Fuel treatment effects on tree mortality following wildfire in dry mixed conifer forests, Washington State, USA

2012 ◽  
Vol 21 (8) ◽  
pp. 1004 ◽  
Author(s):  
Susan J. Prichard ◽  
Maureen C. Kennedy
Keyword(s):  
Pinus Ponderosa ◽  
Tree Mortality ◽  
Prescribed Burning ◽  
Strong Predictor ◽  
Large Diameter ◽  
Lower Probability ◽  
First Year ◽  
Prescribed Burn ◽  
Fuel Treatment ◽  
Crown Scorch

Fuel reduction treatments are increasingly used to mitigate future wildfire severity in dry forests, but few opportunities exist to assess their effectiveness. We evaluated the influence of fuel treatment, tree size and species on tree mortality following a large wildfire event in recent thin-only, thin and prescribed burn (thin-Rx) units. Of the trees that died within the first 3 years, most died in the first year regardless of treatment. First-year mortality was much higher in control and thin-only units (65 and 52%) than in thin-Rx units (37%). Cumulative third-year mortality followed a similar trend (78 and 64% in control and thin-only units) v. 43% in thin-Rx units. Percentage crown scorch is a strong predictor of mortality and is highly dependent on fuel treatment. Across all treatments, Pinus ponderosa had a lower probability of post-fire mortality than did Pseudotsuga menziesii. Finally, the probability of beetle attack on surviving trees was highest in large-diameter trees within thin-only treatments and lowest within thin-Rx treatments. This study contributes further evidence supporting the effectiveness of thinning and prescribed burning on mitigating post-fire tree mortality. We also present evidence that a combination of thinning and prescribed burning is associated with lower incidence of post-fire bark beetle attack.

Predicting Pinus ponderosa Mortality From Dormant Season and Growing-Season Fire Injury

1993 ◽  
Vol 3 (2) ◽  
pp. 65 ◽  
Author(s):  
MG Harrington
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Prescribed Burning ◽  
Growing Season ◽  
Single Class ◽  
Crown Scorch ◽  
Large Trees ◽  
Different Seasons ◽  
Dormant Season

Understory prescribed burning was conducted in an immature Pinus ponderosa (ponderosa pine) stand in southwestern Colorado during three seasons, late spring, midsummer, and autumn. Tree mortality from various levels of crown scorch was compared for the different seasons of injury. A total of 526 trees of different sizes, with crown scorch ranging from 20 to 100%, were monitored annually for 10 years. Over 80% of the 10-year mortality from injury in all three seasons had occurred by year 3, with over 90% occurring by year 4. Mortality of trees scorched in the spring and summer was about 2.5 times greater than that in the autumn for similar crown damage. Most trees larger than 18 cm in diameter survived autumn injury, even with greater than 90% scorching. Following spring and summer injury, trees smaller than 10 cm in diameter died readily with greater than 50% scorching, but about 90% crown scorch was required by large trees to be lethal. A logistic regression model was developed to predict the probability of mortality given tree size, scorch class, and season of injury. Because mortality was similar within scorch classes less than 90%, they were combined into a single class. Scorch thresholds with large increases in mortality occurred at 90% and 100% crown scorch. The season variable includes two groups, dormant (autumn) and growing (spring and summer). Use of this model to predict mortality of immature P. ponderosa is appropriate where stand, fuel, and fire conditions resemble those of this study.

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.

Prescribed-fire effects on fine-root and tree mortality in old-growth ponderosa pine

1991 ◽  
Vol 21 (5) ◽  
pp. 626-634 ◽  
Author(s):  
D. Michael Swezy ◽  
James K. Agee
Keyword(s):  
Ponderosa Pine ◽  
Tree Mortality ◽  
Prescribed Burning ◽  
Fine Root ◽  
Soil Depth ◽  
Fire Severity ◽  
Dry Weight ◽  
Prescribed Burn ◽  
Old Growth ◽  
Root Dry Weight

