>

where 
<math>q_{SEV} = \displaystyle {(1+r)}^{-T}</math> 
 Note that if the discount rate r is 0, then ''qSEV'' will be 1 and the sum will be infinitely large.

====Uneven-aged management (CCF)====
When calculating the net present value for an uneven-aged stand management program, some estimation of the terminal value at the end of the planning horizon must be included. One way is to assume that a steady state is reached at some point in the future. In analogy to even-aged management where a series of identical rotation regimes is assumed to be repeated in perpetuity, we can assume that a series of selection fellings is repeated with a certain cutting cycle after the end of the planning horizon. In the forest economic literature on stand-level management and valuation, one solution for this is called the equilibrium endpoint problem (Haight & Getz 1987, used by for example Wikström 2000, p. 454). A steady state here implies that the number of stems in each diameter class after harvest is the same in two subsequent periods, separated by a certain time interval. Another approach is to use a very long time horizon, such as 150 years, in which the discounted terminal value can be practically negligible of the discount rate is large enough. For example, with a 3 percent discount rate the discount factor for outcomes in 150 years is 1.1 percent. In Heureka a simplified approach is used combining the two approaches, with both a time horizon of at least 100 years (unless explicitly changed by the user), and assuming that the last harvest is repeated with a time interval equal to that passed between the last two harvests during the planning horizon. If there are less than two harvest periods during the planning horizon, Heureka searches up to 50 years beyond the last period. If there are still less than two harvest periods found, Heureka generates an unmanaged program instead. However, Heureka is not currently able to enforce any equilibrium constraints for the tree diameter distribution as described above. Instead, it is assumed that the minimum volume constraint (SVL10, “virkesförrådskurvan”) and the thinning algorithm, which has the same parameters in all periods, both should lead to a steady state after 100 years, at least from an economic perspective.

The net present value for uneven-aged management is calculated as follows. Note that the first summation is done up to the period
before the last cutting period T, since the revenue in period T is already included in the so called Managed Forest Value (MFV). MFV is mathematically analogues to SEV but the value refers to an establied steady state forest, instead of bare land 

<math>NPV_{CCF} = \displaystyle \sum_{t=0}^{U-1} \delta_t R_t + \delta_{U}\cdot MFV</math> 
with the same notations as above, and 
''U'' = Last cutting period 
''MFV'' = So called managed forest value, and similarily to SEV corresponds to an infinite [https://en.wikipedia.org/wiki/Geometric_series geometric series]. The difference to that SEV is calculated as a series of one-rotation net present values, while MFV is ca calculated as a series of identical harvests that takes place every n:th year.

The MFV is calculated as 
<math>MFV = \displaystyle \frac{R_U}{1-q_{CCF}} </math>
 where
 RU = Net revenue in last period U simulated by Heureka (internally by the program or reported). This is the revenue that is assumned to be repeated on perpetuity, and
 <math>q_{CCF} = \displaystyle {(1+r)}^{-n}</math>
Note that the ratio CCF is equivalent to that for SEV, but with the rotation length T replaced by the cutting interval n.
 

====Terminal value====
Heurekas also calculates a result variable called Terminal Value, which has an associated Terminal Value Year. The Terminal Value Year is usually the same as the year after the last planning period. The terminal value represents the part of the net present value that remains after the last planning period. The terminal value is calculated by subtracting the sum of discounted net revenues (that occurs until the last planning period) from the net present value, and the prolonging that value to the last year.

For mer info on terminal value calculation, see [[Media:Berakning_terminala_varden.pdf | Berakning_terminala_varden.pdf]]

====References====
*Haight, R.G., Getz, W.M. 1987. Fixed and equilibrium endpoint problems in uneven-aged management. Forest Science 33:908-931. 
*Haight, R.G. 1987. [https://www.researchgate.net/publication/233630266_Evaluating_the_Efficiency_of_Even-Aged_and_Uneven-Aged_Stand_Management Evaluating the efficiency of even-aged and uneven-aged stand management]. Forest Science 33(1):116-134. 
*Wiktröm, P. 2000. A solution method for uneven-aged management applied to Norway spuce. Forest Science 46(3):452-463

{{VariableCategory}}

About time periods

2021-08-04T07:54:22Z

JeanetteEggers:

[[Category:Reference Manual]]
[[Category:User's Guides]]
[[Category:Result Variables]]
[[Category:Definitions]]

==About time periods, time points and treatment years==
Heureka is using a discrete time period model, typically using five-year time intervals. The term time period is somewhat misleading, because a "time period" may refer to a time point or a period, depending on context. For example, if you use StandWise to project the growth of a stand, the "time period" is actually better interpreted as a time index marking the beginning of a period. For a case with many stands in PlanWise or RegWise on the other hand, the time index marks the midpoint of a time period. The motivation for this is that although all stands scheduled for harvest in the first period have been assigned the same treatment year (year 2.5) in the model, they should harvested simultaneously, but the harvest activities would be spread out evenly over the five-year period.

