Part II: The Macro Approach: Managing Forest Landscapes

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Part II The Macro ApproachManaging Forest
Landscapes

• Species Composition
• Age Structure
• Spatial Heterogeneity
• Edges
• Islands Fragments
• Shores

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Species CompositionPart 4

• Fundamentals
• Understanding trees species
• Distribution across landscape
• Environmental Factors Affecting Forest
  Composition
• Intrinsic
• Climate Soil
• Extrinsic
• Affected by succession
• Presence of competitors
• Changes quickly
• http//www.extension.iastate.edu/Publications/SUL1
  .pdf
• Understanding the Effects of Flooding on Trees
• Ecosystem Relations Straightforward
• Oak-hickory on uplands sugar maple on
  bottomlands

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Species CompositionPart 4

• Tree Species Wildlife
• Trees food, cover, shelter, substrate
• Some relationships specific
• Jack pine have spruce grouse
• Most relationships loose between tree species and
  organisms
• Tree architecture may be more important than food
  abundance
• Bird/mammal movement
• CorrelationBird species diversity and number of
  tree and shrub species

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Species CompositionPart 4

• Conifers Deciduous Trees
• Deciduous trees have richer biota
• Not distasteful
• Evolved at time animals evolved
• Seed dispersal, pollination, herbivory
• More structural diversity
• Conifers
• Distasteful
• Needles unpalatable to decomposers as well
• Do provide winter cover

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Species CompositionPart 4

• Exotic Trees
• Displace natives
• Impacts wildlife, especially herbivores
• Examples of exotics
• Scots pine
• Fraser fir
• Norway spruce
• http//www.extension.iastate.edu/Publications/PM19
  81.pdf
• Woodland Invasive Species

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Species CompositionPart 4

• Monocultures
• Single dominant species
• Moderately common
• Single species only
• Uncommon
• Characterize planted plantations by humans
• Pests and pathogens
• Disease prone
• Simplicity makes easier to manage
• Economic justification

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Species CompositionPart 4

• Longleaf Pine
• Video

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Species CompositionPart 4

• Conclusion
• Choose native species
• Avoid exotics
• Plant two or more species
• Strive for diversity
• Conifer and deciduous tree
• Avoid increasing extent of conifers substantially

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Pines
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Pinus strobus

• White Pine
• Needles in bundles of five
• 2-4 inches long.

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Larix sp.

• Larches or Tamaracks
• Many needles (7-24) per fasticle
• occurring on spur-like shoots
• needles fall in autumn.

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Pinus nigra

• Austrian Pine
• Needles in bundles of two,
• 4-6 inches long needles are thick and stiff,
• folding when bent.

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Pinus resinosa

• Red Pine
• Needles in bundles of two,
• 4-6 inches long.
• Needles are thin and brittle
• snap when bent.

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Pinus ponderosa

• Ponderosa Pine
• Needles in bundles of twos and threes,
• 5-8 inches in length.

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Pinus sysvestris

• Scotch Pine
• Needles in bundles of two,
• 11/2-3 inches long and twisted
• bark on older trees is orange and scaly.

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Pinus banksiana

• Jack Pine
• Needles in bundles of two,
• 3/4-11/2 inches long, twisted
• cone tips curve toward the branch tips.

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Conifer ID

• http//www.extension.iastate.edu/Publications/PM13
  83.pdf

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Age Structure

• Chapter 5

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Age StructurePart 5

• Iowas Woodlands
• http//www.extension.iastate.edu/Publications/IAN2
  02.pdf
• Perspective
• Forest age since last disturbance
• Fire, glacier, logging
• Succession
• Plants influenced by microclimate and competition
• Animals influenced by plant community
• Managing Forests Managing Diversity
• http//www.extension.iastate.edu/Publications/PM13
  51I.pdf
• Managing Patterns of Succession
• Determine age Structure of Landscape
• Iowas Trees

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Age StructurePart 5

• Diversity Succession
• Managing forests for diversity involves patterns
  of succession
• Some successional stages have more species than
  others
• Each stage has a different set of species
• Greatest Diversity
• Climax
• Immediately after disturbance
• Forest landscape with many successional stages
  will be more diverse

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Age StructurePart 5

• Balancing Age Classes
• Failure
• Pest and pathogen outbreaks
• Temporal bottlenecks
• Species of wildlife requiring specific age stands
  of a forest
• Diagrams

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Age StructurePart 5

• Old Forests
• Trees ready for harvest
• Growth rate .0022 cubic meters in 80th year
• Averaged .0023 other 79 years

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Age StructurePart 5

• Old Forests Defined
• Environmentalist Definition
• Primeval
• Ancient
• Wilderness
• Virgin
• Pristine
• Foresters Definition
• Overmature
• Decadent
• senescent
• Scientist Definition
• Old growth

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Age StructurePart 5

• Age Criteria
• Forest age where species composition is stable
• Forest age where average net growth near zero
• Forest significantly older than average interval
  between natural disturbances severe enough to
  lead to succession
• Dominant trees reached life expectancy
• Iowas oak trees
• Iowas Oaks RG701
• Forests current annual growth rate declined
  below the lifetime average annual growth rate

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Age StructurePart 5

• Disturbance Criteria
• Forest extensively or intensively cut?
• Forest converted to another ecosystem?

