Environmental Engineering Reference
In-Depth Information
FEM (three Dimensional Forest Ecosystem Model of the euro-Mediterranean
Centre for Climate Change) (Collalti et al.
2014
) integrates several characteristics
of the functional-structural tree models, based on the light use efficiency (LUE)
approach, to investigate forest growth patterns and yield processes for complex
multi-layer forests.
However, physiological processes are not explicitly accounted for, requir-
ing statistical fitting procedures between each environmental factor and observed
growth (Vacchiano et al.
2012
).
Landscape models comprise a broad class of spatially explicit models that
incorporate heterogeneity in site conditions, neighborhood interactions and
feedbacks between different spatial processes (Pretzsch et al.
2008
). The aims
of these models are to develop scenarios for the sustainability of forest or land-
scape functions (natural resources, habitat, hydrology, socioeconomic), to fore-
cast their response to disturbances and potential environmental change (climate,
N deposition, land use and land use change), to investigate the relationship
between landscape structure and regionally distributed risks, and to assess
regional-scale matter fluxes, e.g. water, carbon and nutrients. One example is the
mesoscale Land Surface Model proposed by Alessandri and Navarra (
2008
) repre-
senting the momentum, heat and water flux at the interface between land-surface
and atmosphere; it has been coupled to a general circulation model (GCM) to esti-
mate the rate of forcing by existing vegetation on precipitation patterns. PBMs can
be defined as a procedure by which the behavior of a system is derived from a
set of functional components and their interactions with each other and the sys-
tem environment, through physical and mechanistic processes occurring over
time (Godfrey
1983
; Bossel
1994
). More generally, these models are part of the
Soil-Vegetation-Atmosphere Transport (SVAT) models giving a representative
description of land surface-atmosphere interaction, and describing the physi-
cal and biological processes in vegetation and soil, as well as physical processes
within the atmospheric boundary layer. SVAT models are commonly used to esti-
mate the exchanges of energy, mass and momentum between the atmosphere and
the land surface. These types of models, which are widely applied and validated
across the world, use the “big leaf ” concept based on one canopy layer or multiple
layer schemes, to simulate water and carbon cycles on a variety of spatial (hectare
to km) and temporal (daily, monthly or annually) scales. The implementation of
these models in forestry in the last decades has been having great success thanks
to the availability of remotely sensed data offering a greater amount of informa-
tion both during the initialization and validation phase. Also, fluxes of energy, CO
2
and water vapor exchanges between the vegetation and the atmosphere measured
by the FLUXNET network give the possibility to test such models over as many
different circumstances as possible. The spatial scale which they generally work
at (ecosystem) can describe the main features in the structure and physiognomy
of the forest and they can be considered a valuable tool in the study of those eco-
physiological fundamental processes, at species level but also at forest typology
level, at an intermediate spatial scale between gap models and Dynamic Global
Vegetation Models (DGVM). An important feature of SVAT models is that they
