Long-term fire history from alluvial fan sediments: the role of drought and climate variability, and implications for management of Rocky Mountain forests

2008 ◽  
Vol 17 (1) ◽  
pp. 84 ◽  
Author(s):  
Jennifer Pierce ◽  
Grant Meyer
Keyword(s):  
Ponderosa Pine ◽  
Fire History ◽  
Fire Regimes ◽  
Alluvial Fan ◽  
Ice Age ◽  
Pine Forests ◽  
Drought Severity ◽  
Ponderosa Pine Forests ◽  
Grass Growth ◽  
In Fire

Alluvial fan deposits are widespread and preserve millennial-length records of fire. We used these records to examine changes in fire regimes over the last 2000 years in Yellowstone National Park mixed-conifer forests and drier central Idaho ponderosa pine forests. In Idaho, frequent, small, fire-related erosional events occurred within the Little Ice Age (~1450–1800 AD), when greater effective moisture probably promoted grass growth and low-severity fires. This regime is consistent with tree-ring records showing generally wetter conditions and frequent fires before European settlement. At higher elevations in Yellowstone, cool conditions limited overall fire activity. Conversely, both Idaho and Yellowstone experienced a peak in fire-related debris flows between ~950 and 1150 AD. During this generally warmer time, severe multidecadal droughts were interspersed with unusually wet intervals that probably increased forest densities, producing stand-replacing fires. Thus, severe fires are clearly within the natural range of variability in Idaho ponderosa pine forests over longer timescales. Historical records indicate that large burn areas in Idaho correspond with drought intervals within the past 100 years and that burn area has increased markedly since ~1985. Recent stand-replacing fires in ponderosa pine forests are likely related to both changes in management and increasing temperatures and drought severity during the 20th century.

A comparison of targeted and systematic fire-scar sampling for estimating historical fire frequency in south-western ponderosa pine forests

2013 ◽  
Vol 22 (8) ◽  
pp. 1021 ◽  
Author(s):  
Calvin A. Farris ◽  
Christopher H. Baisan ◽  
Donald A. Falk ◽  
Megan L. Van Horne ◽  
Peter Z. Fulé ◽  
...  
Keyword(s):  
Ponderosa Pine ◽  
Fire History ◽  
Spatial Scales ◽  
Fire Frequency ◽  
Landscape Scale ◽  
Pine Forests ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
Targeted Sampling ◽  
Statistical Measures

Fire history researchers employ various forms of search-based sampling to target specimens that contain visible evidence of well preserved fire scars. Targeted sampling is considered to be the most efficient way to increase the completeness and length of the fire-scar record, but the accuracy of this method for estimating landscape-scale fire frequency parameters compared with probabilistic (i.e. systematic and random) sampling is poorly understood. In this study we compared metrics of temporal and spatial fire occurrence reconstructed independently from targeted and probabilistic fire-scar sampling to identify potential differences in parameter estimation in south-western ponderosa pine forests. Data were analysed for three case studies spanning a broad geographic range of ponderosa pine ecosystems across the US Southwest at multiple spatial scales: Centennial Forest in northern Arizona (100ha); Monument Canyon Research Natural Area (RNA) in central New Mexico (256ha); and Mica Mountain in southern Arizona (2780ha). We found that the percentage of available samples that recorded individual fire years (i.e. fire-scar synchrony) was correlated strongly between targeted and probabilistic datasets at all three study areas (r=0.85, 0.96 and 0.91 respectively). These strong positive correlations resulted predictably in similar estimates of commonly used statistical measures of fire frequency and cumulative area burned, including Mean Fire Return Interval (MFI) and Natural Fire Rotation (NFR). Consistent with theoretical expectations, targeted fire-scar sampling resulted in greater overall sampling efficiency and lower rates of sample attrition. Our findings demonstrate that targeted sampling in these systems can produce accurate estimates of landscape-scale fire frequency parameters relative to intensive probabilistic sampling.

Fire History in Interior Ponderosa Pine Communities of the Black Hills, South Dakota, USA

1996 ◽  
Vol 6 (3) ◽  
pp. 97 ◽  
Author(s):  
PM Brown ◽  
CH Sieg
Keyword(s):  
Ponderosa Pine ◽  
Fire History ◽  
Land Use Changes ◽  
Black Hills ◽  
Pine Forests ◽  
Southern Rocky Mountains ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
South Central ◽  
Pine Trees

Chronologies of fire events were reconstructed from crossdated fire-scarred ponderosa pine trees for four sites in the south-central Black Hills. Compared to other ponderosa pine forests in the southwest US or southern Rocky Mountains, these communities burned less frequently. For all sites combined, and using all fires detected, the mean fire interval (MFI), or number of years between fire years, was 16 years (± 14 SD) for the period 1388 to 1900. When a yearly minimum percentage of trees recording scars of ≥ 25% is imposed, the MFI was 20 years (± 14 SD). The length of the most recent fire-free period (104 years, from 1890 to 1994) exceeds the longest intervals in the pre-settlement era (before ca. 1874), and is likely the result of human-induced land use changes. Based on fire scar position within annual rings, most past fires occurred late in the growing season or after growth had ceased for the year. These findings have important implications for management of ponderosa pine forests in the Black Hills and for understanding the role of fire in pre-settlement ecosystem function.

Variability in fire - climate relationships in ponderosa pine forests in the Colorado Front Range

2008 ◽  
Vol 17 (1) ◽  
pp. 50 ◽  
Author(s):  
Rosemary L. Sherriff ◽  
Thomas T. Veblen
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire History ◽  
Southern Oscillation ◽  
Primary Objective ◽  
Fire Occurrence ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
Montane Zone ◽  
In Fire

Understanding the interactions of climate variability and wildfire has been a primary objective of recent fire history research. The present study examines the influence of El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) on fire occurrence using fire-scar evidence from 58 sites from the lower ecotone to the upper elevational limits of ponderosa pine (Pinus ponderosa) in northern Colorado. An important finding is that at low v. high elevations within the montane zone, climatic patterns conducive to years of widespread fire are different. Differences in fire–climate relationships are manifested primarily in antecedent year climate. Below ~2100 m, fires are dependent on antecedent moister conditions that favour fine fuel accumulation 2 years before dry fire years. In the upper montane zone, fires are dependent primarily on drought rather than an increase in fine fuels. Throughout the montane zone, fire is strongly linked to variations in moisture availability that in turn is linked to climate influences of ENSO, PDO and AMO. Fire occurrence is greater than expected during the phases of each index associated with drought. Regionally widespread fire years are associated with specific phase combinations of ENSO, PDO and AMO. In particular, the combination of La Niña, negative PDO and positive AMO is highly conducive to widespread fire.

scholarly journals Uncertainty in surface-fire history: the case of ponderosa pine forests in the western United States

2001 ◽  
Vol 31 (7) ◽  
pp. 1205-1226 ◽  
Author(s):  
William L Baker ◽  
Donna Ehle
Keyword(s):  
United States ◽  
Forest Structure ◽  
Ponderosa Pine ◽  
Fire History ◽  
Pine Forests ◽  
Western United States ◽  
Surface Fire ◽  
Population Mean ◽  
Ponderosa Pine Forests ◽  
Fire Scar

Present understanding of fire ecology in forests subject to surface fires is based on fire-scar evidence. We present theory and empirical results that suggest that fire-history data have uncertainties and biases when used to estimate the population mean fire interval (FI) or other parameters of the fire regime. First, the population mean FI is difficult to estimate precisely because of unrecorded fires and can only be shown to lie in a broad range. Second, the interval between tree origin and first fire scar estimates a real fire-free interval that warrants inclusion in mean-FI calculations. Finally, inadequate sampling and targeting of multiple-scarred trees and high scar densities bias mean FIs toward shorter intervals. In ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) forests of the western United States, these uncertainties and biases suggest that reported mean FIs of 2-25 years significantly underestimate population mean FIs, which instead may be between 22 and 308 years. We suggest that uncertainty be explicitly stated in fire-history results by bracketing the range of possible population mean FIs. Research and improved methods may narrow the range, but there is no statistical or other method that can eliminate all uncertainty. Longer mean FIs in ponderosa pine forests suggest that (i) surface fire is still important, but less so in maintaining forest structure, and (ii) some dense patches of trees may have occurred in the pre-Euro-American landscape. Creation of low-density forest structure across all parts of ponderosa pine landscapes, particularly in valuable parks and reserves, is not supported by these results.

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