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Age StructurePart 5

• Importance of Old Forests
• Adequate Number
• Adequate Area
• Represent one portion of successional sequence
• Most biologically diverse portion of sequence
• Species dependent on old forest
• Example Douglas fir wester hemlock stands of
  Pacific northwest
• Northern Spotted owl
• Hammonds flycathers
• Red tree voles
• Lichens
• Saprophytic plants
• Synergism More than a sum of their parts

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Age StructurePart 5

• How Much is Needed?
• Controversial example
• Pacific Northwest virgin old growth forests
• Spatial requirements
• Home ranges
• Minimum area needed

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Age StructurePart 5

• Managing for Old Forest Species
• Provide maximum habitat as feasible
• Disturbances
• Human and natural
• Air pollution
• Lightning
• Forest Management
• Lengthen rotations
• Allow some stands to reach 100 years (normally
  cut _at_ 80 years)
• Allow some to reach 320 years
• Deer needs
• Dense canopy intercepts snow

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Figure 5-12
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Age StructurePart 5

• Spotted Owl
• Pacific Northwest
• Large tracts 1,7000 ha old growth conifer forests
• Economically worth 10,000 per ha
• Northern Spotted Owl
• Estimated population 4,000-6,000
• Home range 1,700 ha in WA to 800 ha in CA
• Old forests virgin stands gt200 years
• Thick canopy may shleter primary prey
• Northern flying squirrels wood rats
• Ill equipped to resist or recover from
  catastrophes
• Breed at 3 years
• .49 fledgings/year
• Juvenile Survivorship 11
• Adult survivorship 80-96
• Value of spotted owl as indicator of condition of
  old growth forest

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Age StructurePart 5

• Conclusion
• Various plant and animal species associated with
  different stages of succession
• Balancing age structure of forest accomplishes
  two objectives
• Sustained yield of forest products
• Provide diverse wildlife habitat
• Forest management can enhance biological
  diversity
• Forests become economically mature long before
  becoming biologically mature
• Important to protect and maintain a reasonable
  area of old forest to maintain a reasonable area
  of old forest to maintain populations of species
  that are associated with this habitat and
  community as whole

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Spatial Heterogeneity

• Chapter 6

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Spatial HeterogeneityPart 6

• Introduction
• Organisms need habitat
• Size of the organism influences size of the
  habitat
• Bears need more room than rabbits
• Predators have to cover large areas to find
  enough herbivores to eat
• Organisms vary in extent to which they need a
  diverse environment
• Habitat specialists
• Some Need uniform environment
• Others Need diverse environment
• Woodcock
• Needs forest openings to roost display, alder
  swamps to forage 15-30 year deciduous stands for
  nesting and brood rearing
• Diversity of forest depends on scale at which it
  is viewed by individual species
• Some species can live in a variety of habitats
  some require a diverse habitat and some require a
  fairly uniform habitat

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Spatial HeterogeneityPart 6

• Natural Disturbance Harvesting Systems
• Inherent spatial heterogeneity in forests
• Soil, topography, patterns of disburbance
• Small scale toppling of tree
• Shade tolerant trees Uneven aged
• Large scale lightning fires
• Average disturbance rate 1 per year
• One age class so even-aged
• Shade tolerant and shade interolerant
• Harvest systems
• Clearcutting even aged management harvest al
  trees
• Selection cutting small portion of trees
  removed uneven aged
• Weeding or grown to maturity
• Patch cut minimum size .1 hectare
• Group selection cutting clumps of trees to be
  removed are identified
• Shelterwood cutting seed source trees left and
  shelter trees left

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Spatial HeterogeneityPart 6

• Managing for Spatial Heterogeneity
• Selection cutting tool for maintaining diversity
  on small scale
• Assures trees of many different ages within each
  stand
• Forest diversity on landscape scale
• Selection cutting
• Patch cutting
• Clear cutting
• Iowas Woodland Management Understanding Trees
  Woodlands

