scholarly journals Black-Backed Woodpecker Nest Density in the Sierra Nevada, California

Diversity ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 364
Author(s):  
Chad T. Hanson ◽  
Tonja Y. Chi
Keyword(s):  
Sierra Nevada ◽  
Bark Beetles ◽  
Wildland Fire ◽  
Fire Suppression ◽  
Small Population ◽  
Nest Density ◽  
Conifer Forests ◽  
Forest Habitat ◽  
High Severity ◽  
Selection Of

In the western U.S., the black-backed woodpecker has been found to be associated with dense montane conifer forests with high snag densities, typically resulting from moderate- to high-severity wildland fires. However, black-backed woodpeckers are occasionally also detected nesting in unburned forests, raising questions about the type of habitat in which they nest and the potential abundance of such habitat. We conducted intensive black-backed woodpecker nest density surveys in large plots within the middle/upper-montane conifer forests of the Sierra Nevada, California, within general (undisturbed) forests, snag forest habitat from moderate/high-severity wildland fire, and unburned snag forest habitat from drought and native bark beetles. We found black-backed woodpeckers nesting only in the two snag forest conditions, mostly in burned snag forest, and their preferential selection of burned snag forest was statistically significant. No nest was found in general forests. Our spatial analysis indicates that snag forest is rare in the forests of the Sierra Nevada due to fire suppression and logging, raising concerns regarding small population size, which we estimate to be only 461 to 772 pairs in the Sierra Nevada.

scholarly journals Is fire severity increasing in the Sierra Nevada, California, USA?

2014 ◽  
Vol 23 (1) ◽  
pp. 1 ◽  
Author(s):  
Chad T. Hanson ◽  
Dennis C. Odion
Keyword(s):  
Climate Change ◽  
Sierra Nevada ◽  
Fire Suppression ◽  
Biological Effects ◽  
Fire Severity ◽  
Fire Regimes ◽  
High Severity ◽  
Current Trends ◽  
In Fire ◽  
Fire Extent

Research in the Sierra Nevada range of California, USA, has provided conflicting results about current trends of high-severity fire. Previous studies have used only a portion of available fire severity data, or considered only a portion of the Sierra Nevada. Our goal was to investigate whether a trend in fire severity is occurring in Sierra Nevada conifer forests currently, using satellite imagery. We analysed all available fire severity data, 1984–2010, over the whole ecoregion and found no trend in proportion, area or patch size of high-severity fire. The rate of high-severity fire has been lower since 1984 than the estimated historical rate. Responses of fire behaviour to climate change and fire suppression may be more complex than assumed. A better understanding of spatiotemporal patterns in fire regimes is needed to predict future fire regimes and their biological effects. Mechanisms underlying the lack of an expected climate- and time since fire-related trend in high-severity fire need to be identified to help calibrate projections of future fire. The effects of climate change on high-severity fire extent may remain small compared with fire suppression. Management could shift from a focus on reducing extent or severity of fire in wildlands to protecting human communities from fire.

scholarly journals Sierra Nevada fire severity conclusions are robust to further analysis: a reply to Safford et al.

2015 ◽  
Vol 24 (2) ◽  
pp. 294 ◽  
Author(s):  
Chad T. Hanson ◽  
Dennis C. Odion
Keyword(s):  
Sierra Nevada ◽  
Wildland Fire ◽  
Fire Severity ◽  
Forest Service ◽  
Conifer Forests ◽  
Forest Types ◽  
Increasing Trend ◽  
Us Forest Service

Safford et al. (this issue) question our earlier findings that fire severity has not increased in Sierra Nevada conifer forests 1984–2010, hypothesising that an increasing trend might have appeared had we restricted our analysis to wildland fire in frequent-fire forest types on US Forest Service lands. Here, we tested that hypothesis and again found no trend of increasing severity.

scholarly journals Prescribed Fire Limits Wildfire Severity Without Altering Ecological Importance for Birds

2021 ◽  
Author(s):  
Quresh Latif ◽  
Victoria Saab ◽  
Jonathan Dudley
Keyword(s):  
Prescribed Fire ◽  
Fire Suppression ◽  
Fire Regimes ◽  
Conifer Forests ◽  
Fuels Reduction ◽  
Positive Effects ◽  
High Severity ◽  
Ecological Implications ◽  
Wildfire Effects ◽  
Ecological Importance

