Transcript Slide 1 - Wildlife Ecology and Conservation

Mechanical Treatments
• Why use mechanical treatments?
• What factors effect use of mechanical
treatments?
• What types of mechanical treatments are
there?
• How effective are mechanical treatments?
Mechanical Treatments
• Why Use Mechanical Treatments?
– Alter dense, closed canopies
• Woody plants (trees & shrubs*)
• Succulents
• Herbaceous plants
Credit: laspilitas.com
Mechanical Treatments
• Why Use Mechanical Treatments?
– Alter woody plants*
• Overstory & understory/shrub
– Competes for
» Sunlight
» Water
» Nutrients
– Limit productivity of herbaceous
– Unsuitable for many wildlife species
» Edge
» Early successional
Credit: ecotours.com
Mechanical Treatments
• Why Use Mechanical Treatments?
– Enhance herbaceous plant growth
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Set back succession
Disrupt compacted soils
Remove debris
Manipulate soil micro-topography
Mechanical Treatments
• Why Use Mechanical Treatments?
– Alter soil & litter conditions
– Site & seed-bed preparation
NOT a substitute for prescribed fire
- Combination often best
Mechanical Treatments
• Factors to Consider
– Wildlife factors
• Obligate wildlife species
– Interior species
• Ecological requirements of species
– Edge species & species with multiple habitat needs
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Native plants: pros & cons
Forage (open area) to cover ratios
Proximity of treated sites to other habitats
Influence on vertical structure
Control of spot grazing (livestock attraction)
Mechanical Treatments
• Factors to Consider
– Watershed/soil factors
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Soil fertility
Soil depth
Debris & litter
Erosion
Aspect
Slope
Topography
Season of treatment
Mechanical Treatments
• Factors to Consider
– Vegetative factors
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Reseeding & plant propagation
Invasion by “weeds” & exotics
Target plants: pros & cons
Sprouting potential (return interval)
Maintenance of openings
Impact on plant diversity
Season of treatment
Credit: californaichaparral.com
Mechanical Treatments
• Overstory Removal
– Areas cleared of trees & tree manipulations
• Harvest (silviculture)
• Timber Stand Improvement
Mechanical Treatments
• Overstory/Tree Removal
– Harvest
• Chainsaw
• Harvester (mechanical shears or saw)
Mechanical Treatments
• Timber Stand Improvements
(TSI; Tending/Intermediate Treatments)
– Thinning
– Pruning
– Vertical & horizontal structure
Mechanical Treatments
• Understory and Shrub Removal
– Areas cleared of woody species
• Mosaic patches
• Cleared strips
• Large areas
Mechanical Treatments
• Level of Understory/Shrub Removal
(Payne and Bryant 1994)
Mechanical Treatments
• Thinning
– Individual tree or shrub treatment
• Chainsaw or handsaw
• Heavy equipment
• Grubbing
– Below ground severing
• Clipping
– Above ground severing
Vegetation/land sculpting
Mechanical Treatments
• Thinning
– Mechanical grubbing
• U-shaped blade mounted on a tractor
– Depending on tree/shrub type and terrain
» Crawler (rough terrain; poor movements; high soil disturbance)
» Wheel loader
» Farm tractor
Mechanical Treatments
• Thinning
– Mechanical grubbing
Credit: reveg-catalog.tamu.edu
Crawler
Wheel-loader
Farm tractor
Mechanical Treatments
• Thinning
– Mechanical grubbing
• Excavator
– Considerable site disturbance
– Wide swath
– 200-500 trees/hr
Credit: reveg-catalog.tamu.edu
Mechanical Treatments
• Thinning
– Mechanical clipping
• Hydraulic shears
– Spray stump for sprouters (e.g., mesquite, redberry juniper)
Credit: onlineattachements.com
Credit: libertyhilltractor.com
Mechanical Treatments
• Clearing
– Areas cleared of all woody species
• Remove aboveground growth
• Sever roots
• Uproot plants from soil
• Usually a combination of methods
Mechanical Treatments
• Clearing
– Chaining (or cabling, railing, etc.)