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Spatial HeterogeneityPart 6

• Model for Spatial Heterogeneity
• Fragmented Forest (Larry Harris)
• Divised ideal frequency distribution for
  different size fragmentsof old-growth forests
• More small stands than large ones
• More populations of small organisms than large
  organisms
• Smaller species have smaller home ranges
• Precedents of natural landscapes
• Watersheds and stream lengths
• Tributaries vs. continent draining rivers
• Model
• 10,000 patches of .01 ha 1,000 ha
• 10,000 patches of .1 ha 1,000ha
• 1,000 patches of 1 ha
• 100 of 10 ha
• 10 of 100 ha

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• Model Rationale
• Harvest forests at a range of different scales
• Allocate approximately equal areas to different
  points along the continuum from small scale to
  large scale
• Large species more likely to be threatened with
  extinction

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Spatial HeterogeneityPart 6

• How big should clearcuts be?
• Size of management unit
• The more land in management unit, larger the
  clearcuts can be
• Coordinate forest management over etremely large
  areas
• Habitat requirement of animals
• Large animals have huge home ranges
• Aesthetics
• Slash of clearcuts people find offfensive
• Straight edges offensive dont seem natural
• Soil erosion and nutrient loss
• Nutrition depletion from removal of trees
  slash greater loss larger cuts
• Natural disturbances as models
• Cuts not to exceed size of natural disasters
• Controversial clearcuts and compromises
• Visual impact
• Negative effective impact on wildlife

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Edges

• Part 7

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EdgesPart 7

• Edge Effect
• Aldo Leopold Game Management
• Create more edge
• Cardinal rule of game management
• Diversity and abundance of wildlife greatest near
  edge
• Edge effect
• No longer accepted as universal rule of game
  management
• Edges
• Where two ecosystems come together
• Ecotones
• Transition zone from one set of environmental
  conditions to another
• May be based on inherent feature of a site
  inherent edges
• Rise in topography
• Altitude
• Permanent or temporary

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EdgesPart 7

• Edge Effect
• Game animals embrace edges
• Tend to be large and shy
• Need food of open, younger area
• Need cover of older ecosystem
• Second group of plants and animals is preferred
  habitat
• Unique conditions of habitat itself
• Many species living in ecotone only secondarily
  edge species
• Tolerate both ecosystems
• Large number of species use edge for variety of
  reasons
• Some species find it preferred habitat

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EdgesPart 7

• Other Side of Edge Effect
• Higher rates of nest predation
• Cowbirds lays its eggs in other birds nests
• 67
• Reductions in regeneration of many trees, shrubs,
  and herbaceous plants
• Species shun edges favor forest interiors
• Invasive species favor edges

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EdgesPart 7

• Creating Edges Through Forest Management
• Edges Geometry
• The more a shape diverges from a circle
• The greater edge is created
• The size of a stand affects edge on relative
  basis
• Linear distances increase as additive function
• Areas increase as square
• Dissecting into many small stands creates more
  edge

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EdgesPart 7

• Coverts, Interspersion, Contrast
• Leopold 1933
• Optimal bobwhite habitat
• Forest, brushland, grassland and cultivation
• Three or more habitats adjoining must be even
  better
• Coverts
• Interspersion
• Dispersion
• Juxtaposition
• All describe them being next to each other

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EdgesPart 7

• Summary
• Edges (ecotones) support diversity of wildlife
  species
• Forest managers have control over amount of edge
• Small stands have more edge than larger edge
• Irregular shaped stands have more edge
• Significant negative side effects
• Species avoid edges
• High rates of predation
• Brood parasitism

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Islands Fragments

• Part 8

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Islands FragmentsPart 8

• Introduction
• Islands of forest habitat
• Island biogeography
• The Fragmented Forest (Larry Harris)
• Forest harvesting can affect biological diversity
  by leaving stands as isolated habitat habitat
  islands

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Islands FragmentsPart 8

• Island Biogeograhy
• Island Size
• Small islands have fewer species than larger
  islands
• As island size increases, the diversity of the
  physical environment increases
• In a large area there are more likely to be
  uncommon species that ive at low population
  densities as well as common species
• Small islands support small populations and small
  populations are more likely to go extinct
• Genetic inbreeding
• Random fluctuations in sex and age structure of
  the population
• Changes in the environment
• Catastrophic events
• Flooding
• Fires
• Hurricanes
• Causing local extinction

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Islands FragmentsPart 8

• Island Isolation
• More isolated an island, few species it will
  support
• Land bridge islands
• Have fairly complete biota
• Species gradually dwindles
• Prone to extinction
• Oceanic Islands
• Begin with no terrestrial plants or animals
• Over time gradually colonized by various species

