Using the photoload technique with double sampling to improve surface fuel loading estimates

2016 ◽  
Vol 25 (2) ◽  
pp. 224 ◽  
Author(s):  
Wade T. Tinkham ◽  
Chad M. Hoffman ◽  
Jesse M. Canfield ◽  
Emma Vakili ◽  
Robin M. Reich
Keyword(s):  
Sampling Rate ◽  
Simple Random Sampling ◽  
Fuel Load ◽  
Double Sampling ◽  
Fuel Loading ◽  
Fuel Loads ◽  
Simulated Fuel ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Loading Estimates

Accurate surface fuel load estimates based on the planar intercept method require a considerable amount of time and cost. Recently the photoload method has been proposed as an alternative for sampling of fine woody surface fuels. To evaluate the use of photoload fuel sampling, six simulated fuel beds of 100 photoload visual estimates and destructively sampled fuel loads were generated at three levels of fuel loading (0.016, 0.060, and 0.120  kg  m–2) and two levels of variability (coefficients of variation of ~42 and 85%). We assessed the accuracy and precision of simple random sampling with and without double sampling on surface fuel load estimation. Direct visual estimates often overestimated fuel loads where actual fuel loading was low and underestimated fuel loads where fuel loads were large. We found that double sampling with a classical regression estimation approach provided the most accurate and precise fuel load estimates, substantially improving the accuracy and precision achieved over standard photoload estimation when ń ≥ 20 and double sampling rate ≥20%. These results indicate that fine woody fuel loading estimation with the photoload technique can be improved by incorporating a double sampling approach.

scholarly journals Impacts of increasing fine fuel loads on acorn germination and early growth of oak seedlings

Fire Ecology ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Rachel E. Nation ◽  
Heather D. Alexander ◽  
Geoff Denny ◽  
Jennifer K. McDaniel ◽  
Alison K. Paulson
Keyword(s):  
Prescribed Fire ◽  
Germination Rate ◽  
Growth Patterns ◽  
Leaf Number ◽  
Fuel Load ◽  
Quercus Alba ◽  
White Oak ◽  
Fuel Treatment ◽  
Basal Diameter ◽  
Fuel Loads

Abstract Background Prescribed fire is increasingly used to restore and maintain upland oak (Quercus L. spp.) ecosystems in the central and eastern US. However, little is known about how prescribed fire affects recently fallen acorns under different fine fuel loads, which can vary with stand composition and basal area, burn season, and fire frequency. We conducted plot-level (1 m2) burns in an upland oak stand in northern Mississippi, USA, during December 2018, using single (i.e., ambient), double, and triple fine fuel loads, representative of those in nearby unburned and recently fire-treated, closed-canopy stands. Pre burn, we placed 30 acorns each of white oak (Quercus alba L.) and Shumard oak (Quercus shumardii Buckley) ~1 cm below the litter surface in five plots of each fuel treatment. Immediately post burn, we planted unburned and burned acorns in a greenhouse. After ~50% of each species’ unburned acorns germinated, we measured percent germination and height, basal diameter, and leaf number of germinating seedlings weekly for 11 weeks. Then, we harvested seedlings to determine above- and belowground biomass. Results The single fuel treatment reduced acorn germination rates of both species to ~40% compared to ~88% in unburned acorns. When burned in double and triple fuel loads, acorns of both species had a <5% germination rate. There was no difference in basal diameter, leaf number, or biomass of seedlings from burned versus unburned acorns for either species. However, seedlings originating from burned acorns of both species were ~11% shorter than those from unburned acorns. Thus, both species responded similarly to fuel load treatments. Conclusions Acorns of both species exhibited greater survival with lower fine fuel loads, and consequently lower percent fuel consumption. Acorns germinating post fire generally produced seedlings with growth patterns similar to seedlings originating from unburned acorns. These findings indicate that regular, repeated prescribed fires or canopy reductions that limit fine fuel accumulation and create heterogeneous fuel beds are likely to increase acorn germination rates relative to unburned sites or those with recently introduced fire.

scholarly journals Generating a Baseline Map of Surface Fuel Loading Using Stratified Random Sampling Inventory Data through Cokriging and Multiple Linear Regression Methods

2021 ◽  
Vol 13 (8) ◽  
pp. 1561
Author(s):  
Chinsu Lin ◽  
Siao-En Ma ◽  
Li-Ping Huang ◽  
Chung-I Chen ◽  
Pei-Ting Lin ◽  
...  
Keyword(s):  
Linear Regression ◽  
Multiple Linear Regression ◽  
Random Sampling ◽  
Fuel Load ◽  
Estimation Accuracy ◽  
Slope Aspect ◽  
Stratified Random Sampling ◽  
Inventory Data ◽  
Fuel Loading ◽  
Regression Methods

