Short-term stem mortality of 10 deciduous broadleaved species following prescribed burning in upland forests of the Southern US

2018 ◽  
Vol 27 (1) ◽  
pp. 42 ◽  
Author(s):  
Tara L. Keyser ◽  
Virginia L. McDaniel ◽  
Robert N. Klein ◽  
Dan G. Drees ◽  
Jesse A. Burton ◽  
...  
Keyword(s):  
Goodness Of Fit ◽  
Prescribed Burning ◽  
Fire Effects ◽  
Quercus Alba ◽  
Widespread Application ◽  
Stem Size ◽  
Southern Us ◽  
Park Service ◽  
Stem Mortality ◽  
Deciduous Broadleaved Species

In upland forests of the Southern US, management is increasingly focussed on the restoration and maintenance of resilient structures and species compositions, with prescribed burning being the primary tool used to achieve these goals and objectives. In this study, we utilised an extensive dataset comprising 91 burn units and 210 plots across 13 National Park Service lands to examine the relationships between the probability of stem mortality (P(m)) 2 years after prescribed fire and stem size and direct fire effects for 10 common deciduous broadleaved species. Post-fire stem mortality ranged from 6.9% for Quercus alba to 58.9% for Sassafras albidum. The probability of stem mortality was positively associated with maximum bole char height (CHAR) and inversely related to diameter at breast height (DBH) for all 10 deciduous broadleaved species. Model goodness-of-fit varied, with the poorest fit generally associated with fire-tolerant species and best fit generally associated with fire sensitive species. The information presented contributes to our understanding of post-fire stem mortality and may contribute to the development of fire-related stem mortality models following prescribed burning for eastern tree species. Models should be validated with independent datasets across upland forests types to test for spatial relationships before widespread application.

The effect of mastication on surface fire behaviour, fuels consumption and tree mortality in pine flatwoods of Florida, USA

2015 ◽  
Vol 24 (4) ◽  
pp. 573 ◽  
Author(s):  
Jesse K. Kreye ◽  
Leda N. Kobziar
Keyword(s):  
Tree Mortality ◽  
Prescribed Burning ◽  
Fire Hazard ◽  
Fire Effects ◽  
Flame Height ◽  
Soil Conditions ◽  
Fire Behaviour ◽  
Pine Flatwoods ◽  
Southern Us ◽  
Limited Effectiveness

Mastication of understorey shrubs and small trees to reduce fire hazard has become a widespread forest management practice, but few empirical studies have quantified the effects of this mechanical treatment on actual fire behaviour and fire effects at the stand scale. We conducted experimental burns in masticated pine flatwoods with palmetto/gallberry understories, a common ecosystem of the Southern US Coastal Plain. Fire behaviour (flame height, rate of spread) and fire effects were compared between treated and untreated sites burned in the typical winter prescribed burning season. Mastication effectively reduced flame heights by 66%, but recovering shrubs (cover, height) influenced fire behaviour within six months following treatment, suggesting time-limited effectiveness. Trees had less crown scorch and bole char in masticated sites, but tree mortality was minimal on both treated and untreated sites. Consumption of masticated fuel was substantial across both treatments, but little duff was consumed under the moist soil conditions. When burning is conducted soon after treatment, mastication may effectively reduce fire behaviour in pine flatwoods sites, but the duration of treatment efficacy remains unclear.

scholarly journals A large database supports the use of simple models of post-fire tree mortality for thick-barked conifers, with less support for other species

Fire Ecology ◽  
2020 ◽  
Vol 16 (1) ◽  
Author(s):  
C. Alina Cansler ◽  
Sharon M. Hood ◽  
Phillip J. van Mantgem ◽  
J. Morgan Varner
Keyword(s):  
Tree Mortality ◽  
Characteristic Curve ◽  
Small Diameter ◽  
Fire Effects ◽  
Tree Level ◽  
Clear Understanding ◽  
Bark Thickness ◽  
Mortality Models ◽  
Species Specific ◽  
Stem Mortality

