MAIDEN is an ecophysiological model that was created to explore the relationships between climate variability and forest growth-productivity. The simulations can be verified using different data to validate the different processes in the model, including dendroecological growth data, 13C and 18O data and measurements of ecosystem carbon and water fluxes.

MAIDENiso simulated processes

Authors and developers

Authors :

Laurent Misson (MAIDEN)

Pierre-Alain Danis (isotopic module)

Developers in alphabetical order :

Etienne Boucher, UQAM, Canada

Guillermo Gea-Izquierdo, INIA, Spain

Fabio Gennaretti, UQAT, Canada

Joël Guiot, CEREGE, France

Laia Andreu-Hayles, Columbia, US

Ignacio Hermoso, UQAM, Canada

Alienor Lavergne, Imperial College, UK



Spatial simulations

Possible but without interaction between pixels

Spatial resolution

1 m2 of forests

Spatial scale

Average tree

Spatial scale of outputs

Forest stand

Temporal resolution


Temporal scale of outputs

From daily to several decades


The model has already been used and tested for several temperate and Mediterranean species (Pinus spp., Quercus spp., Cedrus atlantica), and for alpine and boreal species from the northern and southern hemisphere (Picea mariana, Picea gluaca, Picea abies , Larix decidua, Pinus sylvestris, Nothofagus pumilio).

Stand types

Mainly monospecific stands

Evolution of the environment

Climate, CO2, δ13C of CO2

Input climate data at daily time step : year, Julian day, maximum temperature (°C), minimum temperature (°C), precipitation (cm), CO2 concentration in the atmosphere (ppm)

Other input variables for the isotopic module : δ18O of precipitation, δ13C of CO2

Consideration of forest management

Resetting the stand parameters (i.e., LAI) is necessary after any forest management intervention

Simulated processes

Transmission and absorption of solar radiation in the canopy

Water fluxes in the canopy and in the soil




Allocation of carbon to different tree compartments

Isotopic fractionations of carbon, oxygen and hydrogen

Functional traits modeled

Radiation : LAI, coefficients for absorption and reflection of PAR

Water fluxes in the canopy : interception, maximum storage of water in the canopy

Soil : water infiltration, and thickness, grain size and percentage of roots in four soil layers

GPP : photosynthesis (De Pury and Farquhar) and stomatal conductance (Leuning)

Isotopes : multiple fractionations

Phenology : GDD for budburst, photoperiod for senescence

C Allocation : allometric coefficients and C partitioning according to the phenological phase

Main outputs

At daily resolution : water transfers and budget, GPP, NPP, biomass allocated to specific compartments (trunk, roots, reserves, canopy), cellulose stable isotopes

Average computation time

4 seconds per 100 years for a stand

Deterministic or stochastic modeling


Strengths and weaknesses

Strengths :

  • Use of simple and easily measurable meteorological inputs

  • Possible comparison with metrics that can be used by dendrochronologists (ring widths, wood density, isotopic ratios of cellulose)

  • Consideration of sugar reserves (NSCs)

  • Detailed simulation of C, water and energy fluxes

  • The model has many parameters and it makes no sense to calibrate “blindly” (or just statistically) as many parameters as we want until we get a good calibration. A better approach is to set parameters accordingly to physiological knowledge and only calibrate a short list of them according to the goal of the simulation experiment.

Weaknesses :

  • Lack of a cell differentiation module allowing dimensional comparison with tree-ring width

  • Lack of modeling of stand ecological processes, including disturbance, mortality, dispersal and recruitment

  • Lack of spatial interactions between tree individuals

Most recent developments

Development of a snow accumulation and melting module contributing to the water and isotopic balance of the soil. In the past versions, the model only considers the snow cover in the modeling of the terrestrial albedo.

MAIDENiso documentation


Comments and feedbacks

We encourage future users to give feedback, particularly when they find bugs or things to ameliorate in the model, documentation, and user’s manual. Current developers (see above) are available to discuss projects and simulation experiences using MAIDEN.