United States 

Department of 

Agriculture Cost and Production Analysis 

Forest Service of the Bitterroot Miniyarder on 

~~rthe~ste~~~~~~~~ Experiment Station an Appalachian Hardwood Site 

Research Paper 

N E-557 John - - E. Baumgras 

Penn A. peters 
The Authors 

John E. Baumgras is a forest products technologist, USDA Forest Service, 

Northeastern Forest Experiment Station, Morgantown, WV. 

Penn A. Peters is Project Leader of the Forest Engineering Research 

Project, Northeastern Forest Experiment Station, Morgantown, WV. 

Manuscript received for 

publication 6 August 1984 

- 

Abstract 

An 18-horsepower skyline yarder was studied on a steep slope clearcut, 

yarding small hardwood trees uphill for fuelwood. Yarding cycle characteristics sampled include: total cycle time including delays, 5.20 minutes; yarding 

distance, 208 feet (350 feet maximum); turn volume, 11.6 cubic feet (24 cubic 

feet maximum); pieces per turn, 2.3. Cost analysis shows yarding costs will 

range from $18.00 to $36.00 per cunit, depending upon crew efficiency and 

yarding conditions. - 
Introduction 

The harvest and'utilization of 

small trees are essential to the intensive management of Appalachian 

hardwood forests. Thinnings on the 

better sites and harvest cuts on poorer 

sites require the removal of many 

trees 5 to 10 inches diameter breast 

height (d.b.h.). Much of the fuelwood 

now hawested from standing timber 

or salvaged from logging residue is 

also obtained from small-diameter 

trees or logs. Cable logging is often 

the preferred hawesting method for 

the steep slopes common to Appalachia because of reduced environmental damage. However, logging 

small trees with cable yarders is 

generally too costly considering the 

low value of the products removed. 

The high initial investment and extensive setup and rigging times associated with most cable yarders limit 

their application to high-volume or 

high-value removals (Matics 1982). 

The Bitterroot Miniyarder was 

developed by the USDA Forest Service, Missoula Equipment Development Center, for cable yarding small 

trees and logging slash on steep 

slopes. This small and very mobile 

cable yarder is relatively inexpensive 

to own and operate, quick to setup, 

and easy to operate (USDA Forest 

Service 1983). These characteristics 

identify the Bitterroot Miniyarder as a 

machine with the potential for reducing the cost of cable yarding small 

hardwood trees on steep slopes. 

This small skyline yarder was 

tested in the South and the West 

(American Pulpwood Association 1983, 

Brown and Bergvall 1983, Cubbage 

and Gorse 1984). To obtain detailed 

cost and production information for 

eastern hardwood applications, the 

small yarder was studied logging a 

steep slope Appalachian site. The 

objectives of this study were to determine production rates and costs for 

the Bitterroot Miniyarder and to identify those factors that affect yarding 

cost. 

Yarding Operations, 

The Bitterroot Miniyarder was 

studied yarding fuelwood from a 2-acre 

clearcut block on the Jefferson National Forest in Virginia. On this unit, 

200 trees per acre larger than 4 inches 

d.b.h. were harvested, yielding 1,350 

cubic feet per acre of wood and bark. 

The cutting unit was located in a 

poletimber stand that contained a 

few scattered low-quality sawtimber 

trees. The d.b.h. of cut trees averaged 

7.7 inches, and the diameter distribution shows that more than 90 percent 

of the trees harvested were 10 inches 

d.b.h. or smaller (Fig. 1). Total height 

of the dominant and codominant 

trees ranged from 50 to 60 feet. The 

species composition was predominantly chestnut oak and scarlet oak 

with minor components of hickory, 

red maple, and pitch pine. 

TREE DIAMETER CLASS (Inches) 

Figure 1.-The diameter distribution of merchantable trees on the 

logging site. 
All trees larger than 1.0 inch 

d.b.h. were felled before yarding, but 

few trees smaller than 4.0 inches 

d.b.h. were actually yarded. Trees 

4.0 inches d.b.h. and larger were 

limbed and topped to a variable top 

diameter as small as 2.0 inches diameter outside bark. Sawtimber-size 

trees were bucked into log lengths. 

The resulting piece-volume distribution shows that the volume of most 

pieces yarded was less than 10 cubic 

feet (Fig. 2). Piece volume averaged 

5 cubic feet. 

