scholarly journals Widespread fire years in the US–Mexico Sky Islands are contingent on both winter and monsoon precipitation

2020 ◽  
Vol 29 (12) ◽  
pp. 1072
Author(s):  
Alexis H. Arizpe ◽  
Donald A. Falk ◽  
Connie A. Woodhouse ◽  
Thomas W. Swetnam

The climate of the south-western United States and northern Mexico borderlands is marked by a bimodal precipitation regime with the majority of moisture arriving during the cool season via Pacific frontal storm systems, and intense convective storms during the North American Monsoon (NAM). The fire season occurs primarily during the arid foresummer in May and June, before the development of the NAM. Most tree-ring studies of fire climatology in the region have evaluated only the role of winter precipitation. We used tree-ring-width-based reconstructions of both winter and monsoon precipitation, coupled with fire scar reconstructions of fire history from mountain ranges in the US and Mexico, to quantify the historical role and interactions of both seasons of precipitation in modulating widespread fire years. Winter precipitation was the primary driver of widespread fire years in the region, but years with drought in both seasons had the highest fire frequency and most widespread fires. These relationships define a unique monsoon fire regime, in which the timing and amount of monsoon precipitation are important factors in limiting the length of fire season and regulating widespread fire years.

2004 ◽  
Vol 34 (10) ◽  
pp. 2110-2121 ◽  
Author(s):  
Cathy Whitlock ◽  
Carl N Skinner ◽  
Patrick J Bartlein ◽  
Thomas Minckley ◽  
Jerry A Mohr

Fire-history reconstructions are based on tree-ring records that span the last few centuries and charcoal data from lake-sediment cores that extend back several thousand years. The two approaches have unique strengths and weaknesses in their ability to depict past fire events and fire regimes, and most comparisons of these datasets in western conifer forests have focused on sites characterized by high-severity crown fires. Tree-ring and charcoal data spanning the last 300 years in four watersheds in the montane forests of the Klamath Mountains provided an opportunity to compare the records in a fire regime of frequent low- to moderate-severity surface events. The charcoal data were obtained from small lakes, and tree-ring records were derived from fire-scar chronologies at multiple sites within each watershed. The comparison indicates that the tree-ring records detected individual fires not evident in the lake-sediment profiles, whereas the charcoal data disclosed variations in fuel loading and general levels of burning at broader spatial scales. Regional burning in the late 19th and early 20th centuries was evident in the lake-sediment records, and both datasets registered a decline in fire activity in the late 20th century. Thus, the two types of data provide complementary as well as supplementary information on past fire conditions.


2003 ◽  
Vol 12 (4) ◽  
pp. 349 ◽  
Author(s):  
Cameron Yates ◽  
Jeremy Russell-Smith

The fire-prone savannas of northern Australia comprise a matrix of mostly fire-resilient vegetation types, with embedded fire-sensitive species and communities particularly in rugged sandstone habitats. This paper addresses the assessment of fire-sensitivity at the landscape scale, drawing on detailed fire history and vegetation data assembled for one large property of 9100�km2, Bradshaw Station in the Top End of the Northern Territory, Australia. We describe (1) the contemporary fire regime for Bradshaw Station for a 10 year period; (2) the distribution and status of 'fire sensitive' vegetation; and (3) an assessment of fire-sensitivity at the landscape scale. Fire-sensitive species (FSS) were defined as obligate seeder species with minimum maturation periods of at least 3 years. The recent fire history for Bradshaw Station was derived from the interpretation of fine resolution Landsat MSS and Landsat TM imagery, supplemented with mapping from coarse resolution NOAA-AVHRR imagery where cloud had obstructed the use of Landsat images late in the fire season (typically October–November). Validation assessments of fire mapping accuracy were conducted in 1998 and 1999. On average 40% of Bradshaw burnt annually with about half of this, 22%, occurring after August (Late Dry Season LDS), and 65% of the property burnt 4 or more times, over the 10 year period; 89% of Bradshaw Station had a minimum fire return interval of less than 3 years in the study period. The derived fire seasonality, frequency and return interval data were assessed with respect to landscape units (landsystems). The largest landsystem, Pinkerton (51%, mostly sandstone) was burnt 41% on average, with about 70% burnt four times or more, over the 10 year period. Assessment of the fire-sensitivity of individual species was undertaken with reference to data assembled for 345 vegetation plots, herbarium records, and an aerial survey of the distribution of the long-lived obligate-seeder tree species Callitris intratropica. A unique list of 1310 plant species was attributed with regenerative characteristics (i.e. habit, perenniality, resprouting capability, time to seed maturation). The great majority of FSS species were restricted to rugged sandstone landforms. The approach has wider application for assessing landscape fire-sensitivity and associated landscape health in savanna landscapes in northern Australia, and elsewhere.


