Relationships among indices of fire severity in riparian zones

2009 ◽  
Vol 18 (5) ◽  
pp. 584 ◽  
Author(s):  
Jessica E. Halofsky ◽  
David E. Hibbs
Keyword(s):  
Fire Severity ◽  
Mineral Soil ◽  
Quantitative Measure ◽  
Basal Area ◽  
Remotely Sensed ◽  
Riparian Zones ◽  
Limited Information ◽  
Riparian Areas ◽  
Related Information ◽  
Crown Scorch

There is no standard quantitative measure of fire severity. Although different measures of fire severity are often assumed to be closely related, information on the relationships between these measures of fire severity is limited. Information on the relationship between various fire severity indices is particularly lacking for riparian zones, critical areas of the landscape for both habitat and water quality. The present study explores relationships among several ground-based and remotely sensed indices of fire severity in riparian areas of recent fires in Oregon, including ground-based indices of overstorey fire severity (crown scorch and basal area mortality) and understorey fire severity (height of bole char and exposed mineral soil). There were relatively strong associations between the two overstorey indices of fire severity and also between the two understorey indices of fire severity. However, there were weaker associations between understorey and overstorey fire severity indices, suggesting they are at least partially independent. Results also suggested weak associations between ground-based fire severity indices and remotely sensed fire severity assessments in riparian areas. Overall, we show there are limitations to the interpretation and use of these commonly used fire severity assessments in riparian areas.

Determinants of riparian fire severity in two Oregon fires, USA

2008 ◽  
Vol 38 (7) ◽  
pp. 1959-1973 ◽  
Author(s):  
Jessica E. Halofsky ◽  
David E. Hibbs
Keyword(s):  
Random Sampling ◽  
Sampling Design ◽  
Fire Severity ◽  
Mineral Soil ◽  
Basal Area ◽  
Fire Effects ◽  
Forest Stand ◽  
Riparian Areas ◽  
Fuel Component ◽  
Crown Scorch

We sought to understand how vegetation indicators and local topographic factors interact to influence riparian fire severity in two recent fires in Oregon, USA. A stratified random sampling design was used to select points in a range of fire severity classes, forest stand ages, and stream sizes in each fire. At each point, plots were sampled in riparian areas and adjacent uplands. Fire severity was assessed in each plot, and measurements were made of factors that have been found to influence riparian fire severity. Understory fire severity (percent exposed mineral soil and bole char height) was significantly lower in riparian areas compared with adjacent uplands in both fires, suggesting a decoupling in understory fire effects in riparian areas versus uplands. However, overstory fire severity (percent crown scorch and percent basal area mortality) was similar in riparian areas and adjacent uplands in both fires. Fire severity in riparian areas was most strongly associated with upland fire severity. In addition, vegetation indicators, particularly those describing riparian fine fuel component and species composition, were strong predictors of riparian fire severity. Consistency in factors controlling fire severity in the two fires suggests that controls on riparian fire severity may be similar in other regions.

Recruitment of Picea mariana, Pinus banksiana, and Populus tremuloides across a burn severity gradient following wildfire in the southern boreal forest of Quebec

2004 ◽  
Vol 34 (9) ◽  
pp. 1845-1857 ◽  
Author(s):  
D F Greene ◽  
J Noël ◽  
Y Bergeron ◽  
M Rousseau ◽  
S Gauthier
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Fire Severity ◽  
Mineral Soil ◽  
Basal Area ◽  
Published Data ◽  
Crown Fire ◽  
Conifer Species ◽  
Seed Supply

Most studies of postfire tree recruitment have occurred in severely burned portions, despite the fact that partial burning is common. In this study we examined regeneration following a 1997 fire in the boreal forest of Quebec. A model of postfire recruitment was elaborated using parameters such as the proportion of trees killed (severity), the proportions of postfire seedbed types and their associated juvenile survivorship, the available seed supply, the available bud supply (for Populus tremuloides Michx.), and the granivory rate. All three species had peak recruitment in the first or second summer, and the recruitment episode was essentially finished after the third year. Mineral soil and surviving Sphagnum were the best seedbeds for both conifer species. Seedbed frequency was essentially independent of crown fire severity except for surviving Sphagnum, which was concentrated primarily where severity was light. Conifer fecundity was much lower in the lightly burned stands, a result we attribute to a higher granivory rate. The fecundity (seedlings/basal area for the conifers or suckers/basal area for Populus) in the severe sites was typical of the few other North American studies of postfire recruitment, where the published data permit us to make the comparison.

Seedbed variation from the interior through the edge of a large wildfire in Alberta

2005 ◽  
Vol 35 (7) ◽  
pp. 1640-1647 ◽  
Author(s):  
David F Greene ◽  
S Ellen Macdonald ◽  
Steve Cumming ◽  
Lynn Swift
Keyword(s):  
Populus Tremuloides ◽  
Life Histories ◽  
Fire Severity ◽  
Mineral Soil ◽  
Basal Area ◽  
White Spruce ◽  
Forest Composition ◽  
Fire Intensity ◽  
Soil Exposure ◽  
In Fire

Despite the importance of seedbeds in the life histories of many plant species, there has been little study of the seedbeds created by wildfire in fire-prone vegetation types such as the boreal forest. Both within the interior and at the edge of a very large (>100 000 ha) 2001 wildfire in the mixedwood boreal region of Alberta, we examined the postfire duff depth and the percent coverage of seedbed types. Minimizing the effect of site and forest composition, we looked only at Picea glauca (Moench) Voss – Populus tremuloides Michx. sites burned during a single day of high fire intensity. Good seedbeds (thin humus and exposed mineral soil, with or without ash) averaged 35% coverage within the interior of the fire but varied enormously among stands. There was a weak but significant positive correlation between prefire percent white spruce basal area and percent mineral soil exposure; that is, there is some tendency for conifer stands to create the seedbeds best suited for their own germinants. Fire severity played a clear role in mineral soil exposure, which was greatest in areas with 100% canopy mortality. Mineral soil exposure was far less at the edges of the fire, averaging only 5% even in areas where all trees had been killed; the burn edge was characterized by superficial flaming combustion with no evidence of substantial duff removal via smoldering combustion. In short, the areas where white spruce seed will be most common after the fire, the edges, are where the worst seedbeds in the burn will be found. Regeneration microsites at fire edges appear to be better suited to regeneration of broadleaf species, via suckering; the persistence of white spruce in fire-prone landscapes continues to be difficult to explain.

scholarly journals Urban Fire Severity and Vegetation Dynamics in Southern California

2020 ◽  
Vol 13 (1) ◽  
pp. 19
Author(s):  
Lauren E. H. Mathews ◽  
Alicia M. Kinoshita
Keyword(s):  
Vegetation Cover ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Current Knowledge ◽  
Fire Severity ◽  
Satellite Image ◽  
Burn Severity ◽  
Native Vegetation ◽  
Riparian Areas ◽  
The Impact

A combination of satellite image indices and in-field observations was used to investigate the impact of fuel conditions, fire behavior, and vegetation regrowth patterns, altered by invasive riparian vegetation. Satellite image metrics, differenced normalized burn severity (dNBR) and differenced normalized difference vegetation index (dNDVI), were approximated for non-native, riparian, or upland vegetation for traditional timeframes (0-, 1-, and 3-years) after eleven urban fires across a spectrum of invasive vegetation cover. Larger burn severity and loss of green canopy (NDVI) was detected for riparian areas compared to the uplands. The presence of invasive vegetation affected the distribution of burn severity and canopy loss detected within each fire. Fires with native vegetation cover had a higher severity and resulted in larger immediate loss of canopy than fires with substantial amounts of non-native vegetation. The lower burn severity observed 1–3 years after the fires with non-native vegetation suggests a rapid regrowth of non-native grasses, resulting in a smaller measured canopy loss relative to native vegetation immediately after fire. This observed fire pattern favors the life cycle and perpetuation of many opportunistic grasses within urban riparian areas. This research builds upon our current knowledge of wildfire recovery processes and highlights the unique challenges of remotely assessing vegetation biophysical status within urban Mediterranean riverine systems.

Post-fire survival and flushing in three Sierra Nevada conifers with high initial crown scorch

2009 ◽  
Vol 18 (7) ◽  
pp. 857 ◽  
Author(s):  
Chad T. Hanson ◽  
Malcolm P. North
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Fire Severity ◽  
Conifer Species ◽  
Mature Trees ◽  
Salvage Logging ◽  
Abies Magnifica ◽  
Crown Scorch ◽  
Tree Survival ◽  
Large Trees