The small yarder was mounted 

on a two-wheeled trailer that could 

be towed by a pickup truck (Fig. 3). 

With the exception of the original 

%-inch diameter skyline that had 

been replaced with approximately 

640 feet of %-inch cable, the following 

specifications provided by Missoula 

Equipment Development Center describe the yarder tested. 

Weight: 1,600 pounds rigged 

Engine: 18-hp Briggs and Stratton,' 

twin cylinder, air cooled, electric start 

Transmission: Sundstrand series 1.5 

hydrostat 

Axle: Dana Spicer GT-20 with 72-tooth 

spur gear 

Skyline and Mainline Drums: 800 feet 

of %-inch cable, 0 to 2,000 pound line 

pull, 0 to 400 ftlmin line speed 

Mainline Clutch: Dog type 

Brakes: Band type, mechanically operated, 123h inch diameter 

Boom: 23h-in~h pipe A-frame, 17% 

feet long, 180 degrees fairlead swivel, 

manually raised and lowered 

Controls: 15-foot mechanical push1 

pull cable 

'The use of trade, firm, or corporation 

names in this publication is for the information and convenience of the reader. 

Such use does not constitute an official 

endorsement or approval by the U.S. Department of Agriculture or the Forest 

Service of any product or service to the 

exclusion of others that may be suitable. 

During each yarding cycle, the 

live skyline was lowered for unhooking the chokers at the landing. The 

skyline was also periodically lowered 

to permit the chokersetters to move 

the carriage stop, which was clamped 

on the skyline. The small Christy 

carriage was locked on the skyline 

at the carriage stop, releasing the 

mainline to be pulled laterally by the 

chokersetters. As many as five wirerope chokers were used when yarding 

very small pieces. When a turn of 

choked pieces was laterally yarded 

to the carriage, a ball attached to the 

mainline released the skyline lock 

and simultaneously locked the carriage to the mainline for the trip to 

the landing. The lift provided by the 

skyline generally kept the leading end 

of the pieces off the ground and free 

from stumps and slash. 

45 

- 

2 4 6 8 10 12 14 16 18 20+ 

PIECE VOLUME (Cubic feet) 

Figure 2.-The distribution of piece volume in cubic feet by percent of 

pieces yarded. 
The fan-shaped clearcut block 

was yarded uphill to a single landing 

located below the yarder (Fig. 4). The 

slope distance from the yarder to 

each of the four tailholds used to anchor the skyline ranged from 390 to 

490 feet. Tailholds were rigged at a 

height of 2 to 3 feet by attaching the 

skyline to large standing trees located outside of the unit boundary. 

The slope of the skyline corridors 

ranged from 15 to 40 percent. 

The Forest Service logging crew 

consisted of a yarder operator, two 

chokersetters, and one chaser unhooking at the landing. A tractor 

operator also used a small crawler to 

clear the landing and deck the yarded 

wood along the access road for sale 

at roadside as fuelwood. The tractor 

and operator were not included in the 

time study or the cost analysis. 

Figure 3.-The Bitterroot Miniyarder mounted on a two-wheeled trailer. 

T 

z 

a 

I- 

; 100 - 

- - - T 

B- Unit Boundary a T - Tail hold Locat ion 

-0 T 

1 I J 

100 200 300 400 500 

HORIZONTAL DISTANCE (Feet) 

Figure 4.-Ground profile of three skyline roads. 
Study Methods 

A time study of the yarding 

operation was conducted using continuous timing over the span of each 

yarding cycle. Start and stop times 

were recorded for the productive and 

delay portion of each of the five major 

yarding cycle elements: 

Outhaul starts when the carriage 

leaves the landing and ends when 

the carriage hits the skyline stop 

releasing the mainline. 

Hooking starts when the mainline 

is released and ends when the 

chokers are hooked and the yarder 

operator is signaled to begin 

lateral yarding. 

Lateral yarding starts with the signal to begin lateral yarding and 

ends when the turn is laterally 

yarded, releasing the carriage lock. 

lnhaul starts when the carriage 

lock releases and ends when the 

turn reaches the landing. 

Unhooking starts when the turn 

reaches the landing and ends when 

pieces are unhooked, the skyline is 

raised, and the carriage begins to 

leave the landing. 

