Timber harvest layout by mathematical and Heuristic programming

Although some of the most difficult problems in forest management occur as a result of timber harvest operations, present methodology in harvest planning emphasizes guidelines which rely heavily upon the experience of the individual forest manager for their correct application. This study was undertaken in an effort to develop a comprehensive methodology to assist forest managers in the design of timber harvest cutting units and the assignment of logging equipment: to those units. The objective of the methodology is to maximize the total value of the timber harvested from a planning area, net of variable and fixed harvesting and transportation costs. The methodology thus developed consists of a two-part procedure. The first part considers the specific topographic and timber conditions on the planning area, plus any harvesting restrictions which may have been imposed on portions of the area because of expected environmental problems, This information is combined with the known mechanics of the logging systems under consideration to determine the feasibility and cost of harvesting each parcel of timber from the area. The second part of the methodology consists of a heuristic optimization algorithm which seeks to assign timber parcels to harvesting facilities so that total timber value, net of fixed and variable harvesting and transportation costs, is maximized. The output from this algorithm is a detailed harvest plan which specifies yarding system assignments and the physical layout of cutting units for each yarding system thus assigned. The optimization problem confronted in this study is an application of facilities location theory, but with two unique characteristics which render the conventional mixed integer programming formulation unsuitable for this problem. First, the planning area is visualized as being dichotomized into timber parcels of equal size, each of which is to be assigned to some harvesting facility. Thus, the problem is a fully discrete one, and can be formulated as a 0-1 integer programming problem. Second, the problem exhibits a special "cascading fixed charge" structure. Stated simply, this implies that several levels of fixed charges must be incurred for any complete facility installation. Thus, if a specific logging cableway is to be emplaced at a certain landing, then the fixed charge associated with the construction of the landing must already have been incurred, and the fixed charge associated with the installation of some yarding system at the landing must also have been incurred. Unfortunately the 0-1 integer programming formulation appropriate for this problem requires many thousands of variables and constraints, even for relatively small planning areas. To overcome the computational difficulties associated with the solution of such large integer programming problems, a heuristic algorithm was developed to find satisfactory, rather than optimal solutions. Applied to a realistic forest planning problem with 5507 variables and 6555 constraints, the algorithm found an initial feasible solution after 93.3 minutes on a CDC 3300 computer. The run was terminated after a total of 120 minutes, with the value of the final solution being only 0.09 percent better than that of the initial solution. Although the exact solution could not be verified, computational experience with smaller problems suggests that the initial feasible solution obtained with this algorithm is usually very close to the optimal solution

Production rates and costs for yarding by cable, balloon, and helicopter compared for clearcuttings and partial cuttings

This report supplements Research Bulletin 18 (1975) of the Forest Research Laboratory, School of Forestry, Oregon State University. Bulletin 18 summarized analyses of data for the first field season of the Pansy Basin Study. This Bulletin extends those analyses to the second, and final, field season. Time-study observations during the second field season were made of three yarding systems: running skyline, balloon haulback, and heavy-lift helicopter. The running skyline was observed in a partial cutting, the balloon in a clearcutting, and the helicopter in both clearcuttings and partial cuttings. All of the cutting units were designed to reduce damage to the appearance of the landscape. Results of the analyses suggest that productive yarding time is a function of yarding distance, volume per turn and per log, chordslope, and numbers of logs or chokers per turn. For the running skyline and the balloon, lateral yarding distance was also an important determinant of productive yarding time. In addition, the number of men in the rigging crew was found to be a statistically significant predictor for the running skyline, as was tagline length for the balloon. For the running skyline system, the data in this study support the hypothesis that yarding production rates are significantly influenced by silvicultural treatment. For the helicopter, however, no significant difference appeared in yarding rates between the clearcutting and partial cutting treatments. The effect of cutting unit design on yarding efficiency for cable systems cannot be generalized, although it did not appear to be significant for the cutting units in the Pansy Basin Study. Certainly, cutting units can be designed for which unit shape is an important determinant of cable yarding productivity. Shape of cutting unit would not be expected to influence helicopter yarding productivity, however

Production rates and costs for cable, balloon, and helicopter yarding systems in old-growth Douglas-fir

