Fuel accumulation and forest structure change following hazardous fuel reduction treatments throughout California

2015 ◽  
Vol 24 (3) ◽  
pp. 361 ◽  
Author(s):  
Nicole M. Vaillant ◽  
Erin K. Noonan-Wright ◽  
Alicia L. Reiner ◽  
Carol M. Ewell ◽  
Benjamin M. Rau ◽  
...  
Keyword(s):  
Bulk Density ◽  
Prescribed Fire ◽  
Forest Structure ◽  
Fire Regimes ◽  
Post Treatment ◽  
Fuel Load ◽  
Fire Behaviour ◽  
Fuel Treatments ◽  
Minimal Impact ◽  
Canopy Bulk Density

Altered fuel conditions coupled with changing climate have disrupted fire regimes of forests historically characterised by high-frequency and low-to-moderate-severity fire. Managers use fuel treatments to abate undesirable fire behaviour and effects. Short-term effectiveness of fuel treatments to alter fire behaviour and effects is well documented; however, long-term effectiveness is not well known. We evaluated surface fuel load, vegetation cover and forest structure before and after mechanical and fire-only treatments over 8 years across 11 National Forests in California. Eight years post treatment, total surface fuel load returned to 67 to 79% and 55 to 103% of pretreatment levels following fire-only and mechanical treatments respectively. Herbaceous or shrub cover exceeded pretreatment levels two-thirds of the time 8 years after treatment. Fire-only treatments warranted re-entry at 8 years post treatment owing to the accumulation of live and dead fuels and minimal impact on canopy bulk density. In general, mechanical treatments were more effective at reducing canopy bulk density and initially increasing canopy base height than prescribed fire. However, elevated surface fuel loads, canopy base height reductions in later years and lack of restoration of fire as an ecological process suggest that including prescribed fire would be beneficial.

scholarly journals Improving silvicultural practices for Mediterranean forests through fire behaviour modelling using LiDAR-derived canopy fuel characteristics

2019 ◽  
Vol 28 (11) ◽  
pp. 823 ◽  
Author(s):  
Brigite Botequim ◽  
Paulo M. Fernandes ◽  
José G. Borges ◽  
Eduardo González-Ferreiro ◽  
Juan Guerra-Hernández
Keyword(s):  
Bulk Density ◽  
Forest Type ◽  
Classification Tree ◽  
Airborne Lidar ◽  
Fuel Load ◽  
Mediterranean Forests ◽  
Fire Behaviour ◽  
Fuel Loading ◽  
Fuel Characteristics ◽  
Stand Height

Wildfires cause substantial environmental and socioeconomic impacts and threaten many Spanish forested landscapes. We describe how LiDAR-derived canopy fuel characteristics and spatial fire simulation can be integrated with stand metrics to derive models describing fire behaviour. We assessed the potential use of very-low-density airborne LiDAR (light detection and ranging) data to estimate canopy fuel characteristics in south-western Spain Mediterranean forests. Forest type-specific equations were used to estimate canopy fuel attributes, namely stand height, canopy base height, fuel load, bulk density and cover. Regressions explained 61–85, 70–85, 38–96 and 75–95% of the variability in field estimated stand height, canopy fuel load, crown bulk density and canopy base height, respectively. The weakest relationships were found for mixed forests, where fuel loading variability was highest. Potential fire behaviour for typical wildfire conditions was predicted with FlamMap using LiDAR-derived canopy fuel characteristics and custom fuel models. Classification tree analysis was used to identify stand structures in relation to crown fire likelihood and fire suppression difficulty levels. The results of the research are useful for integrating multi-objective fire management decisions and effective fire prevention strategies within forest ecosystem management planning.

