In Genève, Switzerland, July 2016.

__
Abstract__:

SORTIE is a forest simulator developed by Pacala, Ribbens, Kobe et al. in 1993-1996. It is based on the forest data observed in and around Great Mountain Forest (GMF), a privately owned 2500ha forest located in northwestern Connecticut (41°57'N, 73°15'W), USA in the year 1990-1992. SORTIE is an individual based model (IBM). It consists of four submodels (resource, growth, mortality, and recruitment) to determine the behavior of each individual, from which the behavior of the whole forest community can be determined. The main ingredient taken into account in SORTIE is the competition for light between trees.

In [1] we build a mathematical model (a
state-dependent delay differential equation derived from a
size-structured model) for the adult population of trees
A(t) in two cases (single species case and two-species
case) and we compare it with SORTIE. The models are

Moreover, we extend our model by incorporating the spatial
position of trees. **The
model is**

**
**

In
this figure we plot the numerical simulation of the spatial
model, describing the spread of the adult population of the two species.

** In [2] we use
the above model (in the single species case)
coupled as a predator-prey system. This is to
describe a parasite destroying a pine
forest. The parastite considered is the so
called "pinewood nematode" which destroyed a
large part of Portuguese pine tree forest. **The
model we end up with is the following

In this figure we plot the forest-parasite model with Holling type I functional response in the scenario where the adult population of trees displays the damped oscillation without parasites.