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 Fire Histoy Determination in the Mixed Conifer/Aspen Community of Bryce Canyon National Park

1993 ◽  
Vol 17 ◽  
pp. 31-35
Author(s):  
Michael Jenkins
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
National Park ◽  
Fire History ◽  
Fire Regime ◽  
Mixed Conifer ◽  
Major Objective ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
European Settlement

The major objective of this ongoing study is to document vegetative changes resulting from alteration of the fire regime in the mixed conifer/aspen communities of Bryce Canyon National Park. Previous fire history studies have documented fire return intervals using fire scar analysis of ponderosa pine Pinus ponderosa in the park (Buchannan and Tolman 1983: Wight 1989) and for the Paunsaugunt Plateau (Stein 1988). Numerous other studies have similarly documented the fire regime in pre-European settlement ponderosa pine forests in western North America. The study is being conducted in the more mesic mixed conifer communities at the south end of Bryce Canyon National Park and will specifically document vegetative changes suggested by Roberts et al. (1992) resulting from suppression of frequent low intensity surface fires and overgrazing.

Fire history of pinyon–juniper woodlands at upper ecotones with ponderosa pine forests in Arizona and New Mexico

2008 ◽  
Vol 38 (8) ◽  
pp. 2097-2108 ◽  
Author(s):  
David W. Huffman ◽  
Peter Z. Fulé ◽  
Kristen M. Pearson ◽  
Joseph E. Crouse
Keyword(s):  
New Mexico ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire History ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
Surface Fires ◽  
Pine Stands ◽  
Juniperus Scopulorum ◽  
Vegetative Communities

We used maps of fire evidence, fire scar dendrochronology, forest age-structure analysis, and landscape analysis to investigate fire history at pinyon pine ( Pinus edulis Engelm.) – juniper ( Juniperus osteosperma (Torr.) Little, Juniperus scopulorum Sarg.) woodland – ponderosa pine ( Pinus ponderosa P. & C. Lawson) forest ecotones in Arizona (Tusayan) and in New Mexico (Canjilon). Results showed that charred trees were not evenly distributed across vegetative communities but were significantly (p < 0.001) more abundant than expected in ponderosa pine communities. Composite fire scar analysis indicated that surface fires occurred in ponderosa pine stands at both sites and burned at intervals of 7.2–11.1 years (WMPI; Weibull median probability interval). At Tusayan, landscape structure was fine grained, and maximum pinyon age was >200 years across 80% of the site. At Canjilon, landscape pattern was relatively coarse, and most pinyon patches were 200–300 years old. Cumulative standing age distributions suggested pinyon–juniper fire rotations of 340 and 290 years at Tusayan and Canjilon, respectively. We concluded the following: (i) surface fires in ponderosa pine stands did not spread through pinyon–juniper communities at either site, (ii) fire evidence was prevalent across both sites, but old pinyon trees indicated that no widespread lethal fires had occurred in the last 300–400 years, and (iii) structurally heterogeneous landscapes suggested that historical pinyon–juniper fires were of limited extent but lethal in patches.

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.

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.

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.

Comparing methods of reconstructing fire history using fire scars in a southwestern United States ponderosa pine forest

2006 ◽  
Vol 36 (4) ◽  
pp. 855-867 ◽  
Author(s):  
Megan L Van Horne ◽  
Peter Z Fulé
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire History ◽  
Sampling Methods ◽  
Fire Regime ◽  
Fire Frequency ◽  
Fire Scars ◽  
Fire Scar ◽  
Targeted Sampling ◽  
Fire Intervals

Fire scars have been used to understand the historical role of fire in ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) ecosystems, but sampling methods and interpretation of results have been criticized for being statistically invalid and biased and for leading to exaggerated estimates of fire frequency. We compared "targeted" sampling, random sampling, and grid-based sampling to a census of all 1479 fire-scarred trees in a 1 km2 study site in northern Arizona. Of these trees, 1246 were sufficiently intact to collect cross-sections; of these, 648 had fire scars that could be cross-dated to the year of occurrence in the 200-year analysis period. Given a sufficient sample size (approximately n ≥ 50), we concluded that all tested sampling methods resulted in accurate estimates of the census fire frequency, with mean fire intervals within 1 year of the census mean. We also assessed three analytical techniques: (1) fire intervals from individual trees, (2) the interval between the tree origin and the first scar, and (3) proportional filtering. "Bracketing" fire regime statistics to account for purported uncertainty associated with targeted sampling was not useful. Quantifying differences in sampling approaches cannot resolve all the limitations of fire-scar methods, but does strengthen interpretation of these data.