In addition to yarding time data, 

yarder cycle characteristics were 

recorded, including: slope yarding 

distance, the distance from the landing to the carriage stop measured 

along the slope; slack-pulling distance, the distance from the skyline 

stop to the farthest piece hooked; 

number of pieces hooked; and the 

dimensions of each piece including 

both end diameters outside bark and 

length. From piece dimensions, piece 

volumes and total turn volumes were 

estimated. Piece and turn weights 

were estimated from the volumes 

using conversion factors developed 

by Timson (1975). For the species mix 

sampled, the conversion factor used 

was 59 pounds per cubic foot of wood 

and bark. 

Linear regression methods were 

used to determine the functional relationships between site factors and 

yarding cycle time, and yarding element times. The objectives of this 

analysis were to identify those factors that affect yarder productivity 

and to develop equations for predicting cycle time so that yarding conditions could be used to predict yarder 

production. 

The static mainline pull at a 

250-foot-slope yarding distance was 

measured using a dynamometer anchored to a stump. For the three skyline road profiles shown in figure 4, 

the payload capability of the system 

was estimated using the handheld 

calculator programs developed by 

Falk (1981). These programs include 

the effects of partial load suspension, which was appropriate for this 

application since logs were dragged 

rather than yarded fully suspended. 

The yarding cost model developed by Peters (1984) was used to 

estimate yarding cost and to predict 

the response of yarding cost to 

changes in operating efficiency and 

changes in piece size and volume per 

acre. This model uses the inputs 

listed below to estimate the time 

required to yard a given unit, the 

production rate, and the cost per unit 

of production. 

Site specific variables 

Volume harvested per acre 

Average piece volume 

Harvest unit area 

Percent slope 

Geometric parameters required to 

compute average slope yarding 

distance and lateral yarding 

distance 

Yarder specific variables 

Hourly cost of yarder and crew 

Cycle time regression coefficients 

Yarder payload capacity 

Load curve statistics to estimate 

average volume per turn and number of pieces per turn from average 

piece volume 

Operation specific variables 

Time to move and set up yarder 

Time change to a new skyline 

corridor 

Downtime for mechanical or system delay 

Operational delay time during yarding cycle 
Time Study Results 

The yarding operation was observed a total of 22.4 scheduled work 

hours. Two changes of skyline corridor required a total of 2.1 hours. Of 

the remaining 20.3 hours, the yarder 

operated 19.7 hours. Detailed cycle 

time and production data were collected from 16.1 hours of yarder operating time that included 13.2 hours 

of delay-free yarding time. Within this 

time span, 186 turns were yarded producing 427 pieces and 2,162 cubic 

feet of wood and bark. The estimated 

weight of the pieces yarded was 64 

green tons. The average productivity 

of the yarder was 134 cubic feet or 

4 tons per productive hour, and 164 

cubic feet or 4.8 tons per delay-free 

hour. 

The following summary of cycle characteristics defines the 

yarding conditions sampled: 

Average Minimum Maximum - Slope yarding distance-feet 208 

Slack-pulling distance-feet 26 

Volume per turn-cubic feet 11.6 

Weight per turn-pounds 680 

Number of pieces per turn 2.3 

The dimensions of the clearcut 

unit and the spacing of the skyline 

roads limited slope yarding distance 

to 350 feet and slack-pulling distance 

to 80 feet. With respect to payload, 

the yarder was thoroughly tested as 

several of the turns yarded represented the maximum capacity of this 

4 6 8 10 12 14 16 18 20 22 24 

TURN VOLUME (Cubic feet) 

yarder. Because of the small diameter 

of the pieces yarded, the average 

volume yarded was only half of the 

maximum volume and as many as 

five pieces were yarded per turn. 

Volume yarded per turn seldom exceeded 16 cubic feet (Fig. 5). 

Figure 5.-The distribution of turn volume 

in cubic feet by percent of turns yarded. 
Delay-free cycle time averaged 

4.25 minutes per turn, including 0.48 

minutes outhaul time, 1.46 minutes 

hooking time, 0.33 minutes lateral 

yarding time, 0.89 minutes inhaul 

time, and 1.09 minutes unhooking 

time (Table 1). Together, hooking and 

unhooking accounted for 60 percent 

of delay-free yarding time. The time 

required to move the turn of logs from 

the stump to the landing includes 

lateral yarding and inhaul, and accounts for less than 30 percent of 

delay-free cycle time. 

