FOR 350 Lectures 11-13_2011 Students

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					              Concepts of Regeneration

•   Regeneration vs. reproduction




•   The primary focus of harvest must be regeneration
                  Concepts of Regeneration

•       Key goals of a regeneration program:
    –     Make the results predictable



    –     Affect species composition
           Concepts of Regeneration

–   Appropriately stock the site with desirable species


–   Set the stage for future management


–   Minimize the chance of failure
            Reforestation vs. afforestation

•   Reforestation: reestablishment of forest cover on areas
    where it once occurred

•   Afforestation: introduction of trees to sites that did not
    support forests or had no forest cover for a long period of
    time.
         Artificial vs. natural regeneration

•   Natural Regeneration - Stand establishment is from natural
    sources: natural seeding, sprouting, suckering, layering

•   Artificial Regeneration - Stand establishment is from human
    intervention: planting seedlings or cuttings or by direct
    seeding.
            Concepts of Regeneration

•   Origin of reproduction
                   Concepts of Regeneration

•       Categories of reproduction
    –      New seedlings:


    –      Advance reproduction:


    –      Stump sprout:


    –      Root suckering:
Stump Sprouting Probability by Age and Species




                                  Tree Age
                Regeneration Process
              (its all about species silvics!)

•   New forest communities establish whenever three
    conditions develop:
               Concepts of Regeneration

Seed Supply
•   Flowering and seed production
                Concepts of Regeneration

Seed dispersal
•   Reproductively mature trees within dissemination range required for
    regeneration from seed


•   Factors influencing seed dissemination (i.e., dispersal)
• Seed dispersal distance is species dependent
            Concepts of Regeneration

Seed bank




  • Viability and germination stimuli various among species
               Concepts of Regeneration

Seed Bed and Germination
•   Physical characteristics of forest floor affect germination




•    Position of seed within the seedbed affect predation and
     germination rates
•    Light, temperature, and moisture affect seed viability and
     germination
               Concepts of Regeneration

Generally,
• Light wind-disseminated seeds require mineral seedbed

• Large seeded species like oaks are aided by being buried under
  a litter layer as long is it is not too thick (5 cm)
Species of the Central Hardwood Region

       Species            Seed Dissemination
                          Gravity   Animals    Wind
       Yellow-Poplar                             X
       White Oak              X        X
       Chestnut Oak           X        X
       Black Oak              X        X
       Northern Red Oak       X        X
       Scarlet Oak            X        X
       Sugar Maple                               X
       Red Maple                                 X
       Pignut Hickory         X        X
       American Beech         X        X
              Concepts of Regeneration

•   Established Seedlings
Shade Tolerant and the Understory Environment
 – Tolerant :



 – Intermediate:



 – Intolerant:
Influence of Light Availability on Seedling Photosynthesis
Relationship between Available Sunlight and Stand Structure
Relationship between Canopy Cover, Available Sunlight, Understory
Competition




  • Optimal level dependant on species shade tolerance and growth
  strategy
Species of the Central Hardwood Region

     Species            Shade Tolerance
                          Intolerant      Intermediate   Tolerant
     Yellow-Poplar            X
     White Oak                                 X
     Chestnut Oak                              X
     Black Oak                                 X
     Northern Red Oak                          X
     Scarlet Oak              X
     Sugar Maple                                            X
     Red Maple                                              X
     Pignut Hickory                            X
     American Beech                                         X
                   The Silvicultural System

• Even-aged and Uneven-aged
   – One age class vs. at least three age classes in a stand (an age class is
       defined at 20% of the rotation length)
                The Silvicultural System

• Hybrid Systems
   – Hybrid of even- and uneven-aged.
             The Silvicultural System

• Regeneration methods are classified into distinct
  categories:
Common Even-Aged Systems



         Clearcut




         Seed Tree
                       Shelterwood
                       Clearcuttings

•   Clearcutting vs. clearing—Clearcutting is a regeneration
    method, clearing is removing all of the trees for some non-
    forest use

•   Silvicultural clearcuts differ from ‘commercial clearcuts’.
    The first removes all trees, the second only merchantable
    trees.
                      Clearcuttings

•   Clearcutting changes the microenvironment:
                  Clearcuttings

•   Edge effect
                       Clearcuttings

–   The effect on the hydrologic cycle; increased water yield returns to
    normal within 4 to no more than 10 years following harvest.




–   Where harsh site conditions or silvical characteristics of desired
    species require site amelioration, it can be done by leaving slash on
    site or by switching to some other reproduction method.
                      Clearcuttings

•   Clearcutting technically initiates a new age class AFTER
    overstory removal. The new stand comes from:
                      Clearcuttings

•   Advance reproduction is often helpful and sometimes a
    necessity in even-aged regeneration of some species, most
    notably oaks.
                              Clearcuttings

•       Management of or mitigation of effects of clearcutting
    –      Affect nutrient outflow from harvest by




    –      Rapid regrowth of vegetation will stabilize nutrients on the site
           within 4 years
                                Clearcuttings

•       Alternate configurations for clearcutting
    –      Block clearcutting




    –      Alternate strip or alternate patch
                             Clearcuttings

•       Alternate configurations for clearcutting
    –      Progressive strip method
                           Clearcuttings

•       Alternate configurations for clearcutting
    –      Patch cutting
                      Clearcuttings

•   Alternate methods are often used to:
•   Other considerations when using clearcutting or any even-
    aged method
                            Clearcuttings

•       Site preparation considerations for natural regeneration

    –      Some important questions
                           Clearcuttings

Site preparation and clearcutting: Considerations for natural
     regeneration
   –    Scarification → mineral seedbed

   –    Control slash residues



   –    Mechanical or chemical vegetation control
•   Advantages of the clearcutting method/system
•       Shortcomings of clearcutting with natural regeneration
    –      Problems with dependable seed sources and seedling establishment




    –      Issues associated with no high forest cover and high light
           environment




    –      Reduced chance for genetic improvement
•       Shortcomings of clearcutting with natural regeneration
    –      Impacts on soils and hydrology




    –      Decreased visual aesthetics
    –      Increased fire danger
    –      Decreased wildlife habitat for some species
Coppice Silviculture
                           Coppice
•   The term "coppice" is commonly applied to any regeneration
    arising from sprouts or suckers—typically hardwoods of
    young to moderate age

•   As a method, it is where regeneration is solely from sprouts
    or root-suckers

•   Typically associated with short rotation production of
    pulpwood or fuelwood
                         Coppice

•   Some coppice principles:
                         Coppice

•   Coppice for energy, bioremediation, environmental cleanup
                          Coppice

•   The cutting cycle is set by when the MAI intersects PAI
•   General shortcomings of coppice systems




•   General shortcomings of short-rotation biomass plantations
Coppice with standards: scattered, individual stems allowed to
grow on through several coppice cycles

				
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