Evaluating regression model estimates of canopy fuel stratum characteristics in four crown fire-prone fuel types in western North America

2012 ◽  
Vol 21 (2) ◽  
pp. 168 ◽  
Author(s):  
Miguel G. Cruz ◽  
Martin E. Alexander
Keyword(s):  
North America ◽  
Bulk Density ◽  
Ponderosa Pine ◽  
Stand Structure ◽  
Coniferous Forest ◽  
Fuel Load ◽  
Regression Equations ◽  
Western North America ◽  
Crown Fire ◽  
Canopy Bulk Density

Two evaluations were undertaken of the regression equations developed by M. Cruz, M. Alexander and R. Wakimoto (2003, International Journal of Wildland Fire 12, 39–50) for estimating canopy fuel stratum characteristics from stand structure variables for four broad coniferous forest fuel types found in western North America. The first evaluation involved a random selection of 10 stands each from the four datasets used in the original study. These were in turn subjected to two simulated thinning regimes (i.e. 25 and 50% basal area removal). The second evaluation involved a completely independent dataset for ponderosa pine consisting of 16 stands sampled by T. Keyser and F. Smith (2010, Forest Science 56, 156–165). Evaluation statistics were comparable for the thinning scenarios and independent evaluations. Mean absolute percentage errors varied between 13.8 and 41.3% for canopy base height, 5.3 and 67.9% for canopy fuel load, and 20.7 and 71% for canopy bulk density. Bias errors were negligible. The results of both evaluations clearly show that the stand-level models of Cruz et al. (2003) used for estimating canopy base height, canopy fuel load and canopy bulk density in the assessment of crown fire potential are, considering their simplicity, quite robust.

Fuel properties and fire behaviour characteristics of prescribed fire in pine-dominated forests at Nam Nao National Park, Thailand

2013 ◽  
Vol 22 (5) ◽  
pp. 615 ◽  
Author(s):  
K. Wanthongchai ◽  
V. Tarusadamrongdet ◽  
K. Chinnawong ◽  
K. Sooksawat
Keyword(s):  
Prescribed Fire ◽  
National Park ◽  
Forest Type ◽  
Pine Forest ◽  
Fuel Load ◽  
Fire Behaviour ◽  
Temperature Changes ◽  
Fuel Loads ◽  
Soil Temperatures ◽  
Fuel Components

Anthropogenic burning has become a common phenomenon throughout Thailand’s pine-dominated ecosystems. This study investigated fuel loads and experimental fire behaviour characteristics in a degraded pine forest (PF) and a pine–oak forest (O-PF), at Nam Nao National Park, Thailand in three replicate 50 × 50-m plots of each forest type. Pre-burn fuel loads, fire behaviour descriptors, fire and soil temperature, the residues left after burning and post-burn fuel recovery for 1 year were investigated. The aboveground fuel load in PF (1.29 kg m–2) was significantly higher than in O-PF (0.87 kg m–2). The main fuel components in the PF stand were grass (45%) and litter (44%), whereas leaf litter was the predominant fuel in the O-PF stand (55%). The fire behaviour characteristics in the PF stand were significantly greater than those in the O-PF stand. Burning at the O-PF and the PF was respectively classified as low (48 kW m–1) and medium intensity (627 kW m–1). During the burning experiment, the surface soil temperatures at all sites were higher than 250°C. However, fire did not cause temperature changes in the deeper soil layers. In the pine forest the post-burn fuel loads 1 year after the fire remained lower than the pre-burn level. These results may imply that a pine forest at Nam Nao National Park requires more than 1 year of fire-free period to recover back to the pre-burn conditions.

Development and testing of models for predicting crown fire rate of spread in conifer forest stands

2005 ◽  
Vol 35 (7) ◽  
pp. 1626-1639 ◽  
Author(s):  
Miguel G Cruz ◽  
Martin E Alexander ◽  
Ronald H Wakimoto
Keyword(s):  
Bulk Density ◽  
Fire Behavior ◽  
Fire Regimes ◽  
Management Decision ◽  
Crown Fire ◽  
Conifer Forest ◽  
Data Set ◽  
Rate Of Spread ◽  
Spread Model ◽  
Canopy Bulk Density

The rate of spread of crown fires advancing over level to gently undulating terrain was modeled through nonlinear regression analysis based on an experimental data set pertaining primarily to boreal forest fuel types. The data set covered a significant spectrum of fuel complex and fire behavior characteristics. Crown fire rate of spread was modeled separately for fires spreading in active and passive crown fire regimes. The active crown fire rate of spread model encompassing the effects of 10-m open wind speed, estimated fine fuel moisture content, and canopy bulk density explained 61% of the variability in the data set. Passive crown fire spread was modeled through a correction factor based on a criterion for active crowning related to canopy bulk density. The models were evaluated against independent data sets originating from experimental fires. The active crown fire rate of spread model predicted 42% of the independent experimental crown fire data with an error lower then 25% and a mean absolute percent error of 26%. While the models have some shortcomings and areas in need of improvement, they can be readily utilized in support of fire management decision making and other fire research studies.

