dyntaper - Dynamic stem profile models, aka tree taper equations

An R package that performs calculations with tree taper (or stem profile) equations, including model fitting. Implements the methods of García (2015). The models are parsimonious, describe well the tree bole shape over its full length, and are consistent with wood formation mechanisms through time.

The main functions are taper(), which calculates diameters at specified height levels up the tree, its inverse hlevel(), which gives the height level for a given diameter, and volume(), which computes the volume between two height levels.

For a tutorial, see the vignette.

Installation

Install the stable version from CRAN: install.packages("dyntaper")
or with the RStudio menus: Tools > Install Packages... > dyntaper

For testing a newer development version from here, if any, use remotes::install_github("ogarciav/dyntaper", build_vignettes = TRUE)

Example

library(dyntaper)
dfir <- c(2.569, 0, 1.042, 0.3012, -1)  # params. for D.fir in B.C.
height <- 32; dbh <- 24;  k <- 0.956  # k is a bark conversion factor
# Plot a taper curve (inside-bark diameter over height levels):
curve(
  taper(h, height, k*dbh, dfir, 1.3),  # 1.3 m is the breast height
from = 0, to = 32, xname = "h")
# Height level for a diameter of 10 cm (i.b.):
(h10 <- hlevel(10, height, k*dbh, dfir, 1.3))
# Volume from a 30 cm stump to a 10 cm diameter limit:
volume(0.3, h10, height, k*dbh, dfir, 1.3, 100)

References

García, O. (2015) "Dynamic modelling of tree form". MCFNS 7, 9–15. (http://mcfns.net/index.php/Journal/article/view/MCFNS7.1_2).

Koirala, A., Montes, C. R., Bullock, B. P. and Wagle, B. H. (2021) "Developing taper equations for planted teak (Tectona grandis L. f.) trees of central lowland Nepal". Trees, Forests and People 5. (https://doi.org/10.1016/j.tfp.2021.100103).