The functions estimating tree volume and aboveground (ABG) phytomass for the 2nd Italian National Forest Inventory (2005) are documented in Tabacchi et al. (2011). (The section of the the publication exposing "Methods and results global evaluation" is accessible here) Regression models have been developed based on sample trees collected within three successive projects, in order to consider, as much as possible, all of the most relevant tree species present in Italian forests.

Providing such a general and uniform estimation tool, these functions have been adopted by Italian foresters as reference functions. Many professionals and researchers have copied, from the paper print or the PDF file, the small subset of coefficient values required to tackle their problem at hand.
The package offers an easier (and more reliable) way to proceed. Moreover, since coefficients were not readily available through a digital tool, the valuable information that the work developed for the evaluation of estimates accuracy, has been practically ignored.
Using the ForIT package, all estimates are associated with accuracy evaluations, through attributes.

The independent variables used in the model are the diameter-at-breast-height (