nfiMetrics {basifoR}

Tree metrics from NFI data

Description

This function recursively implements dbhMetric on data bases of the Spanish National Forest Inventory (NFI) to derive a variety of tree metrics. Use metrics2Vol to recursively derive the metrics plus over bark volumes.

Usage

nfiMetrics(nfi, var = c("d", 
    "h", "ba", "n", "Hd"), 
    levels = c("esta", 
        "espe"), ...)

Arguments

nfi

character or data.frame. URL/path to a compressed file of the NFI (.zip) having data of either .dbf or .mdb file extensions, or a data frame such as that produced by readNFI.

var

character. Metrics. These can be five: (1) the mean diameter 'd'; (2) the tree height 'h'; (3) the basal area 'ba'; code(4) the number of trees per hectare 'n'; and (5) the dominant height 'Hd', see Details section in dbhMetric for better understanding of the metrics units. Default c('pr','d','h','ba','n','Hd').

levels

character. levels at which the metrics are computed. Pattern matching is supported. Cases are ignored. Default c('esta','espe') matches both the sample plot 'Estadillos' and tree species 'Especie'.,

...

Additional arguments in readNFI.

Value

data.frame containing columns which match the strings in levels, plus the variables defined in var, including the province pr (dimensionless), the diameter d ('mm'), the tree height h ('dm'), the basal area ba ('m2 tree-1'), the number of trees by hectare n (dimensionless), and the tree dominant height Hd ('m').

Author(s)

Wilson Lara <[e-mail]>, Cristobal Ordonez <[e-mail]>, Felipe Bravo <[e-mail]>

Examples

## seconf NFI
madridNFI <- system.file("ifn3p28_tcm30-293962.zip", package="basifoR")
rmad <- readNFI(madridNFI)[1:10,]
mmad <- nfiMetrics(rmad)
head(rmad,3)
## see metric units
attr(rmad,'units')