| Title: | Functions and Datasets for Forest Biometrics and Modelling | 
| Version: | 1.0.2 | 
| Description: | A system of functions and data aiming to apply quantitative analyses to forest ecology, silviculture and decision-making. Besides, the package helps to carry out data management, exploratory analysis, and model assessment. | 
| License: | GPL (≥ 3) | 
| Encoding: | UTF-8 | 
| RoxygenNote: | 7.3.2 | 
| Depends: | R (≥ 3.5) | 
| LazyData: | true | 
| Imports: | graphics, grDevices, stats, utils | 
| Suggests: | datana, lattice | 
| NeedsCompilation: | no | 
| Packaged: | 2025-08-20 20:36:59 UTC; christian | 
| Author: | Christian Salas-Eljatib | 
| Maintainer: | Christian Salas-Eljatib <cseljatib@gmail.com> | 
| Repository: | CRAN | 
| Date/Publication: | 2025-08-20 21:00:02 UTC | 
Function for building a barplot for one or two factors
Description
The function creates a barplot of numeric vector by one or two factor.
Usage
barplotgr(
  yvar,
  factors,
  data = data,
  percentage = FALSE,
  errbar = !percentage,
  half.errbar = TRUE,
  conf.level = 0.95,
  xlab = NULL,
  ylab = NULL,
  main = NULL,
  names.arg = NULL,
  bar.col = "black",
  whisker = 0.015,
  args.errbar = NULL,
  legend = TRUE,
  legend.text = NULL,
  args.legend = NULL,
  legend.border = FALSE,
  box = TRUE,
  args.yaxis = NULL,
  mar = c(5, 4, 3, 2),
  ...
)
Arguments
| yvar | The column having the variable to represent the height of the bars. | 
| factors | A vector having the columns with the factors to be used in the resulting plot. Notice that the last listed factor, will be used in X-axis plot. | 
| data | A data frame having the above described columns. | 
| percentage | Logical value, set to  | 
| errbar | Please set this option to  | 
| half.errbar | Optional, default set to  | 
| conf.level | Optional, a numeric value for the confidence interval, the default is 0.95. | 
| xlab | Optional, as in the generic barplot function. | 
| ylab | Optional, as in the generic barplot function. | 
| main | Optional, as in the generic barplot function. | 
| names.arg | Optional, as in the generic barplot function. | 
| bar.col | Optional, as in the generic barplot function. | 
| whisker | Optional, A numeric value, the default is 0.015. | 
| args.errbar | Optional, as in the generic barplot function. | 
| legend | Optional, as in the generic barplot function. | 
| legend.text | Optional, as in the generic barplot function. | 
| args.legend | Optional, as in the generic barplot function. | 
| legend.border | Optional, as in the generic barplot function. | 
| box | Optional, as in the generic barplot function. | 
| args.yaxis | Optional, as in the generic barplot function. | 
| mar | Optional, as in the generic barplot function. | 
| ... | list of columns to sort on | 
Value
The function returns the above described graph.
Author(s)
Christian Salas-Eljatib
References
The present function was modified from a similar one available at https://github.com/mrxiaohe/R_Functions/blob/master/functions/bar
Examples
data(standtabRauli2)
df <- standtabRauli2
head(df)
barplotgr(yvar = nha.cd, factors = c(bosque.id,cd), data = df,
errbar = FALSE, ylim=c(0, 640))
Contains tree-level biomass data for four species in Canada.
Description
These are tree-level variables for four species in Canada.
Usage
biomass
Format
Data contain the following columns:
- tree
- Tree number code. 
- spp
- Species common name, as follows: - Balsam firis Abies balsamea,- Black spruceis Picea mariana,- White birchis Betula papyrifera, and- White spruceis Picea glauca.
- dbh
- Diameter at breast height, in cm. 
- toth
- Total height, in m. 
- totbiom
- Total biomass, in kg. 
- bolebiom
- Stem biomass, in kg. 
- branchbiom
- Branches biomass, in kg. 
- foliagebiom
- Foliage biomass, in kg. 
Source
Data were provided by Prof. Timothy Gregoire, School of Forestry and Environmental Studies, Yale University (New Haven, CT, USA).
Examples
data(biomass)
head(biomass)
tapply(biomass$totbiom,biomass$spp,summary)
Biomasa a nivel de árbol para cuatro especies arbóreas de Canadá
Description
Biomasa a nivel de árbol y otras variables, para cuatro especies que crecen en bosques de Canadá.
Usage
biomass2
Format
Los datos contienen las siguientes columnas:
- arbol
- Número del árbol. 
- spp
- Nombre común de la especie, como sigue: - Balsam fires Abies balsamea,- Black sprucees Picea mariana,- White birches Betula papyrifera, y- White sprucees Picea glauca.
- dap
- Diámetro a la altura del pecho (1.3 m), en cm. 
- atot
- Altura total, en m. 
- wtot
- Biomasa total, en kg. 
- wfus
- Biomasa del fuste, en kg. 
- wramas
- Biomasa de las ramas, en kg. 
- whojas
- Biomasa del follaje, en kg. 
Source
Los datos fueron cedidos cortesía del profesor Timothy Gregoire, School of Forestry and Environmental Studies, Yale University (New Haven, CT, USA).
Examples
data(biomass2)
head(biomass2)
tapply(biomass2$wtot,biomass2$spp,summary)
Mortality of lianas (vines) in tropical forests
Description
This study is part of the project "Diversity and dynamics of vascular
epiphytes in Colombian Andes"
supported by COLCIENCIAS (contract 2115-2013). The data corresponds to
the first large-scale
assessment of vascular epiphyte mortality in the neotropics. Based on two
consecutive annual surveys,
we followed the fate of 4247 epiphytes to estimate the epiphyte mortality
rate on 116 host trees
at nine sites. Additional variables were taken from the area of study in
order to find relationships
with epiphyte mortality.
Usage
data(deadlianas)
Format
The data frame contains four variables as follows:
- PlotSite
- Municipality name of the 9 study sites 
- Y.Plot
- Latitude of the plot in decimal degrees 
- X.Plot
- Longitude of the plot in decimal degrees 
- PhoroNo
- ID number of the sampled host trees in each site 
- EpiFam
- Epiphyte taxonomic family 
- EpiGen
- Epiphyte taxonomic genus 
- cf.aff
- Abbreviations of Latin terms in the context of taxonomy. cf. "confer" meaning "compare with". aff.: "affinis" meaning "similar to". 
- Species
- Epiphyte (morpho) species name 
- Author
- Author of the scientific name 
- EpiAzi
- Azimuth of the epiphyte individual on each host tree 
- BraAzi
- Azimuth of the branch in which the epiphyte individual was found 
- EpiDisTru
- Distance in meters from the trunk to the epiphyte attachment site on a branch 
- EpiSize
- Estimated size of the epiphyte individual, in cm. 
- EpiAttHei
- Epiphyte attachment height in meters 
- Date0
- Date of the first census 
- Date1
- Date of the final census 
- Location
- Section (roots, trunks, branches) of the host tree in which theepiphyte individual was found 
- Mortality
- Dichotomous variable. 0 if the epiphyte individual was dead in the final census and 1 if otherwise 
- MorCat
- Mechanical or non-mechanical cause of mortality 
- Elevation
- Elevation (m a.s.l.) of the plot 
- AP_bio12
- Annual precipitation in the plot (mm yr-1) 
- PDM_bio14
- Precipitation of driest month in the plot (mm) 
- PS_bio15
- Precipitation seasonality in the plot (coefficient of variation) 
- MDT_bio2
- Mean Diurnal Range (Mean of monthly (max temp - min temp)) in the plot (oC * 10) 
- TS_bio4
- Temperature seasonality in the plot (standard deviation * 100) 
- ATR_bio7
- Annual temperature range in the plot (10 celsius degrees) 
- AET
- Actual evapotranspiration in the plot (mm yr-1) 
- BasAre
- Basal area of trees with DBH major or equal to 5 cm (AB) in the plot (m - ^{2}/ha)
- BasAre5_10
- Basal area of trees with greater or equal than 5 DBH and less than 10 cm in the plot (m - ^{2}/ha)
- BasAre10
- Basal area of trees with greater or equal than 10 cm DBH in the plot (m - ^{2}/ha)
- Ind10
- Number of canopy trees (with greater or equal than 10 cm DBH ) in the plot 
- Ind5
- Number of understory trees (with greater or equal than 5 DBH and less than 10 cm) in the plot 
- Ind5_10
- Number of trees with greater or equal than 5 DBH and less than 10 cm in the plot 
- Ind10_15
- Number of trees with greater or equal than 10 DBH and less than 15 cm in the plot 
- Ind15_20
- Number of trees with greater or equal than 15 DBH and less than 20 cm in the plot 
- Ind20_25
- Number of trees with greater or equal than 20 DBH and less than 25 cm in the plot 
- Ind25_30
- Number of trees with greater or equal than 25 DBH and less than 30 cm in the plot 
- Ind30
- Number of trees with DBH major or equal to 30 cm in the plot 
- TreeHei
- Total tree height in meters 
- MedHei
- Median height of trees in each plot 
- MaxHei
- Maximum height of trees in each plot 
- BranchNumb
- Number of branches of the host tree 
- Obs
- Observations and notes in Spanish 
Source
Data were retrieved from the DRYAD repository at doi:10.5061/dryad.g5510.
