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PLANS - Preliminary Logging Analysis System

USDA Forest Service, Pacific Northwest Research Station

Software Availability

The PLANS package does not operate on current versions of Windows (64-bit). It may be possible to use the compatibility modes in Windows to configure a command prompt that can be used to run PLANS.

The entire PLANS package consists of two files: INSTALL.EXE and README

EXPORT.EXE, contains utility programs to convert PLANS data files into other formats and to convert selected GIS data formats into formats compatible with PLANS. You should retrieve and install this file if you are working with any data files produced by a GIS. See README.EXPORT for more information.

EXAMPLE.EXE contains example data for use with PLANS.

The distibution contains very little documentation. For the most part, PLANS is very user-friendly.

PLANS logo



This paper presents PLANS (Preliminary Logging Analysis System), a family of computer programs designed to facilitate the development of timber harvest plans for large areas. PLANS supports strategic level planning for areas ranging in size from 2,000 to 20,000 hectares (4,942 to 49,420 acres). Activity schedules for harvest plans developed with PLANS typically span from 5 to 25 years. PLANS relies on digital terrain models (DTM) to provide elevation data to support the analysis of cable logging payload, highlead system yarding reach, ground slope and aspect, and perspective scenes depicting the landscape and harvest plan features. PLANS interacts with databases stored in geographic information systems (GIS) by importing several DTM formats and by exporting harvest plan related line, point, and polygon features in formats suitable for inclusion in GIS data layers.

Keywords: Harvest planning, cable logging, digital terrain model


Successful harvesting in steep terrain requires a thorough planning effort. The harvest system selected for the operation, the silvicultural treatment, and the placement of the harvest system on the terrain influence the economic and environmental success of timber harvesting operations. In the case of cable yarding systems, proper positioning of the cable span permits hauling an ample volume of logs in each yarding cycle resulting in higher production and lower costs while minimizing environmental damage. Improper positioning results in excessive soil disturbance, reduced production, equipment breakdown, unsafe operations, or overall inoperable harvest units. The quality of a timber harvest plan and the actual harvest operation depends on the planner's thoroughness, which is influenced by time constraints, management support, and available planning tools.

The term "harvest planning" can encompass a wide range of activities and outcomes. Long-range planning, often spanning several rotations (150 + years), generally prescribes land allocation strategies and does not necessarily provide a spatially feasible solution (Nelson et al 1991). A more site specific approach, known as area-based planning, involves determination of specific harvest areas that have a unique geographic location and subsequent scheduling of the harvest and road construction activities. PLANS supports area-based planning. As a precursor to harvest unit and road scheduling using network solution techniques (Sessions 1987), PLANS enables users to rapidly design and delineate timber harvest units and road access to timber over extensive areas. Area-based planning that begins with well-designed harvest units and transportation systems can proceed on a solid foundation. The individual harvest units and road alternatives form the foundation of the final management plan, and PLANS helps ensure the operability and soundness of this foundation.

The scenario described for area-based planning varies according to organizational structure and goals. However, some basic considerations of timber harvest planning transcend the details of planning jurisdiction. One basic consideration is the influence of topography on the cost and efficiency of timber harvesting. Topography affects most activities associated with timber harvesting, from felling and yarding to road and landing construction. Timber harvest planners therefore need detailed topographic information. This need has been traditionally met by topographic maps and aerial photographs. Reasonably accurate maps with scales ranging from 1:4,800 to 1:24,000 and contour intervals of 15 meters (50 feet) or less provide an excellent foundation for planning. Using such maps, planners can visualize steepness, ridges, valleys, benches, and profiles of the terrain in sufficient detail to develop operable harvest and transportation plans. The organization and storage of topographic information in a computer usable form is paramount to the success of any harvest planning exercise.


Burke (1974) suggested using a digital terrain model (DTM) to supply topographic data for harvest planning. A DTM is an organized data file containing elevations that represent the ground surface. A DTM, coupled with the appropriate software, can provide nearly instantaneous access to a virtually unlimited number of ground profiles. Young and Lemkow (1976) developed a prototype timber harvest planning system that used a DTM. Their planning system proved that harvest planning using DTM data was practical. However, their system, limited by computing horsepower, did not provide an operational solution to large area planning problems. Reimer (1979) reported that an operational harvest planning system using DTM data was successfully implemented by McMillan Bloedel, Ltd., in Canada. Twito and Mifflin (1982) distributed an early version of PLANS to USDA Forest Service sites and industrial sites with compatible computer hardware. Reutebuch and Evison (1984) reported on an operational system using DTM data for planning cable logging system layout available in New Zealand. Twito and others (1987) distributed an update of PLANS that was operational on a Hewlett-Packard 32-bit workstation. This system provides the analytical foundation for the IBM-PC version of PLANS discussed in this paper.


