Influences of moisture content, mineral content and bulk density on smouldering combustion of ponderosa pine duff mounds

2011 ◽  
Vol 20 (4) ◽  
pp. 589 ◽  
Author(s):  
Emily C. Garlough ◽  
Christopher R. Keyes
Keyword(s):  
Moisture Content ◽  
Bulk Density ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Mineral Content ◽  
Prescribed Burning ◽  
Klamath Mountains ◽  
Root Mortality ◽  
Decision Support Models ◽  
Smouldering Combustion

When applying prescribed fire to long-unburned but fire-adapted ecosystems, fuels managers require better decision-support models to determine appropriate conditions for achieving desired effects. Prolonged combustion in duff accumulations at the base of large conifers may lead to fine root mortality, cambial injury, enhanced susceptibility to bark beetle attack, and possibly tree death. A laboratory experiment was conducted to investigate how moisture content, mineral content, and bulk density affect smouldering combustion in ponderosa pine (Pinus ponderosa C. Lawson) duff mound fuels of the south-eastern Klamath Mountains, California, USA. Samples were divided between upper and lower duff for a total of 100 burn tests. Moisture content was adjusted to observe the transition through the ignition and spread limit. Bulk density, mineral content and percentage consumption were recorded for each burn. The moisture content threshold for smouldering combustion was 57 and 102% respectively for upper and lower duff. Percentage consumption was inversely related to moisture content for both layers of duff, and partially dependent on mineral content for lower duff. Bulk density was a non-significant factor in either ignition or percentage combustion for the conditions examined here. Results from this study identify important attributes of duff that control the burning process in order to inform prescribed burning decisions.

scholarly journals Effect of Prescribed Burning at Different Fuel Moisture Levels on Grasslands in Wind Cave National Park

1979 ◽  
Vol 3 ◽  
pp. 148-152
Author(s):  
F. Gartner ◽  
E. White ◽  
L. Worcester
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
National Park ◽  
Prescribed Burning ◽  
Fire Spread ◽  
Control Treatment ◽  
Grass Species ◽  
Fuel Moisture

The study was designed to determine whether different fuel and soil moisture levels at time of ignition would alter the response of key grass species to prescribed burning. Grasslands occupy approximately 75% of the area of Wind Cave National Park (WCNP); the remainder is dominated by ponderosa pine (Pinus ponderosa), according to Lovass (1973). The Soil Conservation Service (1969) classed only about 17% of the Park area as woodland. Nearly all grassland adjacent to woodland has been invaded by ponderosa pine. Almost without exception, pine invades the little bluestem - big bluestem (Schizachyrium scorparium - Andropogon gerardi) community, but not the wheatgrass - needle-grass - grama (Andropogon - Stipa- Bouteloua) community. While these two communities are frequently interspersed, the bluestem community probably occupies the largest percentage of the total grassland area. The general relationships between fuel moisture content and fire spread (or ease of control) are well known. However, relationships between fuel and surface soil moisture content and responses of plant species to burning are not well documented. Since the key grass species of the bluestem community are major dominants throughout the Park, that community was selected for the study. Examined were the effects of three fuel moisture levels (dry, medium and wet) at ignition on postburn species composition, cover, height, weight, soil moisture and soil chemistry. The design also included an unburned (control) treatment.

Factors affecting sustained smouldering in organic soils from pocosin and pond pine woodland wetlands

2007 ◽  
Vol 16 (1) ◽  
pp. 107 ◽  
Author(s):  
James Reardon ◽  
Roger Hungerford ◽  
Kevin Ryan
Keyword(s):  
Logistic Regression ◽  
Moisture Content ◽  
Mineral Content ◽  
Prescribed Burning ◽  
Organic Soils ◽  
Moisture Contents ◽  
Muck Soil ◽  
Laboratory Results ◽  
Smouldering Combustion ◽  
Pond Pine