References
Zuleta D, Benavides AM, Lopez-Rios V, Duque A. 2016. Local and regional determinants of vascular epiphyte mortality in the Andean mountains of Colombia. Journal of Ecology 104(3): 841-843. doi:10.1111/1365-2745.12563
Examples
data(deadlianas)
head(deadlianas)
Datos de mortalidad de lianas en árboles tropicales
Description
Los datos provienen de un estudio que fue parte del proyecto "Diversidad y dinámica de epífitas vasculares en los Andes colombianos". apoyado por COLCIENCIAS (contrato 2115-2013). Este conjunto de datos tiene 43 columnas y 4247 filas. Cada fila corresponde a un individuo epifito ubicado en secciones confiables de los árboles hospedantes Los datos corresponden a la primera gran escala evaluación de la mortalidad de epífitas vasculares en los neotrópicos. Basado en dos encuestas anuales consecutivas, Seguimos el destino de 4247 epífitas para estimar la tasa de mortalidad de epífitas en 116 árboles hospedantes. en nueve sitios. Se tomaron variables adicionales del area de estudio para encontrar relaciones con mortalidad de epifitas.
Usage
data(deadlianas2)
Format
Variables se describen a continuación::
- PlotSite
- Nombre del municipio de los 9 sitios de estudio. 
- Y.Plot
- Latitud del grafico en grados decimales. 
- X.Plot
- Longitud de la grafica en grados decimales. 
- PhoroNo
- número de identificacion de los árboles hospedantes muestreados en cada sitio 
- EpiFam
- Familia taxonomica de epifitas. 
- EpiGen
- Genero taxonomico de epifitas. 
- cf.aff
- Abreviaturas de terminos latinos en el contexto de la taxonomia. cf. "conferir" que significa "comparar con". aff .: "affinis" que significa "similar a". 
- Species
- Nombre de la especie epifita (morfo) 
- Author
- Autor del nombre científico. 
- EpiAzi
- Azimut del individuo epifito en cada árbol huesped. 
- BraAzi
- Azimut de la rama en la que se encontro el individuo epifito. 
- EpiDisTru
- Distancia en metros desde el tronco hasta el sitio de union de la epifita en una rama. 
- EpiSize
- Tamaño estimado del individuo epifito en centimetros. 
- EpiAttHei
- Altura del accesorio de la epifita en metros. 
- Date0
- Fecha del primer censo. 
- Date1
- Fecha del censo final. 
- Location
- Seccion (raices, troncos, ramas) del árbol anfitrion en el que se encontro el individuo epifito. 
- Mortality
- Variable dicotomica. 0 si el individuo epifito estaba muerto en el censo final y 1 si no. 
- MorCat
- Causa de mortalidad mecanica o no mecánica. 
- Elevation
- Elevacion (msnm) de la parcela. 
- AP_bio12
- Precipitación anual en la parcela, en mm. 
- PDM_bio14
- Precipitación del mes más seco en la parcela, en mm. 
- PS_bio15
- Estacionalidad de la precipitacion en la parcela (coeficiente de variacion) 
- MDT_bio2
- Rango diurno medio (Media mensual (temperatura maxima - temperatura minima)) en la grafica (10°C) 
- TS_bio4
- Estacionalidad de la temperatura en la grafica (desviacion estandar * 100) 
- ATR_bio7
- Rango de temperatura anual en la parcela (10 grados centigrados) 
- AET
- Evapotranspiración anual en la parcela, en mm. 
- BasAre
- Area basal de árboles con DAP mayor o igual a 5 cm en la parcela, en m - ^{2}/ha.
- BasAre5_10
- Area basal de árboles con DAP mayor o igual a 5 y menor a 10 cm en la parcela (m - ^{2}/ha)
- BasAre10
- Area basal de árboles con DAP mayor o igual a 10 cm en la parcela (m - ^{2}/ha)
- Ind10
- Número de árboles del dosel (con un DAP superior o igual a 10 cm) en la parcela 
- Ind5
- Número de árboles de sotobosque (con DAP mayor o igual a 5 y menor a 10 cm) en la parcela 
- Ind5_10
- Número de árboles con un DAP mayor o igual a 5 y menos de 10 cm en la parcela 
- Ind10_15
- Número de árboles con un DAP mayor o igual a 10 y menos de 15 cm en la parcela 
- Ind15_20
- Número de árboles con un DAP mayor o igual a 15 y menos de 20 cm en la parcela 
- Ind20_25
- Número de árboles con un DAP mayor o igual a 20 y menos de 25 cm en la parcela 
- Ind25_30
- Número de árboles con un DAP mayor o igual a 25 y menos de 30 cm en la parcela 
- Ind30
- Número de árboles con DAP mayor o igual a 30 cm en la parcela 
- TreeHei
- Altura total del árbol en metros 
- MedHei
- Altura media de los árboles en cada parcela 
- MaxHei
- Altura maxima de los árboles en cada parcela 
- BranchNumb
- Número de ramas del árbol anfitrion 
- Obs
- Observaciones y notas en español 
Source
Los datos fueron obtenidos desde el repositorio DRYAD doi:10.5061/dryad.g5510.
References
Zuleta D, Benavides AM, Lopez-Rios V, Duque A. 2016. Local and regional determinants of vascular epiphyte mortality in the Andean mountains of Colombia. Journal of Ecology 104(3): 841-843. doi:10.1111/1365-2745.12563
Examples
data(deadlianas2)
head(deadlianas2)
Function to computes the diameter of the tree of average basal area.
Description
Function to compute the diameter of the tree of average basal
area (D_{\overline{g}}),
which depends on stand density (N) and stand basal area (G).
The aforementioned stand diameter is computed as
D_{\overline{g}} = \sqrt{ \frac{G}{N} \frac{k}{pi}}
where the constant k depends on whether the variables are in the
units of measurement of the metric or imperial system.
Usage
dg(N = N, G = G, metrics = TRUE)
Arguments
| N | is stand tree density. By default the unit of measurement
is trees/ha, but if the option 'metrics' is set to  | 
| G | is stand basal area. By default the unit of measurement
must be entered in m | 
| metrics | is a logic value, the default is to  | 
Value
Returns the diameter of the tree of average basal area.
Author(s)
Christian Salas-Eljatib.
Examples
##Using the function
dg(N=1000, G=55)
dg(N=210, G=160, metrics=FALSE)
Function to compute a dominant stand-level variable based on a sample plot data.
Description
Computes the so-called dominant stand-level variable, corresponding to the average of a tree-level variable for the 100 largest sorting-tree-level diameter trees in 1-ha.
Usage
domvar(
  data = data,
  var.int = var.int,
  var.sort = var.sort,
  plot.area = plot.area
)
Arguments
| data | data frame having the tree list of a sample plot. | 
| var.int | The column name of the data having the tree-level variable of interest (e.g., height). Can be entered as the actual name, without the need of using quotation marks. | 
| var.sort | The column name of the data having the tree-level variable to be used as reference (e.g., diameter) for defining the sorting variable of interest. | 
| plot.area | A numeric value of the plot area in m | 
Details
The original function was written by Dr Oscar García for computing top height, and the corresponding reference is provided. Nevertheless, several changes were applied, thus the current function provide a broader application. Regardless, the function aims to calculate a "dominant" stand-level variable by taking into account the plot area. Thus, requires having a dataframe having both the variable of interest (e.g., height) and the sorting variable used for the computation (e.g., diameter) for all trees in a sample plot, as well as, the plot area.
Value
The main output is the calculated dominant stand-variable for the given sample plot. The unit of the computed variable is the same as the one used as variable of interest.
Author(s)
Christian Salas-Eljatib.
References
- García O, Batho A. 2005. Top height estimation in lodgepole pine sample plots. Western Journal of Applied forestry 20(1):64-68. 
Examples
##Creates a fake dataframe
set.seed(45)
x <- round(rnorm(20,mean=45,sd=10),1); y=round(1.3+35*(1-exp(-.07*x)),1)
df<-data.frame(dap=x,atot=y)
head(df)
datana::descstat(df)
##Using the domvar function
domvar(data=df,var.int=atot,var.sort=dap,plot.area=500)
Function to compute basal area of a tree
Description
The function computes the basal area of a tree (g),
which only depends on its diameter at breast-height (d).
The basal area of a tree is computed as
g = \left(\frac{\pi}{k}\right) d^{2}
where the constant k depends on whether the diameter
and the resulting basal area are in the units of
the metric or imperial system.
Usage
gtree(x, metrics = TRUE)
Arguments
| x | is the object (i.e., vector or scalar) having tree diameter. By default the function assumes that the unit of measurement of this variable is cm. | 
| metrics | is a logic value, the default is to  | 
Value
The value of basal area in m^{2} or in ft^{2},
depending on the units of measurement being defined.
Author(s)
Christian Salas-Eljatib
Examples
#Using the function
 gtree(40)
 gtree(x=30)
gtree(x=11.81,metrics=FALSE)
Diameter growth increments of a tropical tree species in Hawaii
Description
Tree size, competition, and diameter growth increment of
Metrosideros polymorpha trees collected in the Kilauea Volcano, Hawaii.
Data containing 64 observations at the current annual growth
rate (defined as dbh increment within one calendar year) of each tree.
Measurements were made from 1986 to 1988.
Usage
data(hawaii)
Format
The dataframe has the following columns:
- tree.code
- Tree number identification. The first letter of the ID represents a cohort. Six cohorts representing a chronosequence were sampled. 
- dbh
- Diameter at breast height, in cm. 
- toth
- Total height, in m. 
- crown.area
- Crown outline area, in square meters. 
- comp.ind
- Competition index (Basal area of nearest neighbor divided by square of distance to nearest neighbor plus basal area of second nearest neighbor divided by square of distance to second nearest neighbor). 
- cai.1986
- Current annual stem diameter increment during 1986, in mm. 
- cai.1987
- Current annual stem diameter increment during 1987, in mm. 
