Different historical fire–climate patterns in California

2017 ◽  
Vol 26 (4) ◽  
pp. 253 ◽  
Author(s):  
Jon E. Keeley ◽  
Alexandra D. Syphard
Keyword(s):  
20Th Century ◽  
Sierra Nevada ◽  
Climate Models ◽  
The State ◽  
California Department ◽  
Current Season ◽  
Area Burned ◽  
Lower Elevation ◽  
Fire Activity ◽  
Summer Temperatures

The relationship between annual variation in area burned and seasonal temperatures and precipitation was investigated for the major climate divisions in California. Historical analyses showed marked differences in fires on montane and foothill landscapes. Based on roughly a century of data, there are five important lessons on fire–climate relationships in California: (1) seasonal variations in temperature appear to have had minimal influence on area burned in the lower elevation, mostly non-forested, landscapes; (2) temperature has been a significant factor in controlling fire activity in higher elevation montane forests, but this varied greatly with season – winter and autumn temperatures showed no significant effect, whereas spring and summer temperatures were important determinants of area burned; (3) current season precipitation has been a strong controller of fire activity in forests, with drier years resulting in greater area burned on most United States Forest Service (USFS) lands in the state, but the effect of current-year precipitation was decidedly less on lower elevation California Department of Forestry and Fire Protection lands; (4) in largely grass-dominated foothills and valleys the magnitude of prior-year rainfall was positively tied to area burned in the following year, and we hypothesise that this is tied to greater fuel volume in the year following high rainfall. In the southern part of the state this effect has become stronger in recent decades and this likely is due to accelerated type conversion from shrubland to grassland in the latter part of the 20th century; (5) the strongest fire–climate models were on USFS lands in the Sierra Nevada Mountains, and these explained 42–52% of the variation in area burned; however, the models changed over time, with winter and spring precipitation being the primary drivers in the first half of the 20th century, but replaced by spring and summer temperatures after 1960.

scholarly journals Socioecological transitions trigger fire regime shifts and modulate fire–climate interactions in the Sierra Nevada, USA, 1600–2015 CE

2016 ◽  
Vol 113 (48) ◽  
pp. 13684-13689 ◽  
Author(s):  
Alan H. Taylor ◽  
Valerie Trouet ◽  
Carl N. Skinner ◽  
Scott Stephens
Keyword(s):  
Climate Change ◽  
Native American ◽  
Sierra Nevada ◽  
Fire History ◽  
Climate Models ◽  
Fire Regime ◽  
Fire Suppression ◽  
Gold Rush ◽  
Climatic Effects ◽  
Fire Activity

Large wildfires in California cause significant socioecological impacts, and half of the federal funds for fire suppression are spent each year in California. Future fire activity is projected to increase with climate change, but predictions are uncertain because humans can modulate or even override climatic effects on fire activity. Here we test the hypothesis that changes in socioecological systems from the Native American to the current period drove shifts in fire activity and modulated fire–climate relationships in the Sierra Nevada. We developed a 415-y record (1600–2015 CE) of fire activity by merging a tree-ring–based record of Sierra Nevada fire history with a 20th-century record based on annual area burned. Large shifts in the fire record corresponded with socioecological change, and not climate change, and socioecological conditions amplified and buffered fire response to climate. Fire activity was highest and fire–climate relationships were strongest after Native American depopulation—following mission establishment (ca. 1775 CE)—reduced the self-limiting effect of Native American burns on fire spread. With the Gold Rush and Euro-American settlement (ca. 1865 CE), fire activity declined, and the strong multidecadal relationship between temperature and fire decayed and then disappeared after implementation of fire suppression (ca. 1904 CE). The amplification and buffering of fire–climate relationships by humans underscores the need for parameterizing thresholds of human- vs. climate-driven fire activity to improve the skill and value of fire–climate models for addressing the increasing fire risk in California.