Yarding delays averaged 0.95 

minutes per turn, increasing the average total cycle time to 5.2 minutes. 

Half of all turns samples encountered 

delays that averaged 1.9 minutes. 

Delays in outhaul, hooking, and inhaul showed low frequencies of occurrence that ranged from 0.02 to 0.08 

per turn. The average duration of 

these delays ranged from 1.0 to 2.9 

minutes per delay (Table 2). Because 

of the low frequencies, the average 

delay time per turn was only 0.05 minutes for outhaul, 0.08 minutes for 

hooking, and 0.12 minutes for inhaul 

(Table 2). Collectively, these delays 

accounted for 26 percent of all yarding delay. 

Collectively, lateral yarding delays and unhooking delays accounted 

for 74 percent of all yarding delay 

time. Both types of delay occurred 

with a frequency of 0.20 delays per 

turn. Average delay time per cycle 

was 0.38 minutes for lateral yarding 

and 0.32 minutes for unhooking 

(Table 2). Nearly all lateral yarding 

delays occurred when excessive 

loads were hooked or heavy logging 

slash covered the pieces and the turn 

had to be rehooked or bucked before 

the small yarder could move the turn 

to the carriage. Half of the unhooking 

delay time was incurred when the 

incoming turn hung on previously 

yarded pieces that extended over the 

downhill edge of the small landing. 

Other unhooking delays occurred 

while the tractor cleared the landing 

Table 1.-Statistical summary of delayfree yarding 

element time. 

Yarding 

element Standard Minimum Maximum Mean deviation 

Outhaul 0.48 0.17 0.09 0.79 

Hooking 1.46 .54 .38 3.14 

Lateral 

yarding .33 .31 .04 2.36 

lnhaul .89 .42 .18 3.38 

Unhooking 1.09 .40 .39 2.80 

Complete 

cycle 4.25 .96 1.65 7.65 

Table 2.-The frequency and average duration of yardin delays, 

average delay time per cycle, and percent of elay time by yarding element. 

dl 

Yarding 

element Frequency 

- - 

Average Averagea 

duration delay time 

Outhaul 

Hooking 

Lateral 

Yarding 

lnhaul 

Unhooking 

Complete 

Cvcle 

Dela yslcycle 

0.02 

.08 

.20 

.04 

.20 

.54 

Minutesldelay Minuteslcycle 

2.33 0.05 

1.03 .08 

1.86 .38 

2.87 .I2 

1.54 .32 

1 .72 .95 

Proportion 

of delay time 

Percent 

5.3 

8.4 

40.0 

12.6 

33.7 

100.0 

aNot equal to product of frequency and duration due to rounding. 

or when the carriage stop was move& 
Mainline Test and 

Payload Analysis 

The maximum static mainline 

pull at a 250-foot-slope yarding distance was 1,150 pounds by measurement. The measured mainline pull 

corresponds to a drum radius of 6.4 

inches; the bare-drum radius is 3.4 

inches. The pull at bare drum is calculated as the product of the measured 

line pull and the ratio of drum radii, or 

1,150 (6.413.4) = 2,165 pounds, which 

agrees with published values of 2,000 

pounds (American Pulpwood Association 1983). Measured line pull also 

correlates closely with the estimated 

weight of the maximum turn volumes 

yarded. The largest turn weighed an 

estimated 1,400 pounds, and only 

eight turns exceeded 1,100 pounds. 

When turn volumes approached 20 

cubic feet, lateral yarding became 

increasingly difficult and delays more 

frequent. Delays related to the mainline pull were also encountered when 

heavy logging slash covered the 

pieces to be yarded. Comparison of 

mainline pull capacity to the Appalachian hardwood tree weights published by Wiant (1977) shows that 

only trees 10 to 11 inches d.b.h. or 

smaller can be yarded stem length to 

a 4-inch outside bark top diameter. 

The estimated payload capability in the skyline corridor, limited by 

the mainline and skyline respectively, 

are: profile 1, 2,000 pounds and 2,360 

pounds; profile 2, 1,780 pounds and 

2,230 pounds; profile 3, 1,720 pounds 

and 1,770 pounds. Therefore, the skyline profile did not determine the payload capacity, but in all instances, 

the payload capacity was determined 

by the mainline pull required to breakout and laterally yard the turn to the 

carriage. If payloads were limited 

only by skyline payload capability, 

they could have been increased by 

35 to 50 percent. 