Old-growth Pinusponderosa Dougl. stands were surveyed at Crater Lake National Park to investigate potential accelerated mortality of large pines due to prescribed burning. Mortality of P. ponderosa greater than 22 cm diameter at breast height was higher in burned areas (19.5%) than in unburned areas (6.6%), and early-season burns had over 30% mortality. Mortality was associated with fire severity, as measured by scorch height and ground char, season of burning, and tree vigor. Pines of high, moderate, and low vigor were subjected to a prescribed burn in June; half of the trees had debris raked from tree bases as an additional treatment. Lethal heat loads (>60 °C) occurred in >75% of samples at the soil surface and at 5 cm soil depth, with duration exceeding 5 h. Burning reduced fine-root dry weight 50–75% 1 and 5 months after burning; raking and burning reduced fine-root dry weight more than burning alone after 1 month and had similar effects to burning after 5 months. A low-vigor tree that had been raked and burned died by the beginning of the fourth dry season after burning. Present fuel loads may be too high to burn during spring if old-growth P. ponderosa are to be protected.

Tree mortality 6 years after burning a thinned Quercuschrysolepis stand

1993 ◽  
Vol 23 (10) ◽  
pp. 2236-2241 ◽  
Author(s):  
Timothy E. Paysen ◽  
Marcia G. Narog
Keyword(s):  
Prescribed Fire ◽  
Tree Mortality ◽  
Prescribed Burning ◽  
Root Zone ◽  
Wildlife Habitat ◽  
Management Tool ◽  
Prescribed Burn ◽  
Live Oak ◽  
San Bernardino ◽  
Favorable Conditions

Managers do not currently use prescribed fire in stands of canyon live oak (Quercuschrysolepis Liebm.) because it is highly susceptible to fire injury. A preliminary study investigating the effects of prescribed burning on this species was initiated on the San Bernardino National Forest in southern California. The purpose was to assess the feasibility of using thinning and prescribed burning to develop shaded fuel breaks in these stands. This paper addresses aboveground tree mortality inventoried 2 and 6 years after a prescribed burn. Aboveground tree stems were judged as live or dead (irrespective of root-zone sprouting). Fire caused approximately 50% mortality in DBH classes ≤15 cm and <10% in larger classes. Between the 2nd and 6th years after burning, tree mortality increased by only 3%. Our results suggest that prescribed fire can be used as a management tool in Q. chrysolepis stands and that tree mortality might be evaluated sooner than previously believed. More investigations are required to identify favorable conditions for prescribed burning in this species, as well as applicability for (i) degree of hazard reduction near the urban wildland interface, (ii) stand improvement by thinning small or crowded trees, and (iii) revitalizing wildlife habitat.

Integrating prescribed burning and clopyralid for the management of yellow starthistle (Centaurea solstitialis)

Weed Science ◽  
2006 ◽  
Vol 54 (4) ◽  
pp. 757-767 ◽  
Author(s):  
Joseph M. DiTomaso ◽  
Guy B. Kyser ◽  
Jessica R. Miller ◽  
Sergio Garcia ◽  
Richard F. Smith ◽  
...  
Keyword(s):  
Large Scale ◽  
Prescribed Burning ◽  
Good Control ◽  
Integrated Weed Management ◽  
Small Scale ◽  
First Year ◽  
Prescribed Burn ◽  
Yellow Starthistle ◽  
Final Treatment ◽  
Second Year