The smouldering combustion of peat and muck soil plays an important role in the creation and maintenance of wetland communities. This experimental study was conducted to improve our understanding of how moisture and mineral content constrain smouldering in organic soil. Laboratory burning was conducted with root mat and muck soil samples from pocosin and pond pine woodland wetlands common on the North Carolina coastal plain. The results of laboratory and prescribed burning were compared. Laboratory results showed that moisture and mineral content influenced sustained smouldering in root mat soils. Predictions based on logistic regression analysis show that root mat soils with an average mineral content of 4.5% had an estimated 50% probability of sustained smouldering at a moisture content of 93%, whereas at moisture contents above 145% the estimated probability was less than 10%. The odds that root mat soil will sustain smouldering decrease by 19.3% for each 5% increase in moisture content. Root mat soils with an average mineral content of 5.5% and a moisture content of 93% had an estimated 61% probability of sustained smouldering. The odds that root mat soil will sustain smouldering combustion increased by 155.9% with each 1% increase in mineral content. Root mat and muck soils differ in physical and chemical characteristics expected to influence smouldering behaviour. The formation of muck soil has led to increases in density, smaller soil particle size, changes in water holding characteristics and increases in waxes, resins and bituminous compounds. Muck soil smouldered at higher moisture contents than root mat soil. Muck soil at a moisture content of 201% had an estimated 50% probability of sustained smouldering, whereas at moisture contents above 260% the estimated probability was less than 10%. The odds that muck soil will sustain smouldering combustion decrease by 17.2% with each 5% increase in moisture content. Ground fire in the prescribed burns stopped its vertical spread in organic soils at moisture contents consistent with logistic regression predictions developed from our laboratory results.

Reproductive output of ponderosa pine in response to thinning and prescribed burning in western Montana

2008 ◽  
Vol 38 (4) ◽  
pp. 844-850 ◽  
Author(s):  
Gregory Peters ◽  
Anna Sala
Keyword(s):  
Pinus Ponderosa ◽  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Reproductive Output ◽  
Management Practices ◽  
Prescribed Burning ◽  
Seed Mass ◽  
Reproductive Traits ◽  
Western Montana ◽  
Cone Production

Thinning and thinning followed by prescribed fire are common management practices intended to restore historic conditions in low-elevation ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.) forests of the northern Rocky Mountains. While these treatments generally ameliorate the physiology and growth of residual trees, treatment-specific effects on reproductive output are not known. We examined reproductive output of second-growth ponderosa pine in western Montana 9 years after the application of four treatments: thinning, thinning followed by spring prescribed fire, thinning followed by fall prescribed fire, and unthinned control stands. Field and greenhouse observations indicated that reproductive traits vary depending on the specific management treatment. Cone production was significantly higher in trees from all actively managed stands relative to control trees. Trees subjected to prescribed fire produced cones with higher numbers of filled seeds than trees in unburned treatments. Seed mass, percentage germination, and seedling biomass were significantly lower for seeds from trees in spring burn treatments relative to all others and were generally higher in trees from fall burn treatments. We show for the first time that thinning and prescribed-burning treatments can influence reproductive output in ponderosa pine.

scholarly journals Antelope Bitterbrush and Scouler's Willow Response to a Shelterwood Harvest and Prescribed Burn in Western Montana

1999 ◽  
Vol 14 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Dayna M. Ayers ◽  
Donald J. Bedunah ◽  
Michael G. Harrington
Keyword(s):  
Fuel Consumption ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Selective Logging ◽  
Western Montana ◽  
Fire Damage ◽  
Prescribed Burn ◽  
Large Trees ◽  
Shelterwood Cut

Abstract In many western Montana ponderosa pine (Pinus ponderosa) stands, fire suppression and past selective logging of large trees have resulted in conditions favoring succession to dense stands of shade-tolerant, but insect- and disease-prone Douglas-fir (Pseudotsuga menziesii). Stand thinning and understory prescribed burning have been proposed as surrogates for pre-Euro-American settlement ecological processes and as potential treatments to improve declining forest condition and reduce the probability of severe wildfire. To test the effectiveness of these silvicultural techniques on overstory and understory conditions, research is ongoing in the Lick Creek Demonstration Site in the Bitterroot National Forest, Montana. Our research examined the response (mortality and vigor) of the dominant browse species, antelope bitterbrush (Purshia tridentata) and Scouler's willow (Salix scouleriana), to a ponderosa pine stand restoration project utilizing four treatments: (1) a shelterwood cut that removed 53% of the tree basal area; (2) a shelterwood cut with a low fuel consumption burn; (3) a shelterwood cut with a high fuel consumption burn; and (4) a control. Prior to the application of treatments, 1,856 bitterbrush and 871 willow were located, and their survival and vigor subsequently monitored for 2 yr posttreatment. The cut and burn treatments resulted in the greatest reduction in antelope bitterbrush and Scouler's willow density averaging 66% and 24% of pretreatment density, respectively. The shelterwood cut reduced bitterbrush and Scouler's willow density by 35% and 14%, respectively. On treatments receiving a shelterwood cut (all treatments but the control), but where antelope bitterbrush and Scouler's willow did not have fire damage, mortality was 45% for bitterbrush and 20% for willow, respectively. For bitterbrush and Scouler's willow plants that received fire damage, mortality was 72% for bitterbrush and 19% for willow. Although the burn and shelterwood harvest treatments resulted in reduced density of antelope bitterbrush and Scouler's willow 2 yr posttreatment, these treatments increased vigor of both species and created mineral seedbeds that may be necessary for establishment of seedlings. West. J. Appl. For. 14(3):137-143.