Short-term effect of fuel treatments on fire behaviour in a mixed heathland: a comparative assessment in an outdoor wind tunnel

2014 ◽  
Vol 23 (8) ◽  
pp. 1097 ◽  
Author(s):  
Eva Marino ◽  
Carmen Hernando ◽  
Javier Madrigal ◽  
Mercedes Guijarro
Keyword(s):  
Wind Tunnel ◽  
Prescribed Burning ◽  
Flame Height ◽  
Fuel Load ◽  
Fire Intensity ◽  
Fuel Management ◽  
Fire Behaviour ◽  
Fuel Treatments ◽  
Relevant Effect ◽  
Significant Difference

Fuel management is one of the main challenges for wildfire prevention in the Mediterranean region, where wildfires have important environmental and socioeconomic effects. Different treatments are usually applied in fire-prone shrubland to try to modify its flammability. However, a knowledge gap on the effectiveness of fuel management techniques still exists. We studied the effects of two mechanical treatments (shrub crushing and shrub clearing with removal) and of prescribed burning, on fire behaviour, and compared them with untreated vegetation. Experimental burns in 0.8 × 6 m samples of regenerated shrubs 2 years after treatments were performed in an outdoor wind tunnel. All fuel treatments effectively modified fire behaviour, but no significant difference between treatment types was observed. Shrub fuel structure was the main factor affecting fire behaviour. Reduction of fuel load and height, especially necromass fraction, decreased flame height and fire intensity but did not affect fire rate of spread. Moisture contents of live and dead fuel fractions were not significant as independent parameters, but the average moisture level of the shrub fuel complex showed a relevant effect in determining fire behaviour. Temperature regime within and above the shrubs was also related to shrub fuel structure. This study contributes to understanding fuel management in shrubland by providing information about different fuel treatments effects on fire behaviour.

scholarly journals Short- and long-term effects of ponderosa pine fuel treatments intersected by the Egley Fire Complex, Oregon, USA

Fire Ecology ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Jessie M. Dodge ◽  
Eva K. Strand ◽  
Andrew T. Hudak ◽  
Benjamin C. Bright ◽  
Darcy H. Hammond ◽  
...  
Keyword(s):  
Prescribed Fire ◽  
Vegetation Cover ◽  
Tree Density ◽  
Tree Canopy ◽  
Fuel Treatments ◽  
Dead Tree ◽  
High Severity ◽  
Short And Long Term ◽  
One Year

Abstract Background Fuel treatments are widely used to alter fuels in forested ecosystems to mitigate wildfire behavior and effects. However, few studies have examined long-term ecological effects of interacting fuel treatments (commercial harvests, pre-commercial thinnings, pile and burning, and prescribed fire) and wildfire. Using annually fitted Landsat satellite-derived Normalized Burn Ratio (NBR) curves and paired pre-fire treated and untreated field sites, we tested changes in the differenced NBR (dNBR) and years since treatment as predictors of biophysical attributes one and nine years after the 2007 Egley Fire Complex in Oregon, USA. We also assessed short- and long-term fuel treatment impacts on field-measured attributes one and nine years post fire. Results One-year post-fire burn severity (dNBR) was lower in treated than in untreated sites across the Egley Fire Complex. Annual NBR trends showed that treated sites nearly recovered to pre-fire values four years post fire, while untreated sites had a slower recovery rate. Time since treatment and dNBR significantly predicted tree canopy and understory green vegetation cover in 2008, suggesting that tree canopy and understory vegetation cover increased in areas that were treated recently pre fire. Live tree density was more affected by severity than by pre-fire treatment in either year, as was dead tree density one year post fire. In 2008, neither treatment nor severity affected percent cover of functional groups (shrub, graminoid, forb, invasive, and moss–lichen–fungi); however, by 2016, shrub, graminoid, forb, and invasive cover were higher in high-severity burn sites than in low-severity burn sites. Total fuel loads nine years post fire were higher in untreated, high-severity burn sites than any other sites. Tree canopy cover and density of trees, saplings, and seedlings were lower nine years post fire than one year post fire across treatments and severity, whereas live and dead tree basal area, understory surface cover, and fuel loads increased. Conclusions Pre-fire fuel treatments effectively lowered the occurrence of high-severity wildfire, likely due to successful pre-fire tree and sapling density and surface fuels reduction. This study also quantified the changes in vegetation and fuels from one to nine years post fire. We suggest that low-severity wildfire can meet prescribed fire management objectives of lowering surface fuel accumulations while not increasing overstory tree mortality.

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.

Fire Management of Rangelands in the Kimberley Low-Rainfall Zone: a Review.

1999 ◽  
Vol 21 (1) ◽  
pp. 39 ◽  
Author(s):  
AB Craig
Keyword(s):  
Fire History ◽  
Fire Management ◽  
Fire Regime ◽  
Fire Regimes ◽  
Environmental Research ◽  
Fire Behaviour ◽  
General Management ◽  
Noaa Avhrr ◽  
Local Experience ◽  
Definition Of

This paper examines a range of environmental, research and practical issues affecting fire management of pastoral lands in the southern part of the Kimberley region in Western Australia. Although spinifex grasslands dominate most leases, smaller areas of more productive pastures are crucially important to many enterprises. There is a lack of local documentation of burning practices during traditional Aboriginal occupation; general features of the fire regime at that time can be suggested on the basis of information from other inland areas. Definition of current tire regimes is improving through interpretation of NOAA-AVHRR satellite imagery. Irregular extensive wildfires appear to dominate, although this should be confirmed by further accumulation, validation and analysis of fire history data. While these fires cause ma,jor difficulties. controlled burn~ng is a necessary part of station management. Although general management guidelines have been published. local research into tire-grazing effects has been very limited. For spinifex pastures, reconimendations are generally consistent with those applying elsewhere in northern Australia. They favour periodic burning of mature spinifex late in the year, before or shortly after the arrival of the first rains, with deferment of grazing. At that time. days of high fire danger may still be expected and prediction of fire behaviour is critical to burning decisions. Early dry-season burning is also required for creating protective tire breaks and to prepare for burning later in the year. Further development of tools for predicting fire behaviour, suited to the discontinuous fuels characteristic of the area, would be warranted. A range of questions concerning the timing and spatial pattern of burning, control of post-fire grazing, and the economics of fire management, should be addressed as resources permit. This can be done through a combination of opportunistic studies, modelling and documentation of local experience. The development of an expert system should be considered to assist in planning and conducting burning activities. Key words: Kimberley, fire regimes, fire management, pastoralism, spinifex

Fuel and fire characteristics in savanna - woodland of West Africa in relation to grazing and dominant grass type

2007 ◽  
Vol 16 (5) ◽  
pp. 531 ◽  
Author(s):  
Patrice Savadogo ◽  
Didier Zida ◽  
Louis Sawadogo ◽  
Daniel Tiveau ◽  
Mulualem Tigabu ◽  
...  
Keyword(s):  
Prescribed Burning ◽  
Management Tool ◽  
Fuel Load ◽  
Maximum Temperature ◽  
Fire Intensity ◽  
Fire Behaviour ◽  
Savanna Woodland ◽  
Vegetation Height ◽  
Average Maximum ◽  
Dominant Grass

Fuel characteristics, fire behaviour and temperature were studied in relation to grazing, dominant grass type and wind direction in West African savanna–woodland by lighting 32 prescribed early fires. Grazing significantly reduced the vegetation height, total fuel load, and dead and live fuel fractions whereas plots dominated by perennial grasses had higher values for vegetation height, total fuel load and the quantity of live fuel load. Although fire intensity remained insensitive (P > 0.05) to any of these factors, fuel consumption was significantly (P = 0.021) reduced by grazing, rate of spread was faster in head fire (P = 0.012), and flame length was shorter in head fire than back fire (P = 0.044). The average maximum temperature was higher (P < 0.05) on non-grazed plots, on plots dominated by annual grasses, on plots subjected to head fire, and at the soil surface. Lethal temperature residence time showed a nearly similar trend to fire temperature. Wind speed and total fuel load were best predictors of fire behaviour parameters (R2 ranging from 0.557 to 0.862). It can be concluded that grazing could be used as a management tool to modify fire behaviour, back fire should be carried out during prescribed burning to lower fire severity, and the fire behaviour models can be employed to guide prescribed early fire in the study area.

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