- cai.1988
- Current annual stem diameter increment during 1988, in mm. 
Source
The data were obtained from Gerrish and Mueller-Dombois (1999).
References
- Gerrish G, Mueller-Dombois D. 1999. Measuring stem growth rates for determining age and cohort analysis of a tropical evergreen tree. Pacific Science. 53(4): 418-429. 
Examples
data(hawaii)
head(hawaii)
Incremento corriente anual en diámetro de una especie tropical en Hawaii
Description
Tamaño del árbol, competencia, e incremento corriente anual de árboles de
Metrosideros polymorpha colectado en el volcán Kilauea, Hawaii.
Los datos contienen 64 observaciones de incremento corriente anual
(definido como el incremento en dap en un año calendario) de cada
árbol. Estos incrementos fueron medidos desde el año 1986 a 1988.
Usage
data(hawaii)
Format
Estos datos contienen las siguientes columnas:
- arb.id
- Código identificador del árbol. La primera letra del ID representa una cohorte. Hay seis cohortes que representan una cronosecuencia. 
- dap
- Diámetro a la altura del pecho, en cm. 
- atot
- Altura total, en m. 
- area.copa
- Área de copa, en metros cuadrados. 
- ind.comp
- Índice de competencia (Área basal del vecino más cercano dividido por la distancia al vecino más cercano al cuadrado más el área basal del segundo vecino más cercano dividio por la distancia al segundo vecino más cercano al cuadrado) 
- ica.1986
- Incremento corriente anual durante el año 1986, en mm. 
- ica.1987
- Incremento corriente anual durante el año 1987, en mm. 
- ica.1988
- Incremento corriente anual durante el año 1988, en mm. 
Source
Los datos fueron obtenidos desde Gerrish and Mueller-Dombois (1999).
References
- Gerrish G, Mueller-Dombois D. 1999. Measuring stem growth rates for determining age and cohort analysis of a tropical evergreen tree. Pacific Science. 53(4): 418-429. 
Examples
data(hawaii2)
head(hawaii2)
A simple linear interpolation function applicable to two vectors
(X and Y), when the first element of Y is missing.
Description
A simple linear interpolation function applicable to two vectors
(e.g., X and Y) of length three, suitable when the first
element of Y is missing.
Usage
interpy1(xs = xs, ys = ys)
Arguments
| xs | A numeric vector of length 3 | 
| ys | A numeric vector of length 3, with the first position empty. | 
Value
The interpolated value for the first element of vector Y.
Author(s)
Christian Salas-Eljatib.
Examples
x<-c(0.2,0.8,1.3)
y<-c(NA,41,38)
interpy1(xs=x,ys=y)
A simple linear interpolation function applicable to two vectors
(X and Y), when the second element of Y is missing.
Description
A simple linear interpolation function applicable to two vectors
(e.g., X and Y) of length three, suitable when the second
element of Y is missing.
Usage
interpy2(xs = xs, ys = ys)
Arguments
| xs | A numeric vector of length 3. | 
| ys | A numeric vector of length 3, with the second position empty. | 
Value
The interpolated value for the second element of vector Y.
Author(s)
Christian Salas-Eljatib.
Examples
x<-c(0.2,0.8,1.3)
y<-c(48,NA,41)
interpy2(xs=x,ys=y)
Function to computes the stem diameter of a tree according to the Kozak (1988) taper equation.
Description
Function of the Kozak (1988) taper equation model, based upon the model parameters, and the tree variables: diameter, total height, and stem height. The mathematical expression is as follows
   d_{l_{i}} =
    \alpha_0d_i^{\alpha_1}\alpha_2^{d_i}X_{l_{i}}^{
\left[\beta_1z_{l_{i}}^{2}+\beta_2\ln{(z_{l_{i}} + 0,001)}
+ \beta_3\sqrt{z_{l_{i}}}+
\beta_4 e^{z_{l_{i}}}+\beta_5(d_i/h_i)\right] 
},
where: d_{l_{i}} is the stem diameter at stem-height
h_{l_{i}} for the i-th tree; and
d_i and h_i are the tree-level variables
diameter at breast height and total height, respectively, for
tje i-th tree.  The other terms are
z_{l_{i}}=\frac{h_{l_{i}}}{h_i},
X_{l_{i}}=\frac{ 1-\sqrt{ z_{l_{i}}} }{ 1-\sqrt{p} },
with p being the inflextion point.
Usage
kozak(d = d, h = h, hl = hl, paramod = paramod, p = 0.2, c0 = 0.001)
Arguments
| d | is the diameter at breast height (1.3 m) of the tree. The measurement unit is cm in the metric system, but ultimately it will depend on how the model was previously fitted, because of the measurement unit of the variables included. | 
| h | is total height of the tree. | 
| hl | is stem height within the tree,
thus  | 
| paramod | is a vector having the eight coefficients
of the taper model in the following order:
 | 
| p | is the inflextion height. By default is set to 0.2 | 
| c0 | is a constant build-in the model. By default is set to 0.001. | 
Value
Returns the diameter of the stem at the
stem-height h_l, thus d_l, for the Kozak (1988)
functional form, based upon tree diameter  d and
total height  h.
Author(s)
Christian Salas-Eljatib.
References
Kozak A. 1988. A variable-exponent taper equation. Canadian Journal of Forest Research 18: 1363-1368. doi:10.1139/x88-213
Examples
# Parameters
a0<- 1.02453; a1<- 0.88809; a2<- 1.00035
b1<- 0.95086; b2<- -0.18090; b3<- 0.61407;
b4<- -0.35105; b5 <- 0.05686;
coefs<-c(a0,a1,a2,b1,b2,b3,b4,b5);p.coef <- 0.25
# Tree attributes
dbh <- 45; toth <- 27
# Using the function
hl.int <- c(0.3, 1.3, 5)
dl.hat <- kozak(d=dbh,h=toth,hl=hl.int,paramod=coefs,p=p.coef)
cbind(hl.int,dl.hat)
Function to computes the stem diameter of a tree according to the Kozak (2004) taper equation.
Description
Function of the Kozak (2004) taper equation model, based upon the model parameters, and the tree variables: diameter, total height, and stem height. The mathematical expression is as follows (escribir la correcta)
   d_{l_{i}} =
    \alpha_0d_i^{\alpha_1}\alpha_2^{d_i}X_{l_{i}}^{
\left[\beta_1z_{l_{i}}^{2}+\beta_2\ln{(z_{l_{i}} + 0,001)}
+ \beta_3\sqrt{z_{l_{i}}}+
\beta_4 e^{z_{l_{i}}}+\beta_5(d_i/h_i)\right] 
},
where: d_{l_{i}} is the stem diameter at stem-height
h_{l_{i}} for the i-th tree; and
d_i and h_i are the tree-level variables
diameter at breast height and total height, respectively, for
tje i-th tree.  The other terms are
z_{l_{i}}=\frac{h_{l_{i}}}{h_i},
X_{l_{i}}=\frac{ 1-\sqrt{ z_{l_{i}}} }{ 1-\sqrt{p} },
with p being the inflextion point.
Usage
kozaklast(d = d, h = h, hl = hl, paramod = paramod)
Arguments
| d | is the diameter at breast height (1.3 m) of the tree. The measurement unit is cm in the metric system, but ultimately it will depend on how the model was previously fitted, because of the measurement unit of the variables included. | 
| h | is total height of the tree. | 
| hl | is stem height within the tree,
thus  | 
| paramod | is a vector having the nine coefficients
of the taper model in the following order:
 | 
Value
Returns the diameter of the stem at the
stem-height h_l, thus d_l, for the Kozak (1988)
functional form, based upon tree diameter  d and
total height  h.
Author(s)
Christian Salas-Eljatib.
References
Kozak A. 2004. My last words on taper equations. The Forestry Chronicle 80: 507–515. doi:10.1139/x88-213
Examples
# Parameters
a0<- 0.80; a1<- 0.88809; a2<- 0.2
b1<- 0.95086; b2<- -0.18090; b3<- 0.61407;
b4<- -0.35105; b5 <- 0.05686; b6 <- 0.001;
coefs<-c(a0,a1,a2,b1,b2,b3,b4,b5,b6);
# Tree attributes
dbh <- 45; toth <- 27
# Using the function
hl.int <- c(0.3, 1.3, 5)
dl.hat <- kozaklast(d=dbh,h=toth,hl=hl.int,paramod=coefs)
cbind(hl.int,dl.hat)
 
Function to computes the stem diameter of a tree according to the log-transformed Kozak (1988) taper equation.
Description
Function of the natural log-transformed Kozak (1988) taper equation model, based upon the model parameters, and the tree variables: diameter, total height, and stem height. The mathematical expression is as follows
 \ln{d_{l_{i}}}=\alpha_0 + \alpha_1 \ln{d_i}+\alpha_2 {d_i}+
\beta_1  \ln{(X_{l_{i}})} z_{l_{i}}^{2} +
\beta_2  \ln{(X_{l_{i}})}  \ln{(z_{l_{i}}+0.001)} +
\beta_3  \ln{(X_{l_{i}})} \sqrt{z_{l_{i}}}  +\\
\beta_4 \ln{(X_{l_{i}})}  e^{z_{l_{i}}} +
\beta_5  \ln{(X_{l_{i}})} \frac{d_i}{h_i},
where: d_{l_{i}} is the stem diameter at stem-height
h_{l_{i}} for the i-th tree; and
d_i and h_i are the tree-level variables
diameter at breast height and total height, respectively, for
tje i-th tree.  The other terms are
z_{l_{i}}=\frac{h_{l_{i}}}{h_i},
X_{l_{i}}=\frac{ 1-\sqrt{ z_{l_{i}}} }{ 1-\sqrt{p} },
with p being the inflextion point.
