Post on 11-Jan-2016
transcript
INTRODUCTION TO EFFECTS OF FIRE MANAGEMENT ACTIONS ON CULTURAL RESOURCES
Nelson Siefkin, ArcheologistFire Management, Pacific West Region
DEFINING CULTURAL RESOURCES
• Archeological Resources
• Structures
• Ethnographic Resources
• Cultural Landscapes
• Museum Objects
ARCHEOLOGICAL RESOURCES
Physical remains of past human activity…prehistoric and historical
STRUCTURES
Material assemblies that extend the limits of human capability…domiciles, barns, bridges, dams, roads...prehistoric and historical
ETHNOGRAPHIC RESOURCESTangible and intangible manifestations of an extant cultural system…vegetation, spiritual/ceremonial sites, languages…generally associated with Native Americans/Hawaiians/Alaskans…often poorly understood
CULTURAL LANDSCAPES
Intertwined patterns of natural and cultural phenomena created by humans…prehistoric and historical
MUSEUM OBJECTS
Objects, specimens, and archival and manuscript collections…found in museums, exhibits, furnished structures, etc.
Cultural Resources of Interest
Critical to distinguish cultural resources of interest…those that are or have the potential to be important (e.g., NRHP listed and eligible) and have the potential to be impacted by fire management actions.
Historic properties--NRHP eligible or listed resources--are de facto resources of interest, but may also include those that do not meet NRHP criteria of significance.
Seemingly marginal cultural resources will become more significant as technology improves, urban encroachment intensifies, etc…Federal lands will become repositories for the preservation of in situ cultural resources
HistoricProperties
Resources ofInterest
Effects of Fire Management Actions on Cultural Resources
Conveniently divide into three types…
Direct Effects: Fire itself is the cause of impacts…due to direct flame exposure, excessive radiant heating, smoke damage, etc.
Operational Effects: Result from associated operations such as line construction, staging, etc. Especially common during the suppression of wildfires.
Indirect Effects: Fire and/or associated operations result in a change in local context such that resources are effected, e.g., erosion, high tree mortality.
DIRECT EFFECTS
Relate strongly to fire behavior…generally speaking, the heavier the fuel load, the more severe and intense the fire behavior, and the greater the potential for direct effects
Cultural Resources differentially impacted by direct fire effects…topic is not well understood
e.g., dimensional lumber ignites at 350 deg. C
glass melts above 400 deg. C
Some obsidian vesiculates above 700 deg. C
Different attributes of a feature or artifact are differentially impacted by direct fire effects
• Context in space• Spatial attributes
• Technological attributes
• Obsidian hydration rind
• Chemical fingerprint
• Distinctive appearance
• Use-wear/organic residues
Compromised >150 Deg. C
Compromised >700 Deg. CCompromised variable temp
Compromised variable temp
Compromised at low temp
What is it that we want to know?
Impediments to Accounting for Direct EffectsFire Behavior is extremely complex…is it reasonable to assume that we can control fire behavior such that damage threshold(s) will not be exceeded?
e.g., allow obsidian hydration rinds to be damaged, but keep fire cool enough so that obsidian artifact morphology is not effected.
Mitigating Direct Effects
Exclusionary Protection Measures
Exclusionary measures...preventing fire from burning on or in close proximity to a cultural resource through the use of some predetermined fire management action
Often employed when it is anticipated, given expected fire behavior, that the fire will burn at an intensity that exceeds the threshold above which a particular resource or resource attribute is impacted
Examples of Exclusionary Measures...
Fire Shelters
Examples of Exclusionary Measures...
Sprinklers, hoses, andwet lines
Examples of Exclusionary Measures...
Fire retardant foams & gels
Examples of Exclusionary Measures...
Fire lines
Benefit of Exclusionary Measures…
Insure that cultural resources are not directly effected by fire
Potential drawbacks of exclusionary measures…
Leave islands of unburned fuel on cultural resources. These can be attractive to looters. Inevitably, unburned areas will eventually burn.
Non-Exclusionary Protection Measures
Non-exclusionary measures... intended to produce fire intensities below that expected to cause resource damage and/or that will not lead to future indirect effects. No attempt to exclude fire from the cultural resource.
Can be used in conjunction with exclusionary protection measures.
Examples of Non-Exclusionary Measures...
PRE-VEGETATIONREMOVAL
POST-VEGETATIONREMOVAL
Manual Fuel Load Reduction
Archeological site (obsidian scatter) subjected tovegetation removal prior to prescribed burn at Lava Beds NM
A job too well done...
Oops.
Examples of Non-Exclusionary Measures...
Burning under circumstances that favor lower intensity fire…e.g., night ignition, backing fire
Examples of Non-Exclusionary Measures...
Permanent or temporary artifact removal
Benefit of Non-Exclusionary Measures…
Allows fire to occur on cultural resources so that fuel loads are reduced
Potential drawbacks of non-exclusionary measures…
Difficulties associated with controlling fire intensity, uncertainty about direct fire effects on cultural resources
OPERATIONAL EFFECTSA large number of potentially damaging activities are carried out in conjunction with the suppression of wildfires
Most of these involve ground disturbance, although the range of potential effects are much greater
Satellite Photograph - Cerro Grande Fire Plume
Bandelier National Monument (Summer 2000)
Examples of Operational Effects...
Constructionof fire lines
Examples of Operational Effects...
Fire camps, staging areas, helispots, etc.
Examples of Operational Effects...
Fire retardant &water drops
Historic Residential Area at Mesa Verde NPLong Mesa Fire, 2002
Examples of Operational Effects...
Mop-up and Rehabilitation
Examples of Operational Effects...
Looting
INDIRECT EFFECTS
Indirect effects are fairly elusive…can occur while fire is still burning, shortly thereafter, or later in time
Can be difficult to recognize and evaluate
Examples of Indirect Effects...
Increased surface runoff and erosion
Post-burn eroding midden in Mojave National Preserve, 2005
Examples of Indirect Effects...
Increased TreeMortality
Examples of Indirect Effects...
Increased TreeMortality
Shorty Lovelace Historic DistrictCrowley CabinSequoia-Kings Canyon NP
Shorty Lovelace at Crowley CabinPre-1940
1997Sugarloaf WFU
2003Williams WFU
Burned Snag
Examples of Indirect Effects...
Looting
Post-burn “Looter’s pile” at Mojave NP, 2005
Examples of Indirect Effects...
Increased populations of burrowing rodents
Cultural Resource Hazards and the Resource Advisor
Resource Advisors can benefit operations by disclosing the location of potential hazards
For example, barbed-wire fences, subsurface mining features,toxic materials, explosives, etc.
Join the Fire Archeology DiscussionGroup…
http://groups.yahoo.com/group/fire_archaeology