The sensitivity of fire activity to interannual climate variability in Victoria, Australia

2019 ◽  
Vol 69 (1) ◽  
pp. 146
Author(s):  
Sarah Harris ◽  
Neville Nicholls ◽  
Nigel Tapper ◽  
Graham Mills
Keyword(s):  
Climate Models ◽  
Fire Management ◽  
Fire Regime ◽  
Maximum Temperature ◽  
Area Burned ◽  
Climate Parameters ◽  
Fire Activity ◽  
Maximum Temperatures ◽  
In Fire ◽  
The Relationship

Climate change is expected to have an impact on fire activity in many regions around the globe.The extent of this can only be determined by first establishing the relationship between climate and fire activity. This study relates observed changes in fire activity in Victoria to observed changes in antecedent and concurrent climate parameters – maximum temperature, rainfall and vapour pressure, using data for 1972–2014. A first-difference approach was adopted to estimate the amount by which the observed changes in the climate parameters would have altered the fire activity in the absence of other confounding effects. This study provides a method for examining the sensitivity of fire activity to changes in climate parameters without the need to consider the complex response of fuel dynamics to future climates and changes in fire regime or fire management. We used stepwise multiple-regression to determine the months whose climate parameters explained much of the variance in the total number of fires (TNF) and area burned in a fire season. The best performing fire–climate models explained almost two-thirds of the variation in year-to-year variability of fire activity. The significant explanatory ability of the fire–climate models established in this study reveals the combination of climate parameters that closely relates to the observed year-to-year changes in fire activity, and this may provide an additional valuable resource for fire management planning. Further, we explored the role changes in climate have had on the trend in fire activity. Natural logarithm of area burned and mean fire size have not significantly increased over the study period, but the TNF has significantly increased. We find that the observed increase in maximum temperatures and decrease in rainfall account for 26% of the observed increase in TNF for the 1972–2014 period. Therefore, most of the upward trend found in fire numbers must be due to factors other than climate (i.e. changes in fire occurrence, reporting/recording, land and fire-management changes). Additionally, this study concludes that total area burned should have also increased significantly due to the observed changes in climate and that improved fire-management practicesmay be offsetting this expected increase in the area burned. Finally, using the relationship established in this study between fire numbers and climate parameters, we estimate that a 2°C increase in mean monthly maximum temperatures could be expected to lead to a 38% increase in fire numbers.

Different fire–climate relationships on forested and non-forested landscapes in the Sierra Nevada ecoregion

2015 ◽  
Vol 24 (1) ◽  
pp. 27 ◽  
Author(s):  
Jon E. Keeley ◽  
Alexandra D. Syphard
Keyword(s):  
Sierra Nevada ◽  
Strong Relationship ◽  
Fire Regimes ◽  
Fuel Load ◽  
Fire Season ◽  
Global Changes ◽  
Land Use Patterns ◽  
Climatic Effects ◽  
Lower Elevation ◽  
Fire Activity

In the California Sierra Nevada region, increased fire activity over the last 50 years has only occurred in the higher-elevation forests on US Forest Service (USFS) lands, and is not characteristic of the lower-elevation grasslands, woodlands and shrublands on state responsibility lands (Cal Fire). Increased fire activity on USFS lands was correlated with warmer and drier springs. Although this is consistent with recent global warming, we found an equally strong relationship between fire activity and climate in the first half of the 20th century. At lower elevations, warmer and drier conditions were not strongly tied to fire activity over the last 90 years, although prior-year precipitation was significant. It is hypothesised that the fire–climate relationship in forests is determined by climatic effects on spring and summer fuel moisture, with hotter and drier springs leading to a longer fire season and more extensive burning. In contrast, future fire activity in the foothills may be more dependent on rainfall patterns and their effect on the herbaceous fuel load. We predict spring and summer warming will have a significant impact on future fire regimes, primarily in higher-elevation forests. Lower elevation ecosystems are likely to be affected as much by global changes that directly involve land-use patterns as by climate change.

scholarly journals Assessing the present and future probability of Hurricane Harvey’s rainfall

