Montana's forest resources, 2003-2009

Abstract

This report presents a summary of the most recent inventory information for Montana's forest lands. The report includes descriptive highlights and tables of area, number of trees, biomass, volume, growth, mortality, and removals. Most of the tables are organized by forest type group, species group, diameter class, or owner group. The report also describes inventory design, inventory terminology, and data reliability. Results show that Montana's forest land totals 25.6 million acres. Sixty percent (15.4 million acres) of this forest land is administered by the USDA Forest Service. Douglas-fir forests cover 7.5 million acres or roughly 29 percent of Montana's forested lands, making it the most abundant forest type in the State. The lodgepole pine type is the second-most common individual forest type comprising 17 percent of Montana's forest land. Lodgepole pine is the most abundant tree species in Montana by number of trees, and Douglas-fir is the most abundant species by volume or biomass. Net annual growth of all live trees 5.0 inches diameter and greater on Montana forest land totaled 289.8 million cubic feet. Average annual mortality totaled nearly 746.3 million cubic feet.

Derivation and quantitative analysis of the differential self-interrogation Feynman-alpha method

“…The drawback of pulsed measurements such as the DDAA method is the necessity of the use of a neutron generator. The stochastic generalization of the DDAA method was recently suggested as an alternative method which eliminates the need for such an external source, namely the so-called Differential Die-away Self-Interrogation (DDSI) technique [6]. The DDSI method utilizes the inherent spontaneous neutron emission of the sample.…”

“…In Ref. [6] the functional form of the DDSI formula, i.e. the two-group Rossi-alpha formula, was derived in an empirical way.…”

Montana’s forest resources, 2006-2015

“…Data from the 1989 inventory are similar enough in format to be housed in the FIA database and are available via the methods above, increasing the temptation for comparison. Data from the annual inventory have been used in a previous 5-year report for data collected from 2003 through 2009 (Menlove et al 2012), which includes a detailed comparison of the two methodologies.…”

Two-point theory for the differential self-interrogation Feynman-alpha method

“…There exists, however, one significant drawback of pulsed measurements, that is the necessity of a neutron generator. The stochastic generalization of the DDAA method was recently suggested as an alternative method which eliminates the need for such an external source, namely the so-called Differential Die-away Self-Interrogation(DDSI) technique [6]. The DDSI method utilizes the inherent spontaneous neutron emission of the sample.…”

“…An empirical two-group Rossi-alpha formula, representing the functional form of the DDSI formula, was derived in Ref. [6]. This result was subsequently re-derived from first principles with the use of the backward-type Kolmogorov equations [7,8].…”