Abstract Background: Fire suppression and anthropogenic land use have increased severity of wildfire in dry conifer forests. Mangers use fuels reduction (e.g., prescribed fire) to limit high-severity wildfire and restore ecological function to fire-adapted dry conifer forests. Many species that evolved in these forests, however, are adapted to high-severity wildfire. To fully understand the ecological implications of fuels reduction treatments, we need to understand direct treatment effects and how treatments modulate subsequent wildfire effects on natural communities. We studied bird population and community patterns over 9 years, including unburned (2002–2003), after prescribed fire (2004–2007), and after wildfire (2008–2010). We used a before-after, control-impact (BACI) approach to analyze shifts in species occupancy and richness with respect to treated units following prescribed fire and burn severity following wildfire.Results: We found both positive and negative wildfire and prescribed fire effects on birds largely consistent with species life history traits; several woodpecker species, secondary cavity-nesting species, aerial insectivores, and understory species exhibited positive effects, whereas open cup canopy-nesting species and foliage- or bark-gleaning insectivores exhibited negative effects. Also as expected, wildfire affected more species more consistently through time than did prescribed fire. Wildfire burned units initially treated with prescribed fire less severely than untreated units, but wildfire effects on birds were similar regardless of treatment.Conclusions: Our results suggest managers can employ prescribed fire to reduce wildfire severity without necessarily altering the ecological importance of wildfire to birds. Additional study of the ecological implications of various fuels reduction practices, representing a range of intensities and fire regimes, would further inform forest management that includes biodiversity objectives.

scholarly journals Impacts of Postfire Management Are Unjustified in Spotted Owl Habitat

2021 ◽  
Vol 9 ◽  
Author(s):  
Chad T. Hanson ◽  
Tonja Y. Chi
Keyword(s):  
Sierra Nevada ◽  
Management Practices ◽  
Current Data ◽  
Conifer Forests ◽  
Spotted Owl ◽  
High Severity ◽  
Rim Fire ◽  
Spotted Owls ◽  
Conifer Regeneration ◽  
Live Tree

In mixed-conifer forests inhabited by California spotted owls, land managers hypothesize that without human intervention natural conifer regeneration will take many decades or longer to begin within interior areas of large high-severity fire patches, due to long distances from live tree seed sources. As a result, widespread post-fire logging, followed by sprayed application of herbicides and planting of conifer seedlings, are used to create tree plantations. These are activities routinely conducted in spotted owl territories following fires, despite current data that indicate this approach has adverse impacts on spotted owl occupancy. Land managers acknowledge such impacts, but continue these forest management practices, assuming they are a necessary harm, one that is warranted to ensure the later return of mature conifer forests used by spotted owls for nesting and roosting. However, few data have been gathered to test this hypothesis. At 5 years post-fire, we surveyed field plots on a grid within large high-severity fire patches in spotted owl habitat within the Rim fire of 2013 in the Sierra Nevada, California. In our analysis the percentage of plots lacking conifer regeneration decreased significantly with larger plot sizes, a finding contrary to previous studies which assumed vast “deforested” areas in wildland fires, a bias created by small plot size. We found higher conifer regeneration closer to live-tree edges, but we consistently found natural post-fire conifer regeneration at all distances into interior spaces of large high-severity fire patches, including >300 m from the nearest live trees. Distance from live-tree edges did not affect pine dominance in post-fire regeneration. The post-fire natural conifer regeneration reported in our results suggests that the adverse effects of current post-fire management in spotted owl habitat are not necessary practices that can be justified.

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.

INFESTATION OF CERATOCYSTIS WAGENERI-INFECTED PONDEROSA PINES BY BARK BEETLES (COLEOPTERA: SCOLYTIDAE) IN THE CENTRAL SIERRA NEVADA

1980 ◽  
Vol 112 (7) ◽  
pp. 725-730 ◽  
Author(s):  
D. J. Goheen ◽  
F. W. Cobb
Keyword(s):  
Sierra Nevada ◽  
Bark Beetle ◽  
Ponderosa Pine ◽  
Bark Beetles ◽  
Dendroctonus Brevicomis ◽  
Disease Category ◽  
The Relationship ◽  
Periodic Examination ◽  
Apparently Healthy

AbstractThe relationship between bark beetle infestation of ponderosa pine and severity of infection by Ceratocystis wageneri was investigated by closely monitoring 256 trees (136 apparently healthy, 60 moderately diseased, and 60 severely diseased at initiation of study) for beetle infestation from summer 1972 to fall 1975. Disease ratings were updated by periodic examination, and some trees changed disease category during the study. Ninety trees were infested by Dendroctonus brevicomis, D. ponderosae, or both, five by buprestids alone, and one tree died from effects of the pathogen alone. Sixty-two of the beetle-infested trees were severely diseased at time of infestation, 25 were moderately diseased, and only three were apparently healthy. Thus, the results showed that bark beetles were much more likely to infest infected than healthy trees. Among diseased trees, those with advanced infections were most likely to be infested. There was evidence that buprestids (especially Melanophila spp.) and possibly Ips spp. attacked diseased trees prior to Dendroctonus spp. infestation.

