amod: Allometric scaling.
In BIOdry: Multilevel Modeling of Dendroclimatical Fluctuations

Description Usage Arguments Details Value Author(s) Examples

Allometric models and parameters are used to scale organic growth.

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

`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]`.

. 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.

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

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

## 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))