scholarly journals Productivity and Cost of Integrated Harvesting of Wood Chips and Sawlogs in Stand Conversion Operations

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Hunter Harrill ◽  
Han-Sup Han
Keyword(s):  
Small Diameter ◽  
Integrated System ◽  
Wood Chips ◽  
Average Moisture Content ◽  
Total System ◽  
Fuel Price ◽  
Energy Wood ◽  
Lithocarpus Densiflorus ◽  
Stand Conversion ◽  
Small Diameter Trees

This study evaluated the operational performance and cost of an integrated harvesting system that harvested sawlogs and biomass (i.e., energy wood chips) in stand conversion clearcut operations. Douglas-fir (Pseudotsuga menziesii) trees were processed into sawlogs while whole trees of tanoak (Lithocarpus densiflorus), and sub-merchantable materials (small-diameter trees, tops and limbs) were fed directly into a chipper to produce biomass for energy production. A standard time study method was used to determine productivity and costs. Over 26 working days, the integrated system produced 1,316 bone-dry metric tonnes (BDTs) of sawlogs, and 5,415.89 BDT of chips, with an average moisture content of 43.2%. Using the joint products allocation costing method, the costs of the integrated system were $29.87/BDT for biomass and $4.26/BDT for sawlogs. Chipping utilization was as low as 41%, directly affecting production and cost of chipping operation. Single-lane, dirt, spur roads were the most costly road type to transport whole trees to a centralized processing site: transportation costs for biomass and sawlogs were increased by $0.08/BDT and $0.02/BDT, respectively, for every 50 meter increase in traveling distance. Diesel fuel price could raise total system cost for each product by $0.78/BDT and $0.08/BDT for each $0.10/liter increase.

Evaluation of moisture reduction in small diameter trees after crushing

1991 ◽  
Vol 37 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Donald L. Sirois ◽  
Cynthia L. Rawlins ◽  
Bryce J. Stokes
Keyword(s):  
Small Diameter ◽  
Small Diameter Trees

scholarly journals Chipping Whole Trees for Fuel Chips: A Production Study

2007 ◽  
Vol 31 (4) ◽  
pp. 176-180 ◽  
Author(s):  
Dana Mitchell ◽  
Tom Gallagher
Keyword(s):  
Loblolly Pine ◽  
Longleaf Pine ◽  
Small Diameter ◽  
Wage Rates ◽  
Time And Motion ◽  
Motion Study ◽  
Average Production ◽  
Production Study ◽  
Small Diameter Trees ◽  
The Cost

Abstract A time and motion study was conducted to determine the productivity and cost of an in-woods chipping operation when processing whole small-diameter trees for biomass. The study removed biomass from two overstocked stands and compared the cost of this treatment to existing alternatives. The treatment stands consisted of a 30-year-old longleaf pine stand and a 37-year-old loblolly pine stand. In the longleaf pine stand, 71% of the trees removed were less than 5 in. dbh. In the loblolly pine stand, approximately 81% of the stems removed were less than 5 in. dbh. The harvesting system consisted of conventional ground-based harvesting equipment and a three-knife chipper that processed the biomass into fuel chips. The average production time to fill a chip van was 24.61 minutes. The chip moisture content averaged 94.11% (dry basis). Using machine rates and federal labor wage rates, the in-woods cost of producing fuel chips was $9.18/green ton (gt). The cost of the biomass chipping operation ($15.18/gt), including transportation, compared favorably to existing alternative treatments of cut-and-pile or mulching.

scholarly journals Dual-Cropping Loblolly Pine for Biomass Energy and Conventional Wood Products

2008 ◽  
Vol 32 (1) ◽  
pp. 33-37 ◽  
Author(s):  
D. Andrew Scott ◽  
Allan Tiarks
Keyword(s):  
Loblolly Pine ◽  
Small Diameter ◽  
Cropping System ◽  
N Fertilization ◽  
Wood Products ◽  
Biomass Energy ◽  
Pine Plantation ◽  
Southern Pine ◽  
Small Diameter Trees ◽  
Viable Method

Abstract Southern pine stands have the potential to provide significant feedstocks for the growing biomass energy and biofuel markets. Although initial feedstocks likely will come from low-value small-diameter trees, understory vegetation, and slash, a sustainable and continuous supply of biomass is necessary to support and grow a wood bioenergy market. As long as solidwood products are more valuable, bioenergy production will not be the primary market for southern pine. A study exploring a dual-cropping system for southern pine bioenergy and solidwood products was begun in 1982 in Louisiana to determine the phosphorus (P) nutritional requirements of the system. Fertilization of 60 kg ha−1 of P was required to produce 90% of the maximum volume at the age of 22 years. Direct-seeding pine in the interrows of a traditional pine plantation produced about 10.2 Mg ha−1 of biomass for energy at the age of 5 years but had no lasting effect on the planted pine height, diameter, or standing volume. The system is a viable method to produce both bioenergy and solidwood products. Herbaceous competition control and nitrogen (N) fertilization likely would make the system even more productive and profitable.