Abstract Background Predictive models of post-fire tree and stem mortality are vital for management planning and understanding fire effects. Post-fire tree and stem mortality have been traditionally modeled as a simple empirical function of tree defenses (e.g., bark thickness) and fire injury (e.g., crown scorch). We used the Fire and Tree Mortality database (FTM)—which includes observations of tree mortality in obligate seeders and stem mortality in basal resprouting species from across the USA—to evaluate the accuracy of post-fire mortality models used in the First Order Fire Effects Model (FOFEM) software system. The basic model in FOFEM, the Ryan and Amman (R-A) model, uses bark thickness and percentage of crown volume scorched to predict post-fire mortality and can be applied to any species for which bark thickness can be calculated (184 species-level coefficients are included in the program). FOFEM (v6.7) also includes 38 species-specific tree mortality models (26 for gymnosperms, 12 for angiosperms), with unique predictors and coefficients. We assessed accuracy of the R-A model for 44 tree species and accuracy of 24 species-specific models for 13 species, using data from 93 438 tree-level observations and 351 fires that occurred from 1981 to 2016. Results For each model, we calculated performance statistics and provided an assessment of the representativeness of the evaluation data. We identified probability thresholds for which the model performed best, and the best thresholds with either ≥80% sensitivity or specificity. Of the 68 models evaluated, 43 had Area Under the Receiver Operating Characteristic Curve (AUC) values ≥0.80, indicating excellent performance, and 14 had AUCs <0.7, indicating poor performance. The R-A model often over-predicted mortality for angiosperms; 5 of 11 angiosperms had AUCs <0.7. For conifers, R-A over-predicted mortality for thin-barked species and for small diameter trees. The species-specific models had significantly higher AUCs than the R-A models for 10 of the 22 models, and five additional species-specific models had more balanced errors than R-A models, even though their AUCs were not significantly different or were significantly lower. Conclusions Approximately 75% of models tested had acceptable, excellent, or outstanding predictive ability. The models that performed poorly were primarily models predicting stem mortality of angiosperms or tree mortality of thin-barked conifers. This suggests that different approaches—such as different model forms, better estimates of bark thickness, and additional predictors—may be warranted for these taxa. Future data collection and research should target the geographical and taxonomic data gaps and poorly performing models identified in this study. Our evaluation of post-fire tree mortality models is the most comprehensive effort to date and allows users to have a clear understanding of the expected accuracy in predicting tree death from fire for 44 species.

Evaluation of the CONSUME and FOFEM fuel consumption models in pine and mixed hardwood forests of the eastern United States

2014 ◽  
Vol 44 (7) ◽  
pp. 784-795 ◽  
Author(s):  
Susan J. Prichard ◽  
Eva C. Karau ◽  
Roger D. Ottmar ◽  
Maureen C. Kennedy ◽  
James B. Cronan ◽  
...  
Keyword(s):  
United States ◽  
Fuel Consumption ◽  
Prescribed Burning ◽  
Forest Type ◽  
Fire Effects ◽  
Eastern United States ◽  
Validation Data ◽  
Data Set ◽  
Predicted Values ◽  
Fine Fuels

Reliable predictions of fuel consumption are critical in the eastern United States (US), where prescribed burning is frequently applied to forests and air quality is of increasing concern. CONSUME and the First Order Fire Effects Model (FOFEM), predictive models developed to estimate fuel consumption and emissions from wildland fires, have not been systematically evaluated for application in the eastern US using the same validation data set. In this study, we compiled a fuel consumption data set from 54 operational prescribed fires (43 pine and 11 mixed hardwood sites) to assess each model’s uncertainties and application limits. Regions of indifference between measured and predicted values by fuel category and forest type represent the potential error that modelers could incur in estimating fuel consumption by category. Overall, FOFEM predictions have narrower regions of indifference than CONSUME and suggest better correspondence between measured and predicted consumption. However, both models offer reliable predictions of live fuel (shrubs and herbaceous vegetation) and 1 h fine fuels. Results suggest that CONSUME and FOFEM can be improved in their predictive capability for woody fuel, litter, and duff consumption for eastern US forests. Because of their high biomass and potential smoke management problems, refining estimates of litter and duff consumption is of particular importance.