Usage
kozakln(d = d, h = h, hl = hl, paramod = paramod, p = 0.2, c0 = 0.001)
Arguments
| d | is the diameter at breast height (1.3 m) of the tree. The measurement unit is cm in the metric system, but ultimately it will depend on how the model was previously fitted, because of the measurement unit of the variables included. | 
| h | is total height of the tree. | 
| hl | is stem height within the tree,
thus  | 
| paramod | is a vector having the eight coefficients
of the taper model in the following order:
 | 
| p | is the inflextion height. By default is set to 0.2 | 
| c0 | is a constant build-in the model. By default is set to 0.001. | 
Value
Returns the diameter of the stem at the
stem-height h_l, thus d_l, for the natural
log-transformed Kozak (1988) functional form, based upon tree
diameter  d and total height  h. Therefore, the
result applies the back-transformation by using the anti-log
function, i.e., exp().
Author(s)
Christian Salas-Eljatib.
References
Kozak A. 1988. A variable-exponent taper equation. Canadian Journal of Forest Research 18: 1363-1368. doi:10.1139/x88-213
Examples
# Parameters
a0<- 0.04338410; a1<- 0.88657485; a2<- 0.00446052;b1<- 1.978196;
b2<- -0.40676847; b3<- 3.50815520; b4<- -1.84177070;b5<- 0.19647175
coefs<-c(a0,a1,a2,b1,b2,b3,b4,b5);p.coef <- 0.25
# Tree attributes
dbh <- 40; toth <- 25
# Using the function
hl.int <- c(0.3, 1.3, 5)
dl.hat <- kozakln(d=dbh,h=toth,hl=hl.int,paramod=coefs,p=p.coef)
cbind(hl.int,dl.hat)
Tree spatial coordinates in a large sample plot in Fennoscandia
Description
Data from a large (8.8 ha) fully mapped plot in a Norway spruce (Picea abies) dominated old-growth forest in the subarctic region of Fennoscandia.
Usage
data(largeplot)
Format
Contains Cartesian position of trees and other variables in a large sample plot, as follows:
- tree
- Tree ID. 
- spp.code
- Species code as follows: 1=Pinus sylvestris,2=Picea abies,3=Betula pubescens, 5=Salix caprea, 8: Sorbus aucuparia. 
- x.coord
- Cartesian position in the X-axis, in m. 
- y.coord
- Cartesian position in the Y-axis, in m. 
- status
- Measurement year. 
- dbh
- Diameter at breast-height, in cm. 
- toth
- Total height, in m. 
Source
Data were retrieved from the paper cited below, where several details might be worth reading.
References
- Pouta P, Kulha N, Kuuluvainen T, Aakala T. 2022. Partitioning of space among trees in an old-growth spruce forest in subarctic Fennoscandia. Frontiers in Forests and Global Change 5: 817248. doi:10.3389/ffgc.2022.817248 
Examples
data(largeplot)
head(largeplot)
df<-largeplot
pine <- df[df$spp.code==1,]
spruce <- df[df$spp.code==2,]
birch <- df[df$spp.code==3,]
plot(spruce$x.coord,spruce$y.coord,cex=(spruce$dbh)/30,col="blue")
points(birch$x.coord,birch$y.coord,cex=(birch$dbh)/30,col="green")
points(pine$x.coord,pine$y.coord,cex=(pine$dbh)/30,col="red")
Climatic, forest structure and forest mortality variables in California (USA)
Description
The data file contains one row per unique 3.5km grid cell by year
combination. The data frame covers
all grid cells within the state of California where at least one Aerial
Detection Survey (ADS) flight
was taken between 2009 and 2015, so each grid cell position has between
1 and 7 years of data
(reflected as 1 to 7 rows in the data file per grid cell position).
The main response variables
are mort.bin (presence of any mortality) and mort.tph (number of dead
trees/ha within the given
grid cell by year).
Usage
data(mortaforest)
Format
The data frame contains four variables as follows:
- live.bah
- Live basal area from the GNN dataset 
- live.tph
- Live trees per hectare from the GNN dataset 
- pos.x
- rank-order x-position of the grid cell (position - 1is western-most)
- pos.y
- rank-order y-position of the grid cell (position - 1is northern-most)
- alb.x
- x-coordinate of the grid cell centroid in California Albers (EPSG 3310) 
- alb.y
- y-coordinate of the grid cell centroid in California Albers (EPSG 3310) 
- mort.bin
- 1= dead trees observed in grid cell.- 0= no dead trees observed
- mort.tph
- Dead trees per hectare from the aggregated ADS dataset 
- mort.tpa
- Dead trees per acre from the aggregated ADS dataset 
- year
- Year of the ADS flight. Most flights occurred from May-August. 
- Defnorm
- Mean annual climatic water deficit for the grid cell, for Oct 1-Sept 31 water year, averaged from 1981-2015 
- Def0
- Climatic water deficit for the grid cell during the Oct-Sept water year overlapping the summer ADS flight of the given year 
- Defz0
- Z-score for climatic water deficit for the given grid cell/water year. Calculated as ( - Def0–- Defnorm)/(standard deviation in deficit among all years 1981-2015 for the given grid cell)
- Defz1
- Z-score for climatic water deficit for the given grid cell in the preceeding water year. 
- Defz2
- Z-score for climatic water deficit for the given grid cell two water years prior. 
- Tz0
- Z-score for temperature for the given grid cell/year. 
- Pz0
- Z-score for precipitation for the given grid cell/year. 
- Defquant
- FDCI variable. Quantile of - Defnormof the given grid cell, relative to the- Defnormof all other grid cells with a basal area within 2.5 m- ^{2}/ha of the given cell is basal area.
Source
The data were obtained from the DRYAD repository doi:10.5061/dryad.7vt36
References
- Young DJN, Stevens JS, Earles JM, Moore J, Ellis A, Jirka AM, Latimer ML. 2017. Long-term climate and competition explain forest mortality patterns under extreme drought. Ecology Letters 20(1):78-86. doi:10.1111/ele.12711 
- Salas-Eljatib C, Fuentes-Ramírez A, Gregoire TG, Altamirano A, Yaitul V. A study on the effects of unbalanced data when fitting logistic regression models in ecology. Ecological Indicators 85:502-508. doi:10.1016/j.ecolind.2017.10.030 
Examples
data(mortaforest)
head(mortaforest)
Mortalidad en bosques, y variables climáticas y de estructura forestal en California (USA)
Description
El archivo de datos contiene una fila por combinación única de celda
de cuadrícula de 3,5 km por año.
El marco de datos cubre todas las celdas de la cuadrícula dentro del
estado de California donde se
tomo al menos un vuelo de la Encuesta de deteccion aérea (ADS) entre
2009 y 2015, por lo que cada posición
de celda de la cuadrícula tiene entre 1 y 7 años de datos (reflejados
como 1 a 7 filas en el archivo de datos
por posición de celda de cuadrícula). Las principales variables de
respuesta son mort.bin (presencia de alguna mortalidad)
y mort.tph (número de árboles muertos /ha dentro de la celda de la
cuadrícula por año).
Usage
data(mortaforest2)
Format
Las variables se describen a continuación::
- live.bah
- Área basal viva del conjunto de datos GNN 
- live.tph
- Árboles vivos por hectárea del conjunto de datos GNN 
- pos.x
- Posición - Xdel orden de clasificación de la celda de la cuadrícula (la posición- 1es la más occidental)
- pos.y
- Posición - Ydel orden de clasificación de la celda de la cuadrícula (la posición- 1es la más al norte)
- alb.x
- Coordenada - Xdel centroide de la celda de la cuadrícula en California Albers (EPSG 3310)
- alb.y
- Coordenada - Ydel centroide de la celda de la cuadrícula en California Albers (EPSG 3310)
- mort.bin
- Codificación para identificar mortalidad. - 1= árboles muertos observados en la celda de la cuadrícula.- 0= no se observaron árboles muertos
- mort.tph
- Árboles muertos por hectárea del conjunto de datos ADS agregado 
- mort.tpa
- Árboles muertos por acre del conjunto de datos ADS agregado 
- year
- año del vuelo de ADS. La mayoría de los vuelos se realizaron entre mayo y agosto 
- Defnorm
- Déficit hídrico climático anual medio para la celda de la cuadrícula, para el año hídrico del 1 de octubre al 31 de septiembre, promediado de 1981 a 2015 
- Def0
- Déficit de agua climática para la celda de la cuadrícula durante el año hidrológico de octubre a septiembre que se superpone al vuelo ADS de verano del año dado 
- Defz0
- Puntaje Z para el déficit hídrico climático para la celda de cuadrícula / año hídrico dado. Calculado como ( - Def0–- Defnorm) / (desviación estándar en el déficit entre todos los años 1981-2015 para la celda de la cuadrícula dada)
- Defz1
- Puntuación Z para el déficit hídrico climático para la celda de la cuadrícula dada en el año hidrológico anterior. 
- Defz2
- Puntuación Z para el déficit hídrico climático para la celda de la cuadrícula dada dos años antes. 
- Tz0
- Puntaje Z para la temperatura para la celda de cuadrícula / año dado. 
- Pz0
- Puntaje Z para la precipitación para la celda / año de la cuadrícula dado. 