This report describes initial results of a yarding time study for the Pansy Basin Study, a cooperative research project designed to test the performance of skylines, balloons, and helicopters operating under various conditions of timber and terrain, and over a range of silvicultural and landscape design prescriptions. Observations during the first field season were limited to a single harvesting prescription (clearcutting) and to conventional cutting patterns. Six yarding systems were studied: highlead, North Bend skyline, Grabinski running skyline, shotgun skyline ("flyer"), balloon, inverted skyline, and helicopter. Results of this study suggest that productive yarding time is a function of yarding distance, volume per turn, number of logs per turn, and conditions at the hooking site. For the helicopter and balloon, productive time also is influenced by chord slope and tagline length. Delays and downtime are important segments of total yarding time for all systems and are unpredictable for the most part. Thus, future analysis of delays may lead to significant improvements in yarding production rates. The report includes a procedure for estimating direct yarding costs from time-study data gathered on a sampling basis. Direct yarding cost is often the largest single item on an appraisal or logging cost analysis, and usually the most difficult to estimate. Sufficient detail is included in the explanation of the procedure to permit its use by field personnel in harvest unit planning and appraisal

Yarding delays for advanced logging systems

Yarding delays add significantly to the time and cost required to obtain a given quantity of timber. In this study, they increased total yarding time by as much as 28 percent. As yarding system complexity increases, the frequency of delays can also be expected to increase. For one balloon yarding system in a clearcutting and for a running skyline in a partial cutting, the frequency of operating delays was positively correlated with yarding distance. Operating delays for cable systems occurred more frequently in partial cuttings than in clearcuttings. Delays on two helicopter operations were caused chiefly by refueling and were not influenced significantly by either yarding distance or silvicultural method

A technique for the solution of the catenary problem in surveying

A technique for solving efficiently the catenary problem encountered in surveying with tapes is presented. The theory of the catenary solution is outlined, and our technique is shown to solve correctly the catenary for all conditions. Analysis of error that compared the catenary correction to the more commonly used parabolic correction indicated that for slopes over 10 degrees and taped distances greater than 200 feet, systematic error inherent in the parabola may preclude the accuracy required for second- or even third-order surveys. An analysis of tension-gauge bias on taping errors is similar, but here the error is found to depend almost entirely upon taping distance

Harmonic BRST Quantization of Systems with Irreducible Holomorphic Boson and Fermion Constraints

We show that the harmonic Becchi-Rouet-Stora-Tyutin method of quantizing bosonic systems with second-class constraints or first-class holomorphic constraints extends to systems having both bosonic and fermionic second-class or first-class holomorphic constraints. Using a limit argument, we show that the harmonic BRST modified path integral reproduces the correct Senjanovic measure.Comment: 11 pages, phyzz

U.S. Billion-ton Update: Biomass Supply for a Bioenergy and Bioproducts Industry

The Report, Biomass as Feedstock for a Bioenergy and Bioproducts Industry: The Technical Feasibility of a Billion-Ton Annual Supply (generally referred to as the Billion-Ton Study or 2005 BTS), was an estimate of “potential” biomass within the contiguous United States based on numerous assumptions about current and future inventory and production capacity, availability, and technology. In the 2005 BTS, a strategic analysis was undertaken to determine if U.S. agriculture and forest resources have the capability to potentially produce at least one billion dry tons of biomass annually, in a sustainable manner—enough to displace approximately 30% of the country’s present petroleum consumption. To ensure reasonable confidence in the study results, an effort was made to use relatively conservative assumptions. However, for both agriculture and forestry, the resource potential was not restricted by price. That is, all identified biomass was potentially available, even though some potential feedstock would more than likely be too expensive to actually be economically available. In addition to updating the 2005 study, this report attempts to address a number of its shortcoming

Sun Protection Intervention for Highway Workers: Long-Term Efficacy of UV Photography and Skin Cancer Information on Men’s Protective Cognitions and Behavior

The risk for skin cancer is increased among older males and outdoor workers who have high levels of ultraviolet (UV) exposure. This study was designed to examine the long-term efficacy of UV photography interventions on male outdoor workers, the potential mediators of its impact, and the efficacy of UV photography and skin cancer vs. aging information with this population. One hundred forty-eight male outdoor workers were randomly assigned to one of four intervention conditions or a control condition in a two by two plus one factorial design. The men in the intervention conditions received or did not receive a UV photo of their face and watched either a photoaging or skin cancer educational video. Participants completed pre-intervention, immediate post-intervention, and 2-month and 1-year follow-up assessments. Analysis of covariance and structural equation modeling revealed that participants in the UV photography and cancer information interventions reported higher levels of sun protection cognitions, which were significant partial mediators of increases in sun protection behaviors and decreases in skin color. This study provides evidence for effective sun protection interventions on male outdoor workers that may help reduce skin cancer risk

Mathematical programming for natural resource management

Dennis P. Dykstra.xvi, 318 p. : ill. ; 24 cm