An experimental demonstration of stem damage as a predictor of fire-caused mortality for ponderosa pine

2004 ◽  
Vol 34 (6) ◽  
pp. 1343-1347 ◽  
Author(s):  
Phillip van Mantgem ◽  
Mark Schwartz
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Control Group ◽  
Critical Determinant ◽  
Dead Trees ◽  
Crown Scorch ◽  
Increased Sensitivity ◽  
Stem Damage ◽  
Removal Group

We subjected 159 small ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) to treatments designed to test the relative importance of stem damage as a predictor of postfire mortality. The treatments consisted of a group with the basal bark artificially thinned, a second group with fuels removed from the base of the stem, and an untreated control. Following prescribed burning, crown scorch severity was equivalent among the groups. Postfire mortality was significantly less frequent in the fuels removal group than in the bark removal and control groups. No model of mortality for the fuels removal group was possible, because dead trees constituted <4% of subject trees. Mortality in the bark removal group was best predicted by crown scorch and stem scorch severity, whereas death in the control group was predicted by crown scorch severity and bark thickness. The relative lack of mortality in the fuels removal group and the increased sensitivity to stem damage in the bark removal group suggest that stem damage is a critical determinant of postfire mortality for small ponderosa pine.

scholarly journals The Effects of Fire on Understory Vegetation in Ponderosa Pine Forests

1980 ◽  
Vol 4 ◽  
pp. 96-97
Author(s):  
Jane Bock ◽  
Carl Bock
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Fire Regime ◽  
Management Plan ◽  
Black Hills ◽  
Pine Forests ◽  
Natural Phenomenon ◽  
Natural Fire ◽  
Ponderosa Pine Forests

This was the second year of our study designed to evaluate the nature of vegetation occurring under Pinus ponderosa canopy in Wind Cave National Park and to define the relationship between this vegetation and fire. Fire is known to be a natural phenomenon in ponderosa pine forests (Wright 1978), and to play a major role in determining the position of the pine-grassland ecotone in the Black Hills (Gartner and Thompson 1973). Wind Cave personnel are developing a fire management plan allowing for prescribed burning, in hopes of bringing the park ecosystems back under a "natural" fire regime. Results of our study will help park management predict the effects of such prescribed burning on the ponderosa pine community.

Prediction of delayed mortality of fire-damaged ponderosa pine following prescribed fires in eastern Oregon, USA

2006 ◽  
Vol 15 (1) ◽  
pp. 19 ◽  
Author(s):  
Walter G. Thies ◽  
Douglas J. Westlind ◽  
Mark Loewen ◽  
Greg Brenner
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Prescribed Burning ◽  
Management Tool ◽  
Experimental Unit ◽  
Full Model ◽  
Prescribed Burns ◽  
Blue Mountains ◽  
Growing Seasons ◽  
Individual Trees

Prescribed burning is a management tool used to reduce fuel loads in western interior forests. Following a burn, managers need the ability to predict the mortality of individual trees based on easily observed characteristics. Astudy was established in six stands of mixed-age ponderosa pine (Pinus ponderosa Dougl. ex Laws.) with scattered western junipers at the south end of the Blue Mountains near Burns, Oregon, USA. Stands were thinned in either 1994 or 1995. Three treatments, a fall burn, a spring burn, and an unburned control, were randomly assigned to 12-ha experimental units within each stand. Prescribed burns occurred during mid-October of 1997 or mid-June of 1998 and were representative of operational burns, given weather and fuel conditions. Within each experimental unit, six 0.2-ha plots were established to evaluate responses to the burns. Ponderosa pine plot trees (n =3415) alive 1 month after the burns were evaluated and observed for four growing seasons. Nine fire damage and tree morphological variables were evaluated by logistic regression. A five-factor full model and a two-factor reduced model are presented for projecting probability of mortality. Significant variables in the full model included measures of crown, bole, and basal damage.

scholarly journals Propagation probability and spread rates of self-sustained smouldering fires under controlled moisture content and bulk density conditions