- Defquant
- Variable FDCI. Cuantil de - Defnormde la celda de la cuadrícula dada, en relación con la- Defnormde todas las demás celdas de la cuadrícula con un área basal dentro de 2.5 m- ^{2}/ha de la celda dada
Source
Los datos fueron obtenidos desde el repositorio DRYAD en doi:10.5061/dryad.7vt36
References
- Young DJN, Stevens JS, Earles JM, Moore J, Ellis A, Jirka AM, LatimerML. 2017. Long-term climate and competition explain forest mortality patterns under extreme drought. Ecology Letters 20(1):78-86. doi:10.1111/ele.12711 
- Salas-Eljatib C, Fuentes-Ramírez A, Gregoire TG, Altamirano A, and Yaitul V. 2018. A study on the effects of unbalanced data when fitting logistic regression models in ecology. Ecological Indicators 85:502-508. doi:10.1016/j.ecolind.2017.10.030 
Examples
data(mortaforest2)
head(mortaforest2)
Extract the n-th element from a list
Description
Extract the n-th element from a list
Usage
nele.list(lst, n)
Arguments
| lst | is the list object | 
| n | is the position of the element in the list to be retrieved | 
Value
object with elements of each list
Author(s)
Christian Salas-Eljatib
Examples
x <- list(list("z","x","y"), list(3,4,99,23,45), list(1,67,5,6,89))
nele.list(x,1)
nele.list(x,2)
nele.list(x,3)
Tree volume for Pinus pinaster in the Baixo-Mino, Galicia, Spain
Description
These are volume measurements data of sample trees in the Baixo-Mino region in Galicia, Spain.
Usage
data(pinaster)
Format
Contains tree-level variables, as follows:
- stand
- Stand number from the sample tree was selected. 
- si
- Site index of the stand. 
- tree.no
- Tree number. 
- dbh
- Diameter at breast height, in cm. 
- toth
- Total height, in m. 
- d4
- Upper-stem diameter at 4 m, in cm. 
- volwb
- Tree gross volume, in m - ^{3}with bark.
- volwob
- Tree gross volume, in m - ^{3}without bark.
Source
The data are provided courtesy of Dr. Christian Salas-Eljatib at the Universidad de Chile (Santiago, Chile).
References
- Salas C, Nieto L, Irisarri A. 2005. Modelos de volumen para Pinus pinaster Ait. en la comarca del Baixo Mino, Galicia, España. Quebracho 12: 11-22. https://eljatib.com/publication/2005-12-01_modelos_de_volumen_p/ 
Examples
data(pinaster)
head(pinaster)
Volumen individual de árboles de Pinus pinaster en Galicia, España
Description
Variables de volumen y otras a nivel de árbol para una muestra de árboles de Pinus pinaster en la comarca del Baixo-Mino en Galicia, España.
Usage
data(pinaster2)
Format
Contiene las siguientes variables a nivel de árbol:
- rodal
- Rodal desde donde el árbol fue muestreado 
- ind.sitio
- Índice de sitio del rodal, en m. 
- arbol
- Número del árbol. 
- dap
- Diámetro a la altura del pecho, en cm. 
- atot
- Altura total, en m. 
- d4
- Diámetro fustal a los 4 m, en cm. 
- vtcc
- Volumen bruto total con corteza, en m - ^{3}.
- vtsc
- Volumen bruto total sin corteza, en m - ^{3}.
Source
Lo datos fueron cedidos cortesía del Dr. Christian Salas-Eljatib de la Universidad de Chile (Santiago, Chile).
References
- Salas C, Nieto L, Irisarri A. 2005. Modelos de volumen para Pinus pinaster Ait. en la comarca del Baixo Miño, Galicia, España. Quebracho 12: 11-22. https://eljatib.com/publication/2005-12-01_modelos_de_volumen_p/ 
Examples
data(pinaster2)
head(pinaster2)
Tree-level variables of several sample plots of invasive Pinus spp in Chile
Description
These are tree-lavel measurement data from Pinus spp invasion in Araucaria-Nothofagus forests in the Malalcahuello National Reserve in La Araucanía region in southhern Chile, measured in 2012. There are 26 plots and plot size is 100 m².
Usage
data(pinusSpp)
Format
Contains eight variables, as follows:
- plot.id
- Plot sample ID. 
- plot.size
- Plot size, en m - ^{2}.
- lat.s
- Decimal coordinate of S latitude. 
- long.w
- Decimal coordinate of W longitude. 
- indv.id
- Tree identificator number in each plot. Same - indv.idfor multi-stem trees.
- stem.id
- Stem identificator number in each plot. 
- spp
- Species. 
- dbh
- Diameter at breast-height, in cm. 
- toth
- Total height, in m. 
- hcb
- Height to crown base, in m. 
- crown.lenght
- Crown lenght, in m. 
Source
The data is provided courtesy of Drs. Aníbal Pauchard and Rafael García at the Laboratorio de Invasiones Biológicas, Universidad de Concepción (Concepción, Chile).
References
- Cobar-Carranza A, Garcia R, Pauchard A, Pena E. 2014. Effect of Pinus contorta invasion on forest fuel properties and its potential implications on the fire regime of Araucaria araucana and Nothofagus antarctica forests. Biological Invasions. 16(11): 2273-2291. doi:10.1007/s10530-014-0663-8 
Examples
data(pinusSpp)
head(pinusSpp)
length(unique(pinusSpp$plot.id))
boxplot(dbh~plot.id, data=pinusSpp)
Variables a nivel de árbol en parcelas de muestreo de Pinus spp en Chile.
Description
Mediciones a nivel de árbol para estudiar la invasión de Pinus spp en
bosques de Araucaria-Nothofagus en
la Reserva Nacional Malalcahuello en la región de la Araucanía en el sur de
Chile.
Hay 26 parcelas, y la superficie de cada una es de 100 m^{2}.
Usage
data(pinusSpp2)
Format
Los datos contienen ocho columnas que se detallan a continuación:
- parcela
- Número de la parcela. 
- sup.parcela
- Superficie de la parcela, en m - ^{2}.
- lat.s
- Coordenada decimal latitud S. 
- long.w
- Coordenada decimal longitud W. 
- indv.id
- Identificador del árbol en la parcela. Mismo - indv.idpara árboles multi-fustales
- fuste.id
- Identificador del fuste. 
- espe
- Especie. 
- dap
- Diámetro a la altura del pecho, en cm. 
- atot
- Altura total, en m. 
- hcc
- Altura comienzo de copa, en m. 
- largo.copa
- Largo de copa, en m. 
Source
Los datos fueron cedidos por los Drs. Aníbal Pauchard y Rafael García del Laboratorio de Invasiones Biológicas, Universidad de Concepción (Concepción, Chile).
References
- Cobar-Carranza A, Garcia R, Pauchard A & Pena E. 2014. Effect of Pinus contorta invasion on forest fuel properties and its potential implications on the fire regime of Araucaria araucana and Nothofagus antarctica forests. Biological Invasions. 16(11):2273-2291. doi:10.1007/s10530-014-0663-8 
Examples
data(pinusSpp2)
head(pinusSpp2)
length(unique(pinusSpp2$parce))
boxplot(dap~parce, data=pinusSpp2)
Maximum plant size in the Hawaiian archipelago
Description
Maximum plant size of 58 tree species, shrub and tree fern species that occur in 530 forest plots across the Hawaiian archipelago.
Usage
data(plantshawaii)
Format
Contains six columns, as follows:
- species
- Genus and epithet of the species. 
- family
- Family of each species. 
- native.status
- Categorical variable ( - native,- alien,- uncertain) indicating alien status of each individual following Wagner et al. (2005).
- n
- Number of individuals used to estimate maximum plant size. 
- d95
- Maximum plant size, estimated as - D950.1(King et al. 2006).
- dmax3
- Maximum plant size, estimated as - Dmax3(King et al. 2006).
Source
The data were obtained from the DRYAD repository at doi:10.5061/dryad.1kk02qr.
References
- Craven D, Knight T, Barton K, Bialic-Murphy L, Cordell S, Giardina C, Gillespie T, Ostertag R, Sack L,Chase J. 2018. OpenNahele: the open Hawaiian forest plot database. Biodiversity Data Journal 6: e28406. 
Examples
data(plantshawaii)
head(plantshawaii)
tapply(plantshawaii$d95,plantshawaii$native.status,summary)
Population of stand-volume for 400 elements.
Description
The data corresponds to a list of 400 elements of a population of
the variable forest volume (in m^{3}/ha) measured in field plots
of 0.1 ha of area. Therefore, the data emerge from a grid of 20 rows by
20 columns, completely covering a forest of 40 ha.
Usage
data(popvol)
Format
Contains two variables, as follows:
- plot.id
- Plot number, or ID. 
- vol
- Stand volume, in m - ^{3}/ha
Source
The values were digitized from Table No. 11 of Zohrer (1980), which is actually based upon Loetsch and Haller (1964).
References
- Zohrer F. 1980. Forstinventur. Ein Leitfaden fur Studium und Praxis. Pareys Studientexte Nr. 26. Parey. Berlin, Germany. 207 
- Loetsch F, Haller KE. 1964. Forest inventory. Volume 1. Bayerischer Landwirtschaftsverlag Gmbh. Munchen, Germany. 436 p. 
Examples
data(popvol)
sum(popvol$vol)
mean(popvol$vol)
hist(popvol$vol)
Población de 400 elementos de la variable volumen de bosque
Description
Los datos corresponden a una lista de 400 elementos de un población de la
variable volumen de bosque (en m^{3}/ha), medida en parcelas
de 0.1 ha de superficie. Por lo tanto, los datos provienen de
una grilla de 20 filas por 20 columnas, que cubren por completo un
bosque de 40 ha de superficie.
Usage
data(popvol2)
Format
Contiene las siguientes dos columnas:
- plot.id
- Número de parcela (i.e., elemento de la población). 