Prescribed burning and the herbicide clopyralid are very effective tools for the management of yellow starthistle. However, repeated use of either can be impractical or can present other problems. The potential solution is the development of an effective integrated weed management strategy using a combination of the two approaches. In small plot studies (0.2 ha), we tested one of five possible treatments: (1) untreated control, (2) 2 consecutive yr of clopyralid (0.105 kg ha−1), (3) 2 consecutive yr of prescribed summer burning, (4) first-year clopyralid followed by second-year prescribed burning, and (5) first-year prescribed burning followed by second-year clopyralid. Treatments were made in 1999 and 2000 at three study sites in California (San Benito, Yuba, and Siskiyou counties). In 2001, the year following the final treatment, 2 consecutive yr of clopyralid or first-year burning followed by second-year clopyralid consistently reduced yellow starthistle cover in the following year by 92 to 100%. However, at the Yuba site, clopyralid alone increased medusahead and ripgut brome cover. Although 2 consecutive yr of burning was effective in Yuba, very high levels of starthistle infestation in San Benito were not completely burned in the second year because of the lack of available consumable fuel. Clopyralid treatment the first year followed by prescribed burning in the second year stimulated yellow starthistle germination and did not reduce the infestation. In a large-scale study conducted at two sites (13 and 81 ha) in southern Monterey County, we used a first-year burn followed by either 2 yr of clopyralid (0.158 kg ha−1) or a single year of clopyralid (0.210 kg ha−1) and a subsequent burn. Results were in close agreement with those found in the small-scale studies. In the year following the final treatment, control of yellow starthistle was greater than 99% when the burn was followed by 2 yr of clopyralid. In contrast, when a prescribed burn was used in the last year of the program, the level of control was not as good, probably because of the increased germination of the remaining soil seedbank. These results indicate that a first-year prescribed burn followed by a second-year clopyralid treatment can provide consistently good control of yellow starthistle, as well as reduced levels of noxious annual grasses, including medusahead and ripgut brome.

Fuel treatments reduce the severity of wildfire effects in dry mixed conifer forest, Washington, USA

2010 ◽  
Vol 40 (8) ◽  
pp. 1615-1626 ◽  
Author(s):  
Susan J. Prichard ◽  
David L. Peterson ◽  
Kyle Jacobson
Keyword(s):  
Prescribed Burning ◽  
Fire Severity ◽  
Large Diameter ◽  
Severity Index ◽  
Prescribed Burn ◽  
Conifer Forest ◽  
Fuel Treatments ◽  
Quantitative Evidence ◽  
Control Units ◽  
And Control

To address hazardous fuel accumulations, many fuel treatments are being implemented in dry forests, but there have been few opportunities to evaluate treatment efficacy in wildfires. We documented the effectiveness of thinning and prescribed burning in the 2006 Tripod Complex fires. Recent fuel treatments burned in the wildfires and offered an opportunity to evaluate if two treatments (thin only and thin and prescribed burn) mitigated fire severity. Fire severity was markedly different between the two treatments. Over 57% of trees survived in thin and prescribed burn (thinRx) units versus 19% in thin only (thin) and 14% in control units. Considering only large-diameter trees (>20 cm diameter at breast height), 73% survived in thinRx units versus 36% and 29% in thin and control units, respectively. Logistic regression modeling demonstrates significant reductions in the log-odds probability of tree death under both treatments with a much greater reduction in thinRx units. Other severity measures, including percent crown scorch and burn severity index, are significantly lower in thinRx units than in thin and control units. This study provides strong quantitative evidence that thinning alone does not reduce wildfire severity but that thinning followed by prescribed burning is effective at mitigating wildfire severity in dry western forests.

scholarly journals Slash Compression Treatment Reduced Tree Mortality from Prescribed Fire in Southwestern Ponderosa Pine

2004 ◽  
Vol 19 (3) ◽  
pp. 149-153 ◽  
Author(s):  
Peter Z. Fulé ◽  
Jason L. Jerman ◽  
Peter J. Gould
Keyword(s):  
Forest Structure ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Prescribed Burning ◽  
Fire Effects ◽  
Fuel Loading ◽  
Old Growth ◽  
Crown Scorch ◽  
Tree Survival ◽  
Compression Treatment

Abstract Intensive thinning prescriptions intended to restore historic forest structure have produced heavy broadcast slash fuel loads in northwestern Arizona, sometimes leading to high tree mortality following prescribed burning. Mechanical slash compression with a D-6 bulldozer to reduce the severity of fire effects on residual trees was evaluated. Ten of 42 measured trees (24%) died within 2 years after burning of broadcast slash, and crown scorch of trees without slash compression treatment averaged 26%. In contrast, no trees died after burning of compressed slash and crown scorch averaged <3%, even though the total fuel loading was indistinguishable from the broadcast slash treatment. The practice of raking fuels away from the boles of old-growth trees also contributed to reduced scorch as compared to younger, unraked trees. Slash compression is a viable method of reducing mortality, offering ecological and economical tradeoffs. Benefits include the ability to reduce large quantities of slash, safeguarding old-growth tree survival while rapidly achieving open forest structure. Costs include paying for equipment operation as well as the possibility of damage to soils or plants. West. J. Appl. For. 19(3):149–153.

