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 | hd_{min} | 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 | hd_{max} | 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 | kW_{1} | Parameter a of the allometric equation for stem wood biomass. | 0.03 |
bmWoody_b | kW_{2} | Parameter b of the allometric equation for stem wood biomass. | 2.75 |
bmFoliage_a | kW_{3} | Parameter a of the allometric equation for foliage biomass. | 0.069 |
bmFoliage_b | kW_{4} | 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 | kW_{5} | Parameter a of the allometric equation for branch biomass.] | 0.022 |
bmBranch_b | kW_{6} | Parameter b of the allometric equation for branch biomass | 2.3 |
finerootFoliageRatio | p_{r} | to observe the functional balance of a tree, the size of the fine root pool is defined relative to the size of the foliage pool, i.e. fineRoots = poolsize foliage * finerootFoliageRatio. | 1 |
cnFoliage | CN_{fol} | C/N ratio of foliage | 75 |
cnFineroot | CN_{fr} | C/N ratio of fine roots | 40 |
cnWood | CN_{w} | 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 | p_{lucky} | probability of a tree to survive "maximumAge" years. See base mortality. A value of 0.01 = 1%. | 0.01 |
probStress | b_{s} | factor b_s (see base mortality) that determines the probability of death based based on a stress index (use values >0). | 6 |
Aging | |||
maximumAge | A_{max} | 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 | H_{max} | 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 | f_{a} | 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 | kT_{1} | Optimum temperature for tree growth. See temperature response | 17 |
respNitrogenClass | k_{N} | 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 | gc_{max} | 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 | a_{mat} | minimum age required for a trees to produce seeds (years) | 30 |
seedYearInterval | a_{seed} | 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 | p_{nsy} | 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 | kK_{1} | dispersal kernel parameter, following Lischke et al. (2006), see dispersal. | 100 |
seedKernel_as2 | kK_{2} | dispersal kernel parameter, following Lischke et al. (2006), see dispersal. | 0 |
seedKernel_ks0 | kK_{3} | dispersal kernel parameter, following Lischke et al. (2006), see dispersal. | 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 | kE_{tmin} | absolute minimum temperature for seed survival (°C) | -39 |
estChillRequirement | kE_{chill} | number of required days since the end of the last vegetation period between -5°C and +5°C. | 56 |
estGDDMin | kE_{GDDmin} | minimum threshold of growing degree days for seedling establishment (GDD must be >GDDMin and < GDDMax to allow establishment) | 177 |
estGDDMax | kE_{GDDmax} | maximum threshold of growing degree days for seedling establishment (GDD must be >GDDMin and < GDDMax to allow establishment) | 3261 |
estGDDBaseTemp | kE_{GDDbase} | 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 | kE_{GDDbb} | 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 | kE_{FF} | required number of days without frost (daily minimum temperature > 0°C) in the year | 65 |
estFrostTolerance | kE_{FT} | 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 |
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 | kM_{ra} | number of consecutive years a sapling can withstand stress. If stress exceeds this threshold, the sapling cohort dies. | 3 |
sapStressThreshold | kM_{rs} | defines threshold for stress. If actual height increment / potential height increment is below sapStressThreshold, the sapling is stressed. The ratio equals therefore f_{env,yr} * f_{light} | 0.1 |
sapHDSapling | hd_{sap} | The dynamic variable in simulating sapling development is height growth. Saplings in iLand have a fixed height-diameter ratio, sapHDSapling, which is used to derive a diameter from sapling height | 80 |
sapReferenceRatio | f_{ref} | The empirically parameterized sapling height growth model (see sapHeightGrowthPotential) uses the same physiological modifiers as calculated for adult trees in iLand. The ratio (f_{ref}) 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 f_{env,yr}. | 1 |
sapReinekesR | SDI_{sap} | Stem number of the 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 estSprouting is not empty and >0. See sprouts. | ||
Snags and carbon dynamics | |||
snagKSW | k_{SWD} | 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 | k_{litter} | litter decomposition rate (10°C, optimal moisture content), (for the labile soil pool) | 0.15 |
snagKYR | k_{DWD} | 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 |