Surface fuel loading is a key factor in controlling wildfires and planning sustainable forest management. Spatially explicit maps of surface fuel loading can highlight the risks of a forest fire. Geospatial information is critical in enabling careful use of deliberate fire setting and also helps to minimize the possibility of heat conduction over forest lands. In contrast to lidar sensing and/or optical sensing based methods, an approach of integrating in-situ fuel inventory data, geospatial interpolation techniques, and multiple linear regression methods provides an alternative approach to surface fuel load estimation and mapping over mountainous forests. Using a stratified random sampling based inventory and cokriging analysis, surface fuel loading data of 120 plots distributed over four kinds of fuel types were collected in order to develop a total surface fuel loading model (lntSFL-BioTopo model) and a fine surface fuel model (lnfSFL-BioTopo model) for generating tSFL and fSFL maps. Results showed that the combination of topographic parameters such as slope, aspect, and their cross products and the fuel types such as pine stand, non-pine conifer stand, broadleaf stand, and conifer–broadleaf mixed stand was able to appropriately describe the changes in surface fuel loads over a forest with diverse terrain morphology. Based on a cross-validation method, the estimation of tSFL and fSFL of the study site had an RMSE of 3.476 tons/ha and 3.384 tons/ha, respectively. In contrast to the average loading of all inventory plots, the estimation for tSFL and fSFL had a relative error of 38% (PRMSE). The reciprocal of estimation bias of both SFL-BioTopo models tended to be an exponential growth function of the amount of surface fuel load, indicating that the estimation accuracy of the proposed method is likely to be improved with further study. In the regression modeling, a natural logarithm transformation of the surface fuel loading prevented the outcome of negative estimates and thus improved the estimation. Based on the results, this paper defined a minimum sampling unit (MSU) as the area for collecting surface fuels for interpolation using a cokriging model. Allocating the MSUs at the boundary and center of a plot improved surface fuel load prediction and mapping.

scholarly journals Modelling and mitigating dose to firefighters from inhalation of radionuclides in wildland fire smoke

2015 ◽  
Vol 24 (5) ◽  
pp. 723 ◽  
Author(s):  
Brian J. Viner ◽  
Tim Jannik ◽  
Daniel Stone ◽  
Allan Hepworth ◽  
Luke Naeher ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Wildland Fire ◽  
Radioactive Material ◽  
Fuel Load ◽  
Base Case ◽  
Published Data ◽  
Case Scenario ◽  
Base Case Scenario ◽  
Fuel Loads ◽  
Radiological Dose

Firefighters responding to wildland fires where surface litter and vegetation contain radiological contamination will receive a radiological dose by inhaling resuspended radioactive material in the smoke. This may increase their lifetime risk of contracting certain types of cancer. Using published data, we modelled hypothetical radionuclide emissions, dispersion and dose for 70th and 97th percentile environmental conditions and for average and high fuel loads at the Savannah River Site. We predicted downwind concentration and potential dose to firefighters for radionuclides of interest (137Cs, 238Pu, 90Sr and 210Po). Predicted concentrations exceeded dose guidelines in the base case scenario emissions of 1.0 × 107 Bq ha–1 for 238Pu at 70th percentile environmental conditions and average fuel load levels for both 4- and 14-h shifts. Under 97th percentile environmental conditions and high fuel loads, dose guidelines were exceeded for several reported cases for 90Sr, 238Pu and 210Po. The potential for exceeding dose guidelines was mitigated by including plume rise (>2 m s–1) or moving a small distance from the fire owing to large concentration gradients near the edge of the fire. This approach can quickly estimate potential dose from airborne radionuclides in wildland fire and assist decision-making to reduce firefighter exposure.

Multiresidue Gas Chromatographic Method for Determining Organochlorine Pesticides in Poultry Fat: Collaborative Study

1984 ◽  
Vol 67 (2) ◽  
pp. 284-289 ◽  
Author(s):  
James A Ault ◽  
Tim E Spurgeon ◽  
◽  
M M Anderson ◽  
R Bowers ◽  
...  
Keyword(s):  
Chromatographic Method ◽  
Collaborative Study ◽  
Gel Permeation Chromatography ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Poultry Fat ◽  
Gel Permeation ◽  
Detector Method ◽  
Gas Chromatographic Method