PLANS is a set of computer programs designed to assist logging engineers and transportation planners as they develop timber harvest plans for large areas. Typical candidate areas for application of PLANS range from 2,000 to 20,000 hectares (4,942 to 49,420 acres) with planned harvest activities spanning from 5 to 25 years. PLANS allows the planner, aided by an interactive computer system, to examine a wide range of design and planning options--a range not possible with earlier planning methods. PLANS, although it does not fully automate the design process, enhances the planner's ability to develop technically sound timber harvest plans. A fundamental concept underlying PLANS is the use of a digital terrain model to provide topographic data needed for harvest planning and transportation system development. By using a DTM to represent the ground surface, PLANS can quickly generate ground profiles, ground slope information, aspect information, and general land form characteristics for use during the development of a harvest plan. In the United States, DTM data are typically available in the form of United States Geological Survey (USGS) digital elevation models (DEM) that correspond to the standard 7.5-minute quadrangle map series. The USGS DEM data are arranged in a 30 by 30 meter (98.43 by 98.43 feet) grid with a vertical accuracy classified as either 7 meter (22.97 feet) RMSE or 15 meter (49.22 feet) RMSE. In general, these data are sufficient for use with PLANS. An analysis of the adequacy of USGS DEM data for timber harvest planning (McGaughey and Twito 1988) showed that USGS DEM data were sufficient for area-based analysis, where the emphasis is on harvest and transportation system feasibility. However, the large grid spacing and possible inaccuracies in the data can present problems for PLANS users who want to develop a detailed plan for individual harvest units.

For areas where USGS DEM coverage does not exist, DTM data must come from an outside source. PLANS does not provide a tool to develop digital terrain models. However, the current version of PLANS can read DTM data from several sources. The underlying requirement for DTM data to be used with PLANS is that is must be stored using a gridded structure. For sites using Arc/Info GIS software (version 6.0), the LATTICEDEM command is available to convert an Arc/Info lattice file into a USGS DEM file (ESRI 1991).

Contour map
Figure 1. PLANS uses an on-screen contour map to help users visualize the digital terrain model.

PLANS employs a familiar interface to the topographic data, an on-screen contour map generated from the digital terrain model (figure 1), to assist users in visualizing the terrain data. Landings, unit boundaries, roads, and other harvest plan components are easily located and evaluated because users can directly specify ground locations from the on-screen contour map. PLANS conducts engineering analyses and encourages users to investigate several alternative treatments for a given area before selecting a specific treatment for further evaluation or implementation. Analysis tools in PLANS provide design feedback quickly without overwhelming the user with excessive detail. The analysis tools attempt to provide summaries of pertinent information to guide the planner rather than detailed reports of analysis results. PLANS allows storage and recall of individual design components and provides tools to integrate various components into harvest plans. Analysis modules in PLANS share data, both input and output, to provide a seamless environment for harvest and transportation plan development. Links to geographic information systems (GIS), using a data formatting utility, promote the integration of timber harvest planning information into other planning processes, e.g., environmental impact assessment and long- range planning.


The following are brief descriptions of the analysis modules currently available in PLANS. The PLANS main menu shown in figure 2 controls access to these modules.
PLANS main menu
Figure 2. The PLANS main menu provides a user-friendly interface to all the PLANS programs.


The SKYTOWER and SKYMOBIL programs analyze the load carrying capacity of skyline yarding systems over terrain profiles extracted from a DTM. The SKYTOWER program analyzes units yarded in a fan-shaped pattern to a central tower location. The SKYMOBIL program operates on individual terrain profiles where the yarder is moved with each yarding corridor change.

Using SKYTOWER, the planner designates a central landing by pointing to the yarder location on the on-screen contour map. The program automatically generates evenly spaced profiles radiating from the landing. The maximum span over which a target load can be yarded is determined for each profile. A planimetric plot of the resulting unit boundary is then displayed on the computer screen (figure 3). At this point, the user can visually assess the overall feasibility of the landing location. If all spans are short, then either the target payload was too large or the landing was not suitable for the yarding system. The user can modify parameters for individual profiles to adjust the unit boundary. Possible modifications include increasing the height of the tailhold, specifying a new tailhold location, changing the target payload, and specifying yarding boundaries. A plan or profile view, depending on the type of modification, shows the results of each modification.

SKYTOWER screen image
Figure 3. SKYTOWER displays the area that can be yarded to a central tower location.

SKYMOBIL, like SKYTOWER, conducts profile analysis. However, SKYMOBIL operates on single terrain profiles designated by pointing to the profile's beginning and ending locations. The program extracts the profile from the DTM and displays the profile on the computer screen. The planner can then specify the yarder or tailhold location by pointing to the on-screen profile (figure 4). SKYMOBIL can solve for either the maximum span over which a specified target payload can be yarded, or the maximum payload that can be yarded over a specified span. SKYMOBIL can be very useful in areas requiring mid-slope roads. A series of parallel profiles running perpendicular to the contour lines is analyzed to locate control points for road layout.