Climate effects on historical fires (1630 - 1900) in Utah

2008 ◽  
Vol 17 (1) ◽  
pp. 28 ◽  
Author(s):  
Peter M. Brown ◽  
Emily K. Heyerdahl ◽  
Stanley G. Kitchen ◽  
Marc H. Weber
Keyword(s):  
Ponderosa Pine ◽  
Southern Oscillation ◽  
Severity Index ◽  
Drought Severity ◽  
Fire Occurrence ◽  
Mixed Conifer ◽  
Climate Effects ◽  
Fire Scar ◽  
Mixed Conifer Forests ◽  
The Pacific

We inferred climate effects on fire occurrence from 1630 to 1900 for a new set of crossdated fire-scar chronologies from 18 forested sites in Utah and one site in eastern Nevada. Years with regionally synchronous fires (31 years with fire at ≥20% of sites) occurred during drier than average summers and years with no fires at any site (100 years) were wetter than average. Antecedent wet summers were associated with regional-fire years in mixed-conifer and ponderosa pine forest types, possibly by affecting fine fuel amount and continuity. NINO3 (an index of the El Niño–Southern Oscillation, ENSO) was significantly low during regional-fire years (La Niñas) and significantly high during non-fire years (El Niños). NINO3 also was high during years before regional-fire years. Although regional fire years occurred nearly twice as often as expected when NINO3 and the Pacific Decadal Oscillation were both in their cool (negative) phases, this pattern was not statistically significant. Palmer Drought Severity Index was important for fire occurrence in ponderosa pine and mixed-conifer forests across the study area but ENSO forcing was seen only in south-eastern sites. Results support findings from previous fire and climate studies, including a possible geographic pivot point in Pacific basin teleconnections at ~40°N.

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.

Fire histories in ponderosa pine forests of Grand Canyon are well supported: reply to Baker

2006 ◽  
Vol 15 (3) ◽  
pp. 439 ◽  
Author(s):  
Peter Z. Fulé ◽  
Thomas A. Heinlein ◽  
W. Wallace Covington
Keyword(s):  
Ponderosa Pine ◽  
Grand Canyon ◽  
Pine Forests ◽  
Fire Scars ◽  
Surface Fire ◽  
Ponderosa Pine Forests ◽  
Fire Scar ◽  
Study Sites ◽  
Fire Intervals ◽  
Old Trees

Fire scars and other paleoecological methods are imperfect proxies for detecting past patterns of fire events. However, calculations of long fire rotations in Grand Canyon ponderosa pine forests by Baker are not convincing in methodology or assumptions compared with fire-scar evidence of frequent surface fires. Patches of severe disturbance are a possible hypothesis to explain the relatively short age structure at the park, where ~12% fewer trees were older than 300 years compared with another unharvested northern Arizona site. However, mapped patterns of old trees as well as the evidence for frequent surface fire from fire scars, charcoal deposition studies, and evolutionary history are more consistent with the dominance of surface fire prior to c. 1880. The most relevant available evidence of fire recurrence at a given point, mean point fire intervals, had median values <16 years at all five study sites, close to filtered composite fire interval statistics (~6–10 years), but much lower than Baker’s calculated fire rotation values (55–110 years). The composite fire interval is not a uniquely important statistic or a numerical guideline for management, but one of many lines of evidence underscoring the ecological role of frequent surface fire in ponderosa pine forests.

scholarly journals Variation in fire scar phenology from mixed conifer trees in the Sierra Nevada

2018 ◽  
Vol 48 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Scott L. Stephens ◽  
Liam Maier ◽  
Lilah Gonen ◽  
Jennifer D. York ◽  
Brandon M. Collins ◽  
...  
Keyword(s):  
Sierra Nevada ◽  
Fire History ◽  
Fire Regimes ◽  
Fire Season ◽  
Mixed Conifer ◽  
Outer Bark ◽  
Individual Tree ◽  
Fire Scar ◽  
The Individual ◽  
In Fire

Fire scar based studies have provided robust reconstructions of past fire regimes. The season in which a fire occurs can have considerable impacts to ecosystems but inference on seasonality from fire scars is relatively uncertain. This study examined patterns in the phenology of cambium formation and wounding responses in the five common mixed conifer tree species of the Sierra Nevada. The outer bark was shaved on 35 trees and individual locations within the shaved portions were wounded systematically by applying direct heat using a handheld torch. Most of the trees had not commenced annual ring development by the first burning treatment in late May. By the second treatment, scars were identified mostly within the early or middle earlywood, although variation was high compared with other treatment periods. By late October, all scars were recorded at the ring boundary. Although intra-ring scar positions generally followed a logical temporal pattern, there was high tree to tree variation such as Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) burned on 26 June induced scars in the early, mid, and late earlywood depending on the individual tree. This high variation makes it somewhat challenging to precisely assign past fire season to published fire history studies.

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