scholarly journals Postglacial fire history and interactions with vegetation and climate in southwestern Yunnan Province of China based on charcoal and pollen records

2016 ◽  
Author(s):  
Xiayun Xiao ◽  
Simon G. Haberle ◽  
Ji Shen ◽  
Bin Xue ◽  
Sumin Wang
Keyword(s):  
Yunnan Province ◽  
Fire History ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Qinghai Lake ◽  
Pollen Record ◽  
Disturbance Factor ◽  
Fire Activity ◽  
Evergreen Oaks

Abstract. A high-resolution, continuous 18.5 ka-long (1 ka=1000 cal yr BP) macroscopic charcoal record from Qinghai Lake in southwestern Yunnan Province, China reveals the postglacial fire frequency and variability history. The results show that three periods with high fire frequency and intensity occurred during the periods 18.5–15.0 ka, 13.0–11.5 ka, and 4.3–~1.0 ka, respectively. This record was compared with the pollen record from the same core, and tentatively correlated with the regional climate proxy records with the aim to separate climate- from human-induced fire activity, and discuss vegetation-fire-climate interactions. The results suggest that fire was mainly controlled by climate before 4.3 ka and by combined action of climate and humans after 4.3 ka. Before 4.3 ka, high fire activity corresponded to cold and dry climatic conditions, while warm and humid climatic conditions brought infrequent and weak fires. Fire was an important disturbance factor and played an important role in forest dynamics around the study area. Vegetation responses to fire before 4.3 ka are not consistent with that after 4.3 ka, suggesting that human influence on vegetation and fire regimes may have become more prevalent after 4.3 ka. The correlations between fire activity and vegetation reveal that evergreen oaks and Alnus are flammable plants. Evergreen oaks are fire-tolerant taxa and Alnus is a fire-adapted taxon. The forests dominated by Lithocarpus/Castanopsis and/or tropical arbors are not easy to ignite, but Lithocarpus/Castanopsis and tropical arbors are fire-sensitive taxa in the study area.

scholarly journals Postglacial fire history and interactions with vegetation and climate in southwestern Yunnan Province of China

2017 ◽  
Vol 13 (6) ◽  
pp. 613-627 ◽  
Author(s):  
Xiayun Xiao ◽  
Simon G. Haberle ◽  
Ji Shen ◽  
Bin Xue ◽  
Mark Burrows ◽  
...  
Keyword(s):  
Yunnan Province ◽  
Fire History ◽  
Regional Climate ◽  
Fire Regimes ◽  
Tropical Trees ◽  
Climatic Conditions ◽  
Qinghai Lake ◽  
Disturbance Factor ◽  
Fire Activity ◽  
Trees And Shrubs

Abstract. A high-resolution, continuous 18.5 kyr (1 kyr  =  1000 cal yr BP) macroscopic charcoal record from Qinghai Lake in southwestern Yunnan Province, China, reveals postglacial fire frequency and variability history. The results show that three periods with high-frequency and high-severity fires occurred during the periods 18.5–15.0, 13.0–11.5, and 4.3–0.8 ka, respectively. This record was compared with major pollen taxa and pollen diversity indices from the same core, and tentatively related to the regional climate proxy records with the aim to separate climate- from human-induced fire activity, and discuss vegetation–fire–climate interactions. The results suggest that fire was mainly controlled by climate before 4.3 ka and by the combined actions of climate and humans after 4.3 ka. Before 4.3 ka, high fire activity corresponded to cold and dry climatic conditions, while warm and humid climatic conditions brought infrequent and weak fires. Fire was an important disturbance factor and played an important role in forest dynamics around the study area. Vegetation responses to fire after 4.3 ka are not consistent with those before 4.3 ka, suggesting that human influence on vegetation and fire regimes may have become more prevalent after 4.3 ka. The comparisons between fire activity and vegetation reveal that evergreen oaks are flammable plants and fire-tolerant taxa. Alnus is a fire-adapted taxon and a nonflammable plant, but density of Alnus forest is a key factor to decide its fire resistance. The forests dominated by Lithocarpus/Castanopsis and/or tropical trees and shrubs are not easy to ignite, but Lithocarpus/Castanopsis and tropical trees and shrubs are fire-sensitive taxa. Fire appears to be unfavourable to plant diversity in the study area.