1990 ◽  
Vol 20 (10) ◽  
pp. 1559-1569 ◽  
Author(s):  
Christopher H. Baisan ◽  
Thomas W. Swetnam

Modern fire records and fire-scarred remnant material collected from logs, snags, and stumps were used to reconstruct and analyze fire history in the mixed-conifer and pine forest above 2300 m within the Rincon Mountain Wilderness of Saguaro National Monument, Arizona, United States. Cross-dating of the remnant material allowed dating of fire events to the calendar year. Estimates of seasonal occurrence were compiled for larger fires. It was determined that the fire regime was dominated by large scale (> 200 ha), early-season (May–July) surface fires. The mean fire interval over the Mica Mountain study area for the period 1657–1893 was 6.1 years with a range of 1–13 years for larger fires. The mean fire interval for the mixed-conifer forest type (1748–1886) was 9.9 years with a range of 3–19 years. Thirty-five major fire years between 1700 and 1900 were compared with a tree-ring reconstruction of the Palmer drought severity index (PDSI). Mean July PDSI for 2 years prior to fires was higher (wetter) than average, while mean fire year PDSI was near average. This 490-year record of fire occurrence demonstrates the value of high-resolution (annual and seasonal) tree-ring analyses for documenting and interpreting temporal and spatial patterns of past fire regimes.


2019 ◽  
Vol 29 (2) ◽  
pp. 3-12
Author(s):  
S. Basnet ◽  
N. P. Gaire ◽  
P. K. Chhetri

This study presents the potential of a conifer species (Abies spectabilis D. Don) to reconstruct fire history by using dendro chronological technique along with thedendroclimatic response in Langtang National Park, Central Himalaya of Nepal. For the fire history reconstruction, altogether eight cross-sections samples from fire affected eight trees and another 20 tree-cores from 10 trees with visible fire scars were taken. In the case of dendroclimatic study, 24 healthy cores of A. spectabilis were selected from the 40 cores extracted from 19 trees. The standard dendro chronological methodology was used for sample preparation and analysis. A 199-year long ring-width chronology of A. spectabilis spanning from 1818 to 2016 AD was developed. In spite of visible fire burn in near bark-surface, no potential fire scars are seen in inner parts in the cross-section samples. However, 12 cores showed that three fire burns occurred simultaneously in the forest area in the years 1917−1918, 1969−1970 and 2009−2010, respectively. Tree-ring-based fire event-record is found to be concurrent to the local people's perceptions/experience about the past fire history in the area. Tree growth climate relationship showed sensitive responses to both growing and non-growing season’s temperature and precipitation variability. Summer temperature had positive influence on growth of the species. Precipitation of monsoon and autumn were found to have negative influence on radial growth whereas pre-monsoon precipitation had positive association with tree radial-growth. This preliminary assessment shows that there is a huge potential of tree-ring research for long-term fire history in the region and helps us to better understand the role of fire in the ecology and management in the Himalayan region. The study can also be replicated in other fire-affected areas of the Himalayan region by using fire sensitive species in the sampling.


2018 ◽  
Vol 48 (1) ◽  
pp. 101-104 ◽  
Author(s):  
Scott L. Stephens ◽  
Liam Maier ◽  
Lilah Gonen ◽  
Jennifer D. York ◽  
Brandon M. Collins ◽  
...  

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.


Author(s):  
Michael Jenkins

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.