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Ship anchor chain
Pulled between two tractors
61-122 m (200-400 ft) in length
59-111 kg/m (40-75 lbs/ft)
U-shape
Mechanical Treatments
• Clearing
– Chaining
Credit: fs.fed.us
Mechanical Treatments
• Clearing
– Chaining
• Uproots plants & severs
• Used for tree felling
– Dense to moderate stands
– High soil moisture best
– Not limber plants
Credit: reveg-catalog.tamu.edu
• Double-chaining (both directions) & Elevated chaining
• Effects short-lived & used with other methods
– Herbicide before and/or burn after
• Common in West
– Pinyon pine, juniper, mesquite
Mechanical Treatments
• Clearing
– Rootplow
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V-shaped, horizontal blade
3-5 m (10-16 ft) wide
Large crawler tractor
Depth 31-36 cm (12-14 in)
Mechanical Treatments
• Clearing
– Rootplow
• Severs roots & crowns
– Best for trees <4” dia.
• Prevents regrowth
– Often followed by chaining or raking
• Severe soil disturbance
– May need to reseed
• Long-term results
– 85-99% tree mortality
– 10-20 yrs before shrubs return
Credit: reveg-catalog.tamu.edu
Mechanical Treatments
• Clearing
– Web plow
• V-shaped, horizontal blade
• Large grader
• Depth 10-15 cm (4-6 in)
Mechanical Treatments
• Clearing
– Web plow
• Severs roots & crowns
• Prevents regrowth
• Worked well on saw palmetto
Mechanical Treatments
• Clearing
– Disking
• Blades 61-91 cm (24-36 in)
• Units 2.5-3.7 m (8-12 ft) width
• Crawler or tractor
Credit: reveg-catalog.tamu.edu
Mechanical Treatments
• Clearing
– Disking
• Severs roots & crowns shallow species
– Not “heavy” shrubs/brush and trees
• Problem severing deep rooted species
• Disturbs soil
– Stimulates early successional growth
• Effects on shrubs short-lived
• May increase deep-rooted species
May benefit wiregrass
Mechanical Treatments
• Clearing
– Roller-chopping
• Cylindrical metal drum
– Adjustable weight
• Blades parallel to axis
• Crawler or tractor
Credit: reveg-catalog.tamu.edu
Mechanical Treatments
• Clearing
– Roller-chopping
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Severs stems
Crushes plants
One or more drums
Water or cement filled
Credit: forestryimages.org
• Disturb soil
• Increase herbaceous plants
• Required every 2-5 years with strong resprouters
• Often used in conjunction with fire
Mechanical Treatments
• Clearing
– Renovators/Aerators (roller chopper)
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Small blades
Staggered, cylindrical pattern
Double drums
46-107 cm (18-42 in) diameter
Filled with water
Credit: reveg-catalog.tamu.edu
Mechanical Treatments
• Clearing
– Renovators/Aerators
• Moderate to dense shrubs
– Can remove top growth to stimulate regrowth
• Small blades
– Chop debris
– Form basins in soil
Credit: noble.org
Mechanical Treatments
• Clearing
– Shredder
• Brush
– Rotating horizontal blade, vertical shaft
• Flail
– Rotating vertical blade, horizontal shaft 2-6 m (7-20 ft) wide
Mechanical Treatments
• Clearing
– Shredder (brush hog & rotobeater)
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Cut woody plants and debris (<12”)
Manicured appearance and level height
Prone to mechanical failures
Effective on sm. trees and non-sprouters
Often in conjunction with fire
Credit: reveg-catalog.tamu.edu
Credit: reveg-catalog.tamu.edu
Mechanical Treatments
• Clearing
– Mower
• Flail
• Rotary
• Sickle-bar
Credit: allswisstractors.com
• Tractor
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Remove top-growth
Herbaceous and very light woody plants
Very temporary effects
Often used in conjunction with fire
Credit: tractorbynet.com
Mechanical Treatments
• Clearing
– Blading or dozing
– Often used with other methods
– Much disturbance
Mechanical Treatments
• Re-sprouting (lots of browse!)
– Disking
– Roller-chopping
– Shredding
– Mowing
• Roots
• Crowns
• Stems
Credit: images.google.com
Mechanical Treatments
• Other
– Raking
– Bailing
Mechanical Treatments
• Planting and tending
– Seeders
• Drills & spreaders
– Planters
– Disturbance
USDA photo by: Tim McCabe
Mechanical Treatments
• Planting and tending
– Cultipackers & rollers
– Hoes, disks, plows, etc.
– Disturbance
– Soil compaction
Mechanical Treatments
• Other Plant Harvesting
Mechanical Treatments
• Mechanical Treatments
– Why they are used
– Types
– Factors affecting their use and effectiveness