Fire regime shift linked to increased forest density in a piñon–juniper savanna landscape

2014 ◽  
Vol 23 (2) ◽  
pp. 234 ◽  
Author(s):  
Ellis Q. Margolis
Keyword(s):  
Regime Shift ◽  
Fire History ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Climatic Conditions ◽  
Tree Density ◽  
High Severity ◽  
Wide Range ◽  
In Fire

Piñon–juniper (PJ) fire regimes are generally characterised as infrequent high-severity. However, PJ ecosystems vary across a large geographic and bio-climatic range and little is known about one of the principal PJ functional types, PJ savannas. It is logical that (1) grass in PJ savannas could support frequent, low-severity fire and (2) exclusion of frequent fire could explain increased tree density in PJ savannas. To assess these hypotheses I used dendroecological methods to reconstruct fire history and forest structure in a PJ-dominated savanna. Evidence of high-severity fire was not observed. From 112 fire-scarred trees I reconstructed 87 fire years (1547–1899). Mean fire interval was 7.8 years for fires recorded at ≥2 sites. Tree establishment was negatively correlated with fire frequency (r=–0.74) and peak PJ establishment was synchronous with dry (unfavourable) conditions and a regime shift (decline) in fire frequency in the late 1800s. The collapse of the grass-fuelled, frequent, surface fire regime in this PJ savanna was likely the primary driver of current high tree density (mean=881treesha–1) that is >600% of the historical estimate. Variability in bio-climatic conditions likely drive variability in fire regimes across the wide range of PJ ecosystems.

Using simulation to map fire regimes: an evaluation of approaches, strategies, and limitations

2003 ◽  
Vol 12 (4) ◽  
pp. 309 ◽  
Author(s):  
Robert E. Keane ◽  
Geoffrey J. Cary ◽  
Russell Parsons
Keyword(s):  
Geographical Information Systems ◽  
Fire History ◽  
Fire Regime ◽  
Wildland Fire ◽  
Fire Regimes ◽  
Simulation Modelling ◽  
Fire Frequency ◽  
Geographical Information ◽  
Spatially Explicit ◽  
Eastern Australia

Spatial depictions of fire regimes are indispensable to fire management because they portray important characteristics of wildland fire, such as severity, intensity, and pattern, across a landscape that serves as important reference for future treatment activities. However, spatially explicit fire regime maps are difficult and costly to create requiring extensive expertise in fire history sampling, multivariate statistics, remotely sensed image classification, fire behaviour and effects, fuel dynamics, landscape ecology, simulation modelling, and geographical information systems (GIS). This paper first compares three common strategies for predicting fire regimes (classification, empirical, and simulation) using a 51�000�ha landscape in the Selway-Bitterroot Wilderness Area of Montana, USA. Simulation modelling is identified as the best overall strategy with respect to developing temporally deep spatial fire patterns, but it has limitations. To illustrate these problems, we performed three simulation experiments using the LANDSUM spatial model to determine the relative importance of (1) simulation time span; (2) fire frequency parameters; and (3) fire size parameters on the simulation of landscape fire return interval. The model used to simulate fire regimes is also very important, so we compared two spatially explicit landscape fire succession models (LANDSUM and FIRESCAPE) to demonstrate differences between model predictions and limitations of each on a neutral landscape. FIRESCAPE was developed for simulating fire regimes in eucalypt forests of south-eastern Australia. Finally, challenges for future simulation and fire regime research are presented including field data, scale, fire regime variability, map obsolescence, and classification resolution.

Fire regimes and their correlates in the Darwin region of northern Australia

2007 ◽  
Vol 13 (3) ◽  
pp. 177 ◽  
Author(s):  
Owen Price ◽  
Bryan Baker
Keyword(s):  
Fire History ◽  
Ad Hoc ◽  
Fire Regime ◽  
Negative Impact ◽  
Fire Suppression ◽  
Landsat Imagery ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Dry Season ◽  
Generalized Linear Modelling

A nine year fire history for the Darwin region was created from Landsat imagery, and examined to describe the fire regime across the region. 43% of the region burned each year, and approximately one quarter of the fires occur in the late dry season, which is lower than most other studied areas. Freehold land, which covers 35% of the greater Darwin region, has 20% long-unburnt land. In contrast, most publicly owned and Aboriginal owned land has very high fire frequency (60-70% per year), and only 5% long unburnt. It seems that much of the Freehold land is managed for fire suppression, while the common land is burnt either to protect the Freehold or by pyromaniacs. Generalized Linear Modelling among a random sample of points revealed that fire frequency is higher among large blocks of savannah vegetation, and at greater distances from mangrove vegetation and roads. This suggests that various kinds of fire break can be used to manage fire in the region. The overall fire frequency in the Darwin region is probably too high and is having a negative impact on wildlife. However, the relatively low proportion of late dry season fires means the regime is probably not as bad as in some other regions. The management of fire is ad-hoc and strongly influenced by tenure. There needs to be a clear statement of regional fire targets and a strategy to achieve these. Continuation of the fire mapping is an essential component of achieving the targets.

