Description Usage Format Details
A dataset used for the examples on how to use the TMC method in the forestgales package.
It contains data for most of the input variables of the fg_tmc
function.
Variables with NAs default automatically to a species-specific value, or to a constant.
Some variables are Essential, others are Desirable, and quite a few are Advanced. See the Wrapper Functions
documentation for more information on inputs.
The variables are as follows:
1 |
A data frame with 8 rows and 42 variables
stand_id. We think it's useful to tag stands for batch simulations. Essential.
tree_id. We think it's useful to tag trees for batch simulations. Essential.
species. Vulnerability is to a large extent species-specific. Note that the species acronyms need to be wrapped in inverted commas (e.g. "SP" for Scots pine). Essential.
tree_ht. Tree height is the main driver of vulnerability (m). Essential.
dbh. Diameter at Breast Height (cm). Dbh is the second main driver of vulnerability. Essential.
spacing_current. Current average spacing of trees (m). When modelling thinnings, this is the spacing after thinning. Essential.
stand_mean_ht. Mean tree height of the trees in the stand (m). Used to calculate the effect of edge and gap, and indirectly to elevate the critical wind speeds (CWS) to match anemometer data. Essential.
stand_mean_dbh. The mean dbh of the trees in the stand (cm). Used indirectly to elevate the critical wind speeds to match anemometer data. Essential.
predominant_species. Required to calculate stand_top_ht
and/or stand_mean_ht
. Note that the species acronyms need to be wrapped in inverted commas (e.g. "SP" for Scots pine). Essential.
weib_a. Scale parameter (A) of the Weibull distribution of mean hourly wind speeds. This parameter is proportional to the mean wind speed. Only used to calculate probabilities of damage, not the CWS. In the UK, if weib_a
is not available it can be calculated from DAMS scores (see the Wrapper Functions
documentation).
weib_k. Shape parameter (k) of the Weibull distribution of mean hourly wind speeds. This parameter (typically ranging between 1 and 3) is indicative of the variability of the mean wind speeds (small values indicating larger variability). Only used to calculate probabilities of damage, not the CWS. Defaults to 1.85.
cr_width. Individual tree crown width (m). Calculated from species-specific parameters if not provided. Desirable.
cr_depth. Individual tree crown depth (m). Calculated from species-specific parameters if not provided. Desirable.
stand_cr_width. Mean tree crown width (m). Calculated from species-specific parameters relative to predominant_species
if not provided. Used to elevate the critical wind speeds to match anemometer data.Desirable.
stand_cr_depth. Mean tree crown depth (m). Calculated from species-specific parameters relative to predominant_species
if not provided. Used to elevate the critical wind speeds to match anemometer data.Desirable.
soil_group. Follows the soil classification described in the Critical Moments
documentation. If not provided it defaults to Soil A - Freely draining mineral soils. Desirable.
rooting. Categorised as: 1 - Shallow (<80cm); 2 - Deep (>80cm); 3 - The average of the Shallow and Deep values. Defaults to the Average value. Desirable.
dist_edge. Distance between an individual tree and the upwind stand edge (m). It defaults to 9 times stand_mean_ht
. Desirable.
gap_size. Size of the upwind gap (m). Defaults to 0m (i.e. no gap), which effectively treats all trees as "middle of the stand" trees. Desirable.
spacing_before. Average spacing of trees before a thinning (m). It defaults to spacing_current
. Desirable.
years_since_thin. Years since the last thinning. It defaults to 5 years (e.g. assumes full acclimation to new wind climate). Desirable.
moe. Modulus of Elasticity (Young's modulus) of green wood (MPa). Defaults to species-specific values unless provided. Advanced.
mor. Modulus of Rupture of green wood (MPa). Defaults to species-specific values unless provided. Advanced.
fknot. Knot factor, scaled (0, 1] (dimensionless). It defaults to species-specific values unless provided. Advanced.
stem_vol. Volume of the stem (m3). Calculated with species-specific formulas and parameters unless provided. Advanced.
crown_vol. Volume of the crown (m3). Calculated with species-specific formulas and parameters unless provided. Advanced.
stem_density. Density of the green wood of the stem (kg m-3). It defaults to species-specific values unless provided. Advanced.
crown_density. Density of the crown (kg m-3). It defaults to species-specific values unless provided. Advanced.
c_reg. Regression coefficient of the critical overturning moment vs stem weight. It defaults to species-specific values for the chosen soil_group
x rooting
depth combination unless provided. Advanced.
c_drag. Value of the drag coefficient at rest (dimensionless). See the Streamlining
documentation. It defaults to species-specific values unless provided. Advanced.
n_drag. Exponent of the power fit of drag to wind tunnel data. See the Streamlining
documentation. It defaults to species-specific values unless provided. Advanced.
drag_upper_limit. Maximum wind speed used during the experiments from which n_drag
and c_drag
were derived (m*s-1). It defaults to species-specific values unless provided. Advanced.
snow_depth. Depth of snow layer on the canopy (m). It defaults to 0m (no snow). Advanced.
snow_density. Density of snow (kg m-3). It defaults to 150 kg m-3. Advanced.
ci. Competition Index. Three options available: "None", "Bal", "Heg" (see Turning coefficients functions
documentation). It defaults to "None". Advanced.
ci_value. Value of the Competition Index. It defaults to 0. Advanced.
ro. Air density (kg m-3). It defaults to 1.2226. Advanced.
x, y, z. Placeholders for tree coordinates. Advanced.
dams. DAMS (Detailed Aspect Method of Scoring) value to describe the local wind climate (for UK conditions only). Only used to calculate probabilities of damage, not the CWS. Advanced.
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