Transcript Artificial Regeneration

Artificial Regeneration (Planting and Direct Seeding)
• Why use artificial regeneration
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no natural seed source
change species composition
genetic improvement
control density/spacing
control time and duration of establishment period
repeatable in event of failure
Artificial Regeneration (Planting and Direct Seeding)
• Cost
– Tends to be high
– Makes biological (as opposed to financial) sense only when natural
regeneration would likely fail
• Important considerations include species selection and
genetics
Species selection
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Choose species suitable for your objectives
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Choose species adapted to the site (wet? dry?)
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Well adapted species grow better and tend to have fewer health
problems
May use a mixed species plantation due to
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growth rates
wood characteristics
wildlife characteristics (e.g. mast production)
multiple objectives
changing site conditions across planting area
to take advantage of differing growth rates or form
Do not plant a species outside its natural range unless it has
been tested
Genetic considerations (for a specific species)
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Use seeds or seedlings from a tree improvement program
whenever feasible and available
Verify traits you desire were selected for:
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growth rate
straightness
small branch size, large branch angle, small crown size (wood
quality issues)
disease resistance
high wood specific gravity
drought resistance
cold hardiness
Genetic considerations (for a specific species)
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If improved seedlings or seeds are not available, use
geographic seed source selection (provenance)
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In a restricted geographic area, individuals in a species tend to have
similar genetic traits
Be careful when moving seed source more than 100 miles north or
south
If unsure, use a local seed source
Planting Forest Tree Seedlings
• In the central and southern US, bare-root seedlings are
typically planted
• Mostly 1-0 planting stock is used in the Central Hardwood
Region
– "1-0" refers to: # seasons in nursery bed - # seasons in transplant bed
• 1-1 and 2-0 seedlings are used in the North and West for some
species
Seedling Quality
• We generally want to plant the largest and best developed seedling that will
survive given the outplanting conditions…and that can be handled
efficiently and economically.
• The traits of a high quality seedling change depending on the site and
planting circumstances.
Seedling Quality
• Root collar diameter (caliper) is the most useful single
indicator (for undamaged seedlings)
– Oaks should be larger 3/16” basal diameter
– Smaller seedlings should be culled
• Larger root mass (not length, due to planting problems) and
more lateral roots (5+) are better, while a lower shoot/root
ratio is better
• Hardwood seedlings should be at least 18" to 24" tall
• Bare-root seedlings should:
– Be dormant before lifting (have winter buds)
– Have met minimum chilling requirements in the nursery if they are to
be stored before planting
Containerized seedlings
• Containerized seedlings: grown in individual containers
• Advantages:
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Extend planting season
shorten production time
Usually increased survival on adverse sites
Lower risk of transplant shock
Often increased performance (growth)
• Disadvantages:
– Usually costs more
– Containers are more difficult to handle than bare-root seedlings
Containerized Seedlings
Nursery practices used to influence seedling quality
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seed source
seedbed density
control insects and disease
control competition
irrigate and fertilize
inoculate with mycorrhizae
top prune
root prune or wrench
Proper Care of Seedlings In Storage:
• Keep cold - 33-40°F (do not freeze); bales should have high
humidity (85-95%)
• Pack roots in a moist medium (e.g., peat moss), or dip in
kaolin clay or a gel
• Water regularly (weekly), if in bales
– not needed if in sealed K-P bags, in wax coated boxes, or if they have a
root coating)
• Provide good air circulation - store on racks, no more than two
bales or bags high, four boxes high
• Do not store non-"dormant" bare-root seedlings (should meet
minimum chilling requirements)
• Keep storage as short as possible--avoid storage longer than 8
weeks (4-6 weeks if not in cooler); no more than 4 weeks, if
in sealed bags or boxes
Proper Care of Seedlings In Transport:
• Refrigerated trucks are best
– Slat-sided trucks covered with a tarp and with back open acceptable in
cool weather: night transport may be needed in warmer weather
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Keep temperature in bags or bales below 50 F (good air
circulation)
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Put on racks or shelves - do not pile more than two high,
unless in boxes
Proper Care of Seedlings At the Planting Site:
• Deliver only one day's supply to each planting site
• Protect seedlings from sun and wind
– keep in insulated or refrigerated trailer or truck, if possible, otherwise
in shade
• Avoid freezing
• Do not expose bare roots for more than 10 minutes, 5 minutes
if temperature >70 F
• Keep seedlings in planting bags or containers as long as
possible
• Keep planting bags watered
Proper Care of Seedlings During Planting:
• Postpone planting if: low soil moisture; hot, dry, windy
weather; below freezing temperatures
• Plant as deep or deeper than seedling grew in nursery
– 2-3" deeper OK, as long as the tip is not covered
• Plant deeper on dry sites (do not bury tip)
• Avoid field root pruning
• Planters should not carry more than one seedling in the hand at
one time
Proper Care of Seedlings During Planting:
• Avoid U or J-rooting
– planting hole/furrow must be deep enough
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Do not leave roots exposed
• Pack soil around roots
• A supervisor should check for: root stripping, discarded
seedlings, correct spacing, proper soil packing, shallow
planting, J-rooting
• For containerized seedlings: be sure to cover the top of the
plug with soil to prevent desiccation
Planting Methods
• Advantages of Machine (vs Hand) Planting:
– Faster, more efficient (especially on large tracts)
– More consistent high quality results, especially with large seedlings
– Better root environment in heavy soils
• Advantages of Hand (vs Machine) Planting:
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More efficient on small tracts
Less restricted in rough or steep terrain
Less intensive site preparation is necessary
Low capital investment in equipment
Less erosion potential (machine planting must be on contour)
Tree Planting Hand Tools
Dibble Bars
Hoedad
Power Auger
Containerized
Seedling Dibble
Machine Tree Planting
Planting Practices
• Planting in the central hardwood region
– Hardwood tree seedlings are best planted when seedlings are dormant
and the ground has thawed
– Timing: March to May
– A cool (35 to 60 F) overcast day with little or now wind is an ideal
planting day
• Spacing
– Generally 8 x 8 ft (681 tpa) or 10 x 10 (436 tpa) foot spacing
recommended for hardwood plantings
Underplanting
• Underplanting is the establishment of nursery grow tree
seedlings under an existing forest canopy
• Purpose:
– Supplement natural advance reproduction
– Establish high-value species
Underplanting
• Field performance linked to: 1) initial seedling size; and 2)
understory growth conditions
• Usually coincides with silvicultural treatments like midstory
removal or shelterwood harvest
• Understory competition control may enhance survival and
growth
• As with natural seedlings of species reliant on advance
reproduction, underplanted seedlings must be allowed to
develop to sufficient size in order to be competitive following
final overstory removal.
Direct Seeding
• Direct seeding is the process of establishing tree plantings by
the used of seed instead of seedlings
• Direct seeding is rarely used in the central hardwood region
for establishing hardwood plantation
• Direct seeding has been used along with soil scarification
operations to successful establish oak advance reproduction in
shelterwood systems
Direct Seeding
• Steps to successful direct seeding operation
– Plan ahead to minimize poor germination seed or seeding failure
– Obtain adequate amounts of quality, viable seed from an appropriate
source and prepare it for sowing
• Match species to site
– Determine the proper sowing rates for desired density and spacing
– Select an appropriate method for dispersing the seed
– Have a follow-up plan if sowing yields too many or too few seedlings
Direct Seeding
• Advantages
– Planting season for direct seeding is longer than for seedling planting
– Less labor intensive
– Allows seedlings to become established in the soil with their root
systems developing naturally
• Roots of planted seedlings are susceptible to damage and
transplanting shock
Direct Seeding
• Disadvantages
– More seed per acre is required to obtain the desired number of
seedlings
– Delayed seed germination, slower rates of development, and loss of
seed to predation and drought may lengthen the time to seedling
establishment (or cause complete failure) when compare to planting.
