Difference between revisions of "DTRAN"

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General System description

System name: DTRAN

Acronym: DTRAN

Brief overview

DTRAN is a computer model designed to help analyze the forest management situation in terms of the forest's ability to supply multiple product flows over time to different market locations.

System origin

DTRAN was developed in 1981 by Professor H. M. Hoganson, from the Department of Forest Resources, College of Natural Resources, University of Minnesota stationed at the North Central Experiment Station, Grand Rapids, Minnesota and D. C. Kapple, research assistant in the same University. The development of this software was supported by University of Minnesota Center for Transportation Studies and the Minnesota Legislature as recommended by the Legislative Commission on Minnessota Resources from the Minnesota Future Resources Fund for the project “Simulating Minnessota’s Future Timber Supply”.

Support for specific issues

DTRAN is a computer model designed to help analyze the forest management situation in terms of the forest's ability to supply multiple product flows over time to different market locations. It was designed with the intent of examining differences in timber supply within a large region where specific product mill requirements for specific locations are important. It can be used to help examine a variety of state-wide or region-wide concerns ranging from specific expansion opportunities in a specific location to broad forest-wide policies influencing forest management practices. It is an extension of the DUALPLAN forest management scheduling model that maintains optimality of the solutions generated yet adds the ability to recognize multiple market locations without the need to specify explicitly each potential shipping option for each harvest option. It is the combinatorial nature of problems with alternative market destinations that makes multiple market locations difficult to address using conventional timber harvest scheduling models based on linear programming, especially when multiple product outputs also need to be considered. Similar to DUALPLAN, DTRAN utilizes a basic understanding of the problem in its mathematical solution process for an optimal solution. Compared to DUALPLAN, the multiple-market considerations in DTRAN add significant complications, but the approach can still consider significant detail as the solution process decomposes the problem into parts. Final results include a set of marginal costs or "shadow prices" that can be used in an economic analysis of individual projects to recognize forest-wide objectives or concerns.

Support for specific thematic areas of a problem type

• Silvicultural
• Transportation
• Policy/management alternatives

Capability to support decision making phases

• Intelligence (The current conditions of the forest can be analysed with various management strategies to achieve targets and a spatially configured harvest schedules be prepared.)
• Design (The simulation tool runs the different management possibilities among the restrictions imposed by the input data to understand forest dynamics. The optimization tool projects the current state of a forest into a target forest under various management prescriptions with objectives and constraints.)
• Choice (Heuristic tools are used in order to ensure the spatial layout of the best management option chosen by the manager. )
• Monitor (Not implemented.)

Related systems

In the Minessota Generic Environmental Impact Statement (GEIS), DTRAN was used in connection to RXWRITE and GISTRAN. RXWRITE generates a set of management alternatives for each inventory plot and projects growth as in STEMS. GISTRAN is a simple GIS able to develop spatial data input to display procurement zone maps.

RXWRITE is a set of programs that can be used to develop prescription options for harvesting and management activities for each management unit. RXWRITE simulates clearcutting and three types of thinning: random, from above and from below. A wide range of options concerning thinning intensity, timing and frequency can be specified by the user. Linkage to at least one regeneration option must also be established for clearcutting option.

RXWRITE is a system of programs that manages forest inventory databases and provides a user-friendly interface for simulating and analyzing alternative management options for forest stands. As a database manager, it allows users to easily browse large forest inventory databases including data on cover types, forests stands, and the tree lists associated with the forest stands. Data can be edited where necessary. The system also allows considerable flexibility in setting up and simulating different stand management options. Users can specify any level of species aggregation and a wide range of products and utilization standards using a user-friendly, menu-driven interface. Similarly, users can specify any range of potencial harvest ages, thinning times, thinning intensities and conversion options. The current values or settings of virtually all system parameters are transparent to the user and they can be edited by the user. Once all system parameters have been set, the system can be used to simulate sets of specified management options for a given stand or group of stands. The output from these simulations can be reviewed or converted into input files to be used by the forest management planning models.

GISTRAN is a system of computer programs designed to perform the critical functions of managing, prodessing and presenting the geographical information. GISTRAN uses Indexed Sequential Access Method (ISAM) databases, random.access binary files, and ASCII text files. It is worth to emphasize, however, that the methods and algorithms developed do not depend upon the data format and the programs can be modified for computer systems where a particular format is unavailable.

