Function evaluates the expected value of a Pettersen-Height Function
based on diameter in breast height and tree species code.
The Pettersen-Function (\(h = 1.3 + (a + \frac{b}{dbh})^{-3}\)) was fitted
on NFI 3 (BWI 3) data, using the main stand only.
d13
and sp
should be of equal length or one of it can
be > 1 if the other is of length 1. Then, the shorter object will be extended
to match the length of the longer object. See examples.
The quantile option return tree height at quantiles 17, 50 or 83. If
qtl
is NULL, the result of a nonlinear least-squares regression is
provided.