User:Kramer koen/sandbox

The ForGEM model is a spatially explicit, individual tree model on Genetics, Ecology and Management of forests. ForGEM is developed to assess impacts of climate change and sylvicultural operations on forest growth and dynamics, the rate of adaptive response of functional traits, and the adaptive potential of tree populations (Kramer et al 2008, 2010).

The genetics module of ForGEM allows to calculate a large number of genetic statistics that characterize the genetic make-up of an individual tree, the diversity of a population and differentiation between populations. Individual tree statistics include the genotype of the individual, and methods for its spatial distribution. The population statistics, within and among populations, include diversity measures, differentiation measures between populations, heterozygozity, fixation, and F-statistics.

The ForGEM model is based on the ecophysiological functioning of whole trees with a mechanistic coupling between genetic and eco-physiological processes. The biophysical- and biochemical environment that drive the eco-physiological processes are described in detail by the model.

Forest management, i.e. sylvicultural operations, can be defined by the user to realistically simulate species composition and demographic dynamics driven by forest management.

The ForGEM model can simulate an understory that consists of grass and herb species distributed over, usually 20x20m, grids though grid size is variable.

ForGEM model description
Genetics:
 * tree genetics - quantitative genetics of functional traits of trees
 * gene flow - production and dispersal of seeds and pollen

Eco-physiology
 * growth and increment - allocation of photosyntates over plant components; increment of height, stem diameter and stem volume of individual trees. Basic growth equation of the ForGEM model.
 * light interception - interception of light by seedling cohorts and crowns of individual saplings and adult trees
 * photosynthesis and transpiration - of seedlings cohorts and individual trees
 * phenology - seasonality in bud burst, leaf fall and flowering
 * tree dynamics - establishment of seedling cohorts and mortality of individual trees

Management
 * forest management - user-defined implementation of forest interventions

 Water balance

Soil
 * soil carbon - dynamics of soil organic matter

( OLD STRUCTURE:

END OF OLD STYRUCTURE)
 * seedling cohort establishment, growth and competition - the establishment, growth and competition for light of seedling cohorts individual seedlings
 * ForGEM environmental heterogeneity: overstorey light interception- light interception by individual crowns of adult trees

ForGEM initialisation
Initialisation of the the ForGEM model means assigning initial values to the variables of the model that are simulated over time. The following aspects of the model needs to be initialised in order to run the model:

initialisation of the genetic system

initialisation of the stand

initialisation of the soil

ForGEM validation

 * validation
 * parameter values
 * sensitivity analyses

source code
ForGEM is programmed in NSM. The source code is curated in a sub-version repository (location). Please contact Bert van der Werf or Wim de Winter if you have trouble accessing the repository.

applications
Category:FORGEM Category:Models Category:Forestry Category:Genetics