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List of Species Parameter

species parameter

Species parameter are defined for each species in the input database. The Name of the variables is the name of the columns in the database. The Short name is the abbreviation used on the wiki pages and iLand related papers. iLand uses a SQLite database for the species parameters. The parameters need to be provided in a table specified in the project file; each tree species occupies a row in that table. iLand loads all species that are in the table and are 'active' (see below).

Name Short Description Example
General
shortName   unique identifier for a species piab
name   descriptive (longer) name of a species Picea Abies
displayColor   color used for drawing trees. The color is defined as a 6-character hexadecimal color in the form 'rrggbb' (red, green, blue, without a # character). 3E9C49
active   flag that allows to disable a species. Disabled species are not loaded into iLand 1=enabled, 0=disableld
LIPFile   filename of the binary LIP (light influence pattern) file. See also Path, LightInfluencePattern piab.bin
isConiferous   0 for broadleaved species, 1 for conifers 1
isEvergreen   1 for wintergreen species 0
Growth
specificLeafArea SLA Factor to calculate LeafArea from Foliage Biomass (LA=FoliageMass*specificLeafArea) 5
turnoverLeaf $\gamma_f$ Senescence factor of foliage. The yearly senescence is Mass*turnover. See also allocation. 0.2
turnoverRoot $\gamma_r$ senescence factor for fine roots. See also allocation. 0.05
HDLow hdmin expression lower bound of height to diameter ratios (i.e., open-grown trees). typical HD-ratios: 50-150. See also stem growth. max(40,80-8*sqrt(d))
HDhigh hdmax expression upper bound of height to diameter ratio (for trees under heavy competition for light). typical HD-ratios: 50-150. See also stem growth. max(80,120-12*sqrt(d))
woodDensity ρ density of the stemwood (kg/m3) (used for calculating the tree volume). See also stem growth. 300
formFactor φ taper factor of the stem (-) (used for calculating the tree volume).See also stem growth. 0.3
Biomass Compartments
bmWoody_a kW1 Parameter a of the allometric equation for stem wood biomass. 0.03
bmWoody_b kW2 Parameter b of the allometric equation for stem wood biomass. 2.75
bmFoliage_a kW3 Parameter a of the allometric equation for foliage biomass. 0.069
bmFoliage_b kW4 Parameter b of the allometric equation for foliage biomass. 1.56
bmRoot_a   Parameter a of the allometric equation for coarse root biomass. 0.004
bmRoot_b   Parameter b of the allometric equation for coarse root biomass. 2.79
bmBranch_a kW5 Parameter a of the allometric equation for branch biomass.] 0.022
bmBranch_b kW6 Parameter b of the allometric equation for branch biomass 2.3
finerootFoliageRatio pr the size of the fine root pool is defined relative to the size of the foliage pool (functional balance), i.e. fineRoots = poolsize foliage * finerootFoliageRatio. 1
cnFoliage CNfol C/N ratio of foliage 75
cnFineroot CNfr C/N ratio of fine roots 40
cnWood CNw C/N ratio of woody tissues (branches, stem, coarse roots) 300
barkThickness   factor to calculate thickness of the bark (cm): thickness = dbh * barkThickness (see wildfire ). 0.065
Mortality
probIntrinsic plucky probability of a tree to survive "maximumAge" years. See base mortality. A value of 0.01 = 1%. 0.01
probStress bs factor b_s (see base mortality) that determines the probability of death based based on a stress index (use values >0). 6
Aging
maximumAge Amax indicates a maximum age for a species. Note that trees can grow older than this value in the model - this parameter is only used to determine aging and mortality probability and is not a deterministic cutoff age. See base mortality and primary production 600
maximumHeight Hmax indicates a maximum height for a species. Note that trees can grow taller than this value in the model - this parameter is only used to determine aging and mortality probability and is not a deterministic cutoff height. See base mortality and expression 60
aging fa used to calculate the decline in production efficiency with "age" (pysiological and/ or based on max. height growth). See primary production 1/(1+(x/0.9)3)
Environmental Responses
lightResponseClass kS determines shade tolerance / efficiency to use low light levels, where 1=very light-demanding, and 5 is very shade tolerant. Floating point values are allowed. See the project file for the definition of the classes and the page on individual tree light availability. 3.4
respVpdExponent kD exponent in the calculation of growth response to vapor pressure deficit (resp=exp(respVpdExponen*vpd)), see vapor pressure deficit response -0.5
respTempMin kT Lower threshold temperature for tree growth. See temperature response -2
respTempMax kT1 Optimum temperature for tree growth. See temperature response 17
respNitrogenClass kN Nitrogen response class. Value must be >=1 and <=3. 3= highly nitrogen-demanding, 1= efficient with low available nitrogen. Response values are interpolated between classes (see project file for class definition and the page on nitrogen response). 2.2
phenologyClass   link to a phenology class. 0= evergreen coniferous, 1= deciduous broadleaved, 2= deciduous coniferous. See project file for details as well as the page on phenology. 0
maxCanopyConductance gcmax maximum conductance of the canopy for water. Used in the calculation of transpiration (m/s) 0.02