- vol
- Volumen en m - ^{3}/ha
Source
Datos digitados desde el cuadro No. 11 de Zohrer (1980), el cual es en realidad un cuadro citado del libro de Loetsch y Haller (1964).
References
- Zohrer F. 1980. Forstinventur. Ein Leitfaden fur Studium und Praxis. Pareys Studientexte Nr. 26. Parey. Berlin, Germany. 207 
- Loetsch F, Haller KE. 1964. Forest inventory. Volume 1. Bayerischer Landwirtschaftsverlag Gmbh. Munchen, Germany. 436 p. 
Examples
data(popvol2)
sum(popvol2$vol)
mean(popvol2$vol)
hist(popvol2$vol)
Function to computes the power model, as a classical allometric functional form.
Description
Function of the power model, based upon the model parameters, and a single predictor variable as follows
 y_i = \alpha x_i^{\beta} 
where: y_i and x_i are the response
and predictor variable, respectively for the i-th observation;
and the rest are parameters (i.e., coefficients).
Usage
powerfx(x = x, paramod = paramod, phi = 0)
Arguments
| x | is the predictor variable. | 
| paramod | is a vector having the  coefficients
of the model in the following order:
 | 
| phi | is an optional constant term that force the prediction
of y when x=0. Thus, the model becomes
 | 
Value
Returns the response variable based upon the predictor variable and the coefficients.
Author(s)
Christian Salas-Eljatib.
References
Salas-Eljatib C. 2025. Funciones matematicas y sus reparametrizaciones para la alometria de arboles. Documento de trabajo No. 1, Serie: Cuadernos de biometria, Laboratorio de Biometria y Modelacion Forestal, Universidad de Chile. Santiago, Chile. 52 p.
Examples
# Parameters
alpha<- 2.86; beta<- 0.49;
coefs<-c(alpha,beta);
# Predictor variable to be used is 30 
# Using the function
powerfx(x=30,paramod=coefs)
 
Tree locations within sample plots in an experimental forest in Austria
Description
The Austrian Research Center for Forests established a spacing experiment
with Norway spruce (Picea abies) in the Vienna Woods. In the “Hauersteig”
experiment, several tree-level variables were measured within four sample
plots over time. The current dataframe has only the measurements
carried out in 1944, for all years see biometrics::spatimepsp.
Usage
data(spataustria)
Format
Contains cartesian position of trees, and covariates, in sample plots, as follows:
- plot
- Plot number. 
- tree
- Tree number. 
- species
- Species code as follows: PCAB=Picea abies, LADC=Larix decidua, PNSY=Pinus sylvestris, FASY=Fagus Sylvatica, QCPE=Quercus petraea, BTPE=Betula pendula. 
- x.coord
- Cartesian position in the X-axis, in m. 
- y.coord
- Cartesian position in the Y-axis, in m. 
- year
- Measurement year. 
- dbh
- Diameter at breast-height, in cm. 
Source
Data were retrieved from the paper cited below, where several details
might be worth reading. For instance, plot size slightly varies among plots:
Plot No. 1=2509.7 m^{2}, Plot No. 2=2474.8 m^{2},
Plot No. 3=2415.9 m^{2}, and Plot No. 4=2482.8 m^{2}.
References
- Kindermann G. Kristofel F, Neumann M, Rossler G, Ledermann T & Schueler. 2018. 109 years of forest growth measurements from individual Norway spruce trees. Sci. Data 5:180077 doi:10.1038/sdata.2018.77 
Examples
data(spataustria)
head(spataustria)
df<-spataustria
oldpar<-par(mar=c(4,4,0,0))
bord<-data.frame(
 x=c(min(df$x.coord),max(df$x.coord),min(df$x.coord),max(df$x.coord)),
 y=c(min(df$y.coord),min(df$y.coord),max(df$y.coord),min(df$y.coord))
 )
plot(bord,type="n", xlab="x (m)", ylab="y (m)", asp=1, bty='n')
points(df$x.coord,df$y.coord,col=df$plot,cex=0.5)
par(oldpar)
Temporal tree locations within a sample plot in the Vienna woods
Description
The Austrian Research Center for Forests established a spacing experiment with Norway spruce (Picea abies) in the Vienna Woods. In the “Hauersteig” experiment, several tree-level variables were measured within four sample plots over time.
Usage
data(spatimepsp)
Format
Contains cartesian position of trees, and covariates, in a sample plot, as follows:
- plot
- Plot number. 
- tree
- Tree number. 
- species
- Species code as follows: PCAB=Picea abies, LADC=Larix decidua, PNSY=Pinus sylvestris, FASY=Fagus Sylvatica, QCPE=Quercus petraea, BTPE=Betula pendula. 
- x.coord
- Cartesian position in the X-axis, in m. 
- y.coord
- Cartesian position in the Y-axis, in m. 
- year
- Measurement year. 
- dbh
- diameter at breast-height, in cm. 
Source
Data were retrieved from the paper cited below, where several details might be worth reading.
References
- Kindermann G. Kristofel F, Neumann M, Rossler G, Ledermann T & Schueler. 2018. 109 years of forest growth measurements from individual Norway spruce trees. Sci. Data 5:180077 doi:10.1038/sdata.2018.77 
Examples
data(spatimepsp)
head(spatimepsp)
df<-spatimepsp
lattice::xyplot(y.coord~x.coord|as.factor(year),
data=df,as.table=TRUE)
Stand tables for Nothofagus alpina (rauli) forests
Description
Stand tables for secondary Nothofagus alpina-dominated forests in different locations in southern Chile.
Usage
data(standtabRauli)
Format
The data has the following columns
- site
- Study site. 
- sector
- Location within a study site. 
- low.cd
- Lower limit of the diameter class, in cm. 
- upp.cd
- Upper limit of the diameter class, in cm. 
- dclass
- Diameter class, in cm. 
- nha.dcl
- Tree density for the respective diameter class, in trees/ha. 
- forest.id
- Forest ID code, a combination of columns 'site' and 'sector'. 
Source
Tree density by diameter classes (i.e., stand table). Data were digitized from table No. 4 of Wadsworth (1976).
References
- Wadsworth RK. 1976. Aspectos ecologicos y crecimiento del rauli (Nothofagus alpina) y sus asociados en bosques de segundo crecimiento de las provincias de Bio-Bio, Malleco y Cautin, Chile. Boletin Tecnico No. 37, Fac. Cs. Forestales, Universidad de Chile, Santiago, Chile. 
Examples
data(standtabRauli)
head(standtabRauli)
df<-standtabRauli
table(df$site,df$sector,df$dclass)
Tablas de rodal para bosques de Nothofagus alpina (rauli)
Description
Tablas de rodal para bosques secundarios dominados por Nothofagus alpina en diferentes localidades del sur de Chile.
Usage
data(standtabRauli2)
Format
Los datos tienen las siguientes columnas
- sitio
- Nombre del sitio de estudio. 
- sector
- Code of a specific location within the study site. 
- linf.cd
- Límite inferior de la clase diamétrica, en cm. 
- lsup.cd
- Límite superior de la clase diamétrica, en cm. 
- cd
- Marca de la clase diamétrica, en cm. 
- nha.cd
- Densidad de la clase diamétrica, en arb/ha. 
- bosque.id
- Identificador del bosque, combinacion de sitio y sector. 
Source
Densidad de árboles por clase diamétrica, i.e., tabla de rodal. Datos digitados desde el cuadro No. 4 de Wadsworth (1976).
References
- Wadsworth RK. 1976. Aspectos ecologicos y crecimiento del rauli (Nothofagus alpina) y sus asociados en bosques de segundo crecimiento de las provincias de Bio-Bio, Malleco y Cautin, Chile. Boletin Tecnico No. 37, Fac. Cs. Forestales, Universidad de Chile, Santiago, Chile. 
Examples
data(standtabRauli2)
head(standtabRauli2)
df<-standtabRauli2
table(df$sitio,df$sector,df$cd)
Datos de ahusamiento de Eucalyptus regnans
Description
Corresponde a mediciones de diámetros fustales, con y sin corteza, para árboles muestra en plantaciones de Eucalyptus regnans en la comuna de Gorbea, región de la Araucanía, Chile. Note que existen por lo tanto, varias mediciones para cada árbol.
Usage
data(tapereuca2)
Format
Contiene las siguientes variables:
- narb
- Número del árbol. 
- sec
- Número de sección del árbol - narb.
- hl
- Altura fustal de la sección - sec, en m.
- dlcc
- Diámetro de la sección - seccon corteza, en cm.
- dlsc
- Diámetro de la sección - secsin corteza, en cm.
- ec
- Espesor de corteza de la sección - sec.
- forma
- Forma del árbol, en donde - 1= Fuste cilíndrico y- 2= Fuste acilíndrico (pequeña curvatura).
- dap
- Diámetro a la altura del pecho (1.3 m) en cm. 
- decdap
- Doble espesor de corteza en el - dap.
- htot
- Altura total del árbol - narb, en m.
- dtoc
- Diámetro con corteza en - hcc.
- hcc
- Altura de comienzo de copa del árbol - narb, m.
Source
Los datos provienen de la Tesis de Ingeniero Forestal de Manuel Morales, UFRO.
References
- Morales, M. (2003). Modelos fustales para Eucalyptus regnans F. Muell., en la comuna de Gorbea, Novena Región. Tesis Ingeniero Forestal. Universidad de La Frontera. Temuco, Chile. 43p. 
Examples
data(tapereuca2)
lattice::xyplot(dlcc~hl, data=tapereuca2, type = "l", groups = narb)
Diameter and height growth of Grand-fir sample trees.
