Optimal harvest scheduling at the forest level in the presence of the risk of fire

1986 ◽  
Vol 16 (2) ◽  
pp. 266-278 ◽  
Author(s):  
W. J. Reed ◽  
D. Errico
Keyword(s):  
Dynamic Equations ◽  
Scheduling Problem ◽  
Deterministic Approach ◽  
Harvest Scheduling ◽  
Forest Harvest ◽  
Timber Supply ◽  
Reasonable Approximation ◽  
Optimal Harvest ◽  
The Impact ◽  
Scheduling Models

The effect of fire on forest yields has been well documented in stand-level analyses; however, forest-level effects are less widely known. A set of dynamic equations can be constructed that describe the evolution of a forest under the impact of harvesting and random fire. When fire is treated in a deterministic fashion, these equations can be used to formulate an optimal harvest scheduling problem that can be solved using linear programming. Examples using white spruce data for the Fort Nelson Timber Supply Area of British Columbia show that even modest rates of fire can have a dramatic impact and that present harvest scheduling models may be considerably overestimating projected forest harvest levels. Results also show that the deterministic approach appears to be a reasonable approximation of the true stochastic fire problem.

scholarly journals Harvest scheduling with spatial aggregation for two and three strip cut system under shelterwood management

2011 ◽  
Vol 57 (No. 6) ◽  
pp. 271-277 ◽  
Author(s):  
M. Konoshima ◽  
R. Marušák ◽  
A. Yoshimoto
Keyword(s):  
Spatial Aggregation ◽  
Decision Variable ◽  
Scheduling Problem ◽  
Harvest Scheduling ◽  
Aggregation Method ◽  
Management Units ◽  
Decision Variables ◽  
Optimal Harvest ◽  
Cutting System ◽  
Sequential Cuts

We propose a spatial aggregation method to solve an optimal harvest scheduling problem for strip shelterwood management. Strip shelterwood management involves either a two-cut system with a preparatory-removal cut cycle, or a three-cut system with a preparatory-establishment-removal cut cycle. In this study we consider these connected sequential cuts as one decision variable, then employ conventional adjacency constraints to seek the best combination of sequential cuts over space and time. Conventional adjacency constraints exclude any spatially-overlapped strips in the decision variables. Our results show the proposed approach can be used to analyze a strip shelterwood cutting system that requires "connectivity" of management units.

scholarly journals EFEITO DAS RESTRIÇÕES ESPACIAIS DE ADJACÊNCIA NO PLANEJAMENTO FLORESTAL OTIMIZADO

FLORESTA ◽  
2010 ◽  
Vol 40 (3) ◽  
Author(s):  
Lucas Rezende Gomide ◽  
Julio Eduardo Arce ◽  
Arinei Lindbeck da Silva
Keyword(s):  
Linear Programming ◽  
Integer Linear Programming ◽  
Net Present Value ◽  
Forest Planning ◽  
Type I ◽  
Harvest Scheduling ◽  
Forest Harvest ◽  
Horizon Planning ◽  
Management Alternatives ◽  
The Impact

O objetivo do estudo foi aplicar restrições espaciais de adjacência no agendamento da colheita florestal em um modelo tradicional de planejamento florestal. Foi analisado e comparado o impacto no VPL (valor presente líquido) e na produção volumétrica de madeira. A área de estudo foi composta por 52 talhões de eucalipto. Foram simuladas 254 alternativas de manejo, sendo então criados 4 cenários de agendamento da colheita florestal envolvendo o uso da programação linear inteira, seguindo a formulação pelo modelo tipo I com maximização do VPL e um horizonte de planejamento de 7 anos. O cenário 1 não considerou a adjacência, enquanto que os cenários 2 (URM), 3 (ARM50) e 4 (ARM70) continham restrições de adjacência. Os resultados demonstraram que as restrições de adjacência reduzem o VPL em 3,74%, 2,24% e 2,10%, e a produção volumétrica em 2,92%, 1,79% e 1,73%, nos cenários 2, 3 e 4 respectivamente. Porém, os cenários 2, 3 e 4 obtiveram sucesso no controle de corte de talhões adjacentes, segundo suas restrições, e impedindo a formação de extensas áreas contiguas como encontrado no cenário 1 (153,25 ha).Palavras-chave: Programação linear inteira; restrição URM; restrição ARM. AbstractSpatial adjacency constraints effect in optimized forest planning. The objective of the study was to apply the spatial adjacency constraints in the forest harvest scheduling when using the traditional forest planning model. It was analyzed and compared the impact on NPV (Net Present Value) and the volumetric production of wood. The area of study was formed by 52 stands of eucalyptus. A total of 254 forest management alternatives were simulated, where 4 forest harvest scheduling scenarios contained the integer linear programming were created, following the model type I and the maximization of the NPV for 7 years of the horizon planning. Spatial adjacency constraints were applied to scenarios 2 (URM), 3 (ARM50) and 4 (ARM70) but not to scenario 1. The results showed that the spatial adjacency constraints reduced NPV in 3,74%, 2,24% and 2,10%, and the volumetric production in 2,92%, 1,79% e 1,73% through the scenarios 2, 3, and 4, respectively. Therefore, the scenarios 2, 3, and 4 obtained success in controlling the adjacent harvested stands, according to their restrictions, and avoiding the creation of large and continuous areas such as observed in the scenario 1 (153,25ha).Keywords: Integer linear programming; URM constraint; ARM constraint.

