fe_stand_spatial: User Friendly Construction of an *fe_stand_spatial* Object...

In ForestElementsR: Data Structures and Functions for Working with Forest Data

User Friendly Construction of an fe_stand_spatial Object from a List of Data Frames

Description

fe_stand_spatial() provides a user-friendly interface for the constructor new_fe_stand_spatial. While the constructor does not prevent users from creating malformed fe_stand_spatial objects, fe_stand_spatial does everything to achieve a well-defined object mostly based on an initial list of data.frames that might be, e.g. drawn out of a user's own data base.

Usage

fe_stand_spatial(
  x,
  tree_frame_name = "trees",
  tree_pos_frame_name = "tree_positions",
  outline_frame_name = "outline",
  orientation = NA,
  tree_id_col,
  species_id_col,
  time_yr_col,
  dbh_cm_col,
  x_m_col,
  y_m_col,
  stand_id = "my_fe_stand_spatial",
  layer_key_col = NA,
  age_yr_col = NA,
  height_m_col = NA,
  crown_base_height_m_col = NA,
  crown_radius_m_col = NA,
  removal_col = NA,
  ingrowth_col = NA,
  n_rep_ha_col = NA,
  small_trees = data.frame(),
  verbose = TRUE
)

Arguments

x	named list of two or three data frames to be coerced into the goal object. One data frame must contain the single tree data; it has the same requirements as for the input data frame x of the function fe_stand. Another data frame must contain the tree positions. The third data frame is optional, if provided it must contain a coordinate description of the stand/plot outline. See the Details section for all requirements.
tree_frame_name	name of the data frame in x that contains the single tree data (default: "trees")
tree_pos_frame_name	name of the data frame in x that contains the tree positions (default: "tree_positions")
outline_frame_name	name of the data frame in x that contains the stand outline information (default: "outline"). It is possible to have no defined stand outline; in this case outline_frame_name must be NULL, and n_rep_ha_col must be given (with no missing values).
orientation	counterclockwise angle in degrees between the y-axis of the coordinate system of the stand outline and the tree positions and the north direction. The value NA is allowed.
tree_id_col	name of the column in the trees and tree_positions data frames which contains the tree id's (character, required, must not contain missing values)
species_id_col	name of the column in trees data frame which contains the species id's. Must be an object of one of the fe_species classes supported by this package. This column is required, must not contain missing values.
time_yr_col	name of the column in the trees data frame which provides time information in years (character, required, must not contain missing values)
dbh_cm_col	name of the column in the trees data frame which contains the dbh in cm (character, required, must not contain missing values)
x_m_col	name of the column in the tree positions data frame that contains the x-coordinates of the tree stem centers in m. The coordinates must adhere to the same coordinate system as the coordinates in the plot outline data frame. If the latter is provided, its x column must also have the name provided with x_m_col.
y_m_col	name of the column in the tree positions data frame that contains the y-coordinates of the tree stem centers in m. The coordinates must adhere to the same coordinate system as the coordinates in the plot outline data frame. If the latter is provided, its x column must also have the name provided with y_m_col.
stand_id	arbitrary id of the stand (character, default: "my_fe_stand_spatial")
layer_key_col	name of the column in x that contains codes for the stand layer a given tree belongs to. These codes are whole numbers. The following values are allowed: 1 - Main stand, 2 - Understorey, 3 - Pregeneration (ger: "Vorausverjuengung"), 4 - Remnant trees, hold over trees, veteran trees (ger: "Nachhiebsreste", "Ueberhaelter", "Altbaeume"). Must not contain missing values if provided. If not provided, it will be set to 1 (main stand) for every tree.
age_yr_col	name of the column in the trees data frame which provides the tree ages in years (character, optional, may contain missing values)
height_m_col	name of the column in the trees data frame which provides the tree heights in m (character, optional, may contain missing values)
crown_base_height_m_col	name of the column in the trees data frame which provides the crown base heights in m (character, optional, may contain missing values)
crown_radius_m_col	name of the column in the trees data frame which provides the crown radii in m (character, optional, may contain missing values)
removal_col	name of the column in the trees data frame which provides the tree's removal status. If TRUE, this indicates the tree was removed or dead at the time indicated in age_yr_col (character, optional, must not contain missing values if provided). If not provided, the removal status will be FALSE for all trees in the resulting fe_stand object.
ingrowth_col	name of the column in the trees data frame which provides the tree's ingrowth status. If TRUE, this indicates a tree that grew newly in at the time indicated in age_yr_col (character, optional, must not contain missing values if provided). If not provided, the ingrowth status will be FALSE for all trees in the resulting fe_stand object.
n_rep_ha_col	name of the column in the trees data frame which provides each tree's representation number per ha. Not required if a stand outline is provided in x. If a stand outline is given, n_rep_ha will be always recalculated based on the outline and the tree positions.
small_trees	An fe_stand_spatial object does contain an extra slot for small trees, defined as trees which are too small to have an own dbh (i.e. having a height > 1.3 m). So far, this slot is still experimental. The only requirement is that it is a data.frame. Such a data.frame can be provided via this parameter, it will be directly put into the goal object's small_trees slot. The default is a data.frame with zero rows and zero columns (data.frame()).
verbose	name of the column in the trees data frame which provides the tree's ingrowth status. If TRUE, this indicates a tree that grew newly in at the time indicated in age_yr_col (character, optional, must not contain missing values if provided). If not provided, the ingrowth status will be FALSE for all trees in the resulting fe_stand object.

