Optimal skyline corridor spacing for partial cutting in second-growth stands of coastal British Columbia

1996 ◽  
Vol 26 (3) ◽  
pp. 368-375
Author(s):  
Andrew F. Howard ◽  
Dag Rutherford ◽  
G. Glen Young
Keyword(s):  
British Columbia ◽  
Cost Savings ◽  
Significant Cost ◽  
Partial Cutting ◽  
Mathematical Basis ◽  
Optimal Distance ◽  
Second Growth ◽  
Optimal Spacing ◽  
Coastal British Columbia

This paper presents the findings of a study on the economically optimal spacing of skyline corridors in partial cuts in second-growth stands of British Columbia. The mathematical basis for optimal spacing of corridors is presented for rectangular settings when trees are felled in a herring-bone pattern to facilitate yarding. The model is used in a case study where optimal spacing is compared with actual spacing for two yarding systems observed in the field. The results indicate that significant cost savings are possible from spacing skyline corridors at the optimal distance compared with conventional spacing used by the logging contractors.

Optimal road spacing for multistage cable yarding operations

1990 ◽  
Vol 20 (6) ◽  
pp. 669-673 ◽  
Author(s):  
Andrew F. Howard ◽  
Jordan S. Tanz
Keyword(s):  
British Columbia ◽  
Cost Savings ◽  
Two Stage ◽  
One Stage ◽  
Optimal Spacing ◽  
Cable Yarding ◽  
Break Even Point ◽  
Site Disturbance ◽  
Coastal British Columbia

Equations needed to determine the economically optimal spacing of roads for multistage, one-way to roadside cable yarding were derived. The equations were used in a case study of optimal road spacing on four grapple yarding operations in coastal British Columbia. Two-stage yarding was cheaper and led to closer road spacing than one-stage yarding in all cases. The break-even point for two- and three-stage yarding with respect to road cost was defined as critical road cost. Three-stage yarding provided cost savings and a substantial increase in road spacing once critical road costs were exceeded. Critical road costs for three-stage yarding were within the range experienced in coastal British Columbia for the operations included in the case study. The potential for cost savings and reduced site disturbance from multistage yarding warrants serious consideration of these systems during harvest planning.

Damage to residual trees from cable yarding when partial cutting second-growth stands in coastal British Columbia

1996 ◽  
Vol 26 (8) ◽  
pp. 1392-1396 ◽  
Author(s):  
Andrew F. Howard
Keyword(s):  
British Columbia ◽  
Partial Cutting ◽  
Western Redcedar ◽  
Second Growth ◽  
Cable Yarding ◽  
Cable Systems ◽  
Residual Tree ◽  
Stand Damage ◽  
Stand Conditions ◽  
Coastal British Columbia

Damage to residual trees associated with a specific combination of stand conditions, silvicultural treatment, and harvesting system must be known if this information is to guide foresters in the design of prescriptions for individual stands planned for partial cutting. A study was made of residual tree damage in two stands of second growth in coastal British Columbia that were partially cut and the timber was yarded with cable systems. Damage to residual trees was found to be high at both sites. The percentage of trees damaged decreased with increasing distance from the skyline corridor, and bigger trees were less likely to be damaged than small ones. Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was shown to be the least susceptible to damage, followed by western hemlock (Tsugaheterophylla (Raf.) Sarg.) and finally western redcedar (Thujaplicata Donn ex D. Don). Wider spacing of skyline corridors is suggested as one means for reducing stand damage.

Progressive Collapse Approach Compared to the Traditional Temperature Screening on Structural Assessment of Offshore Structures Against Fire

2016 ◽  
Author(s):  
Paula T. Nascimento ◽  
Marco A. P. Rosas ◽  
Leonardo Brandão ◽  
Fernando Castanheira
Keyword(s):  
Traditional Approach ◽  
Progressive Collapse ◽  
Screening Method ◽  
Substantial Reduction ◽  
Cost Savings ◽  
Offshore Structures ◽  
Significant Cost ◽  
Fire Scenarios

The present study compares the progressive collapse approach with the traditional temperature screening method on determination of PFP requirements at topside offshore structures. The advantage to evaluate the consequences of fire scenarios on the global integrity and stability of topside modules can be revealed by a substantial reduction of the required amount of PFP, and consequently significant cost savings for operators, when compared to the traditional approach. In the case study presented in this paper, there is a reduction of 79% in PFP allocation.

