Habitat management 2

What is a “forest”?

Woody plats (trees, shrubs) are dominant vegetation

• however, usually distinct from woodland

Often associated with precipitation

Components of forest management

Trees (species) define ecology

• species describe “forest type”

Ecosystem structure

• herbivores, predators, detritivores

• Soil biota

Ecosystem function

• productivity, energy sequestration, nutrient flow

• Plant-soil feedback

brown food web important component of forest management

tree decomposition

primary and secondary cavity nesters

vertical structure important component of forest management

ground, shrub, midstory, canopy layers

species occupy different layers

scale is important component of habitat management

vegetation long-lived; long term management strategies necessary

age structure: even or uneven aged forests

forest succession component of forest management

stand initiation phase

stem exclusion phase

understory reinitiation phase

old growth phase

even-aged regeneration

removal of many trees, all same age class

• clearcuts

• seed-tree cuts

• shelterwood cuts

single age-class dominates community

long regeneration period

• early colonizers shade intolerant

even-aged regeneration: clearcuts

most common management; 2/3 of timber harvest

early successional habitat persists 5-20 years post cut

irreparable damage to understory

even-aged regeneration: clearcuts effects on wildlife

small clearcuts: (<10 ha provide habitat for edge species)

• generalists, invasive species, early successional species

• dense brush, understory cover

larger clearcuts provide habitat for some early successional birds

• can promote shade intolerant oaks and shortleaf pines

what factors are important for management of clearcuts

size of clearcut

age of stands/time since clearcut

isolation of clearcut/heterogeneity

plant (species) composition

environmental characteristics

even-aged regeneration: thinning

killing or removal of trees to promote a certain density or structure

• promotes space for trees to grow, reduce competition

precommercial

commercial

precommercial thinning

done prior to tree maturity, reduces cost of management

• promotes growth of remaining trees

  • prolongs early successional communities and understory diversity

commercial thinning

select trees harvested throughout management to offset costs

even-aged regeneration: seed tree cuts

small group of trees (~5-10/ha) retained

benefits?

• refuge for wildlife, plant species

• birds facilitate regeneration

consequences?

• reduced population diversity

  • susceptibility to disease, invasion

even-aged regeneration: shelterwood cuts

~10 year rotation:

• preparatory cut

• establishment cut

• removal cut

retain trees to shelter regenerating trees

• encourage shade-tolerant species

uneven aged management

fewer trees removed, variable age classes (~3)

• cutting cycles (15-30 yrs NA)

• promotes age class retention

shorter regeneration time

• shade-tolerant species more likely

small scale management

horizontal structure management

line between clearcut and large-scale group tree removal vague

uneven aged management (horizontal structure management)

species vary in tolerance to shade for growth and development

single tree removal

group tree removal

what is the best approach for management? (forest)

goals of land use (timber production) define the approach

• harvest (yield) important, but so is regeneration

depends on landscape characteristics

• dominant plant type/species, soil, hydrology, etc

target species defines management

• edge species vs interior species

• sensitive/rare species, threatened/endangered species

  • are there additional patches of habitat available?

cavities and cavity nesting

primary cavity nesters/excavators

secondary cavity nesters

primary cavity nesters/excavators

excavate cavities of soft or rotting wood

may include living or dead plant tissue

occupancy depends on:

• availability of food items (wood-boring prey)

• competition

secondary cavity nesters

use cavities in trees that the animals themselves do not produce

obligate cavity nesters

opportunistic cavity nesters

obligate cavity nesters

require cavities to breed, incubate, and rear young

opportunistic cavity nesters

will use cavities only if available

retaining snags

how much cavities and usable positions animals have in order to be primary or secondary nester

S=DCX

S-suitable snag density (# snags/n ha)

D-density (max # nesting pairs/n ha)

C-# cavities excavated per pair/yr

X-# used + unused snags/n ha

estimate should support max # of pairs of a primary cavity nester

rotting logs and woody debris

decomposition rates depend on Decay Rate Constant

D_t+D₀e^-kt

where:

• D=wood density (# trees/ha)

• t=time (years)

• e=natural log

• k=decay rate constant (species-specific)

woodpeckers (picidae)

important habitat characteristics:

• dead wood for cavity nesting

• diverse vertical structure

• plant composition/species

• dead wood snags

virginia mixed-oak forests underwent clear-cut

• improved habitat quality first year, but not second year

• 1st yr- increased litter and debris (arthropods)

• 2nd yr-fewer cavities

plethodon salamanders (caudata, plethodontidae)

important habitat characteristics

• water bodies (larva), soil moisture (adults)

• canopy cover

• plant composition (understory)

• litter composition/abundance

• arthropod availability (prey)

clearcut oak-hickory forests in north carolina

pennsylvania, virginia, west virginia

salamanders (clearcut oak-history forests in north carolina)

reduced canopy cover led to:

• reduced soil moisture

• reduced plant litter

• increased bare ground cover

1st year: salamanders decline by 40%

2nd year: only one salamander found

4th year: no individuals

salamanders (pennsylvania, virginia, west virginia)

compared clearcut to single-tree management

clearcuts reduced salamanders by 70%

single cuts improved salamander habitat

• mature trees increased horizontal structure; more canopy

• more canopy increased soil/litter moisture

dead wood in forest management

use unmanaged sites for reference when possible

target species define management

• natural vs artificial cavities

• hardwood vs softwood

• young vs mature snags/logs

• artificial snags

What is a grassland?