psiMin $\Psi_{min}$ maximum soil water potential that a species can access (i.e. +/- a species' permanent wilting point), in MPa. See the page on soil water response -1.5
Seed production / dispersal
maturityYears amat minimum age required for a tree to produce seeds (years) 30
seedYearInterval aseed Interval between seed years. Each year has a probability of 1/seedYearInterval that a year is a seed year. This is calculated once per species and year, and applies for the entire landscape (years). 5
nonSeedYearFraction pnsy fraction of the seed production in non-seed-years. 0.25
fecundity_m2   seedlings produced and surviving the first weeks per m² canopy cover (see also fecundity). 100
seedKernel_as1 kK1 dispersal kernel parameter, following Lischke et al. (2006), see dispersal. The shape parameter for wind / ballistic dispersal (1-1/e = ~63% of wind dispersal is between 0 and as1 meter). Find full equation here 100
seedKernel_as2 kK2 dispersal kernel parameter, following Lischke et al. (2006), see dispersal. Shape parameter for zoochorous dispersal (~63% of zoochorous dispersals are below as2 meter) 0
seedKernel_ks0 kK3 dispersal kernel parameter, following Lischke et al. (2006), see dispersal. Proportion of zoochorous dispersal (0..1) 0
serotinyFormula   function that decides (probabilistic) if a tree is serotinous. The variable is the age of the tree, expected return is a number between 0 and 1.
empty: serotiny not active
serotinyFecundity  
multiplier that increases fecundity for post-fire seed rain of serotinous species
Establishment
estMinTemp kEtmin absolute minimum temperature for seed survival (°C) -39
estChillRequirement kEchill number of required days since the end of the last vegetation period between -5°C and +5°C. 56
estGDDMin kEGDDmin minimum threshold of growing degree days for seedling establishment (GDD must be >GDDMin and < GDDMax to allow establishment) 177
estGDDMax kEGDDmax maximum threshold of growing degree days for seedling establishment (GDD must be >GDDMin and < GDDMax to allow establishment) 3261
estGDDBaseTemp kEGDDbase base temperature (°C) for GDD calculation. GDD is the running sum of (mean daily temp - GDDBaseTemp) for all days with mean temp > GDDBaseTemp. 4.3
estBudBirstGDD kEGDDbb required GDD before bud burst. Calculation is similar to GDD described above, except that the counter is reset when mean daily temp is below 0°C 255
estFrostFreeDays kEFF required number of days without frost (daily minimum temperature > 0°C) in the year 65
estFrostTolerance kEFT frost tolerance parameter for frost events after bud burst (kF in Eq.2 of establishment). 0.5
estPsiMin $k\Psi_r$ minimum soil water potential for establishment; establishment probability is reduced linearly between $k\Psi_r$ (p=0), and field capacity (p=1, no limitation). Null or 0 disables soil water limitation. 0
estSOLthickness   effect of thickness of the soil organic layer on establishment probability. Multiplier calculated as exp( -estSOLthickness * SOLdepthcm). Null or 0 disables effect. 0
Sapling growth
sapHeightGrowthPotential   expression to calculate the maximum height of the sapling for the next timestep. see sapling growth and competition. The first variable is interpreted as "height" (m). 40*1-(h/40)(1/3*exp(-0.1))3
sapMaxStressYears kMra number of consecutive years a sapling can withstand stress. If stress exceeds this threshold, the sapling cohort dies. 3
sapStressThreshold kMrs defines threshold for stress. If actual height increment / potential height increment is below sapStressThreshold, the sapling is stressed. The ratio equals therefore fenv,yr * flight 0.1
sapHDSapling hdsap Saplings in iLand have a fixed height-diameter ratio, sapHDSapling, which is used to derive a diameter from sapling height 80
sapReferenceRatio fref The empirically parameterized sapling height growth model (see sapHeightGrowthPotential) uses the same physiological modifiers as adult trees in iLand. The ratio (fref) grants consistency between saplings and adult trees in iLand by specifying the physiological constraints for an optimal site (as specified in sapHeightGrowthPotential); This is used in calculation of fenv,yr. 1
sapReinekesR SDIsap Stem number estimates of regeneration cohorts are derived by means of an allometric relationship to diameter following Reinekes stem density index, with sapReinekesR being the maximum stem number for a dg of 25.4 cm. See sapling growth and competition 1450.
sapSproutGrowth   multiplier for accelerated height growth of resprouted tree cohorts in the regeneration layer. Resprouting is enabled, when the value of sapSproutGrowth is not empty and >0. See sprouts.  
Snags and carbon dynamics
snagKSW kSWD snag decomposition rate (10°C, optimal moisture content), (see snag dynamics ). 0.015
snagHalfLife hl half life (years) used for calculation of transition probability from snag to downded woody debris as described in snag dynamics 10
snagKYL klitter litter decomposition rate (10°C, optimal moisture content), (for the labile soil pool) 0.15
snagKYR kDWD downed woody debris (dwd) decomposition rate (10°C, optimal moisture content), (for the refractory pool) 0.0807
browsingProbability   annual probability that saplings (up to 2m height) are browsed by game and ungulates. See browsing. 0.1

 


Created by werner. Last Modification: Tuesday 07 of May, 2024 16:32:28 GMT by werner.