2017 ◽  
Vol 114 (48) ◽  
pp. 12681-12684 ◽  
Author(s):  
Kerry Emanuel
Keyword(s):  
Climate Change ◽  
Tropical Cyclones ◽  
20Th Century ◽  
Climate Models ◽  
The State ◽  
Representative Concentration Pathway ◽  
Intergovernmental Panel ◽  
Late 20Th Century ◽  
Large Numbers ◽  
Annual Probability

We estimate, for current and future climates, the annual probability of areally averaged hurricane rain of Hurricane Harvey’s magnitude by downscaling large numbers of tropical cyclones from three climate reanalyses and six climate models. For the state of Texas, we estimate that the annual probability of 500 mm of area-integrated rainfall was about 1% in the period 1981–2000 and will increase to 18% over the period 2081–2100 under Intergovernmental Panel on Climate Change (IPCC) AR5 representative concentration pathway 8.5. If the frequency of such event is increasingly linearly between these two periods, then in 2017 the annual probability would be 6%, a sixfold increase since the late 20th century.

Historical reconstructions of California wildfires vary by data source

2016 ◽  
Vol 25 (12) ◽  
pp. 1221 ◽  
Author(s):  
Alexandra D. Syphard ◽  
Jon E. Keeley
Keyword(s):  
United States ◽  
Fire History ◽  
Fire Suppression ◽  
Resource Assessment ◽  
Fire Frequency ◽  
The State ◽  
Annual Reports ◽  
Spatially Explicit ◽  
California Department ◽  
Area Burned

Historical data are essential for understanding how fire activity responds to different drivers. It is important that the source of data is commensurate with the spatial and temporal scale of the question addressed, but fire history databases are derived from different sources with different restrictions. In California, a frequently used fire history dataset is the State of California Fire and Resource Assessment Program (FRAP) fire history database, which circumscribes fire perimeters at a relatively fine scale. It includes large fires on both state and federal lands but only covers fires that were mapped or had other spatially explicit data. A different database is the state and federal governments’ annual reports of all fires. They are more complete than the FRAP database but are only spatially explicit to the level of county (California Department of Forestry and Fire Protection – Cal Fire) or forest (United States Forest Service – USFS). We found substantial differences between the FRAP database and the annual summaries, with the largest and most consistent discrepancy being in fire frequency. The FRAP database missed the majority of fires and is thus a poor indicator of fire frequency or indicators of ignition sources. The FRAP database is also deficient in area burned, especially before 1950. Even in contemporary records, the huge number of smaller fires not included in the FRAP database account for substantial cumulative differences in area burned. Wildfires in California account for nearly half of the western United States fire suppression budget. Therefore, the conclusions about data discrepancies and the implications for fire research are of broad importance.

Documents from the State Archive of the Orel Region as a Source for Studying Peasant Legal Sense in Early 20th Century

2018 ◽  
pp. 98-108
Author(s):  
Vadim V. Kulachkov ◽  
Keyword(s):  
20Th Century ◽  
Comparative Method ◽  
Arable Land ◽  
The State ◽  
Early 20Th Century ◽  
State Archive ◽  
Public Authorities ◽  
Agrarian Question ◽  
Archival Documents ◽  
Legal Sense