Riparian and adjacent upland forests burned synchronously during dry years in eastern Oregon (1650–1900 CE), USA

2020 ◽  
Vol 29 (7) ◽  
pp. 602
Author(s):  
Grant L. Harley ◽  
Emily K. Heyerdahl ◽  
James D. Johnston ◽  
Diana L. Olson
Keyword(s):  
Forest Fires ◽  
Fire History ◽  
Riparian Forest ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Riparian Forests ◽  
Landscape Context ◽  
Blue Mountains ◽  
Study Sites

Riparian forests link terrestrial and freshwater communities and therefore understanding the landscape context of fire regimes in these forests is critical to fully understanding the landscape ecology. However, few direct studies of fire regimes exist for riparian forests, especially in the landscape context of adjacent upland forests or studies of long-term climate drivers of riparian forest fires. We reconstructed a low-severity fire history from tree rings in 38 1-ha riparian plots and combined them with existing fire histories from 104 adjacent upland plots to yield 2633 fire scars sampled on 454 trees. Historically (1650–1900), low-severity fires burned more frequently in upland than in riparian plots, but this difference was not significant (P=0.15). During more than half of the fire years at both sites, fires were extensive and burned synchronously in riparian and upland plots, and climate was significantly dry during these years. However, climate was not significantly dry when fires burned in only one plot type. Historically, entire riparian zones likely burned in these two study sites of the Blue Mountains during dry years. This study suggests that riparian and upland forests could be managed similarly, especially given the projected increases to fire frequency and intensity from impending climate change.

Presence of lakes and wetlands decreases resilience of jack pine ecosystems to late-Holocene climatic changes

2014 ◽  
Vol 44 (11) ◽  
pp. 1331-1343 ◽  
Author(s):  
Elizabeth A. Lynch ◽  
Randy Calcote ◽  
Sara C. Hotchkiss ◽  
Michael Tweiten
Keyword(s):  
Pinus Banksiana ◽  
Late Holocene ◽  
Fire History ◽  
Climate Changes ◽  
Sediment Cores ◽  
Fire Regimes ◽  
Jack Pine ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Positive Feedbacks

We reconstructed vegetation and fire histories from four sites located on a sandy outwash plain in northwestern Wisconsin (USA) to test whether lakes and wetlands have influenced how vegetation and fire regimes in pine–oak forests responded to late-Holocene climatic changes. Because of positive feedbacks between jack pine (Pinus banksiana Lamb.) and fire, communities with few fire breaks should be more resilient to changing climatic conditions. Pollen and charcoal from lake-sediment cores were used to reconstruct vegetation changes at 50- to 100-year intervals and forest fire history at decadal time scales for the past 2500 years. The presence of fire breaks affected both fire regimes and the response of vegetation to climatic changes. Areas with more fire breaks had smaller charcoal peaks and the vegetation was more responsive to climate changes. The vegetation in areas with few fire breaks was more resilient, maintaining higher amounts of jack pine and (or) red pine than the more protected sites. We interpret these findings as evidence that positive feedbacks between fire and jack pine forests stabilized vegetation at sites where fire breaks were absent, and that such sites may be relatively resilient to future climate changes, until jack pine is no longer able to regenerate under the regional climatic conditions.

The influence of a variable fire regime on woodland structure and composition

2015 ◽  
Vol 24 (1) ◽  
pp. 59 ◽  
Author(s):  
Emma E. Burgess ◽  
Patrick Moss ◽  
Murray Haseler ◽  
Martine Maron
Keyword(s):  
Fire History ◽  
Stand Structure ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Fire Event ◽  
Time Since Fire ◽  
Eucalypt Woodlands ◽  
Vegetation Structures ◽  
The Relationship

The post-fire response of vegetation reflects not only a single fire event but is the result of cumulative effects of previous fires in the landscape. For effective ecological fire management there is a need to better understand the relationship between different fire regimes and vegetation structure. The study investigated how different fire regimes affect stand structure and composition in subtropical eucalypt woodlands of central Queensland. We found that fire history category (i.e. specific combinations of time since fire, fire frequency and season of last burn) strongly influenced richness and abundance of species categorised as mid-storey trees and those individuals currently in the mid-level strata. Time since fire and fire frequency appeared to have the strongest influence. A longer time since fire (>4 years since last burn), combined with infrequent fires (<2 fires in 12 year period) appeared to promote a dense mid-storey with the opposite conditions (<4 years since last burn; >2 fires in 12 year period) promoting more-open woodlands. Consideration of these combined fire regime attributes will allow fire managers to plan for a particular range of fire-mediated patches to maintain the desired diversity of vegetation structures.

scholarly journals Effect of Fire Frequency on the Flammability of Two Mediterranean Pines: Link with Needle Terpene Content

Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2164
Author(s):  
Bastien Romero ◽  
Anne Ganteaume
Keyword(s):  
Fire History ◽  
Pinus Halepensis ◽  
Adaptive Strategies ◽  
Fire Regimes ◽  
Adaptive Strategy ◽  
Fire Frequency ◽  
Plant Evolution ◽  
Fire Event ◽  
Terpene Content ◽  
Mediterranean Plant