scholarly journals Multi-objective models for the forest harvest scheduling problem in a continuous-time framework

2022 ◽  
Vol 136 ◽  
pp. 102687
Author(s):  
José Mario González-González ◽  
Miguel Ernesto Vázquez-Méndez ◽  
Ulises Diéguez-Aranda
Keyword(s):  
Continuous Time ◽  
Scheduling Problem ◽  
Harvest Scheduling ◽  
Forest Harvest ◽  
Multi Objective

Importance of considering the growth response after partial harvesting and economic risk of discounted net revenues when optimizing uneven-aged forest management

2020 ◽  
Vol 50 (5) ◽  
pp. 487-499 ◽  
Author(s):  
Katharina Messerer ◽  
Tim Kacprowski ◽  
Horst Kolo ◽  
Jan Baumbach ◽  
Thomas Knoke
Keyword(s):  
Growth Response ◽  
Harvest Scheduling ◽  
Price Fluctuations ◽  
Density Reduction ◽  
Partial Harvest ◽  
Partial Harvesting ◽  
Optimal Harvest ◽  
Forest Economic ◽  
The Impact ◽  
Modelling Approach

Because of the very high complexity of modern optimization models based on single trees, uncertainties are often disregarded. In this study, we present a modelling approach that allows partial harvesting but is still simple enough to consider risk. Our modelling approach investigates whether the inclusion of timber price uncertainty influences the harvesting schedule. The model considers positive growth response to the density reduction that follows harvesting. Testing the impact of uncertainty, we define the discounted net revenues of each harvest operation as random variables. We compare harvest scheduling both with and without the inclusion of uncertainty. We first model growth response based on a partial-harvest schedule, without integrating uncertainty from timber price fluctuations. The results show that harvesting tree cohorts at different times is financially optimal. We run the same model again, including the risk of timber price fluctuations. The inclusion of risk leads to slightly greater differences in recommended harvest timings. Because of the small difference observed, we conclude that it is unlikely that risk arising from fluctuating timber prices would strongly affect the results for more complex forest economic models concerning the optimal harvest schedules.

Influence of land classification systems on timber harvest scheduling models

1990 ◽  
Vol 20 (2) ◽  
pp. 172-178 ◽  
Author(s):  
M. S. Jamnick ◽  
L. S. Davis ◽  
J. K. Gilless
Keyword(s):  
Objective Function ◽  
Timber Harvest ◽  
Management Unit ◽  
Harvest Scheduling ◽  
Land Classification ◽  
Decision Variables ◽  
Optimal Harvest ◽  
Stand Type ◽  
Objective Function Values ◽  
Scheduling Models

Differences between linear program based timber harvest schedules that use decision variables based on stand types (homogeneous but generally noncontiguous areas) and management units (generally heterogeneous but contiguous areas) were investigated. It was proposed that (i) optimal harvest schedules identified using stand type decision variables should have larger present net value objective function values than those identified using models with management unit decision variables, (ii) optimal present net value objective function values in management unit models should decline as management unit size is increased, and (iii) as the number of management choices increases, differences between stand type and management unit optimal present net values should decrease. The propositions were tested using 48 linear programming timber harvest scheduling models constructed for the University of California's Blodgett Forest Experiment Station. These models, which form 12 model groups, differ in the numbers and type of prescriptions considered for existing or regenerated stands, and harvest flow or ending inventory policies. The results generally supported the propositions and indicate that the number of management choices considered in the timber harvest scheduling model is probably a more important factor influencing the optimal harvest schedules than is land classification.