SKYMOBIL profile screen imge
Figure 4. SKYMOBIL allows users to locate the tower and tailhold on a ground profile.


The HIGHLEAD program analyzes settings yarded in a fan-shaped pattern to a central landing. Like SKYTOWER, the HIGHLEAD program automatically analyzes evenly spaced profiles radiating from a user-specified yarder location. Either the first instance of blind lead along each profile or the maximum reach of the yarder determines the yarding limit. HIGHLEAD displays the resulting unit boundary in plan view and gives the planner the opportunity to modify the unit boundary. HIGHLEAD allows analysis for tight-lining (tension the haulback line to increase lift and permit yarding beyond a point of blind lead). The planner can also specify yarding limits, change the tailhold height, or remove profiles entirely to reduce the area included in the unit boundary.

VISUAL Program

The VISUAL program produces perspective views of terrain, roads, harvest units, and other harvest plan components from user-selected viewpoints. These perspective views, such as the one shown in figure 5, provide a preview of the visual impact of proposed management activities. VISUAL also provides an important tool for developing an understanding of the project area. The perspective projection of the terrain provides an intuitive picture of the land form when compared to a topographic map and many planners find that they are better able to identify subtle benches and other terrain features when viewing the perspective projection.
VISUAL screen image
Figure 5. VISUAL produces perspectives of terrain and harvest plan features.

SLOPE Program

The SLOPE program produces overlays, either on-screen or hard copy plots, that delineate areas of equal slope, aspect, or elevation within user-specified categories. SLOPE can also produce overlays that show any combination of topographic attributes, e.g., areas with slopes ranging from 0 to 30 percent (0 to 17 degrees) with northerly aspect and elevations ranging from 0 to 914 meters (0 to 3000 feet). In addition to overlays, SLOPE also produces tabular summaries of the slope, aspect, or elevation information and the land area included in each category. These attribute overlays provide an excellent aid for interpreting topographic maps.


The PLANCAD program allows planners to assemble various harvest plan components into an integrated harvest plan. PLANCAD can read any design file produced by a PLANS program and incorporate the appropriate information into a database that represents the harvest plan. This database can be exported to other systems, such as geographic information systems (GIS), for additional analysis. PLANCAD can also plot harvest plan maps at any scale for use when communicating planning results. Harvest plans can be stored and later retrieved for manipulation or output. Harvest plans are stored as a list of references to the various design components, so changes to individual design components are automatically included in the harvest plan.

MAP_REG Program

The MAP_REG program allows planners to register a paper map mounted on a digitizing tablet to the on-screen contour map generated from the digital terrain model. The lower left, lower right, and upper right corners of the DTM boundary are digitized to register a map. Three arbitrary points on the map whose ground coordinates are known can also be used for registration. Any type of map can be registered using MAP_REG. For example, a map delineating forest cover types produced by a GIS could be registered to provide this information to the planner as they interact with the on-screen contour map.

DIG_DATA Program

The DIG_DATA program helps users enter planimetric data into PLANS. For example, data sets describing existing transportation networks and stream systems or a group of possible landing locations can be built using DIG_DATA. Various modules in PLANS can access the data files to provide detailed analysis or simply to provide additional visual information for the on-screen contour map display.

SQZDTM Program

The SQZDTM program imports digital terrain models into PLANS. PLANS uses a very compact and somewhat unique data format to provide rapid access to topographic information. SQZDTM translates several common DTM formats into the format expected by PLANS. Formats include USGS DEM, SURFER (PC-based surface analysis), TerraSoft (PC-based GIS system), and a generic ASCII format. Any DTM used with PLANS must first be processed by SQZDTM to ensure compatibility with the PLANS DTM format.


The GRDCONVT program translates PLANS output to a variety of other data formats. GRDCONVT accepts a generic data format containing the (X,Y,Z) coordinates for the data points. The coordinates can be converted to a variety of formats including Arc/Info generate format, AUTOCAD DXF format, MOSS import format, SURFER boundary file format, and generic ground profiles containing horizontal distances and elevations. GRDCONVT allows PLANS users to share their results digitally with both upstream and downstream analysis packages.


The benefits of harvest planning are many. Dollar savings in the harvesting and hauling cost for an area can result from several activities carried out during the planning process. First, by using PLANS to identify the harvesting and transportation system best suited to the local conditions, you ensure that operations are feasible. Second, using PLANS to provide harvest unit and road locations that provide optimum or near optimum operating conditions for the selected harvest systems, minimizes environmental damage. Third, by considering the interaction of harvest unit locations, road locations, and silvicultural treatments over many time periods, scheduling conflicts are minimized and it is possible to analyze the cumulative effects associated with the harvest plan.

