Role of burning season on initial understory vegetation response to prescribed fire in a mixed conifer forest

2007 ◽  
Vol 37 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Eric E Knapp ◽  
Dylan W Schwilk ◽  
Jeffrey M Kane ◽  
Jon E Keeley
Keyword(s):  
Prescribed Burning ◽  
Understory Vegetation ◽  
Fire Intensity ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Fuel Loading ◽  
Significant Drop ◽  
Early Season ◽  
Late Season ◽  
Mixed Conifer Forest

Although the majority of fires in the western United States historically occurred during the late summer or early fall when fuels were dry and plants were dormant or nearly so, early-season prescribed burns are often ignited when fuels are still moist and plants are actively growing. The purpose of this study was to determine if burn season influences postfire vegetation recovery. Replicated early-season burn, late-season burn, and unburned control units were established in a mixed conifer forest, and understory vegetation was evaluated before and after treatment. Vegetation generally recovered rapidly after prescribed burning. However, late-season burns resulted in a temporary but significant drop in cover and a decline in species richness at the 1 m2 scale in the following year. For two of the several taxa that were negatively affected by burning, the reduction in frequency was greater after late-season than early-season burns. Early-season burns may have moderated the effect of fire by consuming less fuel and lessening the amount of soil heating. Our results suggest that, when burned under high fuel loading conditions, many plant species respond more strongly to differences in fire intensity and severity than to timing of the burn relative to stage of plant growth.

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 Comparing Modeled Emissions from Wildfire and Prescribed Burning of Post-Thinning Fuel: A Case Study of the 2016 Pioneer Fire

Fire ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 22
Author(s):  
Josh Hyde ◽  
Eva K. Strand
Keyword(s):  
Air Quality ◽  
Prescribed Fire ◽  
Prescribed Burning ◽  
Effective Means ◽  
National Forest ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Fuel Treatments ◽  
Mixed Conifer Forest

Prescribed fire is often used by land managers as an effective means of implementing fuel treatments to achieve a variety of goals. Smoke generated from these activities can put them at odds with air quality regulations. We set out to characterize the emission tradeoff between wildfire and prescribed fire in activity fuels from thinning in a case study of mixed conifer forest within the Boise National Forest in central Idaho. Custom fuelbeds were developed using information from the forest and emissions were modeled and compared for four scenarios, as follows: Untreated fuels burned in wildfire (UNW), prescribed fire in activity fuels left from thinning (TRX), a wildfire ignited on the post-treatment landscape (PTW), and the combined emissions from TRX followed by PTW (COM). The modeled mean total emissions from TRX were approximately 5% lower, compared to UNW, and between 2–46% lower for individual pollutants. The modeled emissions from PTW were approximately 70% lower than UNW. For the COM scenario, emissions were not significantly different from the UNW scenario for any pollutants, but for CO2. However, for the COM scenario, cumulative emissions would have been comprised of two events occurring at separate times, each with lower emissions than if they occurred at once.

Tree mortality from fire and bark beetles following early and late season prescribed fires in a Sierra Nevada mixed-conifer forest

2006 ◽  
Vol 232 (1-3) ◽  
pp. 36-45 ◽  
Author(s):  
Dylan W. Schwilk ◽  
Eric E. Knapp ◽  
Scott M. Ferrenberg ◽  
Jon E. Keeley ◽  
Anthony C. Caprio
Keyword(s):  
Sierra Nevada ◽  
Bark Beetles ◽  
Tree Mortality ◽  
Prescribed Fires ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Late Season ◽  
Mixed Conifer Forest

Tree mortality patterns following prescribed fires in a mixed conifer forest

2006 ◽  
Vol 36 (12) ◽  
pp. 3222-3238 ◽  
Author(s):  
Leda Kobziar ◽  
Jason Moghaddas ◽  
Scott L Stephens
Keyword(s):  
Sierra Nevada ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Fire Behavior ◽  
Mortality Rates ◽  
Fire Intensity ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Mixed Conifer Forest ◽  
White Fir

During the late fall of 2002 we administered three burns in mixed conifer forest sites in the north-central Sierra Nevada. Eight months later we measured fire-induced injury and mortality in 1300 trees. Using logistic regression, an array of crown scorch, stem damage, fuels, and fire-behavior variables were examined for their influence on tree mortality. In Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), white fir (Abies concolor (Gord. & Glend.) Lindl.), and incense cedar (Calocedrus decurrens (Torr.) Florin), smaller trees with greater total crown damage had higher mortality rates. Smaller stem diameters and denser canopies predicted mortality best in ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws). Duff consumption and bark char severity increased model discrimination for white fir and incense cedar and California black oak (Quercus kelloggii Newberry), respectively. In tanoak (Lithocarpus densiflorus (Hook. & Arn.) Rehd.), greater total crown damage in shorter trees resulted in higher mortality rates. Along with tree diameter and consumption of large (>7.6 cm diameter at breast height, DBH) rotten downed woody debris, fire intensity was a significant predictor of overall tree mortality for all species. Mortality patterns for white fir in relation to crown damage were similar among sites, while those for incense cedar were not, which suggests that species in replicated sites responded differently to similar burns. Our results demonstrate actual fire-behavior data incorporated into mortality models, and can be used to design prescribed burns for targeted reduction of tree density in mixed conifer forests.

scholarly journals A Case Study Comparison of LANDFIRE Fuel Loading and Emissions Generation on a Mixed Conifer Forest in Northern Idaho, USA

Fire Ecology ◽  
2015 ◽  
Vol 11 (3) ◽  
pp. 108-127 ◽  
Author(s):  
Josh Hyde ◽  
Eva K. Strand ◽  
Andrew T. Hudak ◽  
Dale Hamilton
Keyword(s):  
Conifer Forest ◽  
Mixed Conifer ◽  
Fuel Loading ◽  
Mixed Conifer Forest ◽  
Northern Idaho
Sign in / Sign up

Export Citation Format

Share Document