1 UW Forest Engineering Schiess & Jaross Long-Span VS. Conventional Skyline Yarding: Road Densities,...

1UW Forest Engineering Schiess & Jaross

Long-Span VS.Long-Span VS.Conventional Skyline Yarding:Conventional Skyline Yarding:Road Densities, EconomicsRoad Densities, Economicsand Silvicultural Optionsand Silvicultural Options

Peter Schiess & Weikko JarossPeter Schiess & Weikko JarossForest Engineering, University of Washington & Forest Engineering, University of Washington & Departement of Natural Resources, WashingtonDepartement of Natural Resources, Washington


OverviewOverview

• Issues and Objectives - why are we interested in long-span systems, what are the objectives

• General Skyline Systems Developments

European Long-Span Systems

North American Slackline Systems• Production and Cost Issues• Discussion and Conclusions


IssuesIssues

• Agreement between DNR and the Federal Government resulted in a Habitat Conservation Plan

• Ultimate goal is to reduce impact on sensitive habitats (fish/wildlife/water quality)


Several ApproachesSeveral Approaches

• minimize road densities by increasing yarding distances (Current External Yarding Distances

are < 1200 ft)

• reduce sediment deliveries to streams

-road locations

-construction practices

-road system management (traffic/closures)


USFSSilen,1953

HeckleCreek1985

Siouxon

1988

Washougal

1998Planning area(Acres)

2985 2850 13000

Setting size(Acres)

30 41 36

AverageYardingDistance * (ft)

531 612 670

Road Densitymiles/squaremile)

5.19 3.35 4.55 4.16

Road Densities in Relation to Yarding Distances (AYD’s)Road Densities in Relation to Yarding Distances (AYD’s)for Several Harvest Plans in Western Washingtonfor Several Harvest Plans in Western Washington


ObjectivesObjectives

• assess current state of cable yarding production and costs for EYD > 2000 ft

(1500 to 4000 ft EYD)

• Outline the critical issues


Skyline Operations Skyline Operations - Turn of the Century- Turn of the Century

• Yarding Yarding

Distances > 4000 ftDistances > 4000 ft

• up to 40,000 ft of cableup to 40,000 ft of cable

• crew of 26 people and crew of 26 people and moremore

• cheap labor - expensive cheap labor - expensive transportation system transportation system (railroads)(railroads)


Skyline System DevelopmentsSkyline System Developments• changes in labor marketschanges in labor markets

increased wagesincreased wages

• improved transportationimproved transportation

(diesel trucks- dozer)(diesel trucks- dozer)

• cheaper to haul/build roads than to yardcheaper to haul/build roads than to yard

• Slackline systems Slackline systems EYDEYD < < 20002000 ftft Highlead Highlead < < 1000ft1000ft


European Long-Span European Long-Span Cable SystemsCable Systems

• cheap laborcheap labor

-high priced timber-high priced timber

-difficult terrain-difficult terrain• long-span cable systemslong-span cable systems• Standing skylinesStanding skylines

(or Wyssen Systems)(or Wyssen Systems)

Wyssen, Gantner, BacoWyssen, Gantner, Baco• Yarding spans 1500 - 4000 ftYarding spans 1500 - 4000 ft


System Characteristics for a System Characteristics for a Wyssen-type Cable SystemWyssen-type Cable System

• Yarder W-90, 4400 lbs.

• Carriage

• Skyline, 5000 ft, 1 1/4 in

• Mainline 5000 ft, 5/8 in

• Spool truck

• Rigging Hardware

• Radios

• Landing Cat

• Loader

• Low-power, one-drum system with low drum speeds

• Relies on gravity for inhaul (down)

• Outhaul under power to get carriage out (up)

• Simple set-up (except for intermediate supports)


SwissSwissExperiencesExperienceswithwithLong-SpanLong-SpanSystemsSystems


Cycle Elements for a Wyssen-TypeCycle Elements for a Wyssen-TypeLong-Span System Reported byLong-Span System Reported byDifferent AuthorsDifferent Authors

AuthorsHensel1977

E-Wash/Idaho

Abegg et al.1986*

Switzerland

Akre1967

E-Wash.

YardingDirection

Uphill Downhill Uphill Downhill Downhill

Crew Size 4.5 4.5 4 4 3

YardingDistance(ft)

1990 1470 2000 2600 2600

Cycle Times(min)

19.3 11.8 18.3 15.3 18.5

Logs/Turn 4 - 5 2 - 4 4 - 6 4 - 6 2 - 3

* Model


Total Cycle Times for Three Cable Total Cycle Times for Three Cable Systems, a Highlead, Large Tower and Systems, a Highlead, Large Tower and

Wyssen SystemsWyssen Systems

0

5

10

15

20

25

30

Slope Yarding Distance(ft)

To

tal

Cyc

le T

ime

s (

min

.)

Highlead

Long-spanTower/BinkleyWyssen Uphill/Hensel

Wyssen-Downhill/Hensel

Wyssen-Uphill/Swiss

Wyssen-Downhill/Swiss


North American Long-Span Tower SystemNorth American Long-Span Tower System

• Only few, documented studiesOnly few, documented studies

Binkley, 1965Binkley, 1965

• Skagit BX 185, 3-drum yarderSkagit BX 185, 3-drum yarder

• 4,400 ft of 1-inch mainline4,400 ft of 1-inch mainline

• 5700 ft of 3/4-inch haulback5700 ft of 3/4-inch haulback

• 5000 ft of 7/165000 ft of 7/16

• 5,000 ft of 1 3/4 inch skyline on 5,000 ft of 1 3/4 inch skyline on spool truckspool truck

• Average cycle time 9 min. for Average cycle time 9 min. for 1300 ft of AYD1300 ft of AYD