Regression Analysis Results 

The independent variables tested 

in the regression analyses of delayfree cycle time and cycle element 

time include slope yarding distance, 

slack-pulling distance, number of 

pieces yarded per turn, and cubic volume per turn. Only variables that were 

significant at the 0.05 level are included in the final equation shown in 

table 3. With the exception of slackpulling distance, all variables that 

appear in the element time equations 

also appear in the cycle time equation. 

The results shown in table 3 indicate that the independent variables 

in the equations for outhaul time, inhaul time, and cycle time explained 

32 to 84 percent of the variation sampled. The equations for hooking, lateral yarding, and unhooking time 

explained only 3 to 12 percent of the 

sampled variation. Increases in slope 

yarding distance, turn volume, and 

number of pieces hooked all result in 

increased cycle time. 

Table 3.-Regression equations, where Y = delayfree yarding element time in minutes, X, = slope yarding distance in feet, X, = slackpulling distance in feet, X, = number of pieces 

per turn, and X,, = volume per turn in cubic 

feet of w~od and bark. 

Yarding 

element Equation 

- 

Regression 

R2 S.E. 

Outhaul 

Hooking 

Laterial 

yarding 

lnhaul 

Unhooking 

Complete 

cycle 
The relationships between predicted delay-free varder ~roduction 300 3 \ PIECES PER TURN 

and slope yarding distance, turn volume, and number of pieces per turn 

are shown in figure 6. The equation 

P = (6OICT)V was used; where P is - 250 - production, CT is delay-free cycle w a, time, and V is turn volume. To simplify 2 the illustration, the effects of pieces .- " 

per turn are shown only for the 15- a cubic-foot turn volume. 3 2 200 - 

- 0 3 0 

Because of the effect of yarding z c 

distance on cycle time, increasing 0 a, 

- 

yarding distance from 100 feet to 

600 feet, reduces delay-f ree produc- 2 150 1 

tion from 163 to 89 cubic feet per hour 5 - when yarding a 10-cubic-foot turn PZ - (Fig. 6). Although cycle time also increases with turn volume, the effect $ 100 1 

of fewer Q turns per hour is offset by a, - 

the additional volume. Yarding 300 z - 

feet, the increase in turn volume from p 

- 

10 to 20 cubic feet boosts the produc- - 

tion estimate from 122 cubic feet to a 50 

230 cubic feet per delay-free hour > - 

(Fig. 6). 

2 

3 

4 

5 TURN VOLUME20 

15 

The five production curves shown I I I I I I 1 I I I I 

for the Iscubic-foot turn volume in 0 

100 200 300 400 500 600 

figure 6 indicate that production will 

decline when piece size dictates that SLOPE YARDING DISTANCE (Feet) 

more pieces must be hooked to main- Figure 6.-The effects of slope yarding distance, pieces per turn, and 

tain a specific turn volume. H~~~~~~, volume per turn on estimated delay-free yarder production. 

production will generally increase 

when hooking more pieces results in 

additional volume. Yarding 300 feet 

with a Bpiece, 15-cubic-foot turn, the 

estimated production rate is 185 cubic feet per hour. Adding a B-cubicfoot piece and yarding a 3-piece, 

20-cubic-foot turn, increases the estimated production rate to 230 cubic 

feet per delay-free hour (Fig. 6). 
Yarding Cost Analysis 

The total labor and equipment 

cost for the yarding operation; excluding felling, decking, and hauling, 

was estimated to be $270.00 per 

8-hour day based upon 220 operating 

days per year. Fixed and operating 

costs for the yarder, chainsaws, and 

communications equipment totaled 

$62.00 per day (Appendix). Although 

the crew used handheld two-way 

radios for communications between 

the chokersetters and the yarder 

operator, the cost estimate includes 

the talkie-tooter type radio and transmitters normally used with cable 

yarders. Payroll cost for the crew of 

four with wages averaging $5.00 per 

hour and associated costs of 30 percent were $208.00 per day. Since labor cost represents 77 percent of the 

total cost, the daily yarding cost will 

be much more sensitive to changes in 

labor cost than to changes in the 

equipment costing assumptions. 

