Thesis (M.F.)--Oregon State University, 1977. / Includes bibliographical references (p. 40-43). Also available on the World Wide Web.

This thesis provides a methodology for examining forest harvesting operations through simulation. The model is capable of simulating multiple landing, single dump logging configurations. Facility locations, equipment types and numbers, parameters, and functional relationships may be varied so that a wide range of west coast British Columbia logging operations can be represented. The model was written in General Purpose Simulation System V (GPSSV) language. A substantial saving in development cost is realized over a FORTRAN-based simulation. The model allows independent users to make modifications within the program in order to adapt to the particular operating rules and policies of their operations. Model formulation for this thesis is based on an actual west coast logging division. Verification of the model involves a three-stage approach. First, a set of hypotheses and postulates are constructed for the subsystems of the harvesting operation and, secondly, these are empirically tested. Historical data is compared to simulation results in order to confirm that particular subsystems adequately model the real system. Tactical considerations and experimental design regarding model execution are presented. It is shown that antithetic variates can be effectively used to reduce the variance of the mean of a response. An improved truck dispatching routine is developed with the objective of maximizing productivity, subject to the availability of yarding and trucking resources. This policy balances the objectives of minimizing truck travel time, truck delays at landings, and yarding stoppages due to timber "saturated" landings. In comparison with other dispatching policies, productivity can be increased from two to over ten percent. The dispatching algorithm has been programmed for a Hewlett-Packard 9830A desktop computing system. The dispatcher, utilizing radio communications with all of the landings and trucks, can theoretically be supplied with the optimum landing to which a truck should be dispatched. Some other practical applications of the timber harvesting simulation model are discussed. Flexibility in the model, in parameter initialization and the substitution of new relationships, allows the investigation of many features of forest resource planning and machine allocation and scheduling. The determination of equipment requirements for various configurations, the evaluation of new equipment and the comparison of different operating policies can be undertaken with the model. Another benefit derived from the development of the model is an increased understanding of the timber harvesting system which allows the design of better operating policies and greater control within the system. / Forestry, Faculty of / Graduate

Mémoire (M.Ress.Renouv.)--Université du Québec à Chicoutimi, 1999. / Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Ress.Renouv.)--Université du Québec à Chicoutimi, 1997. / Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Ress.Renouv.)--Université du Québec à Chicoutimi, 2001. / Document électronique également accessible en format PDF. CaQCU

Measurements of DBH, upper diameters, merchantable height and total heights were made on 80 standing white oaks (<i>Quercus alba</i>) which were then felled for detailed measurements of the same parameters. The data obtained were used to evaluate the accuracy of standing tree measurements, to develop and compare volume equations that used upper diameter as one of the predictor variables and to examine the contributions of individual predictor variables to total volume prediction bias and precision. Relative bias ranged from 0.85% for DBH measurement errors to 2.88% for total height measurement errors. Relative standard deviation ranged from 1.52% to 10.13% for DBH and total height errors respectively. When both bias and precision ( standard deviation ) were considered jointly, the relative root mean squared error ranged from 1.75% to 10.48% for DBH and total height errors respectively. Upper diameter and merchantable height showed negative bias. A comparison of eight fitted models against the combined variable model revealed a gain in precision and a reduction in bias for models that used upper diameter as a third predictor variable. The improvement as based on the relative root mean squared error ranged from 28.8% to 71.3% for taped measurements. However, models that used upper diameter as a substitute for either DBH or merchantable height performed worse than the combined variable model. An analytic examination of the impact of measurement error on volume prediction bias showed that merchantable height errors accounted for most of the bias and that DBH and upper diameter errors contributed almost equal amounts(in absolute terms) to the volume bias. / Master of Science

Beavers have been described as a “keystone species” and “ecosystem engineers”, and in this dual role have great potential to physically modify their environment through tree-felling, foraging and construction activities. The resultant change in habitat heterogeneity can affect the flora and fauna that share the habitat with them. There has been recent interest in reintroducing the Eurasian beaver to the United Kingdom after an absence of over 400 years. To date, no research (aside from this thesis) has focussed on beaver ecology and behaviour in Scotland. This study has investigated the ecological effects of a small number of beavers in two enclosed but semi-natural Scottish sites at Bamff in Perthshire. The research conducted over a three-year period, with particular emphasis on the effects of tree-felling, foraging and construction activities. Trees were felled for both dietary and construction purposes, with felling rates being influenced by habitat availability, quality and the degree of habitat modification required. Highest rates were evident during the initial colonisation period of marginal sites (c. >300 trees / beaver / calendar year), and lowest rates in later years of occupation of more optimal sites (c. 55 – 70 trees / beaver / calendar year). Preferences were generally for willow and aspen trees, with conifers almost entirely avoided, and smaller trees preferred over larger ones. Proximity of trees to waterbodies was also an important factor, with nearer trees favoured, and generally most felling occurred within 50 m of water. Such behaviour followed the principles of optimal central place foraging. These preferences were less predictable however when intense construction activity was undertaken, with larger trees preferred and generic preferences for deciduous trees apparently invalid. In such cases, close proximity to the construction site was of prime importance. Increased cover of herbaceous plant species was observed in beaver-created canopy gaps in riparian woodland, whilst macrophyte diversity within waterbodies increased slightly in areas of herbaceous grazing. The diversity of terrestrial ground invertebrates was highest in areas of heavy tree-felling, and invertebrate richness and abundance was greatest in areas of herbaceous grazing under an intact tree-canopy. Furthermore, the abundance, diversity and richness of macroinvertebrate communities were increased by beaver-generated woody debris in ponds and streams. Overall, 30% of all macroinvertebrate species collected were found only in beaver-affected areas, due to the refugia and food supply provided by beaver dams, caches and lodges, as well as hydrological effects of these structures. These results are discussed with reference to future plans to return the beaver to Scotland. The habitat usage and modification of riparian ecosystems in northern Britain is likely to be similar to that found in this study, and the results are believed to be relevant, applicable and transferable to many areas of Scotland.

<p><a>The primary goal of this research was to summarize the occupational farm-related fatalities of Indiana farmers 55 years and older and to recommend evidence-based intervention strategies targeting older farmers who perform activities that involve the cutting and trimming of trees. The primary activities consisted of (1) preparing a summary of occupational farm-related fatalities of farmers who were 55 years and older, (2) preparing a summary of occupational farm-related fatalities of older farmers who were performing activities in a woodlot setting or that included the occasional cutting and trimming of trees, and finally (3) the development of recommendations for evidence-based injury prevention strategies targeting older farmers who conduct occasional woodcutting activities. </a></p> <p>The summary of older Indiana farmer fatalities identified a total of 388 fatalities reported between 1988 and 2017 with an increase in the number of reported fatalities over the period of 2012-2017. Tractors were identified as the most common source of injury (40.5%) with tractor overturns involved in no fewer than 86 cases or 22.2% of all cases. Older farmer fatalities for occasional woodcutters accounted for 40 fatalities with the cutting and trimming of trees to be the most common cause of injury (67.5%). </p> <p>Core desired safety competencies were identified that were used to develop injury prevention strategies based upon the summary of injuries, areas of concerns reported in the review of literature and the results gathered from the summaries of Indiana older farmers killed while performing woodcutting activities. A pilot evidence-based intervention instructional presentation was developed with the assistance of a panel of experts to be used by Extension Educators to increase awareness of the target population of current safety practices relating to woodlot activities. </p>