Abstract A gas chromatographic electron capture detector method is described for the quantitative determination of organochlorine pesticide residues in poultry fat. The samples are rendered and cleaned up using automated gel permeation chromatography. The collaborative samples consisted of 10 fortified samples and one incurred residue sample, all in duplicate. Fortification levels ranged from 0.15 to 1.0 ppm for a-BHC, lindane, cis- and frans-chlordane, octachlor epoxide, o,p' and p,p'-DDT, p,p'-DDE, p,p'-TDE, hexachlorobenzene, heptachlor epoxide, dieldrin, endrin, methoxychlor, mirex, and toxaphene. The average recovery was 91.9% with a range of 81-102%. The ranges of coefficients of variation were: CVo = 3.39-14.79%; CVL = 0-16.6%; and CVx = 5.82-19.0%. The results indicate accuracy and precision comparable to other official methodology. The method has been adopted official first action.

scholarly journals Days to visit an offshore island: effect of weather conditions on arrival fuel load and potential flight range for common blackbirds Turdus merula migrating over the North Sea

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Natalie A. Kelsey ◽  
Ommo Hüppop ◽  
Franz Bairlein
Keyword(s):  
Relative Humidity ◽  
North Sea ◽  
Spring Migration ◽  
Low Energy ◽  
Energy Resources ◽  
Fuel Load ◽  
Physiological Conditions ◽  
Fuel Loads ◽  
The North ◽  
The North Sea

Abstract Background Crossing open water instead of following the coast(line) is one way for landbirds to continue migration. However, depending on prevailing weather and the birds’ physiological conditions, it is also a risky choice. To date, the question remains as to which interplay between environmental and physiological conditions force landbirds to stop on remote islands. We hypothesise that unfavourable winds affect lean birds with low energy resources, while poor visibility affects all birds regardless of their fuel loads. Methods To test this hypothesis, we caught 1312 common blackbirds Turdus merula stopping over on Helgoland during autumn and spring migration. Arrival fuel load was measured using quantitative magnetic resonance technology. Weather parameters (wind and relative humidity as a proxy for visibility) were interpolated for the night before arrival. Further, we calculated whether caught individuals would have successfully crossed the North Sea instead of landing on Helgoland, depending on wind conditions. Results Both wind and relative humidity the night before arrival were correlated with arrival fuel load. After nights with strong headwinds, birds caught the following day were mostly lean, most of which would not have managed to cross the sea if they had not stopped on Helgoland. In contrast, fat birds that could have successfully travelled on were caught mainly after nights with high relative humidity (≥ 80%). Furthermore, the rate of presumably successful flights was lower due to wind: although only 9% of all blackbirds captured on Helgoland had insufficient fuel loads to allow safe onward migration in still air, real wind conditions would have prevented 30% of birds from successfully crossing the sea during autumn and 21% during spring migration. Conclusions We were able to decipher how physiological condition, wind and relative humidity partially force blackbirds to stop on a remote island. Adverse winds tend to affect lean birds with low energy resources, while poor visibility can affect blackbirds, regardless of whether the arrival fuel load was sufficient for onward flight. Our findings will help to understand different migratory strategies and explain further questions like migration timing.

Visual assessments of fuel loads are poorly related to destructively sampled fuel loads in eucalypt forests

2016 ◽  
Vol 25 (11) ◽  
pp. 1193 ◽  
Author(s):  
Liubov Volkova ◽  
Andrew L. Sullivan ◽  
Stephen H. Roxburgh ◽  
Christopher J. Weston
Keyword(s):  
Visual Assessment ◽  
Fuel Load ◽  
Poor Correlation ◽  
Random Allocation ◽  
Near Surface ◽  
Forest Fuels ◽  
Fuel Loads ◽  
Rate Of Spread ◽  
Eucalypt Forests ◽  
Visual Assessments

Fire managers around the world commonly use visual assessment of forest fuels to aid prediction of fire behaviour and plan for hazard reduction burning. In Australia, fuel hazard assessment guides also allow conversion of visual assessments to indicative fuel loads, which is essential for some rate of spread models and calculation of fireline intensity or emissions. The strength of correlation between fuel hazard and destructively sampled (directly measured) fuel load was tested using a comprehensive dataset of >500 points from across a range of eucalypt forests in Australia. Overall, there was poor correlation between the assigned fuel hazard rating and measured biomass for surface, near-surface and elevated fuel components, with a clear tendency for these systems to under-predict fuel load at low hazard ratings, and over-predict it at high hazard ratings. Visual assessment of surface fuels was not statistically different from a random allocation of hazard level. The considerable overlap in fuel load between hazard ratings at higher ranges suggests the need to reduce the number of hazard classes to provide clearer differentiation of fuel hazard. To accurately assess forest fuel condition, improvements in fuel hazard descriptions and calibration of visual assessment with destructively measured fuels is essential.