The stump to landing yarding 

cost at the study site was estimated 

using the yarding cost model with 

two sets of inputs to show the effects 

of nonproductive time. Case 1 and 

Case 2 differ only with respect to the 

following nonproductive time elements. Case 1 represents the operation studied with the site, yarder, 

and operational variables required by 

the costing model being obtained 

from the study data. Because the 

short duration of the time study did 

not provide an adequate sample of 

downtime, the percent of scheduled 

operating time lost to mechanical or 

systems delays was assumed to be 

10 percent in Case 1 and 5 percent in 

Case 2. 

Corridor change, minutes per move 

Yarding delay, minutes per turn 

Downtime, percent of scheduled 

operating time 

Production rate, cunits 

per &hour day 

Yarding cost, dollar per cunit 

The increased efficiency shown 

in Case 2 might be expected as the 

crew became more experienced in 

cable logging and learned the limitations of the small yarder. The net result of these prospective improvements would be a 20 percent increase 

in production and a 17 percent reduction in yarding cost. 

The yarding cost estimates in 

Cases 1 and 2 are specific to the conditions at the study site. These include an average piece volume of 

5 cubic feet and a volume per acre of 

1,350 cubic feet. To determine the 

sensitivity of yarding cost to changes 

in these two variables, the yarding 

cost model was applied to the conditions specified in Case 2, changing 

only volume per piece and volume per 

acre. Piece volume was incremented 

in I-cubic-foot intervals from 3 to 12 

cubic feet for each of three volumeper-acre levels-1,000, 2,000, and 

3,000 cubic feet. 

Case 1 

60 

0.95 

10 

7.6 

35.70 

Case 2 

30 

0.50 

5 

9.1 

29.50 
The results of this sensitivity 

analysis indicate that yarding costs 

will decline significantly with increases in either average piece size 

or volume per acre. Yarding 1,000 

cubic feet per acre when piece size 

averages 4 cubic feet costs $34.00 per 

cunit. This compares to $18.00 per 

cunit when 3,000 cubic feet are yarded 

per acre and piece volume averages 

12 cubic feet (Fig. 7). 

These variations in yarding cost 

reflect a change in the expected production rate from 7.8 cunits to 15.0 

cunits per 8-hour day. As volume per 

acre increases, proportionately more 

time is spent yarding and less time is 

spent moving the yardes or changing 

tailholds. Increasing average piece 

volume results in greater turn volumes and fewer pieces per turn. 

Based upon the results of this 

study and the assumption incorporated into the cost analysis, $18.00 to 

$20.00 per cunit might well be the 

minimum expected yarding cost for 

the Bitterroot Miniyarder and a crew 

of four. The cost curves shown in figure 7 represent an efficient operation 

with an average yarding distance of 

200 feet, and nonproductive time elements at the levels shown in Case 2. 

Furthermore, on sites with piece sizes 

consistent with the capacity of this 

yarder, volume per acre and average 

piece volume will seldom exceed 

those values that correspond with the 

cost curves at $20.00 per cunit. Under 

less favorable conditions, such as 

those at the study site, the costs 

would exceed $30.00 per cunit. 

Aside from the increases in yarding production that are linked to crew 

efficiency and site conditions, yarding costs can also be controlled 

through crew size. The yarding operation studied used a crew of four. However, this and other small yarders can 

operate efficiently with crews of three 

or even two (Kellogg 1983, Brown and 

Bergvali 1983). At the wage rate used 

in the previous cost analyses, a crew 

of three cuts the daily cost of the 

yarding operation from $270.00 to 

$218.00 per day. This cost is $166.00 

per day with a crew of two. To yard for 

$20.00 per cunit, the crew of four 

must produce 13.5 cunits per day, 

whereas the crew of three needs 10.9 

cunits, and the crew of two only 8.3 

cunits. Assuming that mechanical 

downtime, outhaul, lateral yarding, 

and inhaul are unaffected by crew 

size; there must be significant increases in the remaining time elements to offset the economic advantages of smaller crews. 

VOLUME 

HARVESTEC 

1 I I I I 1 I I I I 

3 4 5 6 7 8 9101112 

AVERAGE PIECE VOLUME (Cubic feet) 

Figure 7.-The effects ofvolume harvested per acre and averaae -. Diece 

vohme on estimated yarding cost. 
Conclusions 

For successful application of 

cable yarding technology, the cost of 

yarding must be kept within the allowable limits. These limits will depend upon the forest management 

objectives of the landowner; the value 

attached to the environmental benefits of cable logging; and the difference between product value and the 

sum of additional costs such as felling, decking, loading, and hauling. 