Flammability is a major factor involved in Mediterranean plant evolution that has led to the diversity of fire-related traits according to fire regimes and fire-adaptive strategies. With on-going climate change, new fire regimes are threatening plant species if they do not adapt or acclimate. Studying flammability and terpene content variation according to the different fire frequencies in the recent fire history represents a great challenge to anticipating the flammability of ecosystems in the near future. The flammability of shoots and litter as well as the needle terpene contents of two pine species with different fire adaptive strategies (Pinus halepensis and Pinus sylvestris) were measured according to two fire modalities (0 vs. 1–2 fire events over the last 60 years). Results showed that, regardless of the species and the fuel type, flammability was higher in populations having undergone at least one past fire event even when factors influencing flammability (e.g., structural traits and hydric content) were considered. The terpene content did not vary in P. sylvestris’ needles according to the fire modality, but that of sesqui- and diterpenes was higher in P. halepensis’ needles sampled in the “Fire” modality. In addition, associations made between flammability and terpene content using random forest analyses indicated that the terpene molecules differed between fire modalities for both species and fuel types. The same results were obtained with significant terpenes driving flammability as were highlighted in the PLS analyses, especially for P. halepensis for which enhanced shoot flammability in the “Fire” modality agreed with the adaptive strategy of this species to fire.

Millennial-scale changes in local vegetation and fire regimes on Mount Constitution, Orcas Island, Washington, USA, using small hollow sediments

2008 ◽  
Vol 38 (3) ◽  
pp. 539-552 ◽  
Author(s):  
Wendy Y. Sugimura ◽  
Douglas G. Sprugel ◽  
Linda B. Brubaker ◽  
Philip E. Higuera
Keyword(s):  
Fire History ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Central Plateau ◽  
Northern Site ◽  
Local Site ◽  
Surface Samples ◽  
South Central ◽  
Close Proximity ◽  
In Fire

We used pollen and charcoal records from small hollows plus a network of surface samples to reconstruct stand-level vegetation and fire history at three sites on the Mount Constitution plateau of Orcas Island, Washington, USA. One record (beginning ca. 7100 calibrated years BP) is from a xeric site on the northern plateau, and two (beginning 3800 and 7650 years BP, respectively) are from mesic sites on the central and south-central plateau. Before 5300 years BP, vegetation and fire regimes at both the northern and south-central sites resembled those of current Mount Constitution forests. Around 5300 years BP, Alnus increased and Pinus decreased at the mesic south-central site, suggesting a change to moister and (or) cooler conditions, but Pinus remained dominant at or near the more xeric northern site. At both sites, charcoal deposition decreased, suggesting a decrease in fire frequency and (or) severity consistent with wetter conditions. After 2000 years BP, charcoal deposition increased at all three sites, and Pinus increased in the central and south-central sites, suggesting a return to drier conditions. Thus, stands on different sites in close proximity responded individually to the same climate change, depending on local site conditions and the ecology of the dominant trees.

Influence of short-interval fire occurrence on post-fire recovery of fire-prone shrublands in California, USA

2013 ◽  
Vol 22 (2) ◽  
pp. 184 ◽  
Author(s):  
Caitlin L. Lippitt ◽  
Douglas A. Stow ◽  
John F. O'Leary ◽  
Janet Franklin
Keyword(s):  
Life Histories ◽  
Fire History ◽  
Short Interval ◽  
Fire Regimes ◽  
Fire Frequency ◽  
Natural Occurrence ◽  
Contributing Factors ◽  
Type Conversion ◽  
Short Intervals ◽  
Mean Fire Interval

In recent decades, fire frequency has increased with population growth at the wildland–urban interface in southern California, USA. Short intervals (<5 years) between successive fires can be detrimental to plant species that require longer intervals between fires to reach reproductive maturity. The resilience of vegetation to changes in fire regimes is of particular interest for shrublands in Mediterranean climates, which in general are susceptible to high frequencies of wildfire. Research on how fire has shaped the life histories of shrubs in Mediterranean climates is central to understanding how to protect sensitive habitat while allowing for the natural occurrence of wildfire in these regions. Frequently burned chamise chaparral shrublands in San Diego County, California, were mapped in the field with the aid of satellite imagery and analysed to investigate changes in vegetation condition and composition associated with short intervals between fires. Fire history, terrain and land-cover characteristics of mapped stands were tested to determine the factors associated with disturbed and converted vegetation. Results indicate that number of burns and mean fire interval are contributing factors in post-fire change in chaparral stands. Chamise chaparral is vulnerable to alteration and type conversion when fire return intervals are 4–5 years or less.

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