PackageOverview.RmdThe R package medfateland has been designed to run simulations of forest functioning and dynamics at the landscape and regional scales. The package allows executing the stand-level models available in package medfate on points and cells within landscape, in either sequential or parallel computation. In addition, medfateland allows considering spatial hydrological processes in forested watersheds. Hence, medfateland can be used as a tool for eco-hydrological applications.
IMPORTANT: All data the following data structures have been deprecated because of their dependencies with package sp.
Package medfateland offers three spatial classes that inherit fields from three corresponding classes in package meteoland:
SpatialPointsLandscape: represents a set of forest
stands (including soil description) as points within a landscape.
Extends class SpatialPointsTopography.SpatialPixelsLandscape: represents a set of forests
(including soil description) or other land cover units
(i.e. agricultural, rock outcrops or urban areas) as pixels within a
gridded landscape. Extends class
SpatialPixelsTopography.SpatialGridLandscape: represents a set of forests
(including soil description) or other land cover units
(i.e. agricultural, rock outcrops or urban areas) as pixels within a
complete grid. Extends class SpatialGridTopography.Spatial objects SpatialPointsLandscape,
SpatialPixelsLandscape and
SpatialGridLandscape allow simulations to be performed
straightforwardly for a set of forests distributed spatially.
Simulations of local processes are performed sequentially or in parallel
computation for all forest stands, because landscape processes are not
considered.
An additional spatial class is defined for watershed ecohydrological modelling:
DistributedWatershed: Represents a (forested)
watershed, including land cover units (i.e. agricultural, rock outcrops
or urban areas), forest and soil information as well as bedrock
properties. Extends class SpatialPixelsLandscape.Simulating water balance on objects DistributedWatershed
allows considering an aquifer compartment for each cell as well as
simulating spatial water transfer between cells, i.e. overland,
subsurface water and groundwater flows.
Eco-hydrological processes are fundamental for the simulation models
included in the medfate package. Eco-hydrological processes
can be divided into local and landscape processes.
By local water balance we refer to the water balance of soils and plants within forest stands. Processes affecting soil water content include rainfall, canopy interception, infiltration and runoff, percolation and deep drainage, soil evaporation and plant transpiration.
In package medfate, the local soil water balance of
a forest is primarily used to predict drought stress for living plants
in it using function spwb(). Package
medfateland allows simulating water balance for
multiple stands distributed spatially over a given time period using
function spwb_spatial(), which makes internal calls to
spwb() on elements the spatial classes introduced above.
Function spwb_spatial_day() is analogous to the former, but
are used for the simulation of a single day, using internal calls to
function spwb_day() of medfate. Function
spwb_spatial() and its one-day counterpart may be used
to:
Changes in leaf area and plant growth are key to evaluate the influence of climatic conditions on forest structure and function. Processes affecting annual changes leaf area and plant size are those involved water and carbon balances, as well as those affecting growth directly. Processes influencing plant water balance include those affecting soil water content, such as rainfall, canopy interception, infiltration and runoff, percolation and deep drainage, soil evaporation and plant transpiration. Carbon balance arises from the relationship between plant photosynthesis and respiration, although carbon reserves play a role in the availability of carbon for growth. Water and carbon balances are coupled through the regulation of transpiration done by stomata. Plant growth is affected by the availability of carbon (source limitation), but also by temperature and water status (sink limitation). Leaf area of plants can be severely decreased by drought stress, causing an increase in dead leaf area and affecting carbon and water fluxes.
Package medfate allows simulating plant growth and
mortality of a set of cohorts (competing for light and water) in a
single forest stand using function growth(). Package
medfateland extends this by providing function
growth_spatial(), which operates on spatial classes and
makes internal calls to function growth(). Function
growth_spatial_day() is analogous to the former, but are
used for the simulation of a single day, using internal calls to
function growth_day() of medfate. Function
growth_spatial() and its one-day counterpart may be used
to:
Changes in forest structure and composition result from the interplay of demographic processes (growth, mortality and recruitment) and may include forest management.
Package medfate includes function
fordyn(), which allows simulating these processes at yearly
time steps on a given forest stand, building on previous models. Package
medfateland extends this by providing function
fordyn_spatial(), which operates on spatial classes and
make internal calls to function fordyn(). In addition,
medfateland provides function
fordyn_scenario(), which allows performing simulations of
forest dynamics for a set of forest stands, while controlling management
actions following a timber demand-based approach.
When input data is in form of continuous spatial variation of forests
over a landscape, the medfateland package allows
studying local soil water balance in combination with lateral water
transfer processes using function spwb_land(). The package
also allows studying local water balance and plant growth processes in
combination with lateral water transfer processes using function
growth_land(). Three lateral flows are considered in
medfateland:
Functions spwb_land() and growth_land() may
be used to: