Forest Disease Management

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Forest Disease Management

• Reading Chapter 16

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Forest Disease Management
Disease Evaluation

• Detection
• Recognition
• Appraisal
• What type of management is appropriate?

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Disease Management Strategies
Disease Management Strategies

• Cultural
• Chemical
• Biological
• Genetics
• Quarantine and inspection
• Passive
• Increasing pathogens

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Cultural
Cultural Techniques

• Clearcutting
• Pruning
• Thinning
• Sanitation inoculum removal
• Species selection
• Fertilization
• Prescribed fire
• Avoidance

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Clearcutting

• For dwarf mistletoe, cankers, decay
• Not effective on root rots and rusts

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Thinning
Thinning

• Increase stand health by reducing crowding
• Remove mistletoe-infected trees
• Reduce humidity and foliage diseases
• Root diseases may increase in fresh stumps
  (Armillaria and H. annosum), but not invade older
  stumps (Phellinus sulphurascens).

18 year old Southern pine stand was thinned at
age 15
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Pruning
Pruning

• Reduces mistletoe, canker, rust, and wilt
  diseases
• Improper pruning can increase some cankers and
  wood decay

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Sanitation
Sanitation

• Removal of inoculum prevents further infection
• Root rots stump removal
• Mistletoe repeated thinning
• Dutch elm disease burning of brood material
• Phytophthora equipment and foot washing

Push over logging with an excavator (with claw)
to remove infected stumps
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Species selection
Species Selection

• Non-host species in high disease areas
• Red alder, western white pine, western red cedar
  instead of Douglas-fir for laminated root rot
• Western red cedar instead of Port Orford cedar
  for Phytophthora
• Mixed species stands

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Prescribed fire

• Useful in controlling mistletoe, foliage
  diseases, cankers
• Not effective on root rots

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Fertilizing
Fertilizing

• Nitrogen (N)
• Phosphorus (P)
• Potassium (K)
• Trace elements (Ca, Mg, Cu, Zn, B)
• Generally improves tree health
• May make some diseases worse

Helicopter applying fertilizer in Blue Mountains
Wallowa-Whitman National Forest
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Avoidance
Avoidance

• Thinning and pruning when spores are not present
• Site selection soil, drainage, climate,
  identify high hazard sites (white pine blister
  rust, Annosus Root Disease)

Stand infested with white pine blister rust
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Other strategies- Chemical Control
Chemical Control

• Soil fumigation in nurseries
• Borax stump treatment for annosum root rot
• Herbicide or growth regulator mistletoe
• Injections vascular wilts
• Foliar spraying Xmas trees

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Biological control
Biological Control

• Competition
• Decay fungi in stumps
• Trichoderma
• Phlebiopsis gigantea
• for H. annosum (Rotstop)
• Protection - mycorrhizae

Mycorrhiza at base of seedling from nursery
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Genetics
Genetics Breeding for resistance

• Breeding for resistance
• Better for introduced pathogens than for native
  ones
• Works well for rusts
• Not as effective for root diseases

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Quarantine and Inspection

• To prevent new pathogens and pests from being
  introduced
• White pine blister rust, Port Orford cedar root
  disease, Dutch elm disease, Sudden oak death
• Many pathogens come in on infected soil or plant
  material (APHIS Animal Plant Health Inspection
• Service of USDA)
• Transporting fumigated seeds is best
• www.exoticforestpests.or
  g

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APHIS has importation requirements for
logs, lumber, wood chips/bark chips, mulch,
humus, compost,litter, Cork bark. See Text Table
25.2.
Pest introductions are continuing to increase
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Passive management
Passive Management

• doing nothing
• When managing for wildlife habitat
• When not much damage is expected

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Increasing decay
Increasing Decay

• For wildlife habitat

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Integration of disease. insect and fire
management

• Forests are now being managed as ecosystems
  rather than as croplands
• USDA Forest Service guidelines for east and west
  of the Cascades

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East Cascades

• Thinning to reduce stress
• Harvest to create uneven aged stands to prevent
  bark beetle outbreaks in lodgepole pine stands
• Reduce fuel on forest floor with prescribed fire
  and removal of true firs

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West Cascades

• Multiple species stands to reduce impacts of
  insects and diseases
• Use natural regeneration or seed from local
  sources to prevent needle-cast due to off-site
  planting
• Uniform stands are more susceptible than mixed
  age and species

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Modeling Forest Diseases
Modeling Forest Diseases

• Differential equations
• Regression equations
• Simulation models
• Economic spread sheet
• models

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Regression models
Regression
models e.g., Spread of ponderosa pine dwarf
mistletoe in AZ and CA in uneven-aged stands
Y 11.7X1 0.02 X2 0.8X3 Where Y estimated
distance of spread (in feet) X1 6 class dwarf
mistletoe rating X2 Density of trees
(trees/acre) X3 infection age (years)

• Prediction
• Several variables
• Apply only to area where data were collected

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Simulation models
Simulation Models

• Can include many variables
• Apply to more situations
• Validate model with actual data
• Western Root Disease model

LMS Landscape Management System
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Root disease model can be interfaced with LMS
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Economic Models Cost of Laminated Root Disease