Transcript Ground-Based Primary Transport

Ground-Based Primary Transport
TOPICS:
• Conventional ground skidding equipment
• Mechanical felling, tree processing &
forwarding equipment & systems
• Management alternatives for soil
compaction
• Operational planning & principles in
designing skid trail systems
Ground-Based Primary Transport
COURSE LEARNING OBJECTIVES:
1. Harvesting process terminology;
Capabilities & limitations of equipment &
systems in a range of different silviculture
systems
2. Select/match ground-based equipment/
systems to different operating
environments – considering equipment
limitations, economics, environmental
impact & social factors
Ground-Based Primary Transport
ASSIGNMENT
(Due Monday, Oct. 11 @ 11:00 AM
• Review SLC Video #850 (32 minutes) on
Soil Compaction on Forest Lands
•Review SLC Video #903 (27 minutes) on
Designated Skid Trails
•Submit a written summary of five alternatives
for managing soil compaction
Ground-Based Primary Transport
CONVENTIONAL GROUND SKIDDING ALTERNATIVES:
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Animals
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Track Skidders
- Rigid Track
- Flexible Track
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Rubber Tire Skidders
- Line skidders
- Grapple skidders
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Excavator Forwarder (shovel logging or hoe chucking)
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Clambunk Skidders
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Forwarders
Ground-Based Primary Transport
GENERAL CHARACTERISTICS (ALL EQUIPMENT/SYSTEMS):
1.
Lower productivity & lower logging costs than cable systems
2.
Soil disturbance/compaction is a more significant concern with
ground-based logging systems
3.
Several excellent planning and management alternatives are available
for controlling soil disturbance/compaction
4.
Some equipment is best matched with thinning; others for
clearcutting; others for both
5.
Downhill transport is preferred
6.
Terrain limits are generally: Downhill <35% Uphill < 20%
Sidehill <20%
7.
Economic maximum transport distances range from 500 to 2000 feet
(downhill). Uphill transport is approx. half of downhill distance.
Horse Logging
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Animal weights: 1,500–2,000 lbs
800 – 1500 lbs payloads
< 25% downhill slope
500 ft. max. skidding distance
Low productivity (2-3 MBF/day)
Approx. average skidding cost:
$50/MBF (all ground-based
systems)
• Niche applications
Rigid-Track Skidders (Crawler Tractors)
• Uniform ground contact only on
even surfaces
• Rear or elevated drive wheel
• Loaded weight distribution (level
surface): 80/20
• Equipment weight: 30 – 50 K lbs
• 70 – 200 horsepower
• < 40% downhill slope
• 600 ft. max. skidding distance
Rigid-Track Skidders (Crawler Tractor)
• Clearcut and partial cut
applications
• Equipment versatility
• Average productivity (clearcut
with favorable conditions):
20 MBF/day
Flexible-Track Skidders (High Speed or LGP Track Skidder)
• FMC transferred rights to KMC
• Uniform ground contact on
uneven surfaces
• Front drive wheel
• Independent torsion suspension
• Loaded weight distribution (level
surface: 60/40
• Equipment weight: 30 – 40 K lbs
• Average of 200 horsepower
• Faster travel speed than crawler
tractor
• < 50% downhill slope
• 800 ft. max. skidding distance
Flexible-Track Skidders (High Speed or LGP Track Skidder)
• Clearcut and partial cut
applications
• Low ground pressure applications
• Higher equipment purchase cost
and maintenance cost
• Average productivity similar to
crawler tractor
Rubber Tire Skidder
• All-wheel drive
• Articulated steering (hinged in the
center for steering)
• Loaded weight distribution (level
surface): 80/20
• Equipment weight: 20 – 35 K lbs
• 100 – 200 horsepower
• Travel speed similar to flexible
track skidder
• < 30% downhill slope
• 600 ft. max. skidding distance
Rubber Tire Skidder
• Line Skidders
Rubber Tire Skidder
• Grapple Skidders (log or bunching)
• Often matched with a fellerbuncher in a whole tree skidding
system
Rubber Tire Skidder
• Lower payload capacity
• Lower equipment purchase
cost
• Clearcut and partial cut
applications
• Potential for higher damage in
thinnings than track skidder
Rubber Tire Skidder
• Wide Tire Skidders
(average width of 32” vs. 43”-50”)
• Better “flotation” on low-strength
soils
• Lower tire sinkage & rolling
resistance
• Traction problems on wet steep
slopes with logging slash
Excavator Forwarder (Shovel Logging or Hoe Chucking)
• Modified hydraulic log loader
• < 20% downhill
(non self-leveling)
• 400 ft. max. swing distance
• High productivity
(e.g.80 MBF/day)
• Low ground impact in
favorable operating conditions
• Clearcut operations preferred
• Serpentine or bunching
patterns of operation
Excavator Forwarder (Shovel Logging or Hoe Chucking)
Serpentine Forwarding Pattern
Bunching Pattern with a Skidder Swing
Excavator Forwarder (Shovel Logging or Hoe Chucking)
Hydraulic Log Loader with Winches
• Steep slope cable yarding
• Preferred yarding distances
<400 ft. (max. 800 ft.)
• Equipment versatility
• Short cable yarding distance
applications
Clambunk Skidders
• Articulated chasis
• Integral grapple arm and
Inverted bunk grapple
• Bogie wheels: Tandem axles
driven by a single differential
(lower ground pressure than
single axles); often used with halftracks for better traction
Clambunk Skidders
• Matched with a fellerbuncher and whole tree
skidding system
• High payloads (15 tons)
• 1500 ft. max. skidding
distance
• <30% downhill slope
• Clearcut operations –
natural or plantation
forests
• Consider road impacts
Forwarders
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Articulated chasis
Hydraulic loading grapple
Bogie wheels
5 to 19 ton payload range
Short logs
Forwarders
• Matched with a single-grip
harvester and a CTL system
• 2000 ft. max. skidding distance
• < 30% ground slope
• Thinning and fuels reduction
applications
Ground-Based Primary Transport
The actual equipment performance, productivity and costs,
and soil impacts depends on site-specific conditions…..
….Logging mechanics consideration of factors including
grade resistance (or assistance), skidding resistance, rolling
resistance, soil strength and traction