The use of an intensive preliminary harvest planning procedure ensures that land managers have based harvesting decisions on a thorough analysis of all available data and are seen to be doing so by concerned public groups. In addition, the analytical tools in PLANS can provide information to help educate the lay public about the factors that influence the success or failure of a harvest operation. This education should not be under-valued. Managers may find that previous adversaries are much more willing to participate in the planning process if they are made aware of and given access to the analysis techniques being used.

The costs of harvest planning are generally low in comparison to the harvesting and hauling costs--generally less than one percent of the total cost incurred to deliver timber to the market. The planning cost is justified by the potential for saving 10 percent or more of the harvesting and transportation costs through proper selection and application of harvesting systems (Sauder and Nagy 1977). Economic profits are not the only justification for better planning. The benefits of improved harvest plans are often related to better resource protection and less damage to the environment. Additional expenditures to support harvest planning can be justified through net benefit to the environment, rather than simply considering harvest and transportation planning as an added cost. Selling the concept of area-based planning can be a difficult task. However, PLANS streamlines the area-based planning process, reducing both the time and money required, making it possible to implement a level of analysis and planning previously considered impossible.


The minimum recommended computer configuration for PLANS is:
  • IBM-AT compatible computer (80286, 80386SX, 80386DX, or 80486 processor)
  • Hard disk (minimum of 4-6 Mbytes free space)
  • 80X87 math co-processor
  • 640 Kbytes RAM (512 Kbytes available after boot-up)
  • EGA or VGA color graphics
  • Microsoft or compatible mouse
  • Dot-matrix printer
PLANS will run on a PC-XT with no math co-processor.

PLANS will not function on computer systems equipped with monochrome graphics adapters (Hercules or compatible clones).

PLANS supports the use of several digitizer tablets to allow the registration of paper maps to the digital terrain model.


Burke, Doyle. 1974. Skyline logging profiles from a digital terrain model. In: Proceedings of the 1974 skyline logging symposium; January 23-24, 1974; Seattle, WA. Seattle, WA; University of Washington, College of Engineering. p. 52-55.

ESRI. 1991. Arc/Info command references and user's guides. Version 6.0. Environmental Systems Research Institute, Inc. Redlands, California.

McGaughey, Robert J. and Roger H. Twito. 1988. Large-area timber harvest planning with digital elevation models. In: Proceedings of the international mountain logging and pacific northwest skyline symposium; December 12-16, 1988; Portland, OR. (Place of publication unknown): (Publisher unknown). p. 87-92. Sponsored by: Oregon State University, Department of Forest Engineering and International Union of Forest Research Organizations, Mountain Logging Section.

Nelson, John, J. Douglas Brodie and John Sessions. 1991. Integrating short-term, area-based logging plans with long term harvest schedules. Forest Science. 37:101-122.

Sauder, Brent J. and Michael M. Nagy. 1977. Coast logging: highlead versus long reach alternatives. FERIC Tech. Rep. TR-19. Vancouver, BC: Forest Engineering Research Institute of Canada. 51 p.

Reimer, Donald R. 1979. An operational computer assisted forest engineering system. In: Proceedings of the International Union of Forest Research Organizations symposium on mountain logging; September 10-14, 1979; Seattle, WA: University of Washington, College of Forest Resources. p. 17-19.

Reutebuch, Stephen E. and David C. Evison. 1984. The cable hauler planning package: user's guide. FRI Bull. 46. Rotorua, New Zealand: New Zealand Forest Service, Forest Research Institute. 81 p. Sessions, John. 1987. A heuristic algorithm for the solution of the fixed and variable cost problem. In: Proceedings of the Society of American Foresters symposium on system analysis in forest resources. Univ. of Georgia, Athens, GA. p. 324-336.

Twito, Roger H. and Ronald W. Mifflin. 1982. Computer assisted evaluation of skyline thinning opportunities. In: Proceedings 7306, The small tree resource: a materials handling challenge; April 19-21, 1982; Portland, OR. Madison, WI: Forest Products Research Society. p. 73-79.

Twito, Roger H., Stephen E. Reutebuch, Robert J. McGaughey and Charles N. Mann. 1987. Preliminary logging analysis system (PLANS): overview. Gen. Tech. Rep. PNW- GTR-199. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 24 p.

Young, G. Glen and Daniel Z. Lemkow. 1976. Digital terrain simulators and their application to forest development planning. In: Proceedings of the 1976 skyline logging symposium; December 8-10, 1976; Vancouver, BC. Vancouver, BC: University of British Columbia Press. p. 81-99.

This page was last updated on June 11, 2018 by Bob McGaughey