Highlead Yarding Productivity and Costs in Coastal British Columbia: Predicted vs. Actual

1989 ◽  
Vol 4 (3) ◽  
pp. 98-101 ◽  
Author(s):  
Andrew F. Howard ◽  
Dusan Dodic
Keyword(s):  
British Columbia ◽  
Simulation Program ◽  
Production Rates ◽  
Deterministic Simulation ◽  
Second Growth ◽  
Scheduled Time ◽  
Coastal British Columbia

Abstract A production equation taken from the literature was used to estimate productivity and costs for an ongoing highlead yarding operation. The equation was encoded in a deterministic simulation program, which was used to predict production rates and costs for a contractor yarding second-growth timber in coastal British Columbia. The equation yielded estimates of scheduled time and total costs within 3.4% of actual costs experienced by the contractor for two tracts of timber. The findings suggest that published production equations might have wider application than generally thought. West. J. Appl. For. 4(3):98-101, July 1989.

Analysis and Cost Estimation of a Total Site Using R-Curve

2009 ◽  
Author(s):  
Sh. Karimkashi ◽  
M. Amidpour
Keyword(s):  
Cost Estimation ◽  
Cost Savings ◽  
Analysis Tool ◽  
Significant Cost ◽  
R Ratio ◽  
Utility System ◽  
Graphical Tool ◽  
A Site ◽  
The Cost

In large processing sites the cost of fuel and power can be very significant and better management of the utility system can lead to significant cost savings. The R-curve is an analysis tool that provides guidelines for the cogeneration efficiency for a given site power-to-heat ratio demand of an ideal utility system. In this paper, the actual R-curve is combined with another graphical tool, representing the cost of cogeneration potential of a site. In fact in each case, actual R-curve is constructed and then another curve of ‘R-ratio vs. TAC’ is constructed to demonstrate the cost of each point of the R-Curve. Finally showing the results obtained for a case study, it is suggested to change sizes of the turbines in the utility system to improve the R-curve and also decrease the TAC for the same R-ratios. These changes are almost dependent to the case being studied.

Impact of feeding damage by the porcupine on western hemlock – Sitka spruce forests of north-coastal British Columbia

1986 ◽  
Vol 16 (3) ◽  
pp. 642-647 ◽  
Author(s):  
Thomas P. Sullivan ◽  
William T. Jackson ◽  
James Pojar ◽  
Allen Banner
Keyword(s):  
British Columbia ◽  
Small Diameter ◽  
Sitka Spruce ◽  
Control Measures ◽  
Western Hemlock ◽  
Feeding Damage ◽  
Red Cedar ◽  
Total Percentage ◽  
Second Growth ◽  
Coastal British Columbia

This study measured the incidence of feeding damage by porcupines (Erethizondorsatum Allen) within the second-growth western hemlock (Tsugaheterophylla Raf. (Sarg.)) – Sitka spruce (Piceasitchensis (Bong.) Carr.) forest of Khutzeymateen Inlet, 45 km northeast of Prince Rupert, British Columbia. Tree mensuration and damage assessments were conducted in 69 sample plots located on four transects. Western hemlock, which composed 67% of sampled stands, was the most severely (52.7% of trees, of which 5.1% were newly attacked) damaged species followed by Sitka spruce with minor (7.8%) damage. The less frequent amabilis fir (Abiesamabilis (Dougl.) Forbes) and western red cedar Thujaplicata Donn.) were not attacked. The total percentage of girdled (mortality) hemlock stems was 30.9%. Hemlock trees with a dbh > 27.4 cm had 55.9% of stems girdled. Porcupines attacked and girdled a significantly greater proportion of large than small diameter hemlock trees. Stems smaller than 125.5 cm dbh had little (3.7%) damage. Significantly more damage wounds were recorded in the middle and upper thirds of hemlock stems than in the lower bole. Dominant and codominant hemlock were preferred by porcupines in their feeding attacks. In combination with porcupine control measures, these stands clearly require some form of silvicultural treatment, such as sanitation spacing, conducted initially as an operational trial on at least a 20-ha block.

New Technology to Recycle and Rebuild Worn Polyurethane Pipeline Pigs

2000 ◽  
Author(s):  
Graham D. Bruce
Keyword(s):  
High Performance ◽  
Mechanical Characteristics ◽  
New Technology ◽  
Cost Savings ◽  
Process Technology ◽  
Significant Cost ◽  
Oil Pipeline ◽  
Successful Program ◽  
Thermoset Polymer

SUNcast Polyurethanes Inc. has developed a proprietary process technology that makes it possible to rebuild worn Polyurethane (PU) discs, cups and solid cast pipeline pigs. The technology creates a completely secure bond between the virgin and cured cast elastomer PU enabling rebuilt parts to perform “as new”. This paper addresses the mechanical characteristics of the bond possible with this technology and offers the results of a case study on a successful program to rebuild over fifty 24″ solid cast pigs for a crude oil pipeline. Cast elastomer PU is an expensive thermoset polymer which has not been readily recyclable. SUNcast’s technology offers pipeline operators, contractors and inspection companies an opportunity to recycle what is now waste back into high performance pigging products at significant cost savings.

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