Effects of Prescribed Fire and Fire Surrogates on Saproxylic Coleoptera in the Southern Appalachians of North Carolina

2008 ◽  
Vol 43 (1) ◽  
pp. 57-75 ◽  
Author(s):  
Joshua W. Campbell ◽  
James L. Hanula ◽  
Thomas A. Waldrop
Keyword(s):  
North Carolina ◽  
Species Richness ◽  
Management Practices ◽  
Prescribed Burning ◽  
Linear Regression Analysis ◽  
First Year ◽  
Prescribed Burn ◽  
Ips Grandicollis ◽  
Saproxylic Beetle ◽  
Hylobius Pales

We examined the effects of forest management practices (prescribed burning, mechanical, and prescribed burn plus mechanical) on saproxylic forest Coleoptera in the southern Appalachian Mountains of North Carolina. During the 2-yr study, we captured 37,191 Coleoptera with baited multiple-funnel traps and pipe traps, comprising 20 families and 122 species that were used for our analysis. Saproxylic beetle numbers increased greatly from the first year to the second year on all treatments. Species richness and total abundance of Coleoptera were not significantly affected by the treatments, but several families (e.g., Elateridae, Cleridae, Trogositidae, Scolytidae) were significantly more abundant on treated plots. Abundances of many species, including various species of Scolytidae were significantly affected by the treatments. However, these scolytids (Hylastes salebrosus Eichoff, Ips grandicollis Eichoff, Xyloborinus saxeseni Ratzburg, Xyleborus sp., Xyleborus atratus Eichoff) did not respond in the same way to the treatments. Likewise, other Coleoptera such as Pityophagus sp. (Nitidulidae), Hylobius pales Herbst (Curculionidae), and Xylotrechus sagittatus Germar (Cerambycidae) also varied in their responses to the treatments. Species richness was not significantly different for the spring 2003 trapping seasons, but the fall 2003 sample had a higher number of species on mechanical shrub removal only and mechanical shrub removal plus prescribed burning plots compared with controls. Linear regression analysis suggests that increased dead wood caused by hot fires on mechanical plus burn and burn only treatments resulted in increases among various Coleoptera families and species. We saw no evidence that the treatments negatively impacted saproylic species and in most cases they benefited from the disturbances.

Season of prescribed burn in ponderosa pine forests in eastern Oregon: impact on pine mortality

2005 ◽  
Vol 14 (3) ◽  
pp. 223 ◽  
Author(s):  
Walter G. Thies ◽  
Douglas J. Westlind ◽  
Mark Loewen
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Tree Mortality ◽  
Experimental Unit ◽  
Prescribed Burn ◽  
Prescribed Burns ◽  
Blue Mountains ◽  
Ponderosa Pine Forests ◽  
Growing Seasons ◽  
Mixed Age

A study of the effects of season of prescribed burn on tree mortality was established in mixed-age ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at the south end of the Blue Mountains near Burns, Oregon. Each of six previously thinned stands was subdivided into three experimental units and one of three treatments was randomly assigned to each: fall 1997 burn, spring 1998 burn, and no burning (control). Burns were conducted as operational prescribed burns. Trees within six 0.2-ha circular plots on each experimental unit were observed for four post-burn growing seasons to determine fire damage and to detect immediate and delayed mortality and occurrence of black stain root disease (BSRD). There were 5321 tagged ponderosa pines alive at the time of the burns. The percentage of ponderosa pine dying was higher after fall burns than after spring burns. Differences in percentages of fire-caused mortality may be because fall burns are inherently more severe than spring burns. Although present in many trees, BSRD appeared to have little impact on mortality. The lion’s-tail appearance, thought to be a symptom of BSRD, was found to be an unreliable indicator of BSRD in the six test stands.

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