Description
Diameter and height growth of 66 Grand-fir trees. Data derived from stem analysis sample trees collected by Dr. Albert Stage (US Forest Service, Moscow, ID, USA.)
Usage
data(treegrowth)
Format
Contains seven column, as follows:
- tree.no
- Tree number identificator. An unique number to each sample tree. 
- forest
- Forest type. 
- habitat
- Forest habitat type. 
- tree.code
- A composite tree code representing the following columns: - tree.id-forest-habitat
- age
- Age, in yr 
- dbh
- Diameter at breast-height, in cm. Originally measured in inches, and was converted to cm using a single decimal. 
- toth
- Total height, in m. Originally measured in feet, and was converted to m using a single decimal. 
Source
Originally, the data were provided by Dr. Albert Stage (R.I.P) to Professor Andrew Robinson (University of Idaho, USA), whom used them to explain the fitting of statistical models. Dr Christian Salas-Eljatib was a former graduate student of Statistics of Prof. Robinson at the Univ. of Idaho.
References
- Stage, A. R., 1963. A mathematical approach to polymorphic site index curves for Grand fir. Forest Science 9 (2), 167–180. 
Examples
data(treegrowth)
df<-treegrowth
head(df)
require(lattice)
xyplot(dbh~age, groups = tree.code,data=df, type="b")
Crecimiento en diámetro y altura de árboles muestra de Grand-fir.
Description
Crecimiento en diámetro y altura de 66 árboles de Grand-fir. Los datos fueron derivados a partir de árboles muestras de análisis fustal colectados por el Dr. Albert Stage (US Forest Service, Moscow, ID, USA.)
Usage
data(treegrowth)
Format
Contiene las siguientes siete columnas:
- num.arb
- Número identificador del árbol. Único para cada árbol muestra. 
- bosque
- Tipo forestal. 
- habitat
- Clasificacion de tipo de hábitat. 
- cod.arb
- Un código que combina a las siguientes columnas: - num.arb-bosque-habitat
- edad
- Edad, en años. 
- dap
- Diámetro a la altura del pecho, en cm. Originalmente fue medido en pulgadas, y acá se transformó empleando un solo decimal. 
- atot
- Altura total, in m. Originalmente esta variable fue medido en pies, y acá se transformó empleando un solo decimal. 
Source
En un principio los datos fueron cedidos por el Dr. Albert Stage (Q.E.P.D) al Profesor Andrew Robinson (University of Idaho, USA), quien los usaba para explicar el ajuste de modelos estadísticos. El Dr. Christian Salas-Eljatib fue un estudiante de postgrado en estadistica del Prof. Robinson en la Univ. of Idaho.
References
- Stage, A. R., 1963. A mathematical approach to polymorphic site index curves for Grand fir. Forest Science 9 (2), 167–180. 
Examples
data(treegrowth2)
df<-treegrowth2
head(df)
require(lattice)
xyplot(dap~edad, groups = cod.arb,data=df, type="b")
Tree-list data from a forest sampling work
Description
Tree-level variables measured within three sample plots in a forest sampling effort. This sort of work is commonly referred as a forest inventory. Notice that plots might have different areas. The sampling was carried out in a secondary forest of Nothofagus obliqua in the Rucamanque experimental station, near the city of Temuco, in southern Chile.
Usage
data(treelistinve)
Format
Contains tree-level variables, as follows:
- plot
- Plot number. 
- plot.size
- Plot size, in m - ^{2}.
- tree
- Tree identificator 
- species
- Species common name as follows: Olivillo=Aextocicon puncatatum, Tepa=Laureliopsis philippiana, Lingue=Persea lingue, Coigue=Nothofagus dombeyi, Roble=Nothofagus obliqua, Other=Other 
- dbh
- Diameter at breast-height, in cm. 
- toth
- Total height, in m. Only measured for some sample trees. 
Source
The data is provided courtesy of Prof. Christian Salas-Eljatib, Universidad de Chile (Santiago, Chile).
References
- Salas C. 2001. Caracterización básica del relicto de Biodiversidad Rucamanque. Bosque Nativo, 29:3-9. https://eljatib.com/publication/2001-06-01_caracterizacion_basi/ 
- Salas C. 2002. Ajuste y validación de ecuaciones de volumen para un relicto del bosque de Roble-Laurel-Lingue. Bosque 23(2): 81-92. doi:10.4067/S0717-92002002000200009 https://eljatib.com/publication/2002-07-01_ajuste_y_validacion_/ 
Examples
data(treelistinve)
head(treelistinve)
tapply(treelistinve$dbh,treelistinve$species,summary)
Lista de árboles en un muestreo forestal
Description
Variables a nivel de árbol medidas en tres unidades de muestreo (i.e., parcelas) establecidas en un muestreo forestal. Este tipo de muestreo de bosques, es comunmente conocido como “inventario forestal”. Note que las parcelas podrían tener diferentes superficies. El muestreo fue realizado en un bosque secundario dominado por Nothofagus obliqua en el predio Rucamanque, en las cercanías de la ciudad de Temuco, en el sur de Chile.
Usage
data(treelistinve2)
Format
Contiene variables a nivel de árbol dentro de parcelas.
- parce
- Número de la parcela de muestreo. 
- sup.parce
- Superficie de la parcela, en m - ^{2}.
- arbol
- Número identificador del árbol. 
- spp
- Nombre común de especies como sigue: Olivillo=Aextocicon puncatatum, Tepa=Laureliopsis philippiana, Lingue=Persea lingue, Coigue=Nothofagus dombeyi, Roble=Nothofagus obliqua, Other=Other 
- dap
- Diámetro a la altura del pecho, en cm. 
- atot
- Altura total, en m. Solo medida en algunos árboles muestra. 
Source
Los datos fueron cedidos por el Prof. Christian Salas-Eljatib, Universidad de Chile (Santiago, Chile).
References
- Salas C. 2001. Caracterización básica del relicto de Biodiversidad Rucamanque. Bosque Nativo, 29:3-9. https://eljatib.com/publication/2001-06-01_caracterizacion_basi/ 
- Salas C. 2002. Ajuste y validación de ecuaciones de volumen para un relicto del bosque de Roble-Laurel-Lingue. Bosque 23(2): 81-92. doi:10.4067/S0717-92002002000200009 https://eljatib.com/publication/2002-07-01_ajuste_y_validacion_/ 
Examples
data(treelistinve2)
unique(treelistinve2$parce)
table(treelistinve2$parce,treelistinve2$sup.parce)
tapply(treelistinve2$dap,treelistinve2$spp,summary)
Tree-level volume by species in the Rucamanque forest
Description
These is tree-level measurement data of sample trees in the Rucamanque experimental forest, near Temuco, in the Araucanía region in south-central Chile. Data were measured in 1999.
Usage
data(treevolruca)
Format
Contains tree-level variables, as follows:
- tree
- Tree number identification. 
- spp
- Tree species common name as follows: "Laurel" is Laurelia sempervirens, "Lingue" is Persea lingue, "Olivillo" is Aextoxicon punctatum, "Tepa" is Laureliopsis philippiana, "Tineo" is Weinmannia trichosperma, y "Ulmo" is Eucryphia cordifolia. 
- dbh
- Diameter at breast height, in cm. 
- toth
- Total height, in m. 
- d6
- Upper-stem diameter at 6 m, in cm. 
- totv
- Tree gross volume, in m³ with bark. 
Source
The data were provided courtesy of Dr. Christian Salas-Eljatib, Universidad de Chile (Santiago, Chile).
References
- Salas C. 2002. Ajuste y validación de ecuaciones de volumen para un relicto del bosque de Roble-Laurel-Lingue. Bosque 23(2): 81-92. doi:10.4067/S0717-92002002000200009 https://eljatib.com/publication/2002-07-01_ajuste_y_validacion_/ 
Examples
data(treevolruca)
head(treevolruca)
table(treevolruca$spp)
Volumen a nivel de árbol para especies nativas del bosque de Rucamanque
Description
Volumen, altura y diámetro, entre otras para árboles muestra en el bosque de Rucamanque, cerca de Temuco, en la región de la Araucanía, en el sur de Chile.
Usage
data(treevolruca2)
Format
Las siguientes columnas son parte de la dataframe:
- arbol
- Número del árbol. 
- spp
- Codificación de la especie como sigue: "Laurel" es Laurelia sempervirens, "Lingue" es Persea lingue, "Olivillo" es Aextoxicon punctatum, "Tepa" es Laureliopsis philippiana, "Tineo" es Weinmannia trichosperma, y "Ulmo" es Eucryphia cordifolia. 
- dap
- Diámetro a la altura del pecho, en cm. 
- atot
- Altura total, en m. 
- d6
- Diámetro fustal a los 6 m, en cm. 
- vtot
- Volumen bruto total, en m³ con corteza. 
Source
Los datos fueron cedidos por el Dr. Christian Salas-Eljatib, Universidad de Chile (Santago, Chile).
References
- Salas C. 2002. Ajuste y validación de ecuaciones de volumen para un relicto del bosque de Roble-Laurel-Lingue. Bosque 23(2): 81-92. doi:10.4067/S0717-92002002000200009 https://eljatib.com/publication/2002-07-01_ajuste_y_validacion_/ 
Examples
data(treevolruca2)
head(treevolruca2)
table(treevolruca2$spp)
Tree-level information of forest plots across the Hawaiian archipelago.
Description
Diameter at breast height (or occurrence) of individual trees, shrubs and tree ferns across 530 plots across the Hawaiian archipelago and includes native status and cultivated status of the 185 species.
Usage
data(trlhawaii)
Format
Contains 18 variables, as follows:
- island
- Island name. 
- plot.id
- Unique numeric identifier for each plot. 