With respect to yarding cost and potential applications, the two most important attributes of the Bitterroot 

Miniyarder are its low cost and low 

payload capacity. 

To effectively manage the tradeoff between cost and capacity, it is 

essential to balance the cost of the 

yarding operation against the expected production rate. Although 

yarder production depends on crew 

efficiency and yarding conditions, it 

is constrained by yarder capacity. 

Due to the low cost of owning and 

operating this yarder, this balance 

would best be achieved through labor 

cost. Since the operation studied 

used a crew of four and the minimum 

crew size is two, the relationships between crew size, productivity, and 

yarding cost definitely warrant further investigation. 

The material to be yarded must 

be compatible with the design capacity of the yarder. With the available 

line pull only poletimber and small 

sawtimber-size hardwood trees can 

be yarded in bole length or merchantable sawlog length pieces. Therefore, 

this yarder should be used to harvest 

small diameter sawlogs or sawbolts, 

pulpwood, or fuelwood. The material 

removed from thinnings will generally 

meet these criteria as will residue 

from regeneration cutting. Although 

the widespread need for thinning and 

the abundance of harvesting residue 

create numerous opportunities to use 

this yarder in the eastern hardwood 

region, its application will depend on 

local markets for these products. 

Yarder capacity is an important 

consideration in planning the location of roads, landings, and corridors 

for all cable logging operations. Because of the capacity of this and 

other small yarders; felling, bucking, 

and other operational procedures 

must also be well planned. In the 

yarding corridors, even small trees 

should be felled and large tree tops 

lopped to avoid time consuming 

hangups. Directional felling will also 

reduce yarding delays, particularly in 

thinnings; and stems should be 

bucked to the capacity of the yarder. 

In thinnings, the chokersetter must 

position the carriage stop to keep 

turns within the lateral yarding corridor to reduce both delays and 

damage to the residual stand. The 

implementation of these essential 

practices will undoubtedly require an 

experienced and well-trained crew. 

Landing and decking procedures 

must also be included in the planning 

process. When wood decked at the 

yarder interferes with yarding, either 

wood or the yarder must be moved. 

Often a tracked or wheeled skidder is 

used to swing the wood from the 

yarder to a loading deck. Although a 

small tractor could be used with this 

yarder, the cost of this machine will 

contribute significantly to the cost of 

the operation. When road and landing 

layout permits self-loading trucks to 

work directly from the yarder deck, 

the need for a swing tractor can be 

eliminated. Yarding closely spaced 

parallel corridors, the highly mobile 

yarder can also be moved frequently 

to build a series of decks along the 

access road. 
Literature Cited 

American Pulpwood Association. 

Bitterroot Miniyarder. Washington, 

DC: American Pulpwood Association; 1983; Tech. Release 8344-1 10. 

3 PBrown, Steve L.; Bergvall, John A. 

In-woods testing and feasibility 

study of fuelwood recovery using a 

small scale cable yarding system. 

Olympia, WA: Department of Natural Resources; 1983. 50 p. 

Cubbage, Frederick W.; Gorse, 

August H., IV. Mountain logging 

with the Bitterroot Miniyarder. In: 

Peters, Penn A.; Luchok, John eds. 

Mountain Logging Symposium Proceedings, 1984 June 5-7; Morgantown, WV: West Virginia University 

Press; 1984:81-91. 

Falk, Gary D. Predicting the payload 

capability of cable logging systems 

including the effects of partial sus. 

pension. Res. Pap. NE-479. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern 

Forest Experiment Station; 1981. 

29 p. 

Kellogg, Loren D. Handling the small 

tree resource with cable systems. 

In: Proceedings of the small tree resource: A material handling challenge; 1982 April 19-21; Portland, 

OR.. Madison, WI: Forest Products 

Research Society; 1983:43-54. 

Matics, H. E. Westvaco wood procure. 

ment cable logging program, the 

future situation. In: Proceedings 

Appalachian cable logging symposium; 1982 June 12; Blacksburg, 

VA; Jefferson National Forest, 

Roanoke, VA; l982:17-23. 

