Abstract:Harvesting equipment productivity studies have been conducted in many countries around the world spanning over 25 years. These studies have shown that many factors influence individual machine productivity. These factors include stand and site conditions, equipment configuration, management objectives, and operator experience. Productivity can increase or decrease with slight changes in any of these factors. This literature review also highlights the variety of experimental designs and data collection methods encountered in a cross section of those studies. It further shows the variation in species composition, stand density, tree diameter, and harvest prescription. Although studies that include the influence of operator performance on harvest equipment productivity are limited, they were included in this review where appropriate and available. It is clear that productivity equations should be developed using population-level data with several operators. Some studies were conducted in stands similar to Maine, but they used harvesting equipment that is not commonly used in logging operations in this state. Therefore the applicability of existing studies to the logging industry in Maine, USA, is very limited. Our conclusion is that in order to accurately predict harvesting productivity it is necessary to develop regional harvesting productivity equations using harvesting equipment commonly used in Maine. Forest operations researchers in other regions will be able to use this summary to explore the difficulty of applying productivity information to regional logging operations. OPEN ACCESSForests 2013, 4 899

No abstract

This article focuses on the narrow margins faced by contract loggers under various harvest systems in the forest products supply chain of the northeastern United States. Contract logging firms conduct a majority of the harvesting across the various forest cover types of the region—from spruce-fir to white pine to northern hardwoods—supplying sawlogs, pulpwood, chipwood, and firewood to various markets. Over the past few decades, performance expectations have increased owing to the expansion of harvesting regulations, including best management practices, and the adoption of forest and logger certification programs. These rising expectations have corresponded with increasing logging costs, resulting in narrowing margins for contract loggers. Using results from a recent logger case study, we examine operating margins for three harvest systems under varying terrain, harvest levels, and systems configurations. Results suggest that across all harvest systems, there is a fine line between just making a living (striving), succeeding and growing (thriving), and only partially covering costs while losing equity to uncompensated depreciation (surviving).

Due to the increased partial harvest of small-diameter stems and the lack of feller-buncher time-consumption information in Maine, it was necessary to develop new cycle-time equations. Data were collected from seven different sites in Maine with six different operators to capture the variability in site and stand conditions as well as operator experience and proficiency. The results showed that over 55% of the trees harvested were cut in accumulations of two or more trees. Significant variables in the final model included sum of dbh and stem count per accumulation. An approach to simulate a list of accumulations with the required variables is described based on a tree list with dbh classes. Treating the combination of operator, machine, and site conditions as a random effect in a linear mixed-effects model resulted in an adjusted R 2 of 0.40 for fixed and random effects. The combination of operator, machine, and site conditions explained 32% of the variance caused by random effects. The results of this study can be incorporated into existing harvest cost prediction programs to improve estimates for this region.

No abstract