Details

An object of class fe_stand_spatial is a child object of fe_stand which, however, contains information about the horizontal positions of the trees and the horizontal outline of the stand. All spatial information and its processing is based on the R-package sf.

The input object x to fe_stand_spatial must be a list that comprises two and an optional third data frame(s):

• a data frame containing the single tree information (same requirements as for fe_stand). This data frame must contain a a minimum set of columns (tree id, species id, time variable, diameter at breast height). These columns must not contain missing values. Other columns (containing tree height, height to crown base, crown radius, tree age) are optional for the user to provide. If provided, they may contain missing values. If not provided, these columns will only contain missing values in the fe_stand_spatial object. The columns about the trees' removal and ingrowth status are also optional, but if provided, they must not contain missing values. If not provided, both columns will be filled with FALSE in the resulting fe_stand_spatial object. fe_stand_spatial will automatically add a column n_rep_ha which contains for each tree the number of trees it represents per ha. This may seem redundant if looking at fe_stand objects alone, but it allows a broad range of evaluation functions to be applied to different objects containing trees. Note that in a fe_stand_spatial object trees are allowed which are outside the actual stand outine (e.g. "buffer zone trees"). Such trees will be automatically identified by their coordinates and not taken into account for calculating the stand's growth and yield characteristics. However, they can be included in visual displays.

• a data frame that contains information about the tree positions. This is not part of the first data frame, because the latter could contain several observations (at different times) of the same tree, which would lead to redundant coordinate representation. This data frame must contain a column with tree id's, and the x and y coordinates of the stem center points according to the same coordinate system as the stand outline (see below). NA values are not allowed in this data frame.

• The optional third data frame must comprise the corner points of a polygon that describes the stand's outline. The polygon must not be self-intersection, therefore, the points must be given in correct sequence. The first point does not need to be repeated - fe_stand_spatial will take care for closing the polygon. This data frame needs to contain only the x and y coordinates of the corner points (in m), no NA values allowed.

Value

If the user input allows to construct a well-defined fe_stand_spatial object, this object will be returned. If not, the function will terminate with an error.

Examples

# Transform the example data collection mm_forest_1_raw (could e.g. have
# been drawn out of a user's data base) into an fe_stand_spatial object

mm_forest_spatial <- mm_forest_1_raw |>
  fe_stand_spatial(
    orientation = mm_forest_1_raw$north_dev,
    tree_id_col = "tree_id",
    species_id_col = "species_id",
    time_yr_col = "time_yr",
    dbh_cm_col = "dbh_cm",
    x_m_col = "x",
    y_m_col = "y",
    stand_id = mm_forest_1_raw$stand_id,
    height_m_col = "height_m",
    crown_base_height_m_col = "crown_base_height_m",
    crown_radius_m_col = "crown_radius_m",
    removal_col = "removal"
  )

# Show a little summary, display scientific species names
options(fe_spec_lang = "sci")
mm_forest_spatial |> summary()

ForestElementsR documentation built on April 3, 2025, 7:47 p.m.