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Islands FragmentsPart 8

• Symbiosis on Islands
• Many species develop tight, symbiotic
  relationships
• Relative scarcity of large, showy flowers on
  islands
• Lack of butterflies and bees
• Plants without specialized pollinators by using
  generalist pollinators

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Islands FragmentsPart 8

• Islands in the Landscape
• Human dominated landscapes insulate caves,
  mountaintops and isolated patched of prairies and
  forests
• Conversion of prairie and forest into
  agricultural ecosystems
• Differences between islands and forest fragments
• Water and open land two different barriers
• Terrestrial animals isolated most by water
• Aquatic animals isolated most by land
• Ask isolated from WHAT?
• Scope and intensity of interactions between
  members of a forest fragment community and
  members of the surrounding terrestrial community
  is likely much greater than degree of interaction
  between island and aquatic communities

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Islands FragmentsPart 8

• Birds Forest Fragments
• Bird diversity-forest area relationship
• Long distance migratory birds tend to produce
  only one small clutch of eggs per year, often
  laid in open nest close to ground
• Makes vulnerable to nest predators
• Nest predators and parasites are more effective
  near edges and in small fragments composed
  primarily of edge habitat
• Late arrival of long distance migrants gives less
  opportunity for renesting
• Some species thrive in small forest fragments
• Others seldom found in small forests

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Islands FragmentsPart 8

• Nature Reserves as Islands
• Design features that could help maintain species
  diversity
• Large reserve
• Single large vs. several small
• If several small only choice, group closely
  together
• Arrange in cluster fashion
• Connect reserves with corridors to make dispersal
  easier
• Make reserves circular as possible
• SLOSS Debate (single large vs. several small)
• Minimum viable population of large, wide ranging
  animals
• Catastrophes argue against single large reserve
• Sometimes two species dont coexist because they
  are competitors
• Practical considerations
• Harder to find large tracts of relatively
  undisturbed land

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Islands FragmentsPart 8

• Corridors
• Link network of patches of forest
• Long narrow habitat bridges
• Effectiveness of corridors
• depends on organism
• Type of movement
• Type of corridor
• Iowas corridors
• Waterways
• Shorelands have many ecological values
• Maintain wide bands of vegetation near shores

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Islands FragmentsPart 8

• Forest management Forest Fragmentation
• Forestry Nature Reserves
• Collaborate with other resource managers
• Sensitive low impact techniques
• Without compromising wildlife habitat

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Islands FragmentsPart 8

• Fragmentation in a Forested Landscape
• Negative effects of forest fragments in ag
  regions
• Large decrease in regions total area of forest
• 1960 25 of earths surface
• 2000 20
• 2020 14
• Douglas fir forests 30 year study in California
• Amphibians, reptiles, birds
• Edge and early successional species present
• Interior species avoid these fragments
• Nonmigratory species nesting in cavities
  declinging in populations
• Potential fragmentation issues
• Higher nest predation
• Small mammals reluctant to cross 3m unused
  roadway
• Regional extinction for some species

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Islands FragmentsPart 8

• Fragments Edges
• Multiple use model (MUM)
• Core
• Undisturbed forest
• Buffer zone
• Inner buffer zone of dispersed recreation and
  selection and loging
• Outer buffer zone
• Variety of buffer zone and forestry activities
  and limited agriculture
• Choices
• game vs. nongame
• Edge vs. interior species
• Rare vs. common species

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Islands FragmentsPart 8

• Summary
• Isolated patches of forest
• Low habitat diversity
• High rates of local extinction
• Absence of species that live at low population
  densities
• Deleterious seffects associated with edges
• Avoid future fragmentation
• Subject forest fragments to less disruptive forms
  of management
• Manage extensively forested landscapes on variety
  of scales
• Some most vulnerable species require extensive
  tracts of habitat

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Shores

• Part 9

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ShoresPart 9

• Introduction
• Interface between aquatic and terrestrial
  habitats
• Great importance
• Shores home to unique biota
• Special ecological processes
• Timber management in riparian forests
• Grasslands ribbon of trees marks watercourse
• Forest streams come in different orders of
  classifications
• Tributaries first order Mississippi tenth order
• Parameters for riparian zone
• Hydrologic
• Climatic
• Biological
• Periodically inundated by high water

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ShoresPart 9

• Importance of Riparian Ecosystems
• Aquatic Perspective
• Steams not tremendously productive
• Lack of organic matter
• Invertebrate decomposers
• Large logs stabilize dynamic equilibium
  deposition/erosion
• Beaver dams
• Forest stream biota
• Narrow range of temperature
• Forest canopy shades water
• Holds more dissolved oxygen

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ShoresPart 9

• Terrestrial Perspective

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