Characterizing the light environment in Sierra Nevada mixed-conifer forests using a spatially explicit light model

2004 ◽  
Vol 34 (6) ◽  
pp. 1332-1342 ◽  
Author(s):  
Rolf Gersonde ◽  
John J Battles ◽  
Kevin L O'Hara
Keyword(s):  
Leaf Area ◽  
Sierra Nevada ◽  
Forest Type ◽  
Individual Species ◽  
Spatially Explicit ◽  
Conifer Forests ◽  
Prediction Equations ◽  
Mixed Conifer ◽  
Sapwood Area ◽  
Mixed Conifer Forests

The spatially explicit light model tRAYci was calibrated to conditions in multi-aged Sierra Nevada mixed-conifer forests. To reflect conditions that are important to growth and regeneration of this forest type, we sampled a variety of managed mature stands with multiple canopy layers and cohorts. Calibration of the light model included determining leaf area density for individual species with the use of leaf area – sapwood area prediction equations. Prediction equations differed between species and could be improved using site index. The light model predicted point measurements from hemispherical photographs well over a range of 27%–63% light. Simplifying the crown representation in the tRAYci model to average values for species and canopy strata resulted in little reduction in model performance and makes the model more useful to applications with lower sampling intensity. Vertical light profiles in managed mixed-conifer stands could be divided into homogeneous, sigmiodal, and continuous gradients, depending on stand structure and foliage distribution. Concentration of leaf area in the upper canopy concentrates light resources on dominant trees in continuous canopies. Irregular canopies of multiaged stands, however, provide more light resources to mid-size trees and could support growth of shade-intolerant species. Knowledge of the vertical distribution of light intensity in connection with stand structural information can guide regulation of irregular stand structures to meet forest management objectives.

Minimizing the cost of wildland fire suppression: a model with uncertainty in predicted flame length and fire-line width produced

1994 ◽  
Vol 24 (6) ◽  
pp. 1253-1259 ◽  
Author(s):  
Romain Mees ◽  
David Strauss ◽  
Richard Chase
Keyword(s):  
Line Width ◽  
Wildland Fire ◽  
Fire Suppression ◽  
Flame Length ◽  
Burned Area ◽  
Expected Cost ◽  
Control Time ◽  
The Cost ◽  
Attack Strategy

We describe a model that estimates the optimal total expected cost of a wildland fire, given uncertainty in both flame length and fire-line width produced. In the model, a sequence of possible fire-line perimeters is specified, each with a forecasted control time. For a given control time and fire line, the probability of containment of the fire is determined as a function of the fire-fighting resources available. Our procedure assigns the resources to the fire line so as to minimize the total expected cost. A key feature of the model is that the probabilities reflect the degree of uncertainty in (i) the width of fire line that can be built with a given resource allocation, and (ii) the flame length of the fire. The total expected cost associated with a given choice of fire line is the sum of: the loss or gain of value of the area already burned; the cost of the resources used in the attack; and the expected loss or gain of value beyond the fire line. The latter is the product of the probability that the chosen attack strategy fails to contain the fire and the value of the additional burned area that would result from such a failure. The model allows comparison of the costs of the different choices of fire line, and thus identification of the optimal strategy. A small case study is used to illustrate the procedure.

scholarly journals Clonal selection of Eucalyptus grandis x Eucalyptus globulus for productivity, adaptability, and stability, using SNP markers

2016 ◽  
Vol 65 (2) ◽  
pp. 30-38 ◽  
Author(s):  
D. Torres-Dini ◽  
A. C. P. Nunes ◽  
A. Aguiar ◽  
N. Nikichuk ◽  
C. Centurión ◽  
...  
Keyword(s):  
Eucalyptus Globulus ◽  
Environmental Changes ◽  
Clonal Selection ◽  
Eucalyptus Grandis ◽  
Small Population ◽  
Snp Markers ◽  
Hybrid Population ◽  
Environment Interaction ◽  
Predictive Capacity ◽  
Selection Of

Abstract In Uruguay, reforestations with Eucalyptus sp. is of fundamental importance to supply paper, pulp, and wood production. This study investigates genetic, productivity, stability, and adaptability parameters in the selection of Eucalypts grandis x Eucalyptus globulus full-sib hybrid clones. The study was conducted in a clonal test, repeated in two different soils types, in Rio Negro State, Uruguay. The population was characterized phenotypically for diameter at breast height (dbh) and genotyped for SNP markers (EuCHIP60K chip). Mean dbh was similar between sites and the genotype–environment interaction was simple. We found high genotype correlation in clone performance between environments (0.708), indicating the possibility of selecting the same clones for both study locations. Mean heritability between clones (0.724), coefficient of individual genetic variation (10.9 %), and relative variation (0.916), suggest the possibility of gains (estimated at 3.1 % for both sites together) by selecting clones with higher growth rates. A total of 15,196 SNPs were used to confirm parentage and test a genomic selection model for dbh. The predictive capacity was negative (-0.15) given the small population size (78 individuals). The most adaptable material among the tested study sites presented higher values for SNP heterozygosity. Thus, using molecular markers to identify clones responsive to environmental changes can act as a powerful tool in Eucalyptus breeding programs. The hybrid population showed greater adaptability than E. globulus for this region.

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