– Lack of control over seedling density and unfavorable conditions
during the germination process
– Site preparation must break and mix the seedbed
– Inefficient use of high-value and genetically improved seed
– Stands have irregular spacing and arrangement
Direct Seeding Practices
• Timing:
– By direct seeding in the fall, the natural stratification process (moist,
cold temperatures) breaks seed dormancy and promotes rapid
germination in the spring
• Predation losses with fall planting are higher
– If direct seeding planned for late winter or early spring, proper seed
storage and seed preparation (pre-germination stratification treatment)
must be observed
• Seed storage and preparation depending on species
Direct Seeding Practices
• Depth of sowing
– Depth of sowing is dependant upon the species, seeding method, and
predation pressure
– Generally, the depth for sowing is 2 times the diameter of the seed
– Planting too shallow increases losses to predators and drought, planting
too deep can delay germination
• Seeding rates
– 1 pound per acre for loblolly pine
• 18,200 seeds per acre
– 24 to 36 pounds per acre for northern red oak
• 3000 to 4500 seeds per acre
– 75 to 112 pounds per acre for black walnut
• 3,000 to 4,840 seeds per acre
Direct Seeding Approaches and Methods
• Approaches of direct seeding
– Broadcast seeding
– Spot seeding
– Drilling
• sowing in rows like an agricultural crop
• Methods of disseminating seeds
– Hand sowing
– Machine sowing
– Aerial seeding
Planning an Artificial Regeneration Operation
Site Preparation for Hardwood Plantings
Site Preparation for Hardwood Plantings
Site Preparation for Hardwood Plantings
Site Preparation for Hardwood Plantings
Site Preparation for Hardwood Plantings
Site Preparation for Hardwood Plantings
Site Preparation for
Hardwood Plantings
Site Preparation for Hardwood Plantings
Site Preparation for Hardwood Plantings
Site Preparation for Hardwood Plantings
Post-Planting Maintenance
• Second and possibly third year pre-emergent herbicides should
be sprayed in planting strips or spots where the ground is bare
and herbicides can adequately contact soil
• Overtop sprays of grass herbicides and directed sprays for
broadleaf control can be administered during the first through
third years as needed
• Mowing should be used in combination with herbicide
applications or by itself to control weed competition that
becomes established between rows.
Post-Planting Maintenance
Mowing
• Mowing should be considered when competition control
treatments fail to provide adequate weed control
• Mowing should only be used to:
– Prevent seed development of invasive or problematic weed species
– Prevent development of weeds that have the potential to grow above 4
to 5 feet and occupy a significant portion of the planting site
– Provide access for cultural control of weeds and rescue treatments in
planting rows or spots
Post-Planting Maintenance
More on Mowing
• Mowing to control residual competing vegetation increases the probability
of physical damage to seedlings from mowing equipment, especially if
mowing occurs many times during the growing season for several growing
seasons
• Mowing should be discouraged and is one of the more ineffective methods
to control competitors near planted seedlings
Post-Planting Rescue Treatments
Established tree plantings with vine, tree, and shrub
competition
• If problematic vines are present, either in the row or between rows, they
should be controlled
– Vines in rows can easily wrap around the planted seedlings, especially if
significant tree, shrub or large herbaceous weeds are present
– Problematic vines such as trumpet creeper, morning glory, honeysuckle or
poison ivy, the planting should be treated as soon as possible
• The best control can be achieved by:
– Mowing between rows directly after full leaf-out
– Once new shoots emerge from the root systems and stumps, spray new
foliage with a post-emergent, broad-spectrum herbicide at the end of
the growing season
Post-Planting Rescue Treatments
Established tree plantings with vine, tree, and shrub
competition
• Cutting of trees, shrubs and vines directly adjacent to seedlings is sometimes
required especially when competing vegetation is large
–Treatment should be combined with a cut-stump herbicide treatment to reduce or
eliminate sprouting
• Basal sprays can be used on individual woody plants growing around
seedlings
– Make sure that the basal herbicide spray does not get on the planted seedling
Post-Planting Rescue Treatments
Established tree plantings with broadleaf herbaceous weeds
• The planting should be surveyed to determine if trees are fully overtopped
or will be overtopped by herbaceous weeds.
• If the trees are fully overtopped:
– Overspray the entire planting with a broad spectrum, post-emergent
herbicide
• Proper application rates are critical to minimize drip onto seedlings. Large
drop size and low pressures are needed to ensure penetration
– Use directed sprays of post-emergent herbicides around the seedlings to
further reduce competing species
– In conjunction with the post-emergent sprays, one application of preemergent herbicide should be applied in the rows prior to the growing
season
Post-Planting Rescue Treatments
Established tree plantings with broadleaf herbaceous weeds
• If the trees are not yet overtopped:
– Mowing should be used immediately to provide access to the planting.
– A directed-spray, post-emergent, broad-spectrum herbicide can then be
administered around the seedlings
Post-Planting Rescue Treatments
Established tree plantings with grass competition
• Survey the planting to determine if a problem exists
• Grass should be controlled through the use of overtop sprays of postemergent, grass-specific herbicides and/or the directed spray of broadspectrum, post-emergent herbicides
• The type and amount of herbicide and the timing of herbicide application
are determined by grass species and the site
• Generally, the best control is achieved when herbicides are sprayed onto
relatively young foliage less than 4 to 6 inches tall for most species.