Simplified Plate Diffusion System for Microbial Assays of Antibiotics

1987 ◽  
Vol 70 (4) ◽  
pp. 641-646
Author(s):  
Marietta Sue Brady ◽  
Stanley E Katz
Keyword(s):  
Diffusion System ◽  
Standard Curve ◽  
Single Plate ◽  
Accuracy And Precision ◽  
Coefficients Of Variation

Abstract A protocol for microbial assays of antibiotics, using the plate diffusion system, is presented. The system is based on the concept that a complete standard curve and assay unknowns can be placed on an issay plate and that 2 plates can be a complete assay with an accuracy and precision essentially equivalent to the official AOAC diffusion procedure. Four antibiotics, bacitracin, chlortetracycline, oxytetracycline, and streptomycin, were used in the design and comparison studies with the AOAC protocol. The coefficients of variation (CVs) for the AOAC design, using 10 replicates, ranged from 1.4 to 10.3% with a mean of 4.5%. The CVs for the single-plate option of the simplified design ranged from 4.3 to 9.6% with a mean of 6.6%; the CVs for the 2-plate option ranged from 2.5 to 6.8% with a mean of 43%; the CVs for the 3-plate option ranged from 1.2 to 5.0% with a mean of 3.0%.

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.

Forest fuels and potential fire behaviour 12 years after variable-retention harvest in lodgepole pine

2016 ◽  
Vol 25 (6) ◽  
pp. 633 ◽  
Author(s):  
Justin S. Crotteau ◽  
Christopher R. Keyes ◽  
Elaine K. Sutherland ◽  
David K. Wright ◽  
Joel M. Egan
Keyword(s):  
Lodgepole Pine ◽  
Structural Complexity ◽  
Fuel Load ◽  
Fire Behaviour ◽  
Forest Fuels ◽  
Fuel Loads ◽  
Variable Retention ◽  
Harvesting Technique ◽  
Trade Offs ◽  
Variable Retention Harvesting

Variable-retention harvesting in lodgepole pine offers an alternative to conventional, even-aged management. This harvesting technique promotes structural complexity and age-class diversity in residual stands and promotes resilience to disturbance. We examined fuel loads and potential fire behaviour 12 years after two modes of variable-retention harvesting (dispersed and aggregated retention patterns) crossed by post-harvest prescribed fire (burned or unburned) in central Montana. Results characterise 12-year post-treatment fuel loads. We found greater fuel load reduction in treated than untreated stands, namely in the 10- and 100-h classes (P = 0.002 and 0.049 respectively). Reductions in 1-h (P < 0.001), 10-h (P = 0.008) and 1000-h (P = 0.014) classes were greater in magnitude for unburned than burned treatments. Fire behaviour modelling incorporated the regenerating seedling cohort into the surface fuel complex. Our analysis indicates greater surface fireline intensity in treated than untreated stands (P < 0.001), and in unburned over burned stands (P = 0.001) in dry, windy weather. Although potential fire behaviour in treated stands is predicted to be more erratic, within-stand structural variability reduces probability of crown fire spread. Overall, results illustrate trade-offs between potential fire attributes that should be acknowledged with variable-retention harvesting.

scholarly journals Effects of Basal Area Factor and Plot Size on Precision and Accuracy of Forest Inventory Estimates

2011 ◽  
Vol 28 (3) ◽  
pp. 152-156 ◽  
Author(s):  
Peter Becker ◽  
Tom Nichols
Keyword(s):  
Forest Inventory ◽  
Basal Area ◽  
Cost Effective ◽  
Sampling Errors ◽  
Plot Size ◽  
Accuracy And Precision ◽  
Coefficients Of Variation ◽  
Fixed Radius ◽  
Tree Number ◽  
Biased Estimates

Abstract We tested the effects of plot size (0.05-0.30 ac) and basal area factor (BAF) (5-30) on the accuracy and precision of per-acre estimates of tree number, basal area, biomass (all for trees ≥4.5 in. dbh), and sawtimber volume (for trees ≥11.6 in. dbh). Field sampling errors, such as missing in-trees, did not affect our tests. Virtual variable- and fixed-radius plots were randomly located within an artificial matrix of 130 real plots in well-stocked upland hardwood forests of sawtimber-sized trees in the Missouri Ozarks. Inventory parameters were essentially independent of plot size and BAF, whereas their coefficients of variation decreased with plot size and increased with BAF. Thus, our results for random plots agreed with sampling theory, unlike a previous study using concentric virtual plots in West Virginia forests. A very concentrated zone of high tree density around some plot centers apparently caused the biased estimates by concentric plots. Compared with the entire composite forest, inventory means were accurately estimated (to within 5%) and size class distributions were well represented for plots ≥0.1 ac or ≤15 BAF. Our procedures provide a basis for selecting an efficient and cost-effective sampling design suited to forest characteristics and the inventory's purpose.

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