[[File:Growth.png|450px]]

==Use period midpoints in PlanWise==
When running a TPG simulation in PlanWise, period midpoints are used as default. This means that the initial state is projected 2.5 years, before the actual harvest scheduling begins. After that, five-year intervals are used. The reason for using period midpoints, is that usually some of the stands scheduled for harvesting in a certain five-year period, will not be harvested in the beginning of the period. Instead, some will be harvested early in the period, and other later in the period. Therefore, if period midpoints were not used, the harvest volumes would be underestimated.

We have no definite answer on how few or how many stands there should be to use midpoints, but if you want the results to reflect that "some time during this period these stands should be harvested", then you should use period midpoints.

==Do not use period midpoints in StandWise==
In StandWise you can use period midpoints too, but it would probably make little sense expect if the purpose was to make some comparison or addition to a PlanWise simulation (for a certain stand).

==Period year and treatment year==
In Heureka, each period has an associated year (found in TreatmentData.Year), which refers to the number of years that has passed since the start.

Year 0: Now (start of the analysis) 
Year 5: Five year after the start = Beginning of the sixth year.

Note that when using period midpoints (default in PlanWise), the first period index (0) refers starting states for the analysis. In this case, the first actual planning period where optional treatments can be simulated is period 1. Period 1 has period year 2.5, i.e. the midpoint of the first five years, meaning that the period covers year 1 to 5. Period 2 covers years 6-10, and so on. Figure 1 and 2 and the associated tables illustrate how periods are defined with and without period midpoints.
 
[[File:Periods when NOT periodmidpoint.png|none|thumb|600px|Fig 1. Period definitions when period midpoints are not used, assuming start time 2020-01-01]]
 
{| {{table}}
| align="left" style="background:#f0f0f0;"|'''Period index'''
| align="left" style="background:#f0f0f0;"|'''Description '''
| align="left" style="background:#f0f0f0;"|'''Period year '''
| align="left" style="background:#f0f0f0;"|'''Possible treatment years'''
| align="left" style="background:#f0f0f0;"|'''Date range'''
|-
| 0||First period ||0||0-4||2020-01-01 - 2024-12-31
|-
| 1||Second period||5||5-9||2025-01-01 - 2029-12-31
|-
| 2||etc||10||10-14||2030-01-01 -- 2034-12-31
|-
|
|}
 
[[File:Periods when using periodmidpoint.png|none|thumb|600px|Fig 2. Period definitions when period midpoints are used, assuming start time 2020-01-01]]
 
{| {{table}}
| align="left" style="background:#f0f0f0;"|'''Period index'''
| align="left" style="background:#f0f0f0;"|'''Description '''
| align="left" style="background:#f0f0f0;"|'''Period year '''
| align="left" style="background:#f0f0f0;"|'''Possible treatment years'''
| align="left" style="background:#f0f0f0;"|'''Date range'''
|-
| 0||Start time ||0||0||2020-01-01
|-
| 1||First actual period||2.5||0-4||2020-01-01 - 2024-12-31
|-
| 2||Second actual period||7.5||5-9||2025-01-01 - 2029-12-31
|-
|
|}

Note that period 0 includes the same date interval when we do not apply period midpoints as period 1 does when we apply midpoints. However, the calculated values (volumes etc.) will differ. Assuming harvesting takes places in the beginnning of a period ignores that the trees have grown in average 2.5 years before the forst harvest is carried out.

==”Before” and “After” values==
In Heureka, most variables has a before and after-component, which refers to the state or value before treatment, and immediately after treatment, respectively. Only before-treatment values are saved in the result database (when you run PlanWise or RegWise or save a simulation in StandWise).

==State, yield and change variables==
====State variable====
A '''state''' variable refers to a description variable for a stand at a certain time, for example the mean age or the volume.
====Yield variable====
A '''yield''' variable refers to some output from an activity, such as the harvest volume.

====Change variable====
A third type of variable describes '''change''' of a stand, for example growth and mortality. Growth and mortality that are reported in a certain time period t, represents the growth and mortality that has occurred after harvesting in the previous period (t -1) to the current period year.