2016 ◽  
Vol 25 (4) ◽  
pp. 456 ◽  
Author(s):  
Nuria Prat-Guitart ◽  
Guillermo Rein ◽  
Rory M. Hadden ◽  
Claire M. Belcher ◽  
Jon M. Yearsley
Keyword(s):  
Moisture Content ◽  
Bulk Density ◽  
Infrared Camera ◽  
Fire Spread ◽  
Spread Rate ◽  
Critical Moisture Content ◽  
Moisture Contents ◽  
Milled Peat ◽  
Critical Moisture ◽  
Smouldering Combustion

The consumption of large areas of peat during wildfires is due to self-sustained smouldering fronts that can remain active for weeks. We studied the effect of peat moisture content and bulk density on the horizontal propagation of smouldering fire in laboratory-scale experiments. We used milled peat with moisture contents between 25 and 250% (mass of water per mass of dry peat) and bulk densities between 50 and 150 kg m–3. An infrared camera monitored ignition, spread and extinction of each smouldering combustion front. Peats with a bulk density below 75 kg m–3 and a moisture content below 150% self-sustained smouldering propagation for more than 12 cm. Peat with a bulk density of 150 kg m–3 could self-sustain smouldering propagation up to a critical moisture content of 115%. A linear model estimated that increasing both moisture content and bulk density significantly reduced the median fire spread rate (which ranged between 1 and 5 cm h–1). Moisture content had a stronger effect size on the spread rate than bulk density. However, the effect of bulk density on spread rate depends upon the moisture content, with the largest effect of bulk density at low moisture contents.

Effects of fuel characteristics on horizontal spread rate and ground surface temperatures of smouldering duff

2020 ◽  
Vol 29 (9) ◽  
pp. 820
Author(s):  
Daniel A. Cowan ◽  
Wesley G. Page ◽  
Bret W. Butler ◽  
David L. Blunck
Keyword(s):  
Moisture Content ◽  
Bulk Density ◽  
Ponderosa Pine ◽  
Ground Surface ◽  
Spread Rate ◽  
Fuel Loading ◽  
Surface Temperatures ◽  
Inorganic Content ◽  
Fuel Characteristics ◽  
Horizontal Spread

The slow-moving flameless burning of wildland fuels (i.e. smouldering) can be difficult to detect and challenging to extinguish. Although previous research involving the smouldering of organic fuels (e.g. cotton, cellulose, peat) has investigated the influence of various fuel characteristics (e.g. moisture content, inorganic content, bulk density) on spread rate and surface temperatures, the smouldering behaviour of other common fuels is not well understood. This study expands on previous research to better understand how fuel characteristics influence the smouldering behaviour of duff from coniferous forests. Specifically, horizontal spread rates (0.5–19.5cm h−1) and ground surface temperatures (258–392°C) were measured on 52 duff samples collected from underneath mature ponderosa pine trees (Pinus ponderosa) from sites in the Pacific Northwest, USA, and evaluated in terms of their moisture content (6–113%), inorganic content (3–42%), bulk density (34–130kgm−3) and fuel depth (3.8–16.3cm). The data suggested that horizontal spread rates decrease when inorganic content, inorganic loading and/or moisture loading of the duff increases. Surface temperatures decrease when inorganic bulk density and/or fuel loading increases. Conversely, surface temperatures decrease when moisture content increases for shallow duff. Higher fuel loading increases the likelihood of smouldering below the surface.

Effects of Soil Compaction on Tree Volume in a California Ponderosa Pine Plantation

1986 ◽  
Vol 1 (4) ◽  
pp. 121-124 ◽  
Author(s):  
John A. Helms ◽  
C. Hipkin
Keyword(s):  
Bulk Density ◽  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Soil Compaction ◽  
Unit Area ◽  
Site Index ◽  
Soil Bulk Density ◽  
Pine Plantation ◽  
Alternative Approaches

Abstract Soil bulk density was measured around 423 trees (0.48 ha) in a 16-year-old ponderosa pine (Pinus ponderosa) plantation in the Sierra Nevada of California. A landing, skid trail, and areas adjacent to skid trails had soil bulk density increased by 43, 30, and 18% compared to areas with lowest bulk density. Due to differences in mean tree volume and initial survival, volume per unit area in these three locations was reduced by 69, 55, and 13%. Areas between skid trails were relatively unaffected. Assuming full stocking, reduction in productivity by age 40 yr in the most heavily compacted areas is equivalent to about one site index class. Further reduction in projected volume on highly compacted areas could occur due to lower initial survival. Alternative approaches to skid trail management are suggested. West. J. Appl. For. 1:121:124, Oct. 1986.

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