United States

Department of

Agriculture

Forest Service

Northeastern

Research Station

Research Paper NE-715

Chris B. LeDoux

Neil K. Huyler

Cost Comparisons for Three

Harvesting Systems Operating

in Northern Hardwood Stands
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Abstract

Production rates, break-even piece (tree) sizes/costs (BEP), and operating costs

were compared for a Koller K-300 cable yarder, a cut-to-length (CTL) harvester, and

an A60F Holder tractor operating at three machine utilization rates (MUR) in

northern hardwood stands. The stand prescription for the three systems was

primarily a thinning (light to medium) to reduce the stand basal area to a range of 70

to 95 ft2

. Mean daily/annual production was 3,360/840,200 ft3 for the Koller K-300,

1,825/456,250 ft3

 for the CTL system, and 1,108/277,200 ft3 for the Holder tractor. At

an average product price of $0.40/ft3, the BEP size at an MUR of 90 was 7.64 ft3

 for

the Koller yarder, 4.63 ft3

 for the CTL harvester, and 3.74 ft3 for the A60F tractor,

respectively. At MUR’s of 75 and 60 percent, the break-even piece size was 9.18

and 10.82 ft3 for the Koller, 5.64 and 8.31 ft3 for the CTL harvester, and 4.55 and

5.74 ft3 for the Holder tractor. The most important attributes of these systems are

reduced soil compaction and disturbance, ease of movement to and from the

logging site, and minimal residual stand damage.

The Authors

CHRIS B. LEDOUX, supervisory industrial engineer, received a B.S. degree in forest

management from the University of Idaho, and M.S. and Ph.D. degrees in forest

engineering from Oregon State University. He joined the Northeastern Research

Station in 1983 and currently is engaged in forest engineering research at

Morgantown, West Virginia.

NEIL K. HUYLER, research forester (retired), received a B.S. degree in forestry from

West Virginia University in 1969 and a M.S. degree in industrial wood management

and science in 1971. He joined the Northeastern Research Station in 1963, and

most recently was engaged in research on timber harvesting with sustainable

forestry management concepts at Burlington, Vermont. He retired from the Forest

Service in June 2000.

Manuscript received for publication 14 August 2000
1

Introduction

Rubber-tired skidders have long been used to extract timber

from northern hardwood sites, but public concern about

environmental damage from logging systems and current

forest practices/regulations have forced managers,

planners, and forest-land owners to consider alternative

harvesting technologies to minimize adverse effects on the

harvest site, watershed, and residual stand. This is

particularly true in the Northeastern United States, where

logging is a key activity.

To remain viable in the global wood market, woodland

owners in the Northeast are seeking logging systems that

are cost-effective in meeting standards for timber stand

improvements, cuts and water quality. At the same time,

loggers face tremendous economic pressures and typically

work under conditions of intense competition and narrow

profit margins. Thus, it is important to evaluate the

performance of various harvesting systems to ensure a

profitable operation.

In a series of time and motion studies, we documented the

production rates and costs of small tractors, a cable yarder

(Huyler and LeDoux 1997), and a CTL system (Huyler and

LeDoux 1996). Tractors are effective in removing timber on

hardwood sites with little residual stand damage (Huyler and

LeDoux 1989). However, in a study of partial cuts in New

York, Nyland and Gabriel (1971) found that conventional

logging damaged about 30 percent of the residual trees;

nearly 20 percent incurred major injuries.

In this study, we used ECOST (LeDoux 1985) and ECOST

3.0, stump-to-mill logging models for eastern hardwoods, to

compare the costs of three harvesting systems that are

effective in northern hardwood stands: an A60F Holder

articulated diesel tractor, a single-grip CTL harvester with bidirectional forwarder, and a Koller K-300 uphill cable yarder.

The most important attributes of these systems are reduced

soil compaction and disturbance, ease of movement to and

from logging jobs, and minimal damage to the residual stand

(Huyler and LeDoux 1994, 1999).

Methods

Harvesting Systems

The 48-hp Holder tractor, manufactured in Germany, was

equipped with an Igland-Jones 3000 double-drum winch with

a rated pulling capacity of 6,000 lb. The 55-hp CTL harvester

with a 48-gal/min hydraulic pump system is a Peninsuladesign roller processing sawhead (RP1600) mounted on a

modified 988 John Deere 70 tracked excavator platform. It

has a maximum cutting diameter of 14 inches (limb diameter

0.5 to 9 inches). The system included a Valmet 524

forwarder equipped with a small clam loader and an 8-foot

log bunk. The Koller yarder, manufactured in Austria, has a

minimum power source of 40 hp, a 23-foot tower, and a

payload capacity of 3,500 lb. The trailer- or tractor-mounted

yarder is used mostly for commercial thinning and smallwood

harvesting.

