biometrics (version 1.0.3)

uestimator: Function to compute the U-estimator for a sorted random variable, measured in a given sample plot.

Description

Computes the U-estimator for a number of trees per-are (1 ha=100ares)

Usage

uestimator(sorty, n.per.are)

Value

The main output is the U-estimator for the random variable of interest.

Arguments

sorty

a vector having the tree-level variable of interest being already sorted according to a criterion.

n.per.are

number of needed trees per are for the sample plot. Remember that 1 are=100 m2 or 1 ha=100 ares. If n.per.are is not an integer, it is rounded to the nearest integer, with a warning.

Author

Dr Oscar García and Christian Salas-Eljatib.

Details

Althought the original function was written by Dr Oscar García, and the corresponding reference is provided, the current function has several changes that makes it of a broader use.

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);
sort.h<-sort(h,decreasing=FALSE);sort.h
plot.area.m2<-500;plot.area.ha<-plot.area.m2/10000;plot.area.ha
ndom.ha<-100;n.per.are<-plot.area.ha*ndom.ha;
# Using the  function
uestimator(sort.h,n.per.are)