Landscape dominated by graminoid (grass-like) plants. (>10% canopy cover)

Prairies

Steppes

Rangelands

Include woody vegetation

Prairies

Found on flat land or low elevations

Steppes

Found on mountainsides or high elevations

Rangelands

Used for grazing

Factors influencing grasslands

Precipitation

• influences woody plant establishment, dominant plant type

Temperature

• influences growing season type

Soil nutrient availability

Management practices (burns, plantings)

Factors influencing grasslands: plant structure

Woody plants/scrub important

• perches: visibility

• Cavities: nesting

• Foraging of fruit, seeds, prey, etc.

Consequences of woody scrub:

• may outcompete/shade out herbaceous veg

• Encourage brood parasites

• Encourage predators

Grassland conservation and history

Mass immigration to grasslands during 18th century

Continued use of plowing encouraged annual growth over perennials

Overgrazing and soil erosion led to dust bowl

99% of all grasslands in US either agriculture or rangeland

Managed lands to restore grasslands?

• conservation reserve programs (CRPs)

• conservation reserve enhancement programs (CREP)

• Recreational/tourist hunting

Jointing vs non-jointing

Cool-season vs warm-season

• conversion from cool season to warm season

Jointing grass

Internode elongation

Elevates growing point high up (can be “decapitated”)

Ex: big bluestem, Indiangrass, perennial rye grass, reed canarygrass, smooth bromegrass

Non-jointed grass

Vegetative (sterile) shoots good for grazing

Growing point (meristem) stays low

Ex: bentgrass, blue gramma, buffalograss, Kentucky bluegrass

Cool season (grasslands)

Optimum growth between 18-24C (65-75F)

Tolerate cold snaps, low temperatures

Spring and fall growth, inactive summer

Most non-native, mostly range forage

Warm season (grasslands)

Optimum growth between 28-32C (85-90F)

C4 grasses, often drought-resilient

Summer growth

“Big four”

• big bluestem (Andropogon gerardii)

• Indiangrass (Sorghastrum nutans)

• Little bluestem (Schizachyrium scoparum)

• Switchgrass ( Panicum virgatum)

Many non-natives

Why use fire?

promotes growth of-fire adapted species

• frequency and intensity influences benefit

suppress woody vegetation

control invasive species (plants)

creation of snags

controls pests and parasites

increase bare ground (promotes colonization and regrowth)

encourage a landscape mosaic (more heterogeneity)

sources of ignition

natural fire

anthropogenic fire

natural fire

volcanic activity, lightning, other natural disasters

anthropogenic fire

man-made

deliberate fire

accidental fire

definitions of burns

based on vegetation

based on objective/goal

based on intensity

burn defined based on vegetation

forest fire, brush fire, etc

burn defined based on objective/goal

prescribed burn, hazard reduction fire, controlled burn, etc

burn defined based on intensity

ground fire

surface fire

crown fire

ground fire

burns ground vegetation, litter, and organic soil layer

occurs under drought or dry conditions

long, thorough burn

surface fire

burn litter, woody debris, and ground vegetation

dry conditions needed

intense burn (heat, vegetation)

difficult to control

crown fire

burns at level of tree canopy or crown

requires strong wind, steep slopes, heavy fuel loads

most intense (high heat, long duration)

extremely difficult to control

prescribed burn

application of fire to land to achieve a specific objective

under controlled conditions

requires a fire plan; objectives are clear and defined

low-intensity (ground or surface)

head fire

back fire

flank fire

safety

burn boss

cost efficiency

factors in a fire plan

objectives, goals

weather during burn

fuel

ignition material

crew logistics

fire behavior

factors affecting fire behavior

temperature

relative humidity

soil moisture

wind speed

fuel loads

topography

fire triangle

heat

fuel

oxygen

fire breaks

remove one of the main components of the fire triangle

• blacklining

• clearcuts

• roadway

  • body of water

fuel types

1 hour - >0.25 inches in diameter

10 hour - 0.25-1inch in diameter

100 hour - 1-3 inch in diameter

1000 hour - 3-8 inch in diameter

prescribed burn environmental conditions

relative humidity

temperature

wind

prescribed burn relative humidity

ideal: 50-70%

below 50% too hot

above 70% can result in an uneven burn

prescribed burn temperature

ideal: 40-60F (4.4-15.5C)

prescribed burn wind

3-8 mph (4.8-12.9 kph)

prescribed burn methods of ignition

drip torch

fusees

flare gun

terra torch

DAIDs (delayed aerial ignition device)

head fire

fire burns in direction of wind

burns and spreads quickly

uncontrollable

backfire

burns against direction of wind

burns and spreads slowly

ideal for initial burns

flank fire

multiple burns that spread outward

overlapping flames burn out quick; no fuel

prescribed burn safety

firebreaks defined by wind, weather, and fuel loads

professionals; fire fighters on site or notified

methods to extinguish needed

burn boss

person in charge of prescribed-fire planning

ensures qualifications are met

obtains permits

monitors effects afterwards

prescribed burn cost efficiency

typically around $5 per acre

other methods (grazing, bulldozing, cutting etc.) are typically upwards of $30 per acre