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

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.

2008 ◽  
Vol 17 (1) ◽  
pp. 50 ◽  
Author(s):  
Rosemary L. Sherriff ◽  
Thomas T. Veblen

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.


2008 ◽  
Vol 17 (1) ◽  
pp. 60 ◽  
Author(s):  
A. H. Taylor ◽  
V. Trouet ◽  
C. N. Skinner

The relationship between climate variability and fire extent was examined in montane and upper montane forests in the southern Cascades. Fire occurrence and extent were reconstructed for seven sites and related to measures of reconstructed climate for the period 1700 to 1900. The climate variables included the Palmer Drought Severity Index (PDSI), summer temperature (TEMP), NINO3, a measure of the El Niño–Southern Oscillation (ENSO), and the Pacific Decadal Oscillation (PDO). Fire extent at the site and regional scale was associated with dry and warm conditions in the year of the fire and regional fire extent was not associated with ENSO or PDO for the full period of analysis. The relationship between regional fire extent and climate was not stable over time. The associations of fire extent with PDSI and TEMP were only significant from ~1775 onward and the associations were strongest between 1805 and 1855. PDO and fire extent were also associated during the 1805–1855 period, and ENSO was associated with fire extent before 1800, but not after. The interannual and interdecadal variability of the fire response to temperature and drought suggests that increased periods of regional fire activity may occur when high interannual PDSI variation coincides with warm decades.


2012 ◽  
Vol 21 (5) ◽  
pp. 562 ◽  
Author(s):  
Meredith H. Gartner ◽  
Thomas T. Veblen ◽  
Rosemary L. Sherriff ◽  
Tania L. Schoennagel

This study examines the influence of grasslands on fire frequency and occurrence in the ponderosa pine (Pinus ponderosa)-dominated forests of the central and northern Colorado Front Range. Fire frequency based on tree-ring fire-scar data was compared between 34 fire history sites adjacent to grasslands and 34 fire history sites not adjacent to grasslands for the time period 1675–1920. Relationships were examined between fire occurrence and values of the Palmer Drought Severity Index and sea-surface temperatures from the NINO3 region of the tropical Pacific Ocean (positive values indicating El Niño-like conditions and negative values La Niña-like conditions). Ponderosa pine stands adjacent to grasslands experienced more frequent fire than stands not adjacent to grasslands (P < 0.05) owing to proximity to prevalent fine fuels able to support relatively frequent surface fires. Fire activity adjacent to grasslands showed a lagged positive relationship with moist years (positive Palmer Drought Severity Index and positive NINO3) antecedent to fire events whereas fire occurrence at sites not adjacent to grasslands showed no relationship to antecedent moist years. This study illustrates how the presence of grasslands in a ponderosa pine landscape results in increased fire frequency (a bottom–up influence) and also increases the sensitivity of fire activity to interannual climate variability (a top–down influence).


2008 ◽  
Vol 17 (1) ◽  
pp. 40 ◽  
Author(s):  
Emily K. Heyerdahl ◽  
Donald McKenzie ◽  
Lori D. Daniels ◽  
Amy E. Hessl ◽  
Jeremy S. Littell ◽  
...  

We inferred climate drivers of regionally synchronous surface fires from 1651 to 1900 at 15 sites with existing annually accurate fire-scar chronologies from forests dominated by ponderosa pine or Douglas-fir in the inland Northwest (interior Oregon, Washington and southern British Columbia). Years with widespread fires (35 years with fire at 7 to 11 sites) had warm spring–summers and warm-dry summers, whereas years with no fires at any site (18 years) had the opposite conditions. Spring climate likely affected the length of the fire season via the effects of snowmelt on soil and fuel moisture, whereas summer climate influenced fuel moisture during the fire season. Climate in prior years was not a significant driver of regionally synchronous surface fires, likely because fuels were generally sufficient for the ignition and spread of such fires in these forests. Fires occurred significantly more often than expected by chance when the El Niño–Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) were both warm phase and less often when they were both cool phase. Interactions between large-scale climate patterns influenced fire synchrony in the inland Northwest because phases of ENSO and PDO were associated with changes in the frequency of warm-dry v. cool-wet spring–summer climate.