Model Development & ComparisonModel Development & ComparisonINPUT

Slope Under Skyline 45%Lateral Slope 0%

mbf/acre 45Log Volume (bf/log) 130

Payload Weight (lbs) 6240

# Intermediate supports 0# Logs per Turn 4# Corridors 4Lateral Yarding Dist. (ft) 100

Crew Size 4.5Hours per day 8.5

Road Cost ($/stat) $0

Note:enter 0 for road and rigging cost to get yarding cost

Note diamond red hallow and box black hallow. These are the depreciated production costs for Binckley and Hansel downhill (long-span opportunity)100

Avg. Slope Yarding Dist. (ft) 100 200 300 400 500 600 700 800 900Rigging Time (man hrs)

Highlead <1200 ft 67 76 85 94 103 113 122 131 140Large Tower/Binkley 200-3000Wyssen/Hensel 200-2500 ft 296 310 325 340 355 369 384Wyssen Swiss 300-5000 ft 296 310 325 340 355 369 384

Cycle Time (min)Avg. Slope Yarding Dist. (ft) 100 200 300 400 500 600 700 800 900Highlead 4.6 4.8 4.9 5.1 5.3 5.4 5.6 5.7 5.9Long-span Tower/BinkleyWyssen Uphill/HenselWyssen-Downhill/HenselWyssen-Uphill/Swiss 8.4 8.9 9.5 10.0 10.5 11.0 11.5 12.1 12.6Wyssen-Downhill/Swiss 8.7 9.0 9.4 9.7 10.1 10.4 10.8 11.1 11.5

NEWmbf/day (crew-days)

Avg. Slope Yarding Dist. (ft) 100 200 300 400 500 600 700 800 900Highlead 29.7 32.5 32.8 32.6 32.0 31.4 30.7 30.0 29.3Long-span Tower/BinkleyWyssen Uphill/Hensel

$50

$70

$90

$110

$130

$150

$170

$190

Average Slope Yarding distance (ft)

Pro

du

cti

on

Co

st

($/m

bf)

HighleadLarge Tower/BinkleyWyssen Uphill/Hensel Wyssen Downhill/HenselSwiss Uphill Swiss Downhill PetersBinckleyHansel UphillHansel DownhillSwiss UphillSwiss Downhill


Owning & Operating Costs for a Large Owning & Operating Costs for a Large

Tower and a Wyssen SystemTower and a Wyssen System 220 – 8.5HrOperating Days

Wyssen* >70’ Tower

New UsedYarder $179,200 $609,250 $71,370Rigging $25,000 $25,000 $25,000Carriage $34,000 $43,000 $14,958Crew 4.5 5.5 5.5Total ProductionTime %

80% 92% 85%

Operating Cost($/month)

$17,917 $20,897 $18,434

Total O&O Cost($/month)

$35,630 $61,891 $51,874

* estimate


Variables and Values Used in Production Variables and Values Used in Production EquationsEquations

Harvestable Volume 10 - 45 MBF/acreAverage Log Volume 120 - 167 BDF/logPayload 5100 – 7200 lbs/turnIntermediate Supports 0 - 1Logs per Turn 3.5 - 4.5Corridors 4Lateral Yarding Distance 100 feetCrew Size 4.5 (5-7 for tower)Daily Operating Hours 8.5


Production Rates for Three Cable Systems, a Production Rates for Three Cable Systems, a Highlead, Large Tower and Wyssen System Highlead, Large Tower and Wyssen System

0

5

10

15

20

25

30

35

300

700

1100

1500

1900

2300

2700

3100

3500

3900

Slope Yarding Distance ( ft )

Pro

du

cti

on

(M

BF

/DA

Y) Highlead

Long-spanTower/BinkleyWyssen Uphill/Hensel

Wyssen-Downhill/HenselWyssen-Uphill/Swiss

Wyssen-Downhill/Swiss


Production Costs for Three Systems, a Highlead, a Production Costs for Three Systems, a Highlead, a Large Tower and a Wyssen System Large Tower and a Wyssen System

$0

$50

$100

$150

$200

$250

$300

Slope Yarding Distance (ft)Stu

mp

-to

-Tru

ck C

ost

s ($

/mb

f)

Highlead

Large Tower/Binkley

Wyssen Uphill/Hensel

WyssenDownhill/HenselSwiss Uphill

Swiss Downhill


Rigging Times for Three SystemsRigging Times for Three Systems:: a Highlead, a a Highlead, a Large Tower and a Wyssen System Large Tower and a Wyssen System

0

100

200

300

400

500

600

700

800

900

200

500

800

1100

1400

1700

2000

2300

2600

2900

3200

3500

3800

Slope Yarding Distance (ft)

Rig

gin

g t

ime

s (

ma

n-h

rs)

Highlead <1200 ft

Large Tower/Binkley 200-3000

Wyssen Swiss 300-5000 ft


What does it mean?What does it mean?• North American experiences with

Wysssen long-span systems are well correlated with European experiences

• Production = f( distance, rigging supports, volume/station of corridor removed)

• Production not correlated with silviculture (clearcut - selection cut)


What does it mean?What does it mean?

• Available volume > .7 mbf/station of corridor

• Line speeds are important

• Large, old towers (rebuilt) appear to offer a feasible solution

• Full suspension a key to successful operations over long spans


ConclusionsConclusions• Time studies for Wyssen systems on the West

Coast agreed well with models developed in Switzerland

• Rigging times are a significant factor

• Long-span systems are a promising alternative, when used with appropriate silvicultural systems (selection cuts with appropriate volume removal)

• Turn assembly becomes important (like Heli)

1 UW Forest Engineering Schiess & Jaross Long-Span VS. Conventional Skyline Yarding: Road Densities,...

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