Fire, birds, bears and trees

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Fire, birds, bears and trees

• Conservation and restoration of
• whitebark pine ecosystems

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Harsh Environment

• High elevation (above 7500 ft)
• Cold, moist winters with cool moist summers
• Short growing season (lt60-80 days)

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Importance of whitebark pine

• Broad tree crowns act as snow fences, helping to
  slowly release water into the high mountain
  streams, extending the stream flow to the valleys
  below into summer
• Food for wildlife, including the Clarks
  nutcracker and black and grizzly bears
• Aesthetically pleasing for humans

Baker Lake, Selway Bitterroot Wilderness Area
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Whitebark pine seeds are important to animals
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Clarks nutcrackers and whitebark pine co-evolved

• Nutcrackers cache the seeds preferentially in
  open and burned areas
• This gives whitebark pine a distinct advantage
  over other conifers in regenerating large, burned
  areas
• Lanner "the habits of Clark's nutcrackers
  account for the distribution, site preference,
  successional status, population age structure,
  and spacing of whitebark pine".
• Cache seeds 1-3 cm deep
• Each bird can cache as many as 22,000 seeds each
  year

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Whitebark pine decline

• Whitebark pine has declined from 34 of potential
  whitebark pine habitat historically (1900) to
  19 currently ( 1990) in Idaho and Montana
• Decline due to introduced disease, fire exclusion
  and advancing succession
• Fires allow for mass selection against the
  introduced white pine blister rust
• Whitebark pine is likely to be sensitive to
  climate change

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Ghost forests

• White pine blister rust
• Mountain pine beetle
• Fire exclusion
• Advancing succession

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Reconstructing fire history

• We can date fire scars. There are three fire
  scars on this cross-section of a whitebark pine
  tree cut from a living tree in 1988

Sometimes we can map and date past fires from the
age of trees that grew post-fire
We can also analyze maps of historical fires
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Fire ecology of whitebark pine

• Fires recycle accumulated biomass, recycles
  nutrients, rejuvenates vegetation, and maintains
  the diversity of landscapes
• WBP is readily killed by fires, but sometimes
  survives surface fires
• Fire creates regeneration opportunities
• Clarks nutcrackers disperse the seeds of
  whitebark pine. They prefer to cache them in open
  and burned areas -- conditions where whitebark
  pine thrives.
• In the absence of fire, other trees eventually
  replace whitebark pine on most sites

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Fire exclusion

• Fires were historically infrequent, and of mixed
  or stand-replacing severity
• Large fires historically lasted weeks or months
• Modern fires are usually extinguished at lower
  elevations before they spread to whitebark pine
• Subalpine fuels are usually too moist to support
  extensive fires until late in the summer during
  unusually dry years when fire managers are
  unwilling to risk fire spread from drier areas

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White pine blister rust

• This Eurasian fungus was introduced to the
  Pacific Northwest in 1910
• Whitebark pine is very susceptible, as are all
  5-needled pines
• It reduces cone and seed production long before
  it kills trees
• 3 to 8 of whitebark pine trees are resistant
• Blister rust was found in 59 of the stands
  sampled across the Intermountain region, with
  increasing incidence and intensity over the last
  30 years in the northern Rockies (Smith and
  Hoffman 1998).

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Human-induced climate change threatens whitebark

• WBP will be lost from Yellowstone National Park
  with the warm temperatures and dry summers
  predicted with a doubling of the carbon dioxide
  content of the atmosphere
• Lightning fires are predicted to occur more
  frequently if carbon dioxide content of the
  atmosphere doubles
• Fire frequency, extent and severity of fires in
  subalpine forests could increase
• The outlook is bleak because of blister rust and
  advancing succession

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Functionally extinct in some areas

• 30 of trees are dead and 70 were infected
  with blister rust with an average of 25 crown
  kill in and around Glacier National Park
• Moderate to high whitebark pine mortality across
  61 of the subalpine forest landscapes in the
  600,000-ha Bob Marshall Wilderness area
• In Montana, 42 of all whitebark pine trees on
  permanent plots died in the 20 years between 1971
  to 1992

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Restore natural fire regimes

• Fires recycle accumulated biomass and nutrients,
  rejuvenates vegetation, and maintains the
  diversity of landscapes
• Fires allow for mass selection of blister-rust
  resistant trees
• Using prescribed burning is effective but
  challenging because suitable conditions are rare
• Also use wildland fire for resource benefit
  (let-burn policy)

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Challenges

• Harsh, fragile environment
• Long response time
• Most whitebark pine forests are in parks and
  wilderness areas
• Subject to fire suppression, may not support
  wildland fire use
• Active management, other than wildland fire use,
  is often prohibited or discouraged
• Access is often limited

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