Dendrochronology

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Dendrochronology
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Dendroecology

• Dendroecology uses dated tree rings to study
  ecological events such as fire and insect
  outbreaks
• Was developed by Theodor Hartig and Robert Hartig
  in late 1800s Germany
• In the US, dendroecology did not develop until
  the 1970s with the work of Hal Fritts
• Since the 1970s, dendroecology has come to
  include fire history, insects, masting, stand-age
  structure, pathogen outbreaks, and endogenous
  disturbance history

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Dendropyrochronology

• Reconstruction of fire histories is one of the
  major applications of dendrochronology for use in
  management of forests and the reestablishment of
  fire as a disturbance agent
• The goal of the dendrochronologists is to
  determine the natural range of variability for
  fire on a particular site, which describes

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Fire Regimes

• A natural fire regime is a general classification
  of the role fire would play across a landscape in
  the absence of modern human intervention, but
  including the influence of aboriginal burning.
• In the southeastern US, there have been 4
  different fire regimes

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Southeastern Fire Regimes

• The first fire regime existed prior to
  Euro-American settlement

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Southeastern Fire Regimes

• Fire-tolerant species species that are able to
  survive fire events
• Examples most pines (excluding white pine) and
  several species of oak
• Fire-intolerant species species that are not
  able to survive fire events
• Examples maples, tulip poplars, sycamores, gums

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Southeastern Fire Regimes

• The second type of fire regime began when
  Euro-American settlers arrived and adopted Native
  American burning techniques to manage vegetation.

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Southeastern Fire Regimes

• The third type of fire regime began with the
  Industrial Revolution when widespread timber
  harvesting used steam-driven locomotives that
  also provided the ignition source for an era of
  high-severity fires

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Southeastern Fire Regimes

• Finally, the fourth type of fire regime is marked
  by fire suppression during the 20th century,
  which allowed forests to recover, but also
  allowed fire-intolerant species to increase in
  dominance and hinder regeneration of yellow pines
  and xeric oaks

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Fire exclusion the most successful ad campaign
ever
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Southeastern Fire Regimes

• The current period in fire history is one of fire
  management, where the historic role of fire is
  increasingly studied and integrated into forest
  management, mainly through the use of prescribed
  burns

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The Problem

• The urban-wildland interface can be defined as an
  elevated human population living in a natural
  setting adjacent to population centers

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Types of fires Surface fire - Stand replacing
fire - Ground fire -
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Low severity wildfires stays on the ground.
Kills grass, shrubs, seedlings, saplings, dead
and decayed trees, and diseased trees.
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versus high severity wildfires kills everything
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• Fire regimes
• Fire frequency how often
• Fire seasonality when fires occur throughout
  the year
• Fire severity effects on forests not a
  measure of fire temperature
• Fire intensity a measure of fire temperature
• Fire extent spatial aspects
• Patchy fires versus landscape level fires
• Fire variability changes in fire over time
  and space
• Climatic or human-driven?

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The fire-scar record from tree rings.
Fire scars
Catface on Table Mountain pine log, Reddish Knob,
Virginia
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The fire-scar record from tree rings.
Fire scars on ponderosa pine, El Malpais National
Monument, New Mexico
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Notice how the tree tries to compartmentalize the
fire scar wound by growing succeeding years
around the wound.
Detail of fire scar on ponderosa pine, El Malpais
National Monument, New Mexico