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The first stage in designing the harvest and transportation plan was to digitize preliminary landing locations in the project area using the issues map as a guide. This was accomplished with the combination of a digitizing board and the software PLANS. PLANS, which stands for Preliminary Landing Analysis System, analyzes different yarding equipment in conjunction with a DTM (Digital Terrain Model) to make several calculations regarding possible landing locations.
The first step in this process was to link the digitizing board to the PLANS program so that it would recognize the map being used for analysis. The initial step in this process was to convert the original LIDAR DEM (Digital Elevation Model) into USGS format, and then into a PLANS format DTM.
Once the program recognized this DTM, registration tick marks with corresponding (x,y) locations on the issues map were chosen with the digitizer using the baseline method. This is simply a method that utilizes three tick marks in the outer boundaries of the map to reference accessible area within the planning area of the map. The working area was divided into four equal areas (each referred to as a sheet box). These maps were used for the plans process.
The next step in this process was to enter specifications regarding the different yarding equipment being used. In this process, three main yarders were used. They were the Madill 172 (standing and live), as well as, the Madill 124 and 120 (swing). The Madill 172 was used for central landings, while the Madill 124 and 120 were used for single profiles, predominately. The parameters used in PLANS are summarized below:
Table 9: Specifications regarding these different yarders.
| Live (Madill 172) |
| Max Slope Rigging Dist (ft) | 2600 | |
| Desired Payload (lbs) | 8000 | |
| Minimum required ground clearance (ft) | 5 | |
| Carriage ht when logs fly clear (ft) | 57 | |
| Carriage weight (lbs) | 2600 | Eagle II |
| Tower ht (ft) | 72 | |
| Tailhold ht (2 ft, 20ft, 40ft) | 2 | |
| Allowable skyline tension (lbs) | 43300 | |
| Skyline weight (lbs/ft) | 2.34 | 1 1/8 in diameter |
| Mainline weight (lbs) | 1.42 | 7/8 in diameter |
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| 60 ft Swing Yarder (Madill 124) |
| Max Slope Rigging Dist (ft) | 2550 | |
| Desired Payload (lbs) | 6000 | |
| Minimum required ground clearance (ft) | 5 | |
| Carriage ht when logs fly clear (ft) | 57 | |
| Carriage weight (lbs) | 2300 | |
| Tower ht (ft) | 60 | |
| Tailhold ht (2 ft, 20ft, 40ft) | 2 | |
| Allowable haul back tension (lbs) | 26500 | |
| Haul back line weight (lbs/ft) | 1.42 | 7/8 in diameter |
| Mainline or combined main and slack pulling line weight (lbs/ft) | 1.42 | 7/8 in diameter |
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| 50 ft Swing Yarder (Madill 120) |
| Max Slope Rigging Dist (ft) | 2550 | |
| Desired Payload (lbs) | 6000 | |
| Minimum required ground clearance (ft) | 5 | |
| Carriage ht when logs fly clear (ft) | 57 | |
| Carriage weight (lbs) | 2300 | Eagle IV |
| Tower ht (ft) | 50 | |
| Tailhold ht (2 ft, 20ft, 40ft) | 2 | |
| Allowable haul back tension (lbs) | 19600 | |
| Haul back line weight (lbs/ft) | 1.04 | 3/4 in diameter |
| Mainline or combined main and slack pulling line weight (lbs/ft) | 1.04 | 3/4 in diameter |
After registration of the map had been completed, and appropriate equipment information entered, analysis of landing locations could begin. This required pre-planning of the project area for possible landing locations. These locations were set in areas of low slope, with less than 30% desired. They were arranged to have an overlap of 1/3 to 2/3 of the external yarding distance between adjacent corridors. This provided redundancy in the design to ensure that various options were available for logging one certain area.
Long cable spans, greater than about 1500' were avoided to prevent excessive set-up time, crossing of major haul routes, and long cycle times. Cable harvest settings were also generated in low slope areas, for possible use in winter conditions when access may not be possible with ground-based equipment.
Once a likely area had been chosen, the user either specified a single profile or a central landing to be used. The location was then chosen with the digitizer. The program then prompts the user to specify a certain yarder to be used for analysis. PLANS will then create an image of how the landing profile will look given the specified payload and tailhold height.
Typical payloads ranged throughout the project area from as low as 3500 to as much as 9000 pounds. This was taken into account when choosing the appropriate yarder. This factor was changed in the yarder settings when working in different stands. In most cases, a default tailhold height of 2 feet was set. In many circumstances, though, tailhold height was raised to as much as 40 feet to achieve better deflection, and in turn, an increased payload. In many instances, these high tailholds were put in riparian management zones (RMZ's), where adequate tailhold height would be feasible to achieve. They were also set in mature stands where the average number of trees per acre that satisfied the QMD was over 18.
To manipulate these settings, tailholds could be put further away or closer to the yarder to achieve better payload. This enabled us to put tailholds on existing roads where a dozer with a mast reaching 40 feet, or an excavator reaching 40 feet could be used for the tailhold. The only difference between the two being accessibility. In this sense, we were able to manipulate the length, deflection, and payload of different yarding corridors to achieve units that fit our desired settings. The majority of these landings were analyzed with the Madill 172 Live skyline.
Individual profiles were also analyzed with the Madill 124 swing yarder because they are much faster to set up and are more easily mobile. Landings were typically placed on a road where feasible.
There were several settings upon the completion of digitizing cable yarding systems in PLANS. The total number of central tower landings digitized was 147. These landings led to a total of 1,757 profiles. The total number of mobile tower landings was 208. Since these are single profile settings, the total number of profiles for mobile towers was also 208.
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