tree.ht: Estimates the missing total height of trees from a given plot

In sgezan/Nothopack: G&Y Forest Simulator for Roble-Rauli-Coigue Stands in Chile

Description

Estimates the total height of trees (m) that have missing height that come from fitting a regression model on inventory data. For the missing trees there are two methods: 1) to estimate tree heights according to a parametrized height-DBH model, or 2) to estimate tree heights by fitting a simple height-DBH model that requires at least 10 measurements. Missing values are indentified as 'NA', and regression is fitted without making distinction of species. All input vectors should correspond to the same tree ID.

Usage

tree.ht(DBH, HT, DOM.SP = NA, ZONE = NA, HD = NA, QD = NA, method = 1)

Arguments

DBH	Vector of diameter at breast height (cm)
HT	Vector of total height (m) (with measured and/or missing values)
DOM.SP	Dominant specie (1:Rauli, 2:Roble, 3:Coigue)
ZONE	Growth zone (1, 2, 3, 4)
HD	Dominant height (m) of dominant specie in the current stand
QD	Quadratic diameter (cm) of the stand
method	Method to use to estimate missing heights. 1:Parametrized DBH-height model (which requires input: DBH, DOM.SP, ZONE, HD, QD), and 2:Fits a simple DBH-height model from available measurements using the equation: ln(HT) = b0 + b1/DBH (default = 1)

Value

A list containing the following:

• HTFIN A vector of final tree heigths (m), replacing the missing values for estimated heigths and retaining the observed heights

• r2 A value with the coefficient of determination from the fitting the DBH-height model when method = 2

Author(s)

P. Someda-Dias, and S.A. Gezan

Examples

# Example 1: Method 1 - Parametrized DBH-height model
DBH <- c(9.3, 11.1, 15.5, 9, 14.8, 27.3, 11.4, 6.6, 12.6, 17.5,
         6.3, 7.2, 11.5, 13.6, 7.3, 12, 11.9, 8.1, 7.6, 5)
HT <- c(11.8, 12.3, NA, NA, 15.3, 18, 12, NA, 14.5, NA, NA,
        NA, NA, NA, 10.3, 14.6, NA, NA, NA, NA)
(ht.est <- tree.ht(DBH=DBH, HT=HT, DOM.SP=2, ZONE=2, HD=15, QD=12, method=1)$HTFIN)
plot(DBH, ht.est, ylab='HT (m)', xlab='DBH (cm)', xlim=c(0,30), ylim=c(0,20),
     type='p', col='blue')

# Example 2: Method 2 - Simple DBH-height model
DBH <- c(9.3, 11.1, 15.5, 9, 14.8, 27.3, 11.4, 6.6, 12.6, 17.5,
         6.3, 7.2, 11.5, 13.6, 7.3, 12, 11.9, 8.1, 7.6, 5)
HT <- c(11.8, 12.3, NA, NA, 15.3, 18, 12, NA, 14.5, NA, NA,
        NA, NA, NA, 10.3, 14.6, NA, NA, NA, NA)
(ht.est <- tree.ht(DBH=DBH, HT=HT, DOM.SP=2, ZONE=2, HD=15, QD=12, method=2)$HTFIN)
(r2 <- tree.ht(DBH=DBH, HT=HT, DOM.SP=2, ZONE=2, HD=15, QD=12, method=2)$r2)
plot(DBH, ht.est, ylab='HT (m)', xlab='DBH (cm)',
     xlim=c(0,30), ylim=c(0,20), type='p', col='darkblue')

sgezan/Nothopack documentation built on April 25, 2021, 8:03 a.m.