In selecting these systems for study, we specified only that

they be less than 60 hp and that the two conventional

ground-based systems have 4-wheel drive capability. The

stand prescription was primarily a thinning (light to medium)

to reduce stand basal area to range between 70 and 95 ft2

.

Typically, the long-range plan for the stands in this study was

to grow high-quality hardwoods and provide for other

nontimber uses. Harvesting was conducted during the

summer and early autumn. Skid trails generally were dry and

in good condition. Average skid distances were 927 feet for

the A60F and 402 feet for the CTL forwarder. The Koller

yarder had an average slope yarding distance of 426 feet

(lateral yarding distance of 27 feet).

The hourly machine rate for the Holder tractor was $21.75

(average slope yarding distance of 1,000 feet), $115 for the

CTL system and $30 for the forwarder (500 feet), and $65.92

for the Koller K-300 (400 feet).

Study Site 1

The pre-test inventory on the study site for the Holder tractor

(Huyler and LeDoux 1989) recorded 287 stems per acre with

a mean stand diameter of 8.6 inches and a basal area of

116.2 ft2. The large pole stand was in need of a thinning to

eliminate suppressed, poorly formed, and overmature trees.

The soil was generally well drained but rocky. About 35 ft2

 of

basal area were removed to bring the postharvest stand

basal area to 81 ft2

.

Study Site 2

The study site for the CTL harvester (Huyler and LeDoux

1996) had 256 trees per acre (mostly eastern white pine and

northern red oak) and a mean stand diameter of 11.2 inches.

The stand prescription was primarily a thinning to reduce the

basal area from 128 to 90 ft2. The site was nearly flat except

for a small area with a side slope of about 3 percent.

Study Site 3

The study site for the Koller cable yarder (Huyler and

LeDoux 1997) consisted of overmature, good-quality red oak

trees. The thinning reduced the volume from 12.5 to 9 Mbf

per acre with a residual basal area of 70 ft2

. The soil was well

drained and dry and the mean slope was 40 to 50 percent.

Although the side slope was much greater than on Sites 1

and 2, it was not excessive for cable yarding.

ECOST Costing Models

Average piece sizes and hourly machine rates were used as

inputs to the ECOST models. ECOST 3.0 differs from

previous versions in that it includes skidding cost and
2

productions for four small farm/skidding tractors and for

some skidder sizes. These programs enable users to

estimate costs for felling, bucking, limbing, yarding/skidding,

loading/unloading, and hauling. Costs can be estimated as

components or stump to mill for most of the conditions

encountered in eastern hardwood stands. Estimates from

ECOST were graphed to determine the impact of average

piece size, machine used, and machine utilization rate (MUR)

on stump-to-landing costs and break-even piece sizes/costs.

Machine Utilization Rate

Nonproductive time—scheduled and unscheduled

maintenance, changing landing areas, and “miscellaneous”

delays – can reduce the MUR substantially. Scheduled

maintenance includes regular servicing of skylines and

rigging as well as parts replacement. This work usually is

scheduled during long delays or outside of the normal work

shift. Unscheduled maintenance refers to repairs and

downtime due to equipment, skyline, or rigging failure.

Miscellaneous delays include scheduling delays, time lost to

poor weather, crew breaks, and operator inefficiencies.

Results and Discussion

Figures 1-3 show stump-to-landing cost curves by piece size

for the harvesting systems at MUR’s of 90, 75, and 60

percent. At 90 percent, the effect of size on cost was most

pronounced for the Koller-300. Yarding pieces that average

3.88 ft3

 cost $1.0419/ft3 vs. $0.7168/ft3 for pieces that

average 4.94 ft3

. The cost to harvest the same 3.88 ft3 piece

was $0.4403 for the CTL system and $0.3826/ft3

 for the

Holder tractor. At MUR’s of 75 and 60 percent, the Koller’s

operating costs were $1.2503 ft3 (Fig. 2) and $1.5629 ft3 (Fig.

3). At 90 percent, BEP sizes were 3.74 ft3 for the tractor, 4.63

ft3

 for the CTL harvester, and 7.64 ft3 for the cable yarder,

i.e., loggers operating in stands with average tree sizes that

exceed the BEP would realize a profit. Cost decreased at

decreasing rates (flatter slopes) as piece size increased from

6 to 11.30 ft3 (Fig. 1).

