mechanical treatments why use mechanical treatments? what factors effect use of mechanical...
TRANSCRIPT
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
• 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
• 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
• Soil fertility• Soil depth• Debris & litter• Erosion• Aspect• Slope• Topography• Season of treatment
Mechanical Treatments
• Factors to Consider– Vegetative factors
• 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
Crawler Wheel-loader Farm tractor
Credit: reveg-catalog.tamu.edu
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: libertyhilltractor.comCredit: onlineattachements.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.)
• 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
• 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
Credit: reveg-catalog.tamu.edu
Mechanical Treatments
• Clearing– Rootplow
• 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
• Severs stems• Crushes plants• One or more drums• Water or cement filled
• Disturb soil• Increase herbaceous plants• Required every 2-5 years with strong resprouters
• Often used in conjunction with fire
Credit: forestryimages.org
Mechanical Treatments
• Clearing– Renovators/Aerators (roller chopper)
• 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)
• 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.eduCredit: reveg-catalog.tamu.edu
Mechanical Treatments
• Clearing– Mower
• Flail• Rotary• Sickle-bar
• Tractor
• Remove top-growth• Herbaceous and very light woody plants• Very temporary effects• Often used in conjunction with fire
Credit: allswisstractors.com
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