==Basic calculation steps==
As a Heureka user, it is important that you have a fundamental understanding of how a prognosis is done. The following principal steps are performed when making a prognosis from one time point (t) to another (t+1):

#Calculate state variables for the stand at time t from tree-level data, for example stand volume and mean diameter. This is the Before-value.
#Apply treatment, if a treatment should be applied, and update the After-value for the treatment unit. “After” is the state immediately after the treatment.
#Calculate diameter growth, height growth and mortality for each tree.
#Calculate ingrowth of new trees.
#Update attributes (such as volume, age, diameter, weight) for each tree. The weight is the number of stems that a tree object represents, and is reduced by the mortality rate and by harvesting (for example a thinning will reduce the weight for one or more tree objects).
#Let t = t + 1. Update the tree list for this period and repeat from step 1.

==Subtract half a period’s harvest volume to obtain standing stock if many stands==
If you want to create for example a graph of how the standing stock (the total volume) of a large forest holding develops over time according to a simulation in PlanWise, and you have used period midpoints (the default in a TPG-simulation), you should subtract half the period’s harvest volume from the Before-value. The reason is that the Before-value has been adjusted for a half a period’s growth and mortality, but not for half a periods harvesting. In reality, in a case with many stands, some of the stands will be harvested early in the period, other stands in the middle of the period, and other stand at the end of the period. But in the model, all harvesting takes place in the middle of the period. Extracting half a periods harvesting is a simple way to at least approximately adjust for this error.

==Understanding how growth is calculated==
Growth and mortality [[#change|change]] refers to how a forest stand is changing from one time point to the next. Growth is reported as gross growth and net growth. Gross growth includes mortality, net growth does not.

see [[Growth Results]]

Variable:Area types

2021-08-04T07:52:59Z

JeanetteEggers:

[[Category:Variables|{{SUBPAGENAME}}]]
[[Category:Definitions|{{SUBPAGENAME}}]]
[[Category:Variables_and_Definitions|{{SUBPAGENAME}}]]

==Area types handled by the system and used in table views and reports==
{| class="wikitable"
|+ style = "text-align: left" | Area types handled by the system and used in table views and reports
! Name !! Description !! Unit !! Result category (database table)
|-
! Area
| Productive area for treatment unit || ha || TreatmentUnit
|-
! AreaFactor
| Representative productive area for treatment unit if land use class is productive forest, otherwise total areal. || ha || TreatmentUnit
|-
! AdjustedAreaFactor
| AreaFactor adjusted for number of inventory years when using NFI-data as data source. This area is always used in Heurekas report generator. || ha || TreatmentUnit
|-
! TreatedArea
| Proportion of treatment unit that has been assigned a certain treatment. Normally 1 if a treatment has been applied. Could be less than 1 if a treatment unit has multiple plots (prediction units), and a treatment has been applied only on a subset of plots. For example when using FMPP-data and partial thinnings are allowed. When creating reports on treatment areas, Heureka is automatically adjusting for TreatedArea if you use the Area summation type in the report generator. || proportion [0, 1] || TreatmentUnit
|-
! Impediment
| Proportion of total area that is impediment. Note that there is no result variable for result category TreatmentUnit in Heureka for total area when the land use is productive forest. To calculate it, use formula Total area = AreaFactor/(1-Impediment) || proportion [0, 1] || TreatmentUnit
|}

==Area types in stand register import file (and result category StandObjectData)==

{| class="wikitable"
|+ style = "text-align: left" | Area types imported from stand register file and reported in result category StandObject(Data)
! Name !! Column name in csv file !! Description !! Unit !! Result category
|-
! Productive Area
| ProdArea || Productive area in stand register import file. Should equal TotalArea minus ImpedimentArea || ha || StandObjectData
|-
! Total Area
| TotalArea || Total area in stand register import file || ha || StandObjectData
|-
! Impediment Area
| ImpArea || Impediment area || ha || StandObjectData
|-
! Nature Conservation Area
| NCArea || Productive area of a treatment unit that may be partially set aside (hänsynsyta inom bestånd) in simulations depending on your control tables settings || ha || StandObjectData
|}

Variable:Area types

2021-08-04T07:50:51Z

JeanetteEggers:

[[Category:Variables|{{SUBPAGENAME}}]]
[[Category:Definitions|{{SUBPAGENAME}}]]
[[Category:Variables_and_Definitions|{{SUBPAGENAME}}]]

