| HDmethods {BIOMASS} | R Documentation |
HDmethods
Description
Methods used for modeling height-diameter relationship
Usage
loglogFunction(data, method)
michaelisFunction(data, weight = NULL)
weibullFunction(data, weight = NULL)
Arguments
data |
Dataset with the informations of height (H) and diameter (D) |
method |
In the case of the loglogFunction, the model is to be chosen between log1, log2 or log3. |
weight |
(optional) Vector indicating observation weights in the model. |
Details
These functions model the relationship between tree height (H) and diameter (D). loglogFunction Compute two types of log model (log and log2) to predict H from D. The model can be:
log 1:
log(H) = a+ b*log(D)(equivalent to a power model)log 2:
log(H) = a+ b*log(D) + c*log(D)^2
michaelisFunction Construct a Michaelis Menten model of the form:
H = (A * D) / (B + D)
(A and B are the model parameters to be estimated)
weibullFunction Construct a three parameter Weibull model of the form:
H = a*(1-exp(-(D/b)^c))
(a, b, c are the model parameters to be estimated)
Value
All the functions give an output similar to the one given by stats::lm(), obtained for
michaelisFunction and weibullFunction from minpack.lm::nlsLM).
Result of a model (lm object)
Result of a model (nlsM object)
Result of a model (nlsM object)
Author(s)
Maxime REJOU-MECHAIN, Ariane TANGUY
References
Michaelis, L., & Menten, M. L. (1913). Die kinetik der invertinwirkung. Biochem. z, 49(333-369), 352. Weibull, W. (1951). Wide applicability. Journal of applied mechanics, 103. Baskerville, G. L. (1972). Use of logarithmic regression in the estimation of plant biomass. Canadian Journal of Forest Research, 2(1), 49-53.