The Human Systems Integration Framework: Enhanced HSI support for System Acquisition

2017 ◽  
Vol 61 (1) ◽  
pp. 1720-1724
Author(s):  
Frank C. Lacson ◽  
Matthew R. Risser ◽  
John W. Gwynne ◽  
William D. Kosnik
Keyword(s):  
Systems Engineering ◽  
System Performance ◽  
Web Application ◽  
Human Performance ◽  
Systems Integration ◽  
Integrated System ◽  
Total System ◽  
Human Systems Integration ◽  
System Acquisition ◽  
Human Systems

Ensuring that human performance factors are adequately considered during the system engineering process has proven to be a challenging task for Human Factors and Human Systems Integration (HSI) practitioners. Programs that do not sufficiently include HSI as an integral aspect of planning and execution are at risk of diminished user performance and total system performance, leading to costly and time-consuming re-work. To encourage a greater involvement of HSI in systems engineering, the HSI Framework (HSIF) was developed to explicitly incorporate HSI tasks and products in all stages of system acquisition. The HSIF is a web application that contains general and domain-specific HSI activities, references, and related products. For HSI Practitioners and System Engineers, the HSIF provides technical guidance and best practices, thereby fostering early, explicit, and properly-scoped HSI efforts. In turn, Program Managers and Technical Authorities are provided with the information needed to accurately assess and manage human performance-related risks, leading to relevant, effective, and integrated system performance.

Influence of feeding damage by small mammals on tree growth and wood quality in young lodgepole pine

1993 ◽  
Vol 23 (5) ◽  
pp. 799-809 ◽  
Author(s):  
Thomas P. Sullivan ◽  
Harry Coates ◽  
Les A. Jozsa ◽  
Paul K. Diggle
Keyword(s):  
Lodgepole Pine ◽  
Wood Quality ◽  
Ring Width ◽  
Small Diameter ◽  
Height Growth ◽  
Diameter Increment ◽  
Significant Difference ◽  
Small Diameter Trees ◽  
Severe Degree ◽  
The Impact

This study assessed the impact of feeding injuries by snowshoe hare (Lepusamericanus Erxleben) and red squirrel (Tamiasciurushudsonicus Erxleben) on diameter growth, height growth, and wood quality of juvenile lodgepole pine (Pinuscontorta Dougl. var latifolia Engelm.) at Prince George and in the Cariboo Region, British Columbia. In the Prince George control stand, severe girdling damage (50–99% stem circumference) suppressed diameter and height growth of small-diameter (4.1–6.0 cm) trees, but had no effect on larger stems (6.1–8.0 cm). In the spaced stand, diameter and height increments also declined significantly with degree of partial girdling, particularly in small-diameter (3.1–5.0 cm) trees. Paradoxically, diameter increment increased significantly with degree of partial girdling in both stands at the Cariboo study area. Presumably squirrels prefer to feed on vigorous stems, and the lost growth of these trees may be substantial. There was no significant difference in amount of compression wood nor total solvent and water extractives between undamaged and damaged trees. Fiber lengths in wound-associated wood were consistently 19–21% lower than in controls. Damaged trees had greater average ring width and density than undamaged trees. The average increase in relative density of damaged over undamaged trees was 0.0343. These results suggest that a severe degree of partial girdling (which likely occurs more often in small-diameter trees) may significantly affect growth of lodgepole pine, particularly small (<5.0 cm DBH) trees.

scholarly journals Production Costs and Markets for Pellet Chips: Case Studies in Northern Sweden

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Gunnar Eriksson ◽  
Dimitris Athanassiadis ◽  
Dan Bergström ◽  
Tomas Nordfjell ◽  
Urban Bergsten
Keyword(s):  
Raw Materials ◽  
Small Diameter ◽  
National Forest Inventory ◽  
Production Costs ◽  
Raw Material ◽  
Small Scale ◽  
Northern Sweden ◽  
Forest Residues ◽  
Logging Residues ◽  
Small Diameter Trees