==Area types handled by the system and used in table views and reports==
{| class="wikitable"
|+ style = "text-align: left" | Area types handled by the system and used in table views and reports
! Name !! Description !! Unit !! Result category (database table)
|-
! Area
| Productive area for treatment unit || ha || TreatmentUnit
|-
! AreaFactor
| Representative productive area for treatment unit if land use class is productive forest, otherwise total areal. || ha || TreatmentUnit
|-
! AdjustedAreaFactor
| AreaFactor adjusted for number of inventory years when using NFI-data as data source. This area is always used in Heurekas report generator. || ha || TreatmentUnit
|-
! TreatedArea
| Proportion of treatment unit that has been assigned a certain treatment. Normally 1 if a treatment has been applied. Courld be less than 1 if a treatment unit has multiple plots (prediction units), and a treatment has been applied only on a subset of plots. For example when using FMPP-data and partial thinnings are allowed. When creating reports on treatment areas, Heuireka is automatically adjusting for TreatedArea if ypu use the Area summation type in the report generator. || proportion [0, 1] || TreatmentUnit
|-
! Impediment
| Proportion of total area that is impediment. Note that there is no result variable for result category TreatmentUnit in Heureka for total area when the land use is productive forest. To calculate it, use formula Total area = AreaFactor/(1-Impediment) || proportion [0, 1] || TreatmentUnit
|}

==Area types in stand register import file (and result category StandObjectData)==

{| class="wikitable"
|+ style = "text-align: left" | Area types imported from stand register file and reported in result category StandObject(Data)
! Name !! Column name in csv file !! Description !! Unit !! Result category
|-
! Productive Area
| ProdArea || Productive area in stand register import file. Should equal TotalArea minus ImpedimentArea || ha || StandObjectData
|-
! Total Area
| TotalArea || Total area in stand register import file || ha || StandObjectData
|-
! Impediment Area
| ImpArea || Impediment area || ha || StandObjectData
|-
! Nature Conservation Area
| NCArea || Productive area of a treatment unit that may be partially set aside (hänsynsyta inom bestånd) in simulations depending on your control tables settings || ha || StandObjectData
|}

Definition:TreatmentCode

2021-06-15T10:47:21Z

JeanetteEggers: /* Treatment Codes */

{{Languages}}
[[Category:Definitions | TreatmentCode]]

==Treatment Codes==
{| {{table}}
| align="left" style="background:#f0f0f0;"|'''English'''
| align="left" style="background:#f0f0f0;"|'''Swedish'''
| align="left" style="background:#f0f0f0;"|'''Short name'''
| align="left" style="background:#f0f0f0;"|'''Number Code'''
| align="left" style="background:#f0f0f0;"|'''Comment'''
|-
| Planting||Plantering||Pl||1||
|-
| Natural regeneration||Naturlig föryngring||NR||4096||
|-
| Sowing||Sådd||So||8192||
|-
| Extensive regeneration||Extensiv föryngring||Ext||524288||
|-
| Soil preparation||Markberedning||Pr||16||
|-
| Controlled burning||Hyggesbränning||Bu||512||
|-
| Cleaning||Röjning||Cl||2||
|-
| Thinning||Gallring||Th||4||
|-
| Selection felling||Blädning||Sf||256||
|-
| Final felling||Slutavverkning||FF||8||
|-
| Final felling, leave seed trees/shelterwood||Slutavverkning, lämna fröträd/skärm||ST||16384||
|-
| Removal of overstorey||Avveckla överståndare||RO||32768||
|-
| Fertilization||Gödsling||Fe|| 32 ||
|-

|
|}

{{Definition}}

Definition:TreatmentCode

2021-06-15T06:45:09Z

JeanetteEggers: /* Treatment Codes */

{{Languages}}
[[Category:Definitions | TreatmentCode]]

==Treatment Codes==
{| {{table}}
| align="left" style="background:#f0f0f0;"|'''English'''
| align="left" style="background:#f0f0f0;"|'''Swedish'''
| align="left" style="background:#f0f0f0;"|'''Short name'''
| align="left" style="background:#f0f0f0;"|'''Number Code'''
| align="left" style="background:#f0f0f0;"|'''Comment'''
|-
| Planting||Plantering||Pl||1||
|-
| Natural regeneration||Naturlig föryngring||NR||4096||
|-
| Sowing||Sådd||So||8192||
|-
| Soil preparation||Markberedning||Pr||16||
|-
| Controlled burning||Hyggesbränning||Bu||512||
|-
| Cleaning||Röjning||Cl||2||
|-
| Thinning||Gallring||Th||4||
|-
| Selection felling||Blädning||Sf||256||
|-
| Final felling||Slutavverkning||FF||8||
|-
| Final felling, leave seed trees/shelterwood||Slutavverkning, lämna fröträd/skärm||ST||16384||
|-
| Removal of overstorey||Avveckla överståndare||RO||32768||
|-
| Fertilization||Gödsling||Fe|| 32 ||
|-

|
|}

{{Definition}}