Prescribed Burning for Stand Conversion in Budworm-killed Balsam Fir: An Ontario Case History

1986 ◽  
Vol 62 (2) ◽  
pp. 96-100 ◽  
Author(s):  
D. J. McRae
Keyword(s):  
Fuel Consumption ◽  
Prescribed Burning ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Fire Spread ◽  
Fire Effects ◽  
Balsam Fir ◽  
Prescribed Burn ◽  
Stand Conversion

Recent spruce budworm (Choristoneura fumiferana [Clem.]) infestations have resulted in widespread areas of balsam fir (Abies balsamea [L.] Mill.) mortality in Ontario, and there is growing interest in reestablishing these areas quickly as productive forests. One technique being used is prescribed fire after a salvage and bulldozer tramping operation. A 445-ha prescribed burn was carried out under moderate fire danger conditions in northern Ontario. The site, which was covered by balsam fir fuel that had been killed by spruce budworm, was tramped to improve fire spread. Weather, fuel consumption, and fire effects are reported. The burn effectively reduced heavy surface fuel loadings and consequently planting on the site was easier. Key words: Prescribed burning, fire, spruce budworm. Choristoneura fumiferana, balsam fir, Abies balsamea, fuel consumption, site preparation, tramping, stand conversion.

scholarly journals Prescribed Fire Effects on Advanced Regeneration in Mixed Hardwood Stands

1998 ◽  
Vol 22 (3) ◽  
pp. 138-142 ◽  
Author(s):  
T.A. Barnes ◽  
D.H. Van Lear
Keyword(s):  
South Carolina ◽  
Prescribed Fire ◽  
Prescribed Burning ◽  
Subsequent Development ◽  
Fire Effects ◽  
Hardwood Forests ◽  
Prescribed Fires ◽  
Oak Regeneration ◽  
Advanced Regeneration ◽  
Composition And Structure

Abstract Fire treatments were initiated in 1990 to evaluate effects of low-intensity prescribed fires on composition and structure of the advanced regeneration pool under mature mixed-hardwood stands on upland sites in the Piedmont of South Carolina. One spring burn was as effective as three winter burns in reducing midstory density, considered a prerequisite for subsequent development of oak (Quercus spp.) advanced regeneration. Burning increased the number of oak rootstocks, reduced the relative position of competing species, and increased root-to-shoot ratios of oak stems in the regeneration layer. These favorable effects of fire on oak regeneration outweigh the removal of small, poorly formed oak stems from the midstory/understory strata during burning. Prescribed burning in hardwood forests may solve some of the current oak regeneration problems, especially on better upland sites in the South. South. J. Appl. For. 22(3):138-142.

Spring fire effects on two Aristida/Bothriochloa native pastures in central Queensland, Australia

2018 ◽  
Vol 40 (5) ◽  
pp. 485
Author(s):  
R. G. Silcock ◽  
T. J. Hall ◽  
P. Jones ◽  
P. G. Filet ◽  
J. Douglas
Keyword(s):  
Prescribed Burning ◽  
Woody Plant ◽  
Marked Change ◽  
Ground Cover ◽  
Weather Conditions ◽  
Fire Effects ◽  
Heteropogon Contortus ◽  
Eucalypt Woodlands ◽  
Native Pastures ◽  
The Many

Controlled burns are commonly used to suppress woody plant regrowth and to remove accumulated unpalatable pasture from rangelands and occasionally to alter pasture composition in native pastures in central Queensland, Australia. Outcomes can be somewhat unpredictable and short-term, and reliable evidence is needed to confirm the likely long-term efficacy of such fires. We imposed a regime of repeated spring burns on native Aristida/Bothriochloa pastures growing in two contrasting eucalypt woodlands of central Queensland to determine the effects on pasture composition, ground cover, landscape stability and woody plant recruitment, all in the absence of grazing. The sites selected were a silver-leaved ironbark (Eucalyptus melanophloia F.Muell.) woodland and a poplar box (E. populnea F.Muell.) woodland. Weather conditions precluded spring burns in 3 years out of 7 at the silver-leaved ironbark site and in 2 years out of 8 at the poplar box site. The burn intensity was variable, and frequent fires produced a marked change in abundance of only a few pasture species. Depending on the site, fires significantly increased the frequency of Enneapogon spp., Bothriochloa bladhii (Retz.) S.T.Blake and Dichanthium sericeum (R.Br.) A.Camus and reduced the frequency of some minor components such as Cymbopogon spp., Panicum effusum R.Br., Cenchrus ciliaris L. and, ephemerally, that of some forbs. Contrary to expectation, only Aristida calycina R.Br. declined in abundance among the many Aristida species present, and the abundance of Heteropogon contortus (L.) P.Beauv. ex Roem. & Schult. barely increased under regular spring fires. The total germinable seeds of herbaceous species in the soil each spring was significantly reduced by burning in the previous spring. Repeated spring fires rarely reinforced any initial change induced by burning, and slightly lowered average ground cover as well as various indices of landscape stability and ecosystem functionality. Changes produced were not always consistent across the two communities. Though prescribed burning is often important for maintaining grazing productivity and landscape values, very regular use is not recommended.