With growing debate over the impacts of post-fire salvage logging in conifer forests of the western USA, managers need accurate assessments of tree survival when significant proportions of the crown have been scorched. The accuracy of fire severity measurements will be affected if trees that initially appear to be fire-killed prove to be viable after longer observation. Our goal was to quantify the extent to which three common Sierra Nevada conifer species may ‘flush’ (produce new foliage in the year following a fire from scorched portions of the crown) and survive after fire, and to identify tree or burn characteristics associated with survival. We found that, among ponderosa pines (Pinus ponderosa Dougl. ex. Laws) and Jeffrey pines (Pinus jeffreyi Grev. & Balf) with 100% initial crown scorch (no green foliage following the fire), the majority of mature trees flushed, and survived. Red fir (Abies magnifica A. Murr.) with high crown scorch (mean = 90%) also flushed, and most large trees survived. Our results indicate that, if flushing is not taken into account, fire severity assessments will tend to overestimate mortality and post-fire salvage could remove many large trees that appear dead but are not.

scholarly journals Diversity of Angiospermic Plants in estuarine and Adjoining Riparian Areas of Sabarmati and Mahi Rivers, Gujarat, India

2020 ◽  
pp. 116-124
Author(s):  
Raj B. Patel ◽  
Ketan Tatu ◽  
R. D. Kamboj
Keyword(s):  
Tree Species ◽  
Flowering Plants ◽  
Grass Species ◽  
Riparian Zones ◽  
Ecological Groups ◽  
View Point ◽  
Riparian Areas ◽  
Shrub Species ◽  
Religious Importance ◽  
Herb Species

The present study was conducted with an aim of documenting the diversity of flowering plants in selected localities in the estuarine and adjoining riparian zones of Sabarmati and Mahi rivers of Gujarat, India. The Sabarmati and Mahi rivers are west-flowing perennial rivers having considerable ecological and religious importance. A total of 40 species of flowering plants belonging to 26 different families were recorded in the study area which were dominated by herbaceous plants. Among the 40 species recorded 2 species were trees, 8 species were shrubs, 28 species were herbs and 2 species were grasses. Moreover, as far as ecological groups are concerned, 6 species were halophytes, 13 species were hydrophytes, 17 species were mesophytes and 4 species were xerophytes. In the study area of Sabarmati river, 28 species were recorded that included 2 tree species, 6 shrub species, 18 herb species and 2 grass species. From the view point of ecological groups 5 species were halophytes, 3 species were hydrophytes, 16 species were mesophytes and 4 species were xerophytes. In the study area of Mahi river, 24 species were recorded that included 2 tree species, 6 shrub species, 14 herb species and 2 grass species. From the view point of ecological groups 5 species were halophytes, 12 species were hydrophytes, 5 species were mesophytes and 2 species were xerophytes.

scholarly journals Relating Fire-Caused Change in Forest Structure to Remotely Sensed Estimates of Fire Severity

Fire Ecology ◽  
2016 ◽  
Vol 12 (3) ◽  
pp. 99-116 ◽  
Author(s):  
Jamie M. Lydersen ◽  
Brandon M. Collins ◽  
Jay D. Miller ◽  
Danny L. Fry ◽  
Scott L. Stephens
Keyword(s):  
Forest Structure ◽  
Fire Severity ◽  
Remotely Sensed

Heterogeneity in fire severity within early season and late season prescribed burns in a mixed-conifer forest

2006 ◽  
Vol 15 (1) ◽  
pp. 37 ◽  
Author(s):  
Eric E. Knapp ◽  
Jon E. Keeley
Keyword(s):  
Sierra Nevada ◽  
Prescribed Burning ◽  
Fire Severity ◽  
Basal Area ◽  
Conifer Forest ◽  
Fuel Loading ◽  
Early Season ◽  
Late Season ◽  
Fuel Loads ◽  
In Fire

Structural heterogeneity in forests of the Sierra Nevada was historically produced through variation in fire regimes and local environmental factors. The amount of heterogeneity that prescription burning can achieve might now be more limited owing to high fuel loads and increased fuel continuity. Topography, woody fuel loading, and vegetative composition were quantified in plots within replicated early and late season burn units. Two indices of fire severity were evaluated in the same plots after the burns. Scorch height ranged from 2.8 to 25.4 m in early season plots and 3.1 to 38.5 m in late season plots, whereas percentage of ground surface burned ranged from 24 to 96% in early season plots and from 47 to 100% in late season plots. Scorch height was greatest in areas with steeper slopes, higher basal area of live trees, high percentage of basal area composed of pine, and more small woody fuel. Percentage of area burned was greatest in areas with less bare ground and rock cover (more fuel continuity), steeper slopes, and units burned in the fall (lower fuel moisture). Thus topographic and biotic factors still contribute to the abundant heterogeneity in fire severity with prescribed burning, even under the current high fuel loading conditions. Burning areas with high fuel loads in early season when fuels are moister may lead to patterns of heterogeneity in fire effects that more closely approximate the expected patchiness of historical fires.