- study
- Brief name of study. 
- plot.area
- Plot area in m - ^{2}.
- longitude
- Longitude of plot in decimal degrees; WGS84 coordinate system. 
- latitude
- Latitude of plot in decimal degrees; WGS84 coordinate system. 
- year
- Year in which plot data was collected. 
- census
- Numeric identifier for each census. 
- tree.id
- Unique numeric identifier for each individual. 
- scientific.name
- Genus and species of each individual following TPL v. 1.1. 
- family
- Family of each individual following TPL v. 1.1. 
- angiosperm
- Binary variable ( - 1= yes,- 0= no) indicating whether an individual is classified as an angiosperm following APG III.
- monocot
- Binary variable ( - 1= yes,- 0= no) indicating whether an individual is classified as a monocot following APG III.
- native.status
- Categorical variable ( - native,- alien,- uncertain) indicating alien status of each individual following Wagner et al. (2005).
- cultivated.status
- Binary variable ( - 1= yes,- 0= no,- NA= not applicable) indicating if species is cultivated following PIER.
- abundance
- Number of individuals (all = 1). 
- abundance.ha
- Abundance of each individual on a per hectare basis. 
- dbh
- Diameter at 1.3 m (in cm) for each individual; - NAindicates that size was not measured, but was classified by size class.
Source
The data were obtained from the DRYAD repository at doi:10.5061/dryad.1kk02qr.
References
- Craven D, Knight T, Barton K, Bialic-Murphy L, Cordell S, Giardina C, Gillespie T, Ostertag R, Sack L,Chase J. 2018. OpenNahele: the open Hawaiian forest plot database. Biodiversity Data Journal 6: e28406. 
Examples
data(trlhawaii)
table(trlhawaii$island,trlhawaii$study)
unique(trlhawaii$plot.id)
table(trlhawaii$plot.id)
tapply(trlhawaii$plot.area,trlhawaii$study,summary)
Long term tree-list data from permanent sample plots
Description
Temporal tree-level data within four sample plots
in an experimental forest in Austria. The dataframe contains several
tree-level variables. Plot sizes are 2500 m^{2} (approx.).
Usage
data(trlpsptime)
Format
Contains tree-level variables, as follows:
- plot
- Plot number. 
- tree
- Tree identificator. 
- species
- Species code as follows: PCAB=Picea abies, LADC=Larix decidua, PNSY=Pinus sylvestris, FASY=Fagus Sylvatica, QCPE=Quercus petraea, BTPE=Betula pendula. 
- year
- Year of measurement. 
- obs
- Observation. 
- dbh
- Diameter at breast-height, in mm. 
- dbh2
- Orthogonal measured second diameter, in mm. 
- hmk
- Selection criteria to measure tree height. - 1=systematic,- 2=systematic and in the group of the 100 thickest,- 3=belongs to the 100 thickest,- 4=lying tree,- 5=Standing tree with a ladder,- 6=outlier,- 7=from stem analysis.
- kh
- Type of the height measurement. - 0=tree height,- 1=angle and distances.
- ho
- Tree height in dm when - kh=0. When- kh=1then distance to the tree in dm or in 1977 length of the base bar in cm.
- ka
- Height to the crown base in dm when - kh=0. When- kh=1then angle to the tree top in 1/10 degree.
- kb
- Crown width in dm when - kh=0. When- kh=1then angle to 1.3 m above tree base in 1/10 degree.
- wka
- Angle to crown base in 1/10 degree. 
- crown.cl
- Crown class according to Kraft. - 1=predominant,- 2=dominant,- 3=co-dominant,- 4=dominated,- 5=overtopped.
- crown
- Crown quality. - 0=normal,- 1=broken in the crown region,- 2=substituted tree top,- 3=forked,- 4=bushy, stork nest, witches' broom,- 5=wizen tree top,- 6=again broken tree top.
- stem
- Stem quality. - 0=typical,- 1=crooked,- 2=abiotic damaged,- 3=biotic damaged,- 4=forked stem without damage,- 5=forked stem with damage,- 6=up to 1/3 of the girth is peeled,- 7=more than 1/3 of the girth is peeled,- 8=broken stem,- 9=other stem damages.
- defoliation
- crown defoliation. - 1=low,- 2=medium,- 3=much.
Source
The Austrian Research Center for Forests established a spacing experiment with Norway spruce (Picea abies) in the Vienna Woods. In the “Hauersteig” experiment, several tree-level variables were measured within four sample plots over time. Data were retrieved from the paper cited below, where several details might be worth reading.
References
- Kindermann G. Kristofel F, Neumann M, Rossler G, Ledermann T & Schueler. 2018. 109 years of forest growth measurements from individual Norway spruce trees. Sci. Data 5:180077 doi:10.1038/sdata.2018.77 
Examples
data(trlpsptime)
df<-trlpsptime
head(df)
tapply(df$dbh, list(df$year,df$plot), mean)
Tree-level remeasurements for a sample plot in a Pinus radiata plantation
Description
Temporal tree-level data from a sample plot established in a
Monterey pine (Pinus radiata) forestry plantation in Chile.
The plot size is 1600 m^{2}, and the plantation was established
in 1990.
Usage
data(trlremeasu)
Format
Tree list data for a sample plot remeasured through time, and having the following columns
- plot.id
- Plot code. 
- tree
- Tree number. 
- x.coord
- Cartesian position in the X-axis, in m. 
- y.coord
- Cartesian position in the Y-axis, in m. 
- year
- Measurement year. 
- dead
- Dead identificator, - 0means alive, and- 1otherwise.
- dbh
- diameter at breast-height, in cm. 
Source
Data were retrieved from the paper cited below, where several details might be worth reading.
References
- Pommerening A, Trincado G, Salas-Eljatib C, Burkhart H. 2023. Understanding and modelling the dynamics of data point clouds of relative growth rate and plant size. Forest Ecology and Management Volume 529:120652 doi:10.1016/j.foreco.2022.120652 
Examples
data(trlremeasu)
head(trlremeasu)
df<-trlremeasu
df$fe<-10000/1600
df$garb.ha<- (pi/40000)*df$dbh^2*df$fe
gha.t<-tapply(df$garb.ha, df$year, sum)
nha.t<-tapply(df$fe, df$year, sum);
time<-as.numeric(rownames(gha.t))
plot(nha.t~time, type="b",las=1)
plot(gha.t~time, type="b",las=1)
Smoothed tree list data from permanent sample plots
Description
Temporal tree-level variables (smoothed-values) within four sample plots
in an experimental forest in Austria. The dataframe contains all
the variables for all trees, where observation gaps were
filled from monotone increasing predictive functions.
Plot sizes are 2500 m^{2} (approx.) and the current dataframe
only keeps the measurement years having a more reliable amount of records.
Usage
data(trlsmoopsp)
Format
Contains tree-level variables, as follows:
- plot
- Plot number. 
- tree
- Tree identificator. 
- year
- Year of measurement. 
- species
- Species code as follows: PCAB=Picea abies, LADC=Larix decidua, PNSY=Pinus sylvestris, FASY=Fagus Sylvatica, QCPE=Quercus petraea, BTPE=Betula pendula. 
- obs
- Observation in this year. 
- dbh
- Diameter at breast-height, in cm. 
- toth
- Tree height, in m. 
- hcb
- Height to the crown base, in m. 
Source
The Austrian Research Center for Forests established a spacing experiment with Norway spruce (Picea abies) in the Vienna Woods. In the “Hauersteig” experiment, several tree-level variables were measured within four sample plots over time. Data were retrieved from the paper cited below, where several details might be worth reading.
References
- Kindermann G. Kristofel F, Neumann M, Rossler G, Ledermann T & Schueler. 2018. 109 years of forest growth measurements from individual Norway spruce trees. Sci. Data 5:180077 doi:10.1038/sdata.2018.77 
Examples
data(trlsmoopsp)
df<-trlsmoopsp
head(df)
table(df$year,df$plot)
tapply(df$dbh, list(df$year,df$plot), length)
Function to compute the U-estimator for a variable from a sample plot
Description
Computes the $U$-estimator for integer trees per-are (1 ha=100ares)
Usage
uestimator(y.by.sortx = y.by.sortx, nare = nare)
Arguments
| y.by.sortx | a vector having the tree-level variable of interest being already sorted by a sorting-variable. | 
| nare | number of trees per are for the sample plot. Remember that 1 are=100 m2 or 1 ha=100 ares. "nare" it is an alternative to express stand density in trees/ha, here instead the unit is "trees/are". nare=length(y.by.sortx)/(plot.area.ares). If "nare" is not an integer, it is rounded to the nearest integer, with a warning. | 
Details
The original function was written by Dr Oscar García, and the corresponding reference is provided. The current function has only some small changes.
Value
The main output is the U-estimator
Author(s)
Dr Oscar García.
References
- Garcia O, Batho A. 2005. Top height estimation in lodgepole pine sample plots. Western Journal of Applied forestry 20(1):64-68. 
Examples
#Creates a fake dataframe
h <- c(29.1,28, 24.5, 26, 21,20.5,20.1);
trees.per.plot<-35; plot.area.m2<-500;
exp.factor.ha<-10000/plot.area.m2;exp.factor.ha
#Remember 1 are= 100 m2 o 1 ha= 100 ares
plot.area.ares<-plot.area.m2/100; plot.area.ares
plot.area.ha<-plot.area.m2/10000;plot.area.ha
n.ha<-trees.per.plot/plot.area.ha;n.ha #*(10000/plot.area.m2)
n.are<-trees.per.plot/plot.area.ares;n.are
#Using the domvar function
uestimator(y.by.sortx=h,nare=n.are)