BEP sizes for the three harvesters at MUR’s of 75 and 60

percent were, respectively, 9.18 and 10.82 ft3 for the Koller K300, 5.64 and 8.31 for the CTL system, and 4.55 and 5.74 for

the Holder tractor. Reducing delays and/or downtime can

greatly affect the logger’s profit margin. In stands where the

average piece size is 11.30 ft3

, the operating cost for the

cable yarder at an MUR of 60 percent is $0.3729/ft3

 versus

$0.2486/ft3

 at a utilization rate of 90 percent.

Koller K-300 Yarder

Mean daily/annual production for the Koller K-300 cable

yarder was 3,360/840,200 ft3

. Because cable yarding is more

costly than ground-based systems, this technology requires

a multiproduct market and a site with a large volume of

quality timber. The Koller K-300 is suitable for commercial

thinnings and selection cuts in young, high-quality sawlog

stands, and for uphill yarding in steep terrain in

precommercial thinnings of small, roundwood products such

as firewood. Cable yarding is a good alternative to groundbased skidding where side slopes are greater than 30

percent. In a study that compared the cost of applying

specific standards for water quality, the cost advantage of

ground-based skidding over cable yarding was reduced from

30 to 15 percent (Huyler and LeDoux 1995). This advantage

will become less important as stumpage prices escalate and

restrictions are placed on ground-based systems.

CTL Processor/Forwarder

Mean daily/annual production for the CTL harvester with

forwarding system was 1,825/456,250 ft3

. An important

advantage of CTL system is its ability to lay a mat of limbs

and woody debris in front of the machine to travel on. As a

result, this technology should be considered for operations in

wet and/or muddy areas and where soil erosion, compaction,

and water quality are concerns, e.g., small suburban

woodlands. Also, damage to the residual stand during

thinning operations is minimized because trees can be felled

directionally and whole trees are not pulled through the

stand, as usually is the case with rubber-tired skidders. The

CTL harvester/processor also is efficient in softwood stands

(Huyler and LeDoux 1996).

The CTL system is highly flexible in that it can: 1) be used as

a feller-buncher where whole trees are felled and bunched

for grapple skidding to the landing, 2) produce tree-length

material by delimbing in the woods (a rubber-tired skidder

would be used to move the stems to the landing), and 3) be

programmed to process trees into specific log lengths that

meet specific factory-grade log requirements or pulpwood

lengths.

The greatest drawbacks with this system are high initial

investment and operating costs, reduced productivity on

steep slopes, and the possibility of machine rollover when

processing large hardwood trees. Also, harvesting large

stems can place excessive strain on the processor head. We

observed a high incidence of hydraulic line failure during

extremely cold weather and in deep snow.

A60F Holder Tractor

The Holder tractor is highly maneuverable over most terrain

in dense, small-diameter stands. It operates efficiently in

stands with medium or large stems and skid distances up to

1,000 feet (Huyler and LeDoux 1991). This tractor should be

considered in pole and sawtimber stands on small parcels

where large equipment would not be cost effective and/or

pose a high risk of soil disturbance and residual stand

damage. The Holder tractor also is recommended for

thinning small farm woodlots and in areas where there is a

strong local market for firewood or wood chips.

It is sometimes difficult to locate spare parts for the A60F

Holder and similar tractors. Also, tractor systems cannot

produce sufficient volumes over time to be a sole source of

income for the owner. However, an acceptable income can

be produced by combining the tractor’s use with forestry

activities such as prebunching and forwarding to main skid

trails, or with other farm activities.
3

Figure 1.—Stump-to-landing costs curves and break-even piece (tree) sizes (BEP) for

the A60F Holder tractor, Koller K-300 cable yarder, and cut-to-length (CTL) processor

with forwarding system at a machine utilization rate of 90 percent.

Figure 2.—Stump-to-landing costs curves and break-even piece (tree) sizes (BEP) for

the A60F Holder tractor, Koller K-300 cable yarder, and cut-to-length (CTL) processor

with forwarding system at a machine utilization rate of 75 percent.
4

Literature Cited

Huyler, Neil K.; LeDoux, Chris B. 1989. Small tractors for

harvesting fuelwood in low-volume, small-diameter

hardwood stands. In: Proceedings of the 12th annual

meeting of the Council on Forest Engineering; 1989

August 27-30; Coeur d’Alene, ID. Atlanta, GA: U.S.

Department of Agriculture, Forest Service, Southern

Region: 61-66.