scholarly journals The impact of fire on timber supply in Ontario

1994 ◽  
Vol 70 (2) ◽  
pp. 164-173 ◽  
Author(s):  
David L. Martell
Keyword(s):  
Forest Fire ◽  
Fire Management ◽  
Timber Harvest ◽  
Fire Regimes ◽  
Harvest Scheduling ◽  
Administrative District ◽  
Timber Supply ◽  
Forest Fire Management ◽  
Northwestern Region ◽  
The Impact

Results are presented for an assessment of the impact of fire on timber supply in the province of Ontario. Historical fire report data are used to develop statistical summaries of fire regimes in terms of annual fire occurrence and area burned by administrative district and region. A simple hypothetical jack pine forest is used to illustrate how forest level timber harvest scheduling models can be employed to assess the timber supply implications of fire management regimes. Although fire may have had a significant detrimental impact on timber supply in some parts of the Northwestern region during the 1976-88 period, the effectiveness of Ontario's forest fire management system is such that timber supply in most districts has not been significantly diminished by fire. The results of our timber supply analysis, and the fact that fire management also benefits public safety and reduces property loss, suggest forest fire management is profitable in Ontario. Key words: forest fire impact, timber supply, mathematical programming, Ontario

scholarly journals Deterministic approach for multiple-source tsunami hazard assessment for Sines, Portugal

2015 ◽  
Vol 15 (11) ◽  
pp. 2557-2568 ◽  
Author(s):  
M. Wronna ◽  
R. Omira ◽  
M. A. Baptista
Keyword(s):  
Sea Level ◽  
Wave Height ◽  
Hazard Assessment ◽  
Test Site ◽  
Tsunami Hazard ◽  
Deterministic Approach ◽  
Flow Depth ◽  
Mean Sea Level ◽  
Tsunami Hazard Assessment ◽  
The Impact

Abstract. In this paper, we present a deterministic approach to tsunami hazard assessment for the city and harbour of Sines, Portugal, one of the test sites of project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). Sines has one of the most important deep-water ports, which has oil-bearing, petrochemical, liquid-bulk, coal, and container terminals. The port and its industrial infrastructures face the ocean southwest towards the main seismogenic sources. This work considers two different seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, we selected a total of six scenarios to assess the tsunami impact at the test site. The tsunami simulations are computed using NSWING, a Non-linear Shallow Water model wIth Nested Grids. In this study, the static effect of tides is analysed for three different tidal stages: MLLW (mean lower low water), MSL (mean sea level), and MHHW (mean higher high water). For each scenario, the tsunami hazard is described by maximum values of wave height, flow depth, drawback, maximum inundation area and run-up. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at the Sines test site considering the single scenarios at mean sea level, the aggregate scenario, and the influence of the tide on the aggregate scenario. The results confirm the composite source of Horseshoe and Marques de Pombal faults as the worst-case scenario, with wave heights of over 10 m, which reach the coast approximately 22 min after the rupture. It dominates the aggregate scenario by about 60 % of the impact area at the test site, considering maximum wave height and maximum flow depth. The HSMPF scenario inundates a total area of 3.5 km2.

scholarly journals Improving PV Resilience by Dynamic Reconfiguration in Distribution Grids: Problem Complexity and Computation Requirements

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 830
Author(s):  
Filipe F. C. Silva ◽  
Pedro M. S. Carvalho ◽  
Luís A. F. M. Ferreira
Keyword(s):  
Distributed Generation ◽  
Optimal Solution ◽  
Dynamic Reconfiguration ◽  
Scheduling Problem ◽  
Low Carbon ◽  
Distribution Grid ◽  
Medium Voltage ◽  
Classical Computing ◽  
The Impact ◽  
Distribution Grids

The dissemination of low-carbon technologies, such as urban photovoltaic distributed generation, imposes new challenges to the operation of distribution grids. Distributed generation may introduce significant net-load asymmetries between feeders in the course of the day, resulting in higher losses. The dynamic reconfiguration of the grid could mitigate daily losses and be used to minimize or defer the need for network reinforcement. Yet, dynamic reconfiguration has to be carried out in near real-time in order to make use of the most updated load and generation forecast, this way maximizing operational benefits. Given the need to quickly find and update reconfiguration decisions, the computational complexity of the underlying optimal scheduling problem is studied in this paper. The problem is formulated and the impact of sub-optimal solutions is illustrated using a real medium-voltage distribution grid operated under a heavy generation scenario. The complexity of the scheduling problem is discussed to conclude that its optimal solution is infeasible in practical terms if relying upon classical computing. Quantum computing is finally proposed as a way to handle this kind of problem in the future.

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