Peters, Penn A. Steep slope clearcut 

harvesting with cable yarders. 

In: Proceedings, Harvesting the 

South's small timber; 1983 April 

18-20; Biloxi, MS. Madison, WI: 

Forest Products Research Society; 

1984~69-78. 

Timson, Floyd G. Weightlvolume 

ratios for Appalachian hardwoods. 

Res. Note NE-202. Broomall, PA: 

U.S. Department of Agriculture, 

Forest Service, Northeastern Forest Experiment Station; 1975. 2 p. 

USDA Forest Service. Bitterroot Miniyarder. 8351-2504. Missoula, MT: 

USDA Forest Service Equipment 

Development Center; 1983. 

Wiant, Harry J.; Sheetz, Carter E.; 

Colaninno, Andrew; Demoss, 

James C.; Castaneda, Froylan. 

Tables and procedures for estimating weights of some Appalachian 

hardwoods. Bull. 659 T. Morgantown, WV: West Virginia University 

Agricultural and Forestry Experiment Station; 1977. 36 p. 
Appendix-Yarding Equipment Costs 

FIXED-COST ESTIMATE 

Initial Salvage Average Equipment annual Annual 

description Life cost value investment fixed costa 

Cable yarderb 5 15,750 3,150 , 10,710 4,662 

Chainsaws, 2 1 1,100 0 1,100 1,320 

Radio and 

transmitters 4 4,500 0 2,812 1,688 

Total annual fixed cost 7,670C 

OPERATI NG-COST EST1 MATE 

Equipment 

description Operating cost items Annual operating 

cost 

Dollars 

Cable yarder Maintenance and repair at 50% of depreciation 1,260 

Fuel at 4 gallday, 220 dayslyear 1,100 

Filters, lube, and oil at 15% of fuel 165 

Cable, $1,250 with 2-year life 625 

Chokers, tools, and miscellaneous equipment 350 

Chainsaws Maintenance and repair at 100% depreciation 1,100 

Fuel and oil-220 dayslyear 725 

Miscellaneous equipment (bar, sawchain) 200 

Radio Maintenance and repair 350 

Total annual operating cost 5,875C 

aDepreciation plus sum of taxes, insurance, and interest estimated at 20 percent of average annual 

investment. 

bYarder without cable. 

CTotal annual fixed and operating cost = $13,545 and daily cost at 220 dayslyear = $61.56. 

Baumgras, John E.; Peters, Penn A. Cost and production analysis of the Bitterroot Miniyarder on an Appalachian hardwood 

site. Res. Pap. NE-557. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station; 1985. 13 p. 

An 18-horsepower skyline yarder was studied on a steep slope 

clearcut, yarding small hardwood trees uphill for fuelwood. 

Yarding cycle characteristics sampled include: total cycle time 

including delays, 5.20 minutes; yarding distance, 208 feet (350 

feet maximum); turn volume, 11.6 cubic feet (24 cubic feet maximum); pieces per turn, 2.3. Cost analysis shows yarding costs 

will range from $18.00 to $36.00 per cunit, depending upon crew 

efficiency and yarding conditions. 

ODC 375.1 2:662.2 

I Keywords: Timber harvesting, cable yarding, logging, cost 

a US. GOVERNMENT PRINTING OFFICE: 1985-505-0281545 
Headquarters of the Northeastern Forest Experiment Station are in 

Broomall, Pa. Field laboratories are maintained at: 

Amherst, Massachusetts, in cooperation with the University of 

Massachusetts. 

0 Berea, Kentucky, in cooperation with Berea College. 

0 Burlington, Vermont, in cooperation with the University of 

Vermont. 

@ Delaware, Ohio. 

e Durham, New Hampshire, in cooperation with the University of 

New Hampshire. 

0 Hamden, Connecticut, in cooperation with Yale University. 

0 Morgantown, West Virginia, in cooperation with West Virginia 

University, Morgantown. 

0 Orono, Maine, in cooperation with the University of Maine, 

Orono. 

0 Parsons, West Virginia. 

@ hiiceton, West Virginia. 

4 Syracuse, New York, in cooperation with the State University of 

New York College of Environmental Sciences and Forestry at 

Syracuse University, Syracuse. 

@ University Park, Pennsylvania, in cooperation with the 

Pennsylvania State University. 

4 Warren, Pennsylvania.