scholarly journals Conventional and Mechanized Logging Compared for Ozark Hardwood Forest Thinning: Productivity, Economics, and Environmental Impact

2006 ◽  
Vol 23 (4) ◽  
pp. 264-272 ◽  
Author(s):  
Peter Becker ◽  
Jason Jensen ◽  
Dennis Meinert
Keyword(s):  
Soil Compaction ◽  
Production Cost ◽  
Mineral Soil ◽  
Basal Area ◽  
Production Costs ◽  
Management Approach ◽  
Oak Forest ◽  
Limited Time ◽  
Tree Management ◽  
Revenue Production

Abstract Replicate 4-ac plots in a 70-year-old upland oak forest on slopes averaging 30 percent in southeastern Missouri were harvested by conventional (chainsaw + skidder) and mechanized (small tracked skid steer + feller-buncher and harvester + forwarder) logging equipment.The heavy thinning prescribed by a crop tree management approach removed an average of 1,300 ft3 or 40 tons per acre of pole wood and sawlogs, leaving an average basal area of 36 ft2/ac. The harvester/forwarder was the most productive (ft3/production hour),and the small feller-buncher the least, being the only system whose (unreplicated) production cost exceeded revenue. Production costs (excluding mobilization, overhead, and profit) of the conventional and harvester/forwarder systems were not statistically different on average, but the lowestcost of the latter was 14% less than that of the conventional system. The frequency of residual trees experiencing substantial bole damage was not significantly different among logging technologies, but the harvester/forwarder did have a higher incidence of substantial crown damage.The area of exposed mineral soil did not differ significantly among technologies, and soil compaction sufficient to impede rooting was rare. Lack of site and operator replication and incomplete cost analyses over a limited time prohibit generalization of these conclusions. North. J. Appl. For. 23(4):264 –272.

scholarly journals A meta-analysis on the impacts of partial cutting on forest structure and carbon storage

2013 ◽  
Vol 10 (6) ◽  
pp. 3691-3703 ◽  
Author(s):  
D. Zhou ◽  
S. Q. Zhao ◽  
S. Liu ◽  
J. Oeding
Keyword(s):  
Forest Structure ◽  
Forest Floor ◽  
Recovery Time ◽  
Mineral Soil ◽  
Basal Area ◽  
Partial Cutting ◽  
C Storage ◽  
Cutting Intensity ◽  
Stand Basal Area ◽  
Area And Volume

Abstract. Partial cutting, which removes some individual trees from a forest, is one of the major and widespread forest management practices that can significantly alter both forest structure and carbon (C) storage. Using 748 observations from 81 studies published between 1973 and 2011, we synthesized the impacts of partial cutting on three variables associated with forest structure (mean annual growth of diameter at breast height (DBH), stand basal area, and volume) and four variables related to various C stock components (aboveground biomass C (AGBC), understory C, forest floor C, and mineral soil C). Results show that the growth of DBH increased by 111.9% after partial cutting, compared to the uncut control, with a 95% bootstrapped confidence interval ranging from 92.2 to 135.9%, while stand basal area and volume decreased immediately by 34.2% ([−37.4%, −31.2%]) and 28.4% ([−32.0%, −25.1%]), respectively. On average, partial cutting reduced AGBC by 43.4% ([−47.7%, −39.3%]), increased understory C storage by 391.5% ([220.0%, 603.8%]), but did not show significant effects on C stocks on forest floor and in mineral soil. All the effects, if significant (i.e., on DBH growth, stand basal area, volume, and AGBC), intensified linearly with cutting intensity and decreased linearly over time. Overall, cutting intensity had more strong impacts than the length of recovery time on the responses of those variables to partial cutting. Besides the significant influence of cutting intensity and recovery time, other factors such as climate zone and forest type also affected forest responses to partial cutting. For example, a large fraction of the changes in DBH growth remains unexplained, suggesting the factors not included in the analysis may play a major role. The data assembled in this synthesis were not sufficient to determine how long it would take for a complete recovery after cutting because long-term experiments were scarce. Future efforts should be tailored to increase the duration of the experiments and balance geographic locations of field studies.

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