Huyler, Neil; LeDoux, Chris B. 1991. A comparison of small

tractors for thinning central hardwoods. In: Proceedings

of the 8th central hardwood forest conference; 1991 March

4-6; University Park, PA. Gen. Tech. Rep. NE-148. Radnor,

PA: U.S. Department of Agriculture, Forest Service,

Northeastern Forest Experiment Station: 92-104.

Huyler, N. K.; LeDoux, C. B. 1994. Residual stand damage

survey for three small tractors used in harvesting

northern hardwoods. In: Sessions, John; Kellogg, Loren,

eds. Proceedings of the 17th annual meeting of the

Council on Forest Engineering and International Union of

Forest Resource Organizations, Div. 3; 1994 July 24-29;

Portland, OR. Corvallis, OR: Oregon State University,

Department of Forest Engineering: 173-183.

Huyler, Neil K.; LeDoux, Chris B. 1995. Estimating the cost

of applying AMP’s regulations to logging on moderate

slopes. In: Proceedings of the sustainability, forest health

and meeting the nation’s needs for wood products. 1995

June 5-8; Cashiers, NC. Asheville, NC: U.S. Department

of Agriculture, Forest Service, Southern Region: 165-171.

Huyler, Neil K.; LeDoux, Chris B. 1996. Cut-to-length

harvesting on a small woodlot in New England: a case

study. In: Proceedings of the meeting on planning and

implementing forest operations to achieve sustainable

forests; 1996 July 29 - August 1; Marquette, MI. Gen.

Tech. Rep. NC-186. St. Paul, MN: U.S. Department of

Agriculture, Forest Service, North Central Forest

Experiment Station: 102-108.

Huyler, Neil K.; LeDoux, Chris B. 1997. Yarding cost for the

Koller K300 cable yarder: results from field trials and

simulations. Northern Journal of Applied Forestry. 13(4):

5-9.

Huyler, Neil K.; LeDoux, Chris B. 1999. Performance of a

cut-to-length harvester in a single-tree and groupselection cut. Res. Pap. NE-711. Radnor, PA: U.S.

Department of Agriculture, Forest Service, Northeastern

Research Station. 6 p.

LeDoux, Chris B. 1985. Stump-to-mill timber production

cost equations for cable logging eastern hardwoods.

Res. Pap. NE-566. Broomall, PA: U.S. Department of

Agriculture, Forest Service, Northeastern Forest

Experiment Station. 12 p.

Nyland, R. D.; Gabriel, W. J. 1971. Logging damage to

partially cut hardwood stands in New York state. AFRI

Res. Rep. 5. Syracuse, NY: State University of New York,

Applied Forestry Research Institute. 38 p.

Figure 3.—Stump-to-landing costs curves and break-even piece (tree) sizes (BEP)

for the A60F Holder tractor, Koller K-300 cable yarder, and cut-to-length (CTL)

processor with forwarding system at a machine utilization rate of 60 percent.
Printed on Recycled Paper

LeDoux, Chris B.; Huyler, Neil K. 2000. Cost comparisons for three harvesting

systems operating in northern hardwood stands. Res. Pap. NE-715.

Newtown Square, PA: U.S. Department of Agriculture, Forest Service,

Northeastern Research Station. 4 p.

Production rates, break-even piece (tree) sizes/costs (BEP), and operating costs

were compared for a Koller K-300 cable yarder, a cut-to-length (CTL) harvester, and

an A60F Holder tractor operating at three machine utilization rates (MUR) in

northern hardwood stands. At an average product price of $0.40/ft3

, the BEP size at

an MUR of 90 was 7.64 ft3

 for the Koller yarder, 4.63 ft3 for the CTL harvester, and

3.74 ft3 for the A60F tractor, respectively. At MUR’s of 75 and 60 percent, the breakeven piece size was 9.18 and 10.82 ft3 for the Koller, 5.64 and 8.31 ft3

 for the CTL

harvester, and 4.55 and 5.74 ft3

 for the Holder tractor. The most important attributes

of these systems are reduced soil compaction and disturbance, ease of movement

to and from the logging site, and minimal residual stand damage.

Keywords: CTL systems, cable yarder, tractors, thinning, economics
Headquarters of the Northeastern Research Station is in Newtown Square,

Pennsylvania. Field laboratories are maintained at:

Amherst, Massachusetts, in cooperation with the University of Massachusetts

Burlington, Vermont, in cooperation with the University of Vermont

Delaware, Ohio

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Hamden, Connecticut, in cooperation with Yale University

Morgantown, West Virginia, in cooperation with West Virginia University

Parsons, West Virginia

Princeton, West Virginia

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

College of Environmental Sciences and Forestry at Syracuse University

Warren, Pennsylvania

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