2006 ◽  
Vol 36 (3) ◽  
pp. 699-709 ◽  
Author(s):  
Brandon M Collins ◽  
Philip N Omi ◽  
Phillip L Chapman

Recent studies have linked the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) with drought occurrence in the interior United States. This study evaluates the influence of AMO and PDO phases on interannual relationships between climate and wildfire-burned area during the 20th century. Palmer's Drought Severity Index (PDSI) is strongly related to burned area at both regional and subregional scales. In the southern Interior West, PDSI is most strongly related to yearly burned area during warm-phase AMO, while for the same period no significant relationships exist between PDSI and burned area in the central Interior West. During cool-phase PDO, interannual climate has little influence on burned area in either the northern or the central Interior West. The opposite is true for the southern Interior West and the eastern slope of the Colorado Rockies using the Southern Oscillation Index and PDSI, respectively. The western slope of the Colorado Rockies is the only climate division or region in which burned area is not related to preceding PDSI. During warm-phase PDO, current PDSI explains 67% of the interannual variance in burned area on the western slope. These regional and temporal differences are most likely governed by variations in fuel dynamics associated with dominant regional and subregional vegetation types.


2013 ◽  
Vol 22 (5) ◽  
pp. 588 ◽  
Author(s):  
Ellis Q. Margolis ◽  
Thomas W. Swetnam

Understanding relationships between variability in historical fire occurrence and ocean–atmosphere oscillations provides opportunities for fire forecasting and projecting changes in fire regimes under climate change scenarios. We analysed tree-ring reconstructed regional climate teleconnections and fire–climate relationships in upper elevation forests (>2700m) from 16 sites in eight mountain ranges in the south-western USA. Climate teleconnections were identified by testing for associations between regional Palmer Drought Severity Index (PDSI) and individual and combined phases of El Niño–Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) indices for both the fire exclusion (1905–1978) and reconstructed fire periods (1700–1904). Fire–climate relationships were identified by comparing reconstructed fires (84 fire years) in three classes (all, synchronous and stand-replacing fires) with PDSI, precipitation, temperature, and individual and combined phases of ENSO, PDO and AMO indices. Individual and phase combinations of ENSO, PDO and AMO were associated with variability in regional PDSI. Upper elevation fire occurrence was related to variability in regional drought, ENSO phase and phase combinations of ENSO and PDO. We conclude that ENSO most consistently influenced variability in moisture and upper elevation fire occurrence, including stand-replacing fires, but this relationship was potentially modulated by phases of the PDO.


2014 ◽  
Vol 23 (7) ◽  
pp. 959 ◽  
Author(s):  
Larissa L. Yocom ◽  
Peter Z. Fulé ◽  
Donald A. Falk ◽  
Celia García-Domínguez ◽  
Eladio Cornejo-Oviedo ◽  
...  

We investigated the influence of broad- v. fine-scale factors on fire in an unusual landscape suitable for distinguishing the drivers of fire synchrony. Our study was conducted in the Sierra Madre Oriental mountain range, in north-eastern Mexico. We worked in nine sites on three parallel mountains that receive nearly identical broad-scale climatic influence, but between which fires are unlikely to spread. We collected and cross dated samples from 357 fire-scarred trees in nine sites in high-elevation mixed-conifer forests and identified fire dates. We used Jaccard similarity analysis to evaluate synchrony among sites and quantified relationships between climate and fire occurrence. Fires were historically frequent (mean fire interval ranged from 8 to 16 years in all sites) and dates of fire exclusion ranged from 1887 to 1962. We found low fire synchrony among the three mountains, indicating a strong influence of fine-scale factors on fire occurrence. Fire regime attributes were similar across mountains despite the independence of fire dates. La Niña events were associated with fire over time, although not significantly since the 1830s. Our results highlight the importance of scale in describing fire regimes and suggest that we can use fire history to understand controls on complex ecosystem processes and patterns.


2020 ◽  
Vol 16 (2) ◽  
pp. 783-798
Author(s):  
Sarir Ahmad ◽  
Liangjun Zhu ◽  
Sumaira Yasmeen ◽  
Yuandong Zhang ◽  
Zongshan Li ◽  
...  

Abstract. The rate of global warming has led to persistent drought. It is considered to be the preliminary factor affecting socioeconomic development under the background of the dynamic forecasting of the water supply and forest ecosystems in West Asia. However, long-term climate records in the semiarid Hindu Kush range are seriously lacking. Therefore, we developed a new tree-ring width chronology of Cedrus deodara spanning the period of 1537–2017. We reconstructed the March–August Palmer Drought Severity Index (PDSI) for the past 424 years, going back to 1593 CE. Our reconstruction featured nine dry periods (1593–1598, 1602–1608, 1631–1645, 1647–1660, 1756–1765, 1785–1800, 1870–1878, 1917–1923, and 1981–1995) and eight wet periods (1663–1675, 1687–1708, 1771–1773, 1806–1814, 1844–1852, 1932–1935, 1965–1969, and 1990–1999). This reconstruction is consistent with other dendroclimatic reconstructions in West Asia, thereby confirming its reliability. The multi-taper method and wavelet analysis revealed drought variability at periodicities of 2.1–2.4, 3.3, 6.0, 16.8, and 34.0–38.0 years. The drought patterns could be linked to the large-scale atmospheric–oceanic variability, such as the El Niño–Southern Oscillation, Atlantic Multidecadal Oscillation, and solar activity. In terms of current climate conditions, our findings have important implications for developing drought-resistant policies in communities on the fringes of the Hindu Kush mountain range in northern Pakistan.


Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 505 ◽  
Author(s):  
Feng Chen ◽  
Tongwen Zhang ◽  
Andrea Seim ◽  
Shulong Yu ◽  
Ruibo Zhang ◽  
...  

Coniferous forests cover the mountains in many parts of Central Asia and provide large potentials for dendroclimatic studies of past climate variability. However, to date, only a few tree-ring based climate reconstructions exist from this region. Here, we present a regional tree-ring chronology from the moisture-sensitive Zeravshan juniper (Juniperus seravschanica Kom.) from the Kuramin Range (Tajikistan) in western Central Asia, which is used to reveal past summer drought variability from 1650 to 2015 Common Era (CE). The chronology accounts for 40.5% of the variance of the June–July self-calibrating Palmer Drought Severity Index (scPDSI) during the instrumental period (1901 to 2012). Seven dry periods, including 1659–1696, 1705–1722, 1731–1741, 1758–1790, 1800–1842, 1860–1875, and 1931–1987, and five wet periods, including 1742–1752, 1843–1859, 1876–1913, 1921–1930, and 1988–2015, were identified. Good agreements between drought records from western and eastern Central Asia suggest that the PDSI records retain common drought signals and capture the regional dry/wet periods of Central Asia. Moreover, the spectral analysis indicates the existence of centennial (128 years), decadal (24.3 and 11.4 years), and interannual (8.0, 3.6, 2.9, and 2.0 years) cycles, which may be linked with climate forces, such as solar activity and El Niño-Southern Oscillation (ENSO). The analysis between the scPDSI reconstruction and large-scale atmospheric circulations during the reconstructed extreme dry and wet years can provide information about the linkages of extremes in our scPDSI record with the large-scale ocean–atmosphere–land circulation systems.


2015 ◽  
Vol 24 (4) ◽  
pp. 495 ◽  
Author(s):  
Anna M. Higgins ◽  
Kristen M. Waring ◽  
Andrea E. Thode

Over a century of fire exclusion in frequent-fire ponderosa pine and dry mixed conifer forests has resulted in increased tree densities, heavy surface fuel accumulations and an increase in late successional, fire-intolerant trees. Grand Canyon National Park uses prescribed fires and wildfires to reduce fire hazard and restore ecosystem processes. Research is needed to determine post-fire vegetation response thus enabling future forest succession predictions. Our study focussed on the effects of burn entry and burn severity on species composition and regeneration in two forest types: ponderosa pine with white fir encroachment and dry mixed conifer. We found no difference in tree composition and structure in a single, low-severity burn compared with unburned areas in the white fir encroachment forest type. We found no white fir seedlings or saplings in a second-entry, low-severity burn in the white fir encroachment forest type. Second-entry burns were effective in reducing white fir densities in the white fir encroachment forest type. There was significant aspen regeneration following high-severity fire in the dry mixed conifer forest type. This research suggests that repeated entries and an increase in burn severity may be necessary for prescribed fire or wildfire to be effective in meeting management objectives.


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