Post-fire survival and flushing in three Sierra Nevada conifers with high initial crown scorch

2009 ◽  
Vol 18 (7) ◽  
pp. 857 ◽  
Author(s):  
Chad T. Hanson ◽  
Malcolm P. North
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Fire Severity ◽  
Conifer Species ◽  
Mature Trees ◽  
Salvage Logging ◽  
Abies Magnifica ◽  
Crown Scorch ◽  
Tree Survival ◽  
Large Trees

With growing debate over the impacts of post-fire salvage logging in conifer forests of the western USA, managers need accurate assessments of tree survival when significant proportions of the crown have been scorched. The accuracy of fire severity measurements will be affected if trees that initially appear to be fire-killed prove to be viable after longer observation. Our goal was to quantify the extent to which three common Sierra Nevada conifer species may ‘flush’ (produce new foliage in the year following a fire from scorched portions of the crown) and survive after fire, and to identify tree or burn characteristics associated with survival. We found that, among ponderosa pines (Pinus ponderosa Dougl. ex. Laws) and Jeffrey pines (Pinus jeffreyi Grev. & Balf) with 100% initial crown scorch (no green foliage following the fire), the majority of mature trees flushed, and survived. Red fir (Abies magnifica A. Murr.) with high crown scorch (mean = 90%) also flushed, and most large trees survived. Our results indicate that, if flushing is not taken into account, fire severity assessments will tend to overestimate mortality and post-fire salvage could remove many large trees that appear dead but are not.

Modeling Tree Mortality Following Wildfire in Pinus ponderosa Forests in the Central Sierra-Nevada of California

1993 ◽  
Vol 3 (3) ◽  
pp. 139 ◽  
Author(s):  
JC Regelbrugge ◽  
SG Conard
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Tree Mortality ◽  
Fire Severity ◽  
Tree Height ◽  
Roc Curves ◽  
Stem Bark ◽  
Mortality Probability ◽  
Using Data ◽  
Bark Char

We modeled tree mortality occurring two years following wildfire in Pinus ponderosa forests using data from 1275 trees in 25 stands burned during the 1987 Stanislaus Complex fires. We used logistic regression analysis to develop models relating the probability of wildfire-induced mortality with tree size and fire severity for Pinus ponderosa, Calocedrus decurrens, Quercus chrysolepis, and Q. kelloggii. One set of models predicts mortality probability as a function of DBH and height of stem-bark char, a second set of models uses relative char height (height of stem-bark char as a proportion of tree height) as the predictor. Probability of mortality increased with increasing height of stem-bark char and decreased with increasing tree DBH and height. Analysis of receiver operating characteristic (ROC) curves indicated that both sets of models perform well for all species, with 83 to 96 percent concordance between predicted probabilities and observed outcomes. The models can be used to predict die probability of post-wildfire mortality of four tree species common in Pinus ponderosa forests in the central Sierra Nevada of California.

Stability of the large tree component in treated and untreated late-seral interior ponderosa pine standsThis article is one of a selection of papers from the Special Forum on Ecological Studies in Interior Ponderosa Pine — First Findings from Blacks Mountain Interdisciplinary Research.

2008 ◽  
Vol 38 (5) ◽  
pp. 919-923 ◽  
Author(s):  
Martin W. Ritchie ◽  
Brian M. Wing ◽  
Todd A. Hamilton
Keyword(s):  
Pinus Ponderosa ◽  
Prescribed Fire ◽  
Ponderosa Pine ◽  
Past History ◽  
Mature Trees ◽  
Individual Tree ◽  
Large Tree ◽  
Large Trees ◽  
Tree Component ◽  
Old Trees

Ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.) stands with late-seral features are found infrequently, owing to past management activities throughout western North America. Thus, management objectives often focus on maintaining existing late-seral stands. Observations over a 65 year period of stands with no past history of harvest showed substantial ingrowth in the smaller diameter classes and elevated rates of mortality among the largest mature trees in the stand. Adjacent stands, with combinations of thinning and prescribed fire, had far fewer high-risk mature trees and generally lower rates of mortality after treatment. Forecasts using individual-tree diameter growth and mortality models suggest that observed declines in these stands with remaining old trees and a dense understory will continue in the absence of any treatment. Increased vigor in thinned stands appeared to be offset by an increase in mortality of large trees when thinning was followed by prescribed fire.

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 Remote sensing for prediction of 1-year post-fire ecosystem condition

2009 ◽  
Vol 18 (5) ◽  
pp. 594 ◽  
Author(s):  
Leigh B. Lentile ◽  
Alistair M. S. Smith ◽  
Andrew T. Hudak ◽  
Penelope Morgan ◽  
Michael J. Bobbitt ◽  
...  
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Fire Effects ◽  
Remote Measurement ◽  
Crown Scorch ◽  
Fire Condition ◽  
Tree Survival ◽  
Green Vegetation ◽  
Post Fire Effects ◽  
Normalized Burn Ratio

Appropriate use of satellite data in predicting >1year post-fire effects requires remote measurement of surface properties that can be mechanistically related to ground measures of post-fire condition. The present study of burned ponderosa pine (Pinus ponderosa) forests in the Black Hills of South Dakota evaluates whether immediate fractional cover estimates of char, green vegetation and brown (non-photosynthetic) vegetation within a pixel are improved predictors of 1-year post-fire field measures, when compared with single-date and differenced Normalized Burn Ratio (NBR and dNBR) indices. The modeled estimate of immediate char fraction either equaled or outperformed all other immediate metrics in predicting 1-year post-fire effects. Brown cover fraction was a poor predictor of all effects (r2 < 0.30), and each remote measure produced only poor predictions of crown scorch (r2 < 0.20). Application of dNBR (1 year post) provided a considerable increase in regression performance for predicting tree survival. Immediate post-fire NBR or dNBR produced only marginal differences in predictions of all the 1-year post-fire effects, perhaps limiting the need for prefire imagery. Although further research is clearly warranted to evaluate fire effects data available 2–20 years after fire, char and green vegetation fractions may be viable alternatives to dNBR and similar indices to predict longer-term post-fire ecological effects.

scholarly journals Microsites and structures used by fishers (Pekania pennanti) in the southern Sierra Nevada: A comparison of forest elements used for daily resting relative to reproduction

2020 ◽  
Author(s):  
RE Green ◽  
KL Purcell ◽  
CM Thompson ◽  
DA Kelt ◽  
Heiko Wittmer
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Thermal Protection ◽  
Large Diameter ◽  
Fine Scale ◽  
Pekania Pennanti ◽  
White Fir ◽  
Large Trees ◽  
Black Oak

© 2019 Many wildlife species rely on unique features of trees during daily activities and fundamental parts of their life cycle. The fisher (Pekania pennanti) is a forest-dwelling carnivore of conservation concern in western North America that uses unique habitat elements as refuges during resting bouts and for reproduction. Prior to this study, little was known about the fine-scale habitat used during reproduction at the southernmost extent of the fisher's range. Between 2007 and 2015, we attached radio-collars to 55 male and 72 female fishers in the southern Sierra Nevada and documented resting locations of males on 216 occasions (196 structures) and females on 824 occasions (737 structures). Beginning in 2008, we also monitored females over 8 reproductive seasons, confirming 45 females at dens and documenting 95 natal dens (83 structures) and 206 maternal dens (192 structures). We established 3 comparisons to guide our assessment of fine-scale habitat: resting males versus resting females, natal dens versus maternal dens, and resting fishers (both sexes) versus denning fishers (all dens). We expected the need for physical security and thermal protection in combination with morphology, predation risk, and aspects of reproductive ecology would influence patterns of use. Both sexes used a variety of microsites for resting, but females selected tree cavities most frequently (47%) while males used branch platforms most often (39%). For resting structures, live conifers were used most often by both sexes (males 44%, females 34%), but live hardwoods (males 16%, females 28%) and conifer snags (males 16%, females 22%) were also important. Comparing natal and maternal dens, we found that cavity microsites used early in the den season tended to be higher than those used later, and large live hardwoods comprised roughly half of all natal (46%) and maternal (51%) den structures. For resting versus denning, we found that large diameter hardwoods were an important source of cavities for both activities, live conifers used for denning were larger than those used for resting, and den structures tended to be on steeper slopes than rest structures. White fir (Abies concolor), California black oak (Quercus kelloggii), and ponderosa pine (Pinus ponderosa) were selected most often by both sexes for resting. In contrast, denning females relied on California black oak (55%), but also used white fir (24%) and incense cedar (Calocedrus decurrens; 12%). As noted in studies further north, our findings highlight the value of large trees with decay to support fisher reproduction and daily refugia.