Several requirements influenced the selection of the spatial data and the design and development of GISTRAN.

• Information associating each analysis area with the nearest point in the road network was needed to compute wood transportation costs and to determine the procurement zone in which analysis area is located.
• The shortest or lowest cost route from each node in the road network to each market location was also required to compute transportation costs.
• An ability to display maps showing state and country boundaries, roads and procurement zones are desired
• GISTRAN was required to be compatible with other components of a forest management modeling system.

Data and data models

Typical spatial extent of application

The system may be used both for regional analysis. It may address both national and international policy contexts.

Forest data input

The basic unit of the forest for analysis by DTRAN is referred to as an analysis area. Each analysis area need not to be considered a homogeneous unit, but management alternatives or management prescriptions must refer the entire analysis area. In the solution, DTRAN cannot split acres of any analysis area between prescriptions; all acres are assigned to one prescription. In GEIS study over 10000 analysis units were recognized.

Basic inputs

* Forest Inventory * Road network * Management unit map

Type of information input from user (via GUI)

Models

Forest models

The stand and tree evolution and modeling system (STEMS) developed by USDA Forest Service is used by RxWRITE to model the tree growth.

Social models

-Not available yet

Decision Support

Definition of management interventions

* Management alternatives for each analysis area;
* Consumption levels for each market, product and time period;
* Species requirements for each market and relative value differences between species and size classes at each market;
* Constraint levels on other inputs/outputs;
* Transportation network and associated shipping costs;
* Location information for each analysis area;
* Non-market value estimates for each analysis area or alternative.

Typical temporal scale of application

Usually periods of up 50 years are considered, with period lengths of 5 years, but there is no limit on the time horizon.

Types of decisions supported

• Management level
  • Strategic decisions
  • Operating control decisions
• Management function

Decision-making processes and models

DTRAN optimizes the problem given the user specified constrains using Linear Programming. DTRAN can use either a Model I or Model II (after Johnson and Scheurman) type of formulation with the Model II formulation preferable for most problems as it can reduce the number of alternative management prescription significantly. A Model II formulation breaks the decision the decision process for an individual stand into parts by considering each rotation separately

Output

Types of outputs

• Output variables

     * Marginal cost of production estimation (shadow prices) for each product , market and time period
     * Shadow prices for other resources constraints
     * Management schedule  for each analysis area
     * Forest-wide summary of resource flows (inputs and outputs)
     * Maps of procurement zones for each market, product and period combination.

Abilities to address interdisciplinary, multi-scaled, and political issues

DTRAN specifically has the ability to deal with each mill’s processing capacity and capacity changes in the future. These can be provided by the user as a scenario for expansion or reduction of the mill’s capacity or quality demand. DTRAN doesn’t have any component that takes into account environmental effects of wood processing, however forest wide constraints on non-timber resources can be specified.

System

System requirements

• IBM compatible 386 or larger

Architecture and major DSS components

DTRAN is a desktop application with a modular structure. It was developed with software ?????.

Usage

Computational limitations

Run time is impacted mostly by the number of management units and constraints defined by the user.

User interface

DTRAN has a standard Windows GUI. Thoughtful use of the system requires some good forest management planning and agricultural economics background.

Documentation and support

The graphical user interface provides access to the DTRAN users' manual: Hoganson, H. M., Kapple, D. C., 1991, DTRAN Version 1.0 , A Multi-Market Timber Supply Model, User’s Guide, Staff Paper Series N. 82, Department of Forest Resources, College of Natural Resources, University of Minnesota

Installation

References

Cited references

External resources

Hoganson, H. M., Kapple, D. C., 1991, DTRAN Version 1.0 , A Multi-Market Timber Supply Model, User’s Guide, Staff Paper Series N. 82, Department of Forest Resources, College of Natural Resources, University of Minnesota

McDill, M., Rose, D., 1994, RXWrite. A Forest Management Prescription Writer, User’s Guide, Staff Paper Series N. 82, Department of Forest Resources, College of Natural Resources, University of Minnesota

Kapple, D. C., Hoganson, H. M., 1991, GISTRAN Version 1.0 , A Geographic Information System for Modelling Forest Products Transportation, User’s Guide, Staff Paper Series N. 83, Department of Forest Resources, College of Natural Resources, University of Minnesota