Increasing use of woody fuels requires that nontraditional types of raw materials are exploited, including logging residues and small-diameter trees. Although medium-scale combustors often use pellets, they could conceivably use dried chips of sufficiently narrow size distribution (henceforth pellet chips). The influence of the following factors on the relative cost-effectiveness of producing pellets and pellet chips was investigated for three plant sites in northern Sweden: (1) harvesting and transporting of forest residues; (2) the potential of existing energy plants to supply drying heat in periods of capacity surplus; (3) the distance to potential end-users. Data from the national forest inventory were used to estimate raw material costs. The resulting production costs were 144–176 $ per oven-dry tonnes (OD t) for pellets (27.4–33.5 $ MWh−1) and 143–173 $ OD t−1(27.2–33.0 $ MWh−1) for pellet chips, with harvesting, forwarding, chipping, and transporting of logging residues to the sites amounting to 114–122 $ OD t−1(21.7–23.2 $ MWh−1) for both fuels. Even though the differences in production costs were minor, the production of pellet chips requires significantly less electricity input per OD t of produced fuel. For cost reductions improved methods for wood fuel procurement, compacting and transporting of chips, small-scale low-temperature drying and foliage and bark separation are needed.

scholarly journals Dimensional Stabilization of Wood Originating from Small-diameter Trees through Heat Treatment

BioResources ◽  
2014 ◽  
Vol 9 (3) ◽  
Author(s):  
Cristina Marinela Olarescu ◽  
Mihaela Campean ◽  
Alin Olarescu
Keyword(s):  
Heat Treatment ◽  
Small Diameter ◽  
Small Diameter Trees

scholarly journals The economic efficiency of forest energy wood chip production in regional use – A case study

2013 ◽  
Vol 61 (5) ◽  
pp. 1391-1398 ◽  
Author(s):  
Dalibor Šafařík ◽  
Tomáš Badal
Keyword(s):  
Economic Efficiency ◽  
Wood Chip ◽  
Tipping Point ◽  
Wood Chips ◽  
Raw Material ◽  
Limiting Factors ◽  
Limiting Factor ◽  
Final Consumption ◽  
Energy Wood

This regional project case study deals with the limiting factors of economic efficiency in the production of forest energy wood chips. The evaluation of production efficiency made use of data obtained from the Lesy města Brna, a.s. (Forest of the City of Brno, Corp.), which were subjected to two static methods of investment evaluation: an analysis of the tipping point and determination of the limit of variable costs and a dynamic modified tipping point analysis using cash flow (i.e. cash break even analysis). The results have confirmed an established hypothesis, namely that the decisive factor in the profitability of the production of forest energy wood chips hinges on the costs incurred in the gathering of raw material and the distribution of the produced chips. The results include a further limiting factor: transportation costs to the final consumption location. The output of the study is a recommendation that the concentration of residual forest materials not exceed a distance of 250 m from the place of production to the point of disintegration and that the transport distance of energy chips not exceed 50 km from the place of disintegration to the final consumption point. These limiting values help quantify the full internal costs per cost unit, full internal cost profitability, total revenue profitability and annual profitability expressed in terms of fixed assets depreciation without factoring in financial aid.

scholarly journals Frost Crack Incidence in Northern Hardwood Forests of the Southern Boreal–North Temperate Transition Zone

2008 ◽  
Vol 25 (3) ◽  
pp. 133-138 ◽  
Author(s):  
Julia I. Burton ◽  
Eric K. Zenner ◽  
Lee E. Frelich
Keyword(s):  
Structural Characteristics ◽  
Regional Climate ◽  
Small Diameter ◽  
Basal Area ◽  
Selective Logging ◽  
Tree Level ◽  
Diameter Class ◽  
Northern Hardwood ◽  
Second Growth ◽  
Small Diameter Trees

Abstract Frost cracks are common in northern hardwood stands near their northern range limits. Although they have long been attributed to the regional climate, temperature fluctuations result in surface cracks largely when internal wounds are present. We examined the relationship between the proportion of trees with frost cracks and both tree-level diameter class and stand structural characteristics in primary stands with a history of minimal logging (n = 4) and 67- to 97-year-old second-growth stands subjected to past heavy partial cuts and high grading (n = 8). We hypothesized that frost crack incidence would (1) be greater in the second-growth stands and (2) be associated with differences in structural attributes between the two stand types. High levels of frost cracking in primary stands indicated that cracks are not completely avoidable. However, the proportion of trees with frost cracks was significantly higher in second-growth than primary stands, particularly on small-diameter trees. For example, the odds for frost cracking were 1.66–3.74 times greater in second-growth than in primary stands in the 15-cm diameter class, but were not different in the 45+-cm diameter class. Frost cracking was positively associated with increasing diameter in both stand types. Structural characteristics reflecting tree size, stand basal area, and basal area of hardwoods were positively associated with the proportion of trees with frost cracks in second-growth stands but not in primary stands. Although the basal area of conifers was negatively associated with frost cracking, the effect was likely due to a reduction in hardwood basal area in the vicinity of conifers. We suggest that greater frost crack incidence in second-growth stands is likely a consequence of injuries to residual trees during selective logging.

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