The article studies documents from the State Archive of the Orel Region (GAOO) as an important source for studying the sense of justice of the Oryol gubernia peasants in early 20th century. Introduction of new archival materials allows to flesh out our knowledge and to produce a true-to-life picture of the Oryol peasants’ way of life. The peasant origins of the majority of the population necessitate a comprehensive study of peasant legal consciousness. Historical legacy is pertinent to present day, and forgetting its lessons is fraught with consequences. Evolution of modern Russian statehood hedges on its historical and legal traditions. The article studies documents in the fonds of public authorities, police, gendarmerie, courts, and prosecution offices. Introduction of new materials of public authorities, police, gendarmerie, courts, and prosecution offices into the scholarship promotes the analysis of the evolution of peasant legal sense in early 20th century. The chronological framework of the article is limited to the period from 1900 to 1917, its territorial framework is limited to the Oryol gubernia in its pre-revolutionary borders. The article studies reports, dispatches, and circular letters using the comparative method. The intensification of peasant protest was incidental to the first Russian revolution of 1905-1907 – the peasants hoped to force the government to settle the agrarian question, wherein lay the crux of their interests. As peasants of the Oryol gubernia suffered from shortage of arable land, antimonarchical sentiments gained momentum and translated a growing number of trials for contempt of the Emperor. Illegal literature spreading among the peasants, further radicalized them, and the authorities grew more and more hesitant in their assessment of peasant loyalty, which is quite intelligible in the archival documents. Thus, the use of new archival documents in addition to published materials promotes the scholarship on the peasant legal sense.

Outbreak of beriberi in the state of Maranhão, Brazil: revisiting the mycotoxin aetiologic hypothesis

2010 ◽  
Vol 40 (2) ◽  
pp. 95-97 ◽  
Author(s):  
Helena Cristina Alves Vieira Lima ◽  
Eucilene Alves Santana Porto ◽  
José Ricardo Pio Marins ◽  
Rejane Maria Alves ◽  
Rosângela Rosa Machado ◽  
...  
Keyword(s):  
20Th Century ◽  
Thiamine Deficiency ◽  
Poor Quality ◽  
The State ◽  
Early 20Th Century ◽  
Subsistence Farming

Beriberi is caused by thiamine deficiency. Early 20th century epidemics in Japan were attributed to rice contaminated by citreoviridin mycotoxin. Our investigation of an outbreak of beriberi in Brazil showed an association of beriberi with the consumption of poor quality subsistence farming rice, although, unlike other investigators of this outbreak, we did not identify citreoviridin producing fungi in the implicated rice.

Sunflower Diseases Remain Rare in California Seed Production Fields Compared to North Dakota

2012 ◽  
Vol 13 (1) ◽  
pp. 1 ◽  
Author(s):  
Thomas J. Gulya ◽  
Suzanne Rooney-Latham ◽  
Jean S. Miller ◽  
Kathleen Kosta ◽  
Colleen Murphy-Vierra ◽  
...  
Keyword(s):  
North Dakota ◽  
Sclerotinia Sclerotiorum ◽  
The State ◽  
California Department ◽  
Diagnostic Laboratory ◽  
Plasmopara Halstedii ◽  
Puccinia Helianthi ◽  
Food And Agriculture ◽  
Phoma Macdonaldii ◽  
Sunflower Production

The majority of United States sunflower production is in seven Midwestern states, but hybrid planting seed is almost exclusively produced in California. Due to the lack of summer rains and furrow irrigation, California-produced seed is relatively disease free and thus it regularly meets phytosanitary restrictions imposed by many countries. For the 15-year period from 1997 to 2011, 7231 seed fields in northern California were inspected and samples processed at the state diagnostic laboratory (California Department of Food and Agriculture). Rust (Puccinia helianthi) was the most prevalent quarantine disease, found in 4.3% of fields. Stalk rot (Sclerotinia sclerotiorum) and downy mildew (Plasmopara halstedii) were the only other quarantine pathogens observed, found in 2.6% and 0.5% of the 7231 fields, respectively. Many sunflower pathogens have never been recorded in California, including Phoma macdonaldii, Phomopsis helianthi, or any virus. North Dakota, the state with the highest US sunflower production, had quarantine pathogens in 88% of 1263 fields surveyed from 1995 to 2011. Phoma macdonaldii, Sclerotinia sclerotiorum, Puccinia helianthi, Phomopsis helianthi, Plasmopara halstedii, and Verticillium dahliae were recorded in 62, 54, 37, 33, 14, and 12%, respectively, of North Dakota fields. Accepted for publication 5 November 2012. Published 14 December 2012.

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