The contradictory role of fire from the nature conservation perspective

2020 ◽  
Author(s):  
Orsolya Valkó
Keyword(s):  
Nature Conservation ◽  
Land Surface ◽  
Fire History ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Fire Regimes ◽  
Fire Effects ◽  
Negative Effects ◽  
Fire Policy

&lt;p&gt;Fire is a globally relevant natural or anthropogenic phenomenon with a rapidly increasing importance in the era of the climate change. In each year, approximately 4% of the global land surface burns. For effective ecosystem conservation, we need to understand fire regimes, identify potential threats, and also the possibilities in the application of prescribed burning for maintaining ecosystems.&lt;/p&gt;&lt;p&gt;Here I provide an overview on the contradictory role of fire in nature conservation from two continents with contrasting fire histories, focusing on European and North-American grasslands. I show that the ecological effects of fire depend on the fire regime, fire history, ecosystem properties and the socio-economic environment. Catastrophic wildfires, arson, too frequent or improperly planned human-induced fire often lead to the degradation of the ecosystems, the disappearance of rare plant and animal species, and to the encroachment of weed and invasive species. I illustrate with examples that these negative fire effects act synergistically with the human-induced changes in land use systems.&lt;/p&gt;&lt;p&gt;I also underline with case studies that in both regions, properly designed and controlled prescribed burning regimes can aid the understanding and managing disturbance-dependent ecosystems. Conservation in these dynamic and complex ecosystems is far more than fencing and hoping to exclude disturbance; but the contrary: disturbance is needed for ecosystem functioning. Therefore, the conservation of dynamic, diverse and functioning ecosystems often require drastic interventions and an unconventional conservation attitude. However, the expanding urban-wildlife interface makes the application of prescribed burning challenging worldwide. A major message for the future is about fire policy: it is crucial to moderate the negative effects of fire, however, properly designed prescribed burning should be used as a tool for managing and conserving disturbance-dependent ecosystems.&lt;/p&gt;

scholarly journals Model for diameter distribution from assortments volumes: theoretical formulation and a case application with a sample of timber trade data for clear-cut sections

Silva Fennica ◽  
2019 ◽  
Vol 53 (1) ◽  
Author(s):  
Jouni Siipilehto ◽  
Miika Rajala
Keyword(s):  
Theoretical Model ◽  
Goodness Of Fit ◽  
Stand Structure ◽  
Data Set ◽  
Trade Data ◽  
Stem Size ◽  
Clear Cut ◽  
Timber Trade ◽  
Ks Test ◽  
Stand Characteristics

This study examined a theoretical model for stand structures from the volumes of pulpwood and saw logs of clear-cut stands. The average stem size was used to estimate the number of cut trees. The distribution was solved using nonlinear derivative-free optimization. The truncated 2-parameter Weibull distribution was used to describe the stand structure of the commercial stems. This method was first tested with harvester data collected from seven clear-cut stands in southern Finland. Validation included reliability in the stand characteristics and goodness-of-fit of the species-specific distributions. The distributions provided unbiased estimates for the saw log volume, while the bias in the estimated pulpwood volume was 2%. The standard stand characteristics from the Weibull distributions corresponded notably well with the harvester data. A Kolmogorov-Smirnov (KS) test rejected two distributions out of 21 cases, when the accurate input variables were available for the theoretical model. The results of the study suggest that the presented method is a relevant option for predicting the stand structure. In practice, the reliability of the presented method was dependent on the quality of the information available from the stand prior to cutting. With a timber trade data set, the solution for the distribution for a clear-cut section was found. The goodness-of-fit was dependent on the accuracy of the visually assessed timber trade variables. Especially the average stem size proved difficult to assess due to high number of understorey pulpwood stems. Due to overestimated average stem sizes, the solved number of harvested trees was underestimated. Less than 50% of the distributions predicted for clear-cut sections passed the KS test.

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