amod: Allometric scaling.

Description Usage Arguments Details Value Author(s) Examples

Description

Allometric models and parameters are used to scale organic growth.

Usage

1
amod(x, mp = c(1, 1), fun = y ~ a * (x^b))

Arguments

x

numeric vector.

mp

numeric. Allometric parameters. Default c(1,1) (see details).

fun

formula. Allometric model. To properly specify other formulas, the variables (e.g. x and y) should belong to letters[20:26].

Details

. Allometric models are useful to scale size-components of organisms such as tree diameters (mp = c(2,1)) and basal areas (mp = c(0.25 * pi,2)). Several parameter groups (c(a1,b1,a2,b2, ..., an,bn)) can be recursively processed. This enables computation of complex organic variables. For example, above-ground tree biomass could be computed from two parameter groups for tree-biomass, and over-bark diameter scaling.

Value

data.frame of the scaled variable (x) and relative increments (csx). These are computed with setdiff function.

Author(s)

Wilson Lara <wilarhen@gmail.com>, Felipe Bravo <fbravo@pvs.uva.es>

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
## Simulating TRW records:
set.seed(1)
trw <- ts(abs(rnorm(12,1,1)),start = 1950)
## Cumulative TRW:
cri <- cumsum(trw)
## tree diameters
td <- amod(cri,mp = c(2,1))
## plot of the tree diameters and the
## relative increments:
plot(ts(td))

BIOdry documentation built on May 30, 2017, 6:20 a.m.

Search within the BIOdry package
Search all R packages, documentation and source code