scholarly journals Microsites and structures used by fishers (Pekania pennanti) in the southern Sierra Nevada: A comparison of forest elements used for daily resting relative to reproduction

2020 ◽  
Author(s):  
RE Green ◽  
KL Purcell ◽  
CM Thompson ◽  
DA Kelt ◽  
Heiko Wittmer
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Thermal Protection ◽  
Large Diameter ◽  
Fine Scale ◽  
Pekania Pennanti ◽  
White Fir ◽  
Large Trees ◽  
Black Oak

© 2019 Many wildlife species rely on unique features of trees during daily activities and fundamental parts of their life cycle. The fisher (Pekania pennanti) is a forest-dwelling carnivore of conservation concern in western North America that uses unique habitat elements as refuges during resting bouts and for reproduction. Prior to this study, little was known about the fine-scale habitat used during reproduction at the southernmost extent of the fisher's range. Between 2007 and 2015, we attached radio-collars to 55 male and 72 female fishers in the southern Sierra Nevada and documented resting locations of males on 216 occasions (196 structures) and females on 824 occasions (737 structures). Beginning in 2008, we also monitored females over 8 reproductive seasons, confirming 45 females at dens and documenting 95 natal dens (83 structures) and 206 maternal dens (192 structures). We established 3 comparisons to guide our assessment of fine-scale habitat: resting males versus resting females, natal dens versus maternal dens, and resting fishers (both sexes) versus denning fishers (all dens). We expected the need for physical security and thermal protection in combination with morphology, predation risk, and aspects of reproductive ecology would influence patterns of use. Both sexes used a variety of microsites for resting, but females selected tree cavities most frequently (47%) while males used branch platforms most often (39%). For resting structures, live conifers were used most often by both sexes (males 44%, females 34%), but live hardwoods (males 16%, females 28%) and conifer snags (males 16%, females 22%) were also important. Comparing natal and maternal dens, we found that cavity microsites used early in the den season tended to be higher than those used later, and large live hardwoods comprised roughly half of all natal (46%) and maternal (51%) den structures. For resting versus denning, we found that large diameter hardwoods were an important source of cavities for both activities, live conifers used for denning were larger than those used for resting, and den structures tended to be on steeper slopes than rest structures. White fir (Abies concolor), California black oak (Quercus kelloggii), and ponderosa pine (Pinus ponderosa) were selected most often by both sexes for resting. In contrast, denning females relied on California black oak (55%), but also used white fir (24%) and incense cedar (Calocedrus decurrens; 12%). As noted in studies further north, our findings highlight the value of large trees with decay to support fisher reproduction and daily refugia.

Using light to predict fuels-reduction and group-selection effects on succession in Sierran mixed-conifer forest

2011 ◽  
Vol 41 (10) ◽  
pp. 2051-2063 ◽  
Author(s):  
Seth W. Bigelow ◽  
Malcolm P. North ◽  
Carl F. Salk
Keyword(s):  
Sierra Nevada ◽  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Group Selection ◽  
Wildlife Habitat ◽  
Conifer Forest ◽  
Mixed Conifer ◽  
Fuels Reduction ◽  
Mixed Conifer Forest ◽  
Large Trees

Many semi-arid coniferous forests in western North America have reached historically unprecedented densities over the past 150 years and are dominated by shade-tolerant trees. Silvicultural treatments generally open the canopy but may not restore shade-intolerant species. We determined crossover-point irradiance (CPI) (light at which the height growth rank of pairs of species changes) for seedlings in Sierra Nevada mixed-conifer forest and used these to interpret light environments produced by fuels-reduction thinning and group selection with reserved large trees. Nine of 21 species pairs had well-defined CPIs. The CPI of the most common shade-tolerant and intolerant species (white fir ( Abies concolor (Gordon & Glendl.) Lindl. ex Hildebr.) and ponderosa pine ( Pinus ponderosa Douglas ex P. Lawson & C. Lawson)) was 22.5 mol·m–2·day–1 or 41% of full sun. Median understory irradiance increased from 9.2 mol·m–2·day–1 (17% full sun) in pretreatment forest to 13 mol·m–2·day–1 (24% full sun) in lightly and 15.5 mol·m–2·day–1 (28% full sun) in moderately thinned stands and 37 mol·m–2·day–1 (67% full sun) in group-selection openings. We estimate that 5%–20% of ground area in lightly to moderately thinned stands would have enough light to favor shade-intolerant over shade-tolerant growth compared with 89% of ground area in group-selection openings. The CPI provides a tool to assess regeneration implications of treatment modification such as increasing heterogeneity of thinning to enhance regeneration or reserving large trees in group-selection openings to maintain wildlife habitat.

scholarly journals Vegetation and topographical correlates of fire severity from two fires in the Klamath-Siskiyou region of Oregon and California

2006 ◽  
Vol 15 (2) ◽  
pp. 237 ◽  
Author(s):  
John D. Alexander ◽  
Nathaniel E. Seavy ◽  
C. John Ralph ◽  
Bill Hogoboom
Keyword(s):  
Soil Structure ◽  
Fire Severity ◽  
Weather Conditions ◽  
Northern California ◽  
Moderate Severity ◽  
High Severity ◽  
Crown Scorch ◽  
Large Trees ◽  
Topographic Characteristics

We used vegetation data collected in areas before they were burned by the 2500 ha Quartz fire in southern Oregon and the 50 600 ha Big Bar complex in northern California to evaluate the ability of vegetation and topographic characteristics to predict patterns of fire severity. Fire severity was characterized as high, moderate, or low based on crown scorch and consumption, and changes in soil structure. In both fires, vegetation plots with southern aspects were more likely to burn with high severity than plots with eastern, northern, or western aspects. This was the only consistent predictor across both fires. In the Quartz fire, we found that plots at higher elevations and with larger diameter trees were more likely to burn with low or moderate severity. These correlations may have been influenced in part by the effects of unmeasured weather conditions. We found few strong correlates in the Big Bar complex, owing in part to the fact that most (75%) of our plots were in the low-severity category, providing relatively little variation. These results, in combination with previous studies of fire severity in the Klamath-Siskiyou region, suggest that areas with southern aspects tend to burn with greater severity than those of other aspects, areas with large trees burn less severely than those with smaller trees, and that correlates of fire severity vary extensively among fires.

scholarly journals Fire and Mechanical Forest Management Treatments Support Different Portions of the Bird Community in Fire-Suppressed Forests

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 150
Author(s):  
Lance Jay Roberts ◽  
Ryan Burnett ◽  
Alissa Fogg
Keyword(s):  
Sierra Nevada ◽  
Fire Severity ◽  
Bird Species ◽  
Bird Community ◽  
Fire Disturbance ◽  
Long Term Effects ◽  
High Severity ◽  
Commercial Thinning ◽  
Silvicultural Management ◽  
Total Community

Silvicultural treatments, fire, and insect outbreaks are the primary disturbance events currently affecting forests in the Sierra Nevada Mountains of California, a region where plants and wildlife are highly adapted to a frequent-fire disturbance regime that has been suppressed for decades. Although the effects of both fire and silviculture on wildlife have been studied by many, there are few studies that directly compare their long-term effects on wildlife communities. We conducted avian point counts from 2010 to 2019 at 1987 in situ field survey locations across eight national forests and collected fire and silvicultural treatment data from 1987 to 2016, resulting in a 20-year post-disturbance chronosequence. We evaluated two categories of fire severity in comparison to silvicultural management (largely pre-commercial and commercial thinning treatments) as well as undisturbed locations to model their influences on abundances of 71 breeding bird species. More species (48% of the community) reached peak abundance at moderate-high-severity-fire locations than at low-severity fire (8%), silvicultural management (16%), or undisturbed (13%) locations. Total community abundance was highest in undisturbed dense forests as well as in the first few years after silvicultural management and lowest in the first few years after moderate-high-severity fire, then abundance in all types of disturbed habitats was similar by 10 years after disturbance. Even though the total community abundance was relatively low in moderate-high-severity-fire habitats, species diversity was the highest. Moderate-high-severity fire supported a unique portion of the avian community, while low-severity fire and silvicultural management were relatively similar. We conclude that a significant portion of the bird community in the Sierra Nevada region is dependent on moderate-high-severity fire and thus recommend that a prescribed and managed wildfire program that incorporates a variety of fire effects will best maintain biodiversity in this region.

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