2006 ◽  
Vol 36 (4) ◽  
pp. 855-867 ◽  
Author(s):  
Megan L Van Horne ◽  
Peter Z Fulé

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.


2007 ◽  
Vol 37 (11) ◽  
pp. 2227-2241 ◽  
Author(s):  
Ellis Q. Margolis ◽  
Thomas W. Swetnam ◽  
Craig D. Allen

Dendroecological techniques were applied to reconstruct stand-replacing fire history in upper montane forests in northern New Mexico and southern Colorado. Fourteen stand-replacing fires were dated to 8 unique fire years (1842–1901) using four lines of evidence at each of 12 sites within the upper Rio Grande Basin. The four lines of evidence were (i) quaking aspen ( Populus tremuloides Michx.) inner-ring dates, (ii) fire-killed conifer bark-ring dates, (iii) tree-ring width changes or other morphological indicators of injury, and (iv) fire scars. The annual precision of dating allowed the identification of synchronous stand-replacing fire years among the sites, and co-occurrence with regional surface fire events previously reconstructed from a network of fire scar collections in lower elevation pine forests across the southwestern United States. Nearly all of the synchronous stand-replacing and surface fire years coincided with severe droughts, because climate variability created regional conditions where stand-replacing fires and surface fires burned across ecosystems. Reconstructed stand-replacing fires that predate substantial Anglo-American settlement in this region provide direct evidence that stand-replacing fires were a feature of high-elevation forests before extensive and intensive land-use practices (e.g., logging, railroad, and mining) began in the late 19th century.


2019 ◽  
Vol 28 (6) ◽  
pp. 445 ◽  
Author(s):  
Raphaël D. Chavardès ◽  
Lori D. Daniels ◽  
Bianca N. I. Eskelson ◽  
Paul D. Pickell

We compared three monthly adaptations of the daily Drought Code (DC) of Canada’s Fire Weather Index System and applied them to interpret drought conditions associated with historical fires in montane forests of south-eastern British Columbia. The three adaptations were compared with the monthly mean DC calculated from daily values for the Palliser fire-weather station. Two adaptations improved on the existing Monthly DC calculated from monthly climate data by (1) accounting for overwinter drying and an early start to the fire season, and (2) improving estimates of effective precipitation. Using a cross-dated fire-scar record from 20 sites in montane forests surrounding the Palliser station, we found significant fire–drought associations from June to August with all adaptations, and significant associations in April and May with the two new adaptations. Of the 17 fire years from 1901 to 2013, 6years had low initial drought conditions that increased late in the fire season, and 5 years had high drought conditions throughout the fire season. We conclude that variable drought within and among fire seasons influenced fire severity. Our findings provide a connection between modern drought indices used to rank fire danger and drought effects on the historical mixed-severity fire regime in montane forests of south-eastern British Columbia.


2021 ◽  
Author(s):  
Marina Fonti ◽  
Olga Churakova (Sidorova) ◽  
Ivan Tychkov

<p>Air temperature increase and change in precipitation regime have a significant impact on northern forests leading to the ambiguous consequences due to the complex interaction between the ecosystem plant components and permafrost. One of the major interests in such circumstances is to understand how tree growth of the main forest species of the Siberian North will change under altering climatic conditions. In this work, we applied the process-based Vaganov-Shashkin model (VS - model) of tree growth in order to estimate the daily impact of climatic conditions on tree-ring width of larch trees in northeastern Yakutia (Larix cajanderi Mayr.) and eastern Taimyr (Larix gmelinii Rupr. (Rupr.) for the period 1956-2003, and to determine the extent to which the interaction of climatic factors (temperature and precipitation) is reflected in the tree-ring anatomical structure. Despite the location of the study sites in the harsh conditions of the north, and temperature as the main limiting factor, it was possible to identify a period during the growing season when tree growth was limited by lack of soil moisture. The application of the VS-model for the studied regions allowed establishing in which period of the growing season the water stress is most often manifest itself, and how phenological phases (beginning, cessation, and duration of larch growth) vary among the years.</p><p>The research was funded by RFBR, Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science, project number 20-44-240001 and by the Russian Ministry of Science and Higher Education (projects FSRZ-2020-0010).</p>


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