fg_tmc: ForestGALES - Single-tree (TMC) method.

Description Usage Arguments Value

View source: R/fg_tmc.R

Description

Wrapper for the single-tree (turning moment coefficient) method.

Usage

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fg_tmc(
  stand_id,
  tree_id,
  date = NA,
  species,
  tree_ht,
  dbh,
  spacing_current,
  predominant_species = species,
  stand_mean_ht,
  stand_mean_dbh,
  stand_top_ht,
  full_output = 1,
  weib_a = NA,
  weib_k = NA,
  ci = NA,
  ci_value = NA,
  elev_ht = NA,
  cr_width = NA,
  cr_depth = NA,
  stand_cr_width = NA,
  stand_cr_depth = NA,
  soil_group = NA,
  rooting = NA,
  dist_edge = NA,
  gap_size = NA,
  spacing_before = NA,
  years_since_thin = NA,
  species_parameters = fgr:::species_parameters,
  fgr_constants = fgr:::fgr_constants,
  moe = NA,
  mor = NA,
  fknot = NA,
  stem_vol = NA,
  crown_vol = NA,
  stem_density = NA,
  crown_density = NA,
  c_reg = NA,
  c_drag = NA,
  n_drag = NA,
  drag_upper_limit = NA,
  snow_depth = NA,
  snow_density = NA,
  ro = NA,
  x = NA,
  y = NA,
  z = NA,
  dams = NA
)

Arguments

stand_id

Stand identifier. Essential.

tree_id

Tree identifier. Essential.

date

Date of wind damage risk assessment. Optional (but useful!).

species

Tree species under investigation. Essential.

tree_ht

Individual tree height (m). Essential.

dbh

Diameter of the stem at breast height, i.e. 1.3m above the ground (cm). Essential.

spacing_current

Current mean spacing of trees in the stand (m). Essential.

predominant_species

Predominant species in the stand. Defaults to species.

stand_mean_ht

Arithmetic mean height of the trees in the stand (m). Essential.

stand_mean_dbh

Mean dbh of all trees in the stand (cm) - arithmetic average. Dbh is diameter at breast height, measured at 1.3m above the ground. Essential.

stand_top_ht

Height of the dominant tree(s) in the stand (m). Essential.

full_output

Switch between full and basic outputs.

weib_a

Scale parameter of the Weibull distribution for local wind speeds.

weib_k

Shape parameter of the Weibull distribution for local wind speeds.

ci

Competition Index (BAL, Hegyi, None) used.

ci_value

Value of ci.

elev_ht

The height at which the elevated critical wind speed is calculated (m). For the TMC method, this defaults to 1.05 * stand top height

cr_width

Width of the tree crown (m).

cr_depth

Length of the tree crown (m).

stand_cr_width

Width of the crown of the mean tree in the stand (m).

stand_cr_depth

Length of the crown of the mean tree in the stand (m).

soil_group

Soil group identifier (1 = freely draining mineral soils; 2 = gleyed mineral soils; 3 = peaty mineral soils; 4 = deep peats).

rooting

Rooting depth class (1 = Shallow, 2 = Deep, 3 = Medium).

dist_edge

Distance of tree from the upwind edge (m).

gap_size

Length of the upwind gap (m).

spacing_before

Mean spacing of trees in the stand before any thinning (m).

years_since_thin

Number of years since most recent thinning.

species_parameters

Data.frame covering all species-specific parameters. Defaults to fgr Internal Data species paramters data.frame. If specified by the user, it can have as many or as few species (i.e. rows) as required. It is recommended that when working with user-defined species, stem volume is specified and provided as an input (see below in input list). When this is not possible, stem volume is calculated with Eq. 4 of Fonweban et al. 2012. In order to allow this, letter codes for User-defined species must begin with a capital "U" for the model to recognise that the Fonweban et al. formula needs applied to calculate stem volume.

fgr_constants

Data.frame including all constants required for model execution. Defaults to fgr Internal Data fgr constants data.frame. these include entities that can be individually supplied to the model (e.g. ro, the air density, and snow density - see below in input list), or entities that qould not normally require modification (e.g. constants used in the calculation of the Deflection Loading Factor, the Annual Exceedance Probability, the Edge, Gap, and Gust Factors, aerodynamic quantities such as zpd, z0, and gammasolved - but even von Karman's and the gravitational constants can be modified!)

moe

Modulus of Elasticity of green wood (MPa). Advanced Input.

mor

Modulus of Rupture of green wood (MPa). Advanced Input.

fknot

Knot factor (dimensionless). Advanced Input.

stem_vol

Individual tree stem volume (m3). Advanced Input.

crown_vol

Volume of the crown of individual trees (m3). Advanced Input.

stem_density

Density of green wood of the stem (kg m-3). Advanced Input.

crown_density

Density of the crown of individual trees (kg m-3). Advanced Input.

c_reg

Regression coefficient of uprooting moment against stem weight (N m kg-1). Advanced Input.

c_drag

C parameter of the drag coefficient formula (dimensionless). Advanced Input.

n_drag

N parameter of the drag coefficient formula (dimensionless). Advanced Input.

drag_upper_limit

Maximum wind speed used during the experiments from which n_drag and c_drag were derived (m*s-1). Advanced Input.

snow_depth

Depth of layer of snow on tree crown (cm). Advanced Input.

snow_density

Density of snow (kg m-3). Advanced Input.

ro

Air density (kg m-3). Advanced Input.

x

Spatial coordinate.

y

Spatial coordinate.

z

Spatial coordinate.

dams

DAMS (Detailed Aspect Method of Scoring) value to describe the local wind climate (for UK conditions only).

Value

If full_output = 1, a comprehensive list including: stand and tree id's; for breakage and overturning, the critical wind speeds (m s-1) at canopy top height and anemometer's height; zero plane displacement height (m), canopy surface roughness (m); canopy drag; ratio of critical wind speed at canopy top over friction velocity (uh / u*); drag per unit ground area; the turning moment coefficient; the turning moment ratio; the deflection loading factor; the critical breaking moment and the critical overturning moment; the combined effect of edge and gap on the applied bending moment; the probabilities of damage; the mode of damage; a summary of the inputs. If full_output = 0, a much shorter list including: stand id and tree id's; the critical wind speeds of breakage and overturning, and the associated probabilities.


tom-locatelli/fgr documentation built on Oct. 2, 2020, 2:09 a.m.