A comparison of FORMAN and linear programming approaches to timber harvest scheduling

1990 ◽  
Vol 20 (9) ◽  
pp. 1351-1360 ◽  
Author(s):  
Mark S. Jamnick
Keyword(s):  
Linear Programming ◽  
Timber Harvest ◽  
The Other ◽  
Scheduling Problem ◽  
Harvest Scheduling ◽  
Wood Supply ◽  
Supply Model

Harvest schedules are developed and compared for two hypothetical 129 900-ha forests using the FORMAN wood supply model and linear programming. The purpose is to determine how the harvest schedules and models differ and under what conditions one model would be preferred over the other. The results clearly demonstrate that compared with FORMAN, linear programming is able to find solutions with higher harvest volumes in every case considered. Additionally, fundamental differences between the model capabilities were discovered. The FORMAN model is preferred in situations where the harvest scheduling problem is relatively simple and conforms to the activities included in the model. Linear programming is preferred when the analyst is concerned with the economics of wood supply and controlling a variety of activities and outputs.

scholarly journals A replanning approach for maximizing woodland caribou habitat alongside timber production

2017 ◽  
Vol 47 (7) ◽  
pp. 901-909 ◽  
Author(s):  
Andrew B. Martin ◽  
Jonathan L.W. Ruppert ◽  
Eldon A. Gunn ◽  
David L. Martell
Keyword(s):  
Linear Programming ◽  
Rangifer Tarandus ◽  
Programming Model ◽  
Timber Harvest ◽  
Management Plan ◽  
Harvest Scheduling ◽  
Woodland Caribou ◽  
Habitat Amount ◽  
Trout Lake ◽  
Preferred Habitat

We present a forest harvest scheduling model that meets timber harvest targets while maximizing a proxy measure of woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) habitat based on the configuration of preferred habitat on the landscape. Woodland caribou within the boreal forest region in Canada tend to prefer mature jack pine forest stands, which tend to be rich in their preferred resource, lichen, and also reduce predation pressure. This can create conflict with industrial wood supply needs. We designed a model that can be used to identify good harvest scheduling plans given these competing objectives. Our approach is to use a series of sequential linear programming models that are solved within a replanning framework. Specifically, each individual linear programming model seeks to produce a solution that will meet timber harvest targets while minimizing the harvest of high-quality woodland caribou habitat stands. Stands are assessed with respect to their suitability as woodland caribou habitat based on their contribution to the overall landscape equivalent connected area (ECA), a combined spatial measure of preferred habitat amount and its connectivity. We used our model for a case study of the Trout Lake Forest in northwestern Ontario, Canada, and found that our model creates approximately 10% more caribou habitat than an earlier heuristic procedure and 30% more caribou habitat than the prevailing woodland caribou habitat forest management plan in the Trout Lake Forest while meeting the same timber harvest targets.

Timber harvest scheduling in a fuzzy decision environment

1992 ◽  
Vol 22 (4) ◽  
pp. 423-428 ◽  
Author(s):  
B. Bruce Bare ◽  
Guillermo A. Mendoza
Keyword(s):  
Linear Programming ◽  
Objective Function ◽  
Deterministic Model ◽  
Programming Model ◽  
Timber Harvest ◽  
Harvest Scheduling ◽  
Fuzzy Decision ◽  
Decision Environment ◽  
Objective Function Values ◽  
Scheduling Models

Linear programming is a widely used tool for timber harvest scheduling in North America. However, some potential problems related to infeasible harvest schedules, overly optimistic objective function values, and the need to strictly satisfy all constraints included in deterministic model formulations have been raised. This paper describes a fuzzy approach for explicitly recognizing the imprecise nature of the harvest flow constraints usually included in harvest scheduling models. The objective function and selected constraints are viewed as soft, and satisfactory solutions are derived and discussed for several scenarios. An illustrative sample problem is presented to demonstrate the methodology, and a comparison with solutions derived from a traditional linear programming model is presented.

scholarly journals A case study in spatial wood supply analysis

1992 ◽  
Vol 68 (4) ◽  
pp. 503-516 ◽  
Author(s):  
G. A. Jordan ◽  
E. Z. Baskent
Keyword(s):  
New Brunswick ◽  
Developmental Stages ◽  
Wildlife Habitat ◽  
Harvest Scheduling ◽  
Wood Supply ◽  
Spatial Strategies ◽  
Supply Model ◽  
Supply Analysis ◽  
The University

This paper shows the effects of extraction economics and wildlife habitat values on wood supply for a 9,640 stand forest in New Brunswick. Using a spatial wood supply model developed at the University of New Brunswick, the paper quantifies and explains wood supply effects of harvest blocking, road cost and harvest adjacency delay. Eight spatial strategies test harvest scheduling based on geographic forest structure (distribution of stand developmental types and stages). Given a forest of mostly regenerating and mature developmental stages, wood supply reductions vary from 4.9% to 19.2% when compared to a convention aspatial assessment. The paper presents and explains reductions for all eight spatial strategies; but concludes that all are explained by the impacts that harvest blocking, road cost, or harvest adjacency delay have, singly, or in combination, on either mortality losses or the rate at which harvesting recycles forest area. Key words: Forest management, forest dynamics, GIS, wildlife, simulation, wood supply, harvest scheduling

Vom Forst zum Wald. Entwicklungstendenzen im naturnahen Waldbau | From a Production-Oriented Forest to a Multipurpose Forest. New Trends in Near-Natural Silviculture

1999 ◽  
Vol 150 (12) ◽  
pp. 484-488 ◽  
Author(s):  
Wolf Hockenjos
Keyword(s):  
Forest Management ◽  
Timber Harvest ◽  
Timber Harvesting ◽  
Natural Forest ◽  
The Other ◽  
Private Forest ◽  
Wide Spread ◽  
Great Demand ◽  
The Past ◽  
Forest Enterprises

Concepts of near-natural forestry are in great demand these days. Most German forest administrations and private forest enterprises attach great importance to being as «near-natural» as possible. This should allow them to make the most of biological rationalisation. The concept of near-natural forestry is widely accepted, especially by conservationists. However, it is much too early to analyse how successful near-natural forestry has been to date, and therefore to decide whether an era of genuine near-natural forest management has really begun. Despite wide-spread recognition, near-natural forestry is jeopardised by mechanised timber harvesting, and particularly by the large-timber harvester. The risk is that machines, which are currently just one element of the timber harvest will gain in importance and gradually become the decisive element. The forest would then be forced to meet the needs of machinery, not the other way round. Forests would consequently become so inhospitable that they would bear no resemblance to the sylvan image conjured up by potential visitors. This could mean taking a huge step backwards: from a near-natural forest to a forest dominated by machinery. The model of multipurpose forest management would become less viable, and the forest would become divided into areas for production, and separate areas for recreation and ecology. The consequences of technical intervention need to be carefully considered, if near-natural forestry is not to become a thing of the past.

scholarly journals On Division Versus Saturation in Pseudo-Boolean Solving

2019 ◽  
Author(s):  
Stephan Gocht ◽  
Jakob Nordström ◽  
Amir Yehudayoff
Keyword(s):  
Linear Programming ◽  
Cutting Planes ◽  
The Other ◽  
Sat Solving ◽  
Linear Combinations ◽  
Division Rule ◽  
Clause Learning

The conflict-driven clause learning (CDCL) paradigm has revolutionized SAT solving over the last two decades. Extending this approach to pseudo-Boolean (PB) solvers doing 0-1 linear programming holds the promise of further exponential improvements in theory, but intriguingly such gains have not materialized in practice. Also intriguingly, most PB extensions of CDCL use not the division rule in cutting planes as defined in [Cook et al., '87] but instead the so-called saturation rule. To the best of our knowledge, there has been no study comparing the strengths of division and saturation in the context of conflict-driven PB learning, when all linear combinations of inequalities are required to cancel variables. We show that PB solvers with division instead of saturation can be exponentially stronger. In the other direction, we prove that simulating a single saturation step can require an exponential number of divisions. We also perform some experiments to see whether these phenomena can be observed in actual solvers. Our conclusion is that a careful combination of division and saturation seems to be crucial to harness more of the power of cutting planes.

ONLINE SCHEDULING OF DYNAMIC TREES

1995 ◽  
Vol 05 (04) ◽  
pp. 635-646 ◽  
Author(s):  
MICHAEL A. PALIS ◽  
JING-CHIOU LIOU ◽  
SANGUTHEVAR RAJASEKARAN ◽  
SUNIL SHENDE ◽  
DAVID S.L. WEI
Keyword(s):  
Lower Bound ◽  
Competitive Ratio ◽  
Scheduling Algorithm ◽  
Optimal Schedule ◽  
Online Scheduling ◽  
The Other ◽  
Static Case ◽  
Scheduling Problem ◽  
Dynamic Trees ◽  
Dynamic Tree

The scheduling problem for dynamic tree-structured task graphs is studied and is shown to be inherently more difficult than the static case. It is shown that any online scheduling algorithm, deterministic or randomized, has competitive ratio Ω((1/g)/ log d(1/g)) for trees with granularity g and degree at most d. On the other hand, it is known that static trees with arbitrary granularity can be scheduled to within twice the optimal schedule. It is also shown that the lower bound is tight: there is a deterministic online tree scheduling algorithm that has